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#1
Posted to aus.hi-fi,rec.audio.tubes
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Tube/Valve Amp Noise
Iain Churches wrote: "TT" wrote in message ... "Mark" wrote in message ... "Iain Churches" wrote in message i.fi... I have updated my page on measuring tube amp noise. Any comments/additions would be appreciated http://www.kolumbus.fi/iain.churches...eAmpNoise.html -- My tube amp makes a noise why I turn up the volume knob. Is that what you mean? ...duh! Iain Well, you did say ANY comment would be appreaciated.  Here's a comment then, "Don't give up your day job because you will starve trying to be a comedian". :-) BTW for the record this is one of the reasons why I don't have valve gear, the hiss, hum and other noises are a put off! It is not too difficult to build a tube powered system which is totally silent with the CD player on pause, even ear-against-the-speaker. "Inky blackness" my pal Richard calls it. My 50W PPP EL34 amp has a SNR of 106dB that's 10dB better than a CD:-))) 50 watts into 8 ohms = 20Vrms of signal, and if the noise was 106dB below this, unweighted, 20Hz to 20kHz -3dB BW, then noise = 20V / 200,000 = 0.2mV. This is a fair result achieved easily with most tube power amps if competently designed and not faulty. As long as the noise stays low with an increase of signal level then the noise won't be heard. http://www.kolumbus.fi/iain.churches...em/C50_002.jpg Tube amps usuallly have fairly simple linear PSUs but they need quite a lot of good iron to perform well, and this is first place where builders try to cut corners. The amp shown above has a C-L-C-L-C-R-C supply chain with each stage fed separately. To achieve the above good noise figures, the power supply filtering does not have to be so good for PP circuits and a basic CLC for OPT CT supply is usually very adequate, and Quad-II with their appalling toy like PS simply relied on common mode rejection to allow a good noise performance. But the Quad22 preamp was not so hot. Also special attention needs to be paid to the grounding scheme (there is a good thread on this topic with plenty of info on RAT at the moment) and also to the heater and anode supplies. It can be done. It is well worth the effort - especially if it's a homebrew amp:-) All that is basic good practice. Chinese amps are not silent because, to cut costs, they often have AC heaters and very basic supplies. Some very cheaply priced Chinese Kracker Amplifiers which go off in smoke after a month's use are very quiet, but also very poorly designed in other ways, and they go noisy if at first they were not, simply because of the initial balance of Idc in each half of the OPT and the CMRR in class A PP, like Quad-II. AV heaters do help, but Quad-II never had AC heaters, and hum from heaters was low. Iain You have referred us to your web page on tube amp noise where you introduce the subject with... """"""Measuring Tube Amplifier Noise. Unlike distortion, which is a produced by the amplifier and added to the input signal during the amplification process, amplifier noise is not signal related. It can sometimes be heard during low volume passages of music, and can be measured when there is no input signal present. Such measurements are usually taken with the input grounded. In a tube amplifier, the internal noise is caused by the components which comprise the circuit, such as tubes, resistors, capacitors, gain controls etc. The power supply may add ripple voltage, and there also may be magnetic coupling through the chassis which will cause hum. The noise level can be quoted in two ways, in decibels, referred to the maximum power output, or as a voltage. The first method may be misleading, as the amplifier under test may rarely be reproducing music at full power in the normal listening environment. """""""" I have a few comments. Amplifier noise can be signal related if the noise increases with increased signal. Class AB amps are subject to this phenomena since the PSU has to provide additional Idc to the output stage as the amp crosses over from the class A to AB threshold. Most certainly, the noise of any amp should be measured with its input terminal grounded. For quietest noise performance, series resistance between the input terminal and grid should be minimal, about 3k3 maximum. Large anode swing signals in class AB are therefore in series with PSU ripple at the CT, and not rejected by CMRR, and this rectifier noise is in the output unless excellent hum filtering is used along with a large value of C between the CT ands 0V. The noise of a typical 3 stage amplifier is usually determined by the FIRST tube in the line up. Adding NFB does nothing to reduce the noise in the input tube grid circuit which is responsible for most noise in most power and preamps. SO, if we have done our design homework we will have applied DC to the heaters of at least V1 of a 3 stage amp. We will have chosen the input tube carefully for low grid noise and microphony, especially important with a phono or microphone amp. Suppose we have chosen a quiet 6CG7 for the input tube to a power amp. The grid noise with dc to the heaters will be perhaps 2uV. If the gain with NFB of the power amp is say 20x, or 26dB, then the noise at the output from grid input noise will be 20uV x 20 = 400uV, or 0.4mV. Usually hum from other sources within the amp might equal this hiss noise from the grid and the final outcome could thus be 1.41 x 0.4mV = 0.56mV and quite OK. Phono preamps and mic amps have lots more gain yet the grid noise is the same as above with 2uV being typical noise. So you need a large input signal to get a 60dB SNR. The tube preamp will be the amp which determines the noise figure. I have said a lot more on how to measure preamp tube noise at rec.audio.tubes, and how to test each triode for its noise by amplifying the anode output noise with grid grounded using a typical well measuring opamp preamplifier, gain = 1,000, and with 20Hz to 20kHz BW. Its noise will uisually be well below the tube noise which is being tested. Most ppl wouldn't use a tube to amplify a low level mic signal. They'd have a fet at the input, or a step up tranny. Ditto MC phono. With Phono, the BW of the amp is reduced from 20Kz-20kHz to 20Hz-50Hz because of the RIAA filter. The bandwidth is reduced by a factor of (50 - 20) / (20,000 = 20) = approx to 30/20,000 = 0.0015, and noise is reduced by the square root of this bandwidth reduction factor, ie, by a factor of 0.038 So, if the 20kHz BW noise at the input was 2uV, and gain was say 10,000 without RIAA then noise at the output = 2uV x 10,000 = 20mV, which is loud as bugary! But with RIAA, noise becomes 20mV x 0.038 = 0.76mV, and mainly all rumble at LF and which does not offend the ear as much as it would if the noise was unattenuated at say 1 kHz. SO, if the signal was 0.76Vrms at the output of the phono amp, we'd have an SNR = 60dB. In practice, this would be hopelessly too noisy unless we had a large input signal from an MM cart, and so to get a phono amp to be quiet with tubes we need a step up tranny or use a fet input stage which is tyically 10 times quieter than any tube, because of the higher transconductance. More about noise and its causes is in RDH4, and because j-fets were not invented in 1953 when RDH4 was being written, I suggest interested ppl search on the net and read many books to put themselves in touch with what makes a quiet preamp. A typical tube phono input preamp using a well chosen 12AX7 meant for MM will need at least 2mV of average input signal to give a good enough SNR for most ppl, but 5mV is better, say from a Shure V15. If an MC cart with typically 0.4mV of rated input is used you should hear the amp noise being louder than the noise from an un-modulated vinyl groove. Hence the need for the quieter fet input for MC. Step up trannies with 1:10 voltage ration will lift MC signals from 0.4mV to 4mV without adding noise. The typical output resistance of MC = 20ohms, and such a low Z means very low noise is made by this resistance. When the signal is inceased, the low noise of the 20 ohms is also increased, but the SNR is very good at this early point in the circuit, and better than the following amp. In the past very few commercial phono amps or phono stages within integrated preamps ever had a step up transformer for MC, unless it was used for professional studios or used in broadcast stations. I recall that after FM broadcasting was introduced to Oz in the 1970s, many vinyl records were used as signal source, and usually MC was used. MM was a basically a consumer friendly vinyl replayer, because a broken/worn stylus was so much cheaper than an MM stylus. I like MC better though. Mic amps are more noise prone because they have no filtering of HF. I have cross posted to rec.audio.tubes where there may be some other ppl able to comment and stay on topic, apart from the usual useless crew of no hopers who warp the topic into an abortion. Patrick Turner. |
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#2
Posted to aus.hi-fi,rec.audio.tubes
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Tube/Valve Amp Noise
"Patrick Turner" wrote in message
... "TT" wrote in message ... "Mark" wrote in message ... "Iain Churches" wrote in message i.fi... I have updated my page on measuring tube amp noise. Any comments/additions would be appreciated http://www.kolumbus.fi/iain.churches...eAmpNoise.html My tube amp makes a noise why I turn up the volume knob. Is that what you mean? ...duh! Well, you did say ANY comment would be appreaciated. Here's a comment then, "Don't give up your day job because you will starve trying to be a comedian". :-) BTW for the record this is one of the reasons why I don't have valve gear, the hiss, hum and other noises are a put off! It is not too difficult to build a tube powered system which is totally silent with the CD player on pause, even ear-against-the-speaker. "Inky blackness" my pal Richard calls it. My 50W PPP EL34 amp has a SNR of 106dB that's 10dB better than a CD:-))) 50 watts into 8 ohms = 20Vrms of signal, and if the noise was 106dB below this, unweighted, 20Hz to 20kHz -3dB BW, then noise = 20V / 200,000 = 0.2mV. This is a fair result achieved easily with most tube power amps if competently designed and not faulty. As long as the noise stays low with an increase of signal level then the noise won't be heard. http://www.kolumbus.fi/iain.churches...em/C50_002.jpg Tube amps usuallly have fairly simple linear PSUs but they need quite a lot of good iron to perform well, and this is first place where builders try to cut corners. The amp shown above has a C-L-C-L-C-R-C supply chain with each stage fed separately. To achieve the above good noise figures, the power supply filtering does not have to be so good for PP circuits and a basic CLC for OPT CT supply is usually very adequate, and Quad-II with their appalling toy like PS simply relied on common mode rejection to allow a good noise performance. But the Quad22 preamp was not so hot. Also special attention needs to be paid to the grounding scheme (there is a good thread on this topic with plenty of info on RAT at the moment) and also to the heater and anode supplies. It can be done. It is well worth the effort - especially if it's a homebrew amp:-) All that is basic good practice. Chinese amps are not silent because, to cut costs, they often have AC heaters and very basic supplies. Some very cheaply priced Chinese Kracker Amplifiers which go off in smoke after a month's use are very quiet, but also very poorly designed in other ways, and they go noisy if at first they were not, simply because of the initial balance of Idc in each half of the OPT and the CMRR in class A PP, like Quad-II. AV heaters do help, but Quad-II never had AC heaters, and hum from heaters was low. You have referred us to your web page on tube amp noise where you introduce the subject with... """"""Measuring Tube Amplifier Noise. Unlike distortion, which is a produced by the amplifier and added to the input signal during the amplification process, amplifier noise is not signal related. It can sometimes be heard during low volume passages of music, and can be measured when there is no input signal present. Such measurements are usually taken with the input grounded. In a tube amplifier, the internal noise is caused by the components which comprise the circuit, such as tubes, resistors, capacitors, gain controls etc. The power supply may add ripple voltage, and there also may be magnetic coupling through the chassis which will cause hum. The noise level can be quoted in two ways, in decibels, referred to the maximum power output, or as a voltage. The first method may be misleading, as the amplifier under test may rarely be reproducing music at full power in the normal listening environment. """""""" I have a few comments. Amplifier noise can be signal related if the noise increases with increased signal. Class AB amps are subject to this phenomena since the PSU has to provide additional Idc to the output stage as the amp crosses over from the class A to AB threshold. Most certainly, the noise of any amp should be measured with its input terminal grounded. For quietest noise performance, series resistance between the input terminal and grid should be minimal, about 3k3 maximum. Large anode swing signals in class AB are therefore in series with PSU ripple at the CT, and not rejected by CMRR, and this rectifier noise is in the output unless excellent hum filtering is used along with a large value of C between the CT ands 0V. The noise of a typical 3 stage amplifier is usually determined by the FIRST tube in the line up. Adding NFB does nothing to reduce the noise in the input tube grid circuit which is responsible for most noise in most power and preamps. SO, if we have done our design homework we will have applied DC to the heaters of at least V1 of a 3 stage amp. We will have chosen the input tube carefully for low grid noise and microphony, especially important with a phono or microphone amp. Suppose we have chosen a quiet 6CG7 for the input tube to a power amp. The grid noise with dc to the heaters will be perhaps 2uV. If the gain with NFB of the power amp is say 20x, or 26dB, then the noise at the output from grid input noise will be 20uV x 20 = 400uV, or 0.4mV. Usually hum from other sources within the amp might equal this hiss noise from the grid and the final outcome could thus be 1.41 x 0.4mV = 0.56mV and quite OK. Phono preamps and mic amps have lots more gain yet the grid noise is the same as above with 2uV being typical noise. So you need a large input signal to get a 60dB SNR. The tube preamp will be the amp which determines the noise figure. I have said a lot more on how to measure preamp tube noise at rec.audio.tubes, and how to test each triode for its noise by amplifying the anode output noise with grid grounded using a typical well measuring opamp preamplifier, gain = 1,000, and with 20Hz to 20kHz BW. Its noise will uisually be well below the tube noise which is being tested. Most ppl wouldn't use a tube to amplify a low level mic signal. They'd have a fet at the input, or a step up tranny. Ditto MC phono. With Phono, the BW of the amp is reduced from 20Kz-20kHz to 20Hz-50Hz because of the RIAA filter. The bandwidth is reduced by a factor of (50 - 20) / (20,000 = 20) = approx to 30/20,000 = 0.0015, and noise is reduced by the square root of this bandwidth reduction factor, ie, by a factor of 0.038 So, if the 20kHz BW noise at the input was 2uV, and gain was say 10,000 without RIAA then noise at the output = 2uV x 10,000 = 20mV, which is loud as bugary! But with RIAA, noise becomes 20mV x 0.038 = 0.76mV, and mainly all rumble at LF and which does not offend the ear as much as it would if the noise was unattenuated at say 1 kHz. SO, if the signal was 0.76Vrms at the output of the phono amp, we'd have an SNR = 60dB. In practice, this would be hopelessly too noisy unless we had a large input signal from an MM cart, and so to get a phono amp to be quiet with tubes we need a step up tranny or use a fet input stage which is tyically 10 times quieter than any tube, because of the higher transconductance. More about noise and its causes is in RDH4, and because j-fets were not invented in 1953 when RDH4 was being written, I suggest interested ppl search on the net and read many books to put themselves in touch with what makes a quiet preamp. A typical tube phono input preamp using a well chosen 12AX7 meant for MM will need at least 2mV of average input signal to give a good enough SNR for most ppl, but 5mV is better, say from a Shure V15. If an MC cart with typically 0.4mV of rated input is used you should hear the amp noise being louder than the noise from an un-modulated vinyl groove. Hence the need for the quieter fet input for MC. Step up trannies with 1:10 voltage ration will lift MC signals from 0.4mV to 4mV without adding noise. The typical output resistance of MC = 20ohms, and such a low Z means very low noise is made by this resistance. When the signal is inceased, the low noise of the 20 ohms is also increased, but the SNR is very good at this early point in the circuit, and better than the following amp. In the past very few commercial phono amps or phono stages within integrated preamps ever had a step up transformer for MC, unless it was used for professional studios or used in broadcast stations. I recall that after FM broadcasting was introduced to Oz in the 1970s, many vinyl records were used as signal source, and usually MC was used. MM was a basically a consumer friendly vinyl replayer, because a broken/worn stylus was so much cheaper than an MM stylus. I like MC better though. Mic amps are more noise prone because they have no filtering of HF. I have cross posted to rec.audio.tubes where there may be some other ppl able to comment and stay on topic, apart from the usual useless crew of no hopers who warp the topic into an abortion. A most interesting & informative post Patrick. I hope to add something by way of a reply tomorrow. ruff |
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#3
Posted to aus.hi-fi,rec.audio.tubes
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Tube/Valve Amp Noise
"Patrick Turner" wrote in message ... Iain Churches wrote: It is not too difficult to build a tube powered system which is totally silent with the CD player on pause, even ear-against-the-speaker. "Inky blackness" my pal Richard calls it. My 50W PPP EL34 amp has a SNR of 106dB that's 10dB better than a CD:-))) 50 watts into 8 ohms = 20Vrms of signal, and if the noise was 106dB below this, unweighted, 20Hz to 20kHz -3dB BW, then noise = 20V / 200,000 = 0.2mV. To achieve the above good noise figures, the power supply filtering does not have to be so good for PP circuits and a basic CLC for OPT CT supply is usually very adequate, and Quad-II with their appalling toy like PS simply relied on common mode rejection to allow a good noise performance. Yes. One often sees PP output stages fed straight from the reservoir cap! Also special attention needs to be paid to the grounding scheme (there is a good thread on this topic with plenty of info on RAT at the moment) and also to the heater and anode supplies. It can be done. It is well worth the effort - especially if it's a homebrew amp:-) All that is basic good practice. Easy when you know how:-) It took me a long time by trial and error, and discussion with others, to find out what works and what doesn't. As someone said just recently, the schematic tells you only part of the story. The implementation is a totally different thing. Amplifier noise can be signal related if the noise increases with increased signal. Class AB amps are subject to this phenomena since the PSU has to provide additional Idc to the output stage as the amp crosses over from the class A to AB threshold. Hmm. Yes I see. But one cannot measure the noise floor if the amp is playing music. What would be a typical increase as we move into class AB? Most certainly, the noise of any amp should be measured with its input terminal grounded. For quietest noise performance, series resistance between the input terminal and grid should be minimal, about 3k3 maximum. Yes. That's how I do it. The noise of a typical 3 stage amplifier is usually determined by the FIRST tube in the line up. I found that out, too a long time ago, when pentodes were in vogue! Adding NFB does nothing to reduce the noise in the input tube grid circuit which is responsible for most noise in most power and preamps. Agreed/understood. Wehave discussed this before. SO, if we have done our design homework we will have applied DC to the heaters of at least V1 of a 3 stage amp. We will have chosen the input tube carefully for low grid noise and microphony, especially important with a phono or microphone amp. Suppose we have chosen a quiet 6CG7 for the input tube to a power amp. The grid noise with dc to the heaters will be perhaps 2uV. If the gain with NFB of the power amp is say 20x, or 26dB, then the noise at the output from grid input noise will be 20uV x 20 = 400uV, or 0.4mV. Usually hum from other sources within the amp might equal this hiss noise from the grid and the final outcome could thus be 1.41 x 0.4mV = 0.56mV and quite OK. Thanks. That's good info. I am working on a power amp with a 6CG7 front end. I will take somne measurements and see how it adds up. Phono preamps and mic amps have lots more gain yet the grid noise is the same as above with 2uV being typical noise. So you need a large input signal to get a 60dB SNR. I use 5mV input and 44dB gain (0.775V out) as a design target. It seems to be difficult to better SNR 72dB without a FET or transformer at the input. I have said a lot more on how to measure preamp tube noise at rec.audio.tubes, and how to test each triode for its noise by amplifying the anode output noise with grid grounded using a typical well measuring opamp preamplifier, gain = 1,000, and with 20Hz to 20kHz BW. Its noise will uisually be well below the tube noise which is being tested. Yes. I built a 60dB "measuring amp" with a Hardy type 990 discrete Op-Amp. It rather overkill but I had a box of then. Then I got the Radford ANM3 psophometer (audio noise meter) which has a resolution better than 10µV full scale, on the most sensitive setting. That was a real eye opener! http://www.kolumbus.fi/iain.churches...adfordANM3.jpg It can also measure wide band, audio band, and with various weighting factors. Most ppl wouldn't use a tube to amplify a low level mic signal. There are some very good tube mic preamps available. Many old Neumann studio mics, type U47, U49, U50 which were converted to FET in the 1970s have since been converted back again:-) The bandwidth is reduced by a factor of (50 - 20) / (20,000 = 20) = approx to 30/20,000 = 0.0015, and noise is reduced by the square root of this bandwidth reduction factor, ie, by a factor of 0.038 So, if the 20kHz BW noise at the input was 2uV, and gain was say 10,000 without RIAA then noise at the output = 2uV x 10,000 = 20mV, which is loud as bugary! But with RIAA, noise becomes 20mV x 0.038 = 0.76mV, and mainly all rumble at LF and which does not offend the ear as much as it would if the noise was unattenuated at say 1 kHz. Yes indeed. When I was at Decca, we trainees cut some vinyl with the RIAA record curve switched out, so that it could be replayed through a mic preamp. The surface noise (normally attenuated by the RIAA repro curve) was horrendous. In addition, the LF took up so much lateral space (as it was not attenuated on record) that onlyt about 10-12 mins of playing time was possible. I have cross posted to rec.audio.tubes where there may be some other ppl able to comment and stay on topic, apart from the usual useless crew of no hopers who warp the topic into an abortion. Thanks! Is nice to find someone is still interested. It was alarming to see how fast the thread on Ground busses was morphed into an argument about the relative merits of PC and Mac. Regards Iain |
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#4
Posted to aus.hi-fi,rec.audio.tubes
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Tube/Valve Amp Noise
"Patrick Turner" wrote in message ... SNIP More about noise and its causes is in RDH4, and because j-fets were not invented in 1953 when RDH4 was being written, I suggest interested ppl search on the net and read many books to put themselves in touch with what makes a quiet preamp. **Thanks for all that, Patrick. As always, very interesting. Just a minor nit-pick though. FETs have actually been around for a long time. A very long time. Here's a few patent references: http://v3.espacenet.com/origdoc?DB=E...d3915900a7771e http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=GB439457 Of course, neither device was commercially available. Imagine if people had paid attention to this technology back in the 1930s. Having said all that, practical FETs did not arrive until around 1958. Long after RDH4 was written. Trevor Wilson |
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#5
Posted to aus.hi-fi,rec.audio.tubes
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Tube/Valve Amp Noise
Trevor Wilson wrote: "Patrick Turner" wrote in message ... SNIP More about noise and its causes is in RDH4, and because j-fets were not invented in 1953 when RDH4 was being written, I suggest interested ppl search on the net and read many books to put themselves in touch with what makes a quiet preamp. **Thanks for all that, Patrick. As always, very interesting. Just a minor nit-pick though. FETs have actually been around for a long time. A very long time. Here's a few patent references: http://v3.espacenet.com/origdoc?DB=E...d3915900a7771e http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=GB439457 Of course, neither device was commercially available. Imagine if people had paid attention to this technology back in the 1930s. Having said all that, practical FETs did not arrive until around 1958. Long after RDH4 was written. It has been said by some folks that had someone been able to make a reliable and useful and saleable j-fet or mosfet devices before the germanium transistor was invented then nobody would have bothered with germanium. Germanium transistors were rather awful creatures and every real tubeman laughed at them. Then came the silicon variety, and nobody laughed any more, they cried instead. The consecutive discoveries only became important when there was an application, and now developments spur applications, and applications spur development, and as a species we have learnt to develop many things just for the heck of it because a good use will come along soon enough and money can be made. Usually good uses are defined as being initially useful to the military, so its all a sham anyway..... Now the boffins are into quantum computers and goodness knows what they use, but the holy grail is to have a computer not very big, that can operate like all the PCs now in the world combined, only 1,000 times faster. I dunno what the basic unit is, certainly not a fet, triode or anything I know. The CIA will be able to send a remote nano bot to your toilet seat and relay messages back to the Pentagon about who else other than yourself had a **** this morning, and then work out whether anyone had any rotten anti-establishment thoughts over a glass of plonk the night before. Other nano bots can be sent in to take you out, and unless you have a country as powerful as the US, or as China will be, then youse got no chance. Never mind 1984, wait until 2084, or 3084, and then the fun really begins, but you'll think its just normal...... The trouble is that the Universe contains an infinite amount of information about its own composite nature and about what goes on at every part of it including the billions of planets with life like/unlike ours. Humans have only tiny little finite brains, only very recently evolved from apes, so we have an increasingly difficult task ahead of us to know more about how the Universe and all its matter ticks and tocks. So we need to have more powerful computers and better devices. Meanwhile, a lot of wisdom could be classified as noise because there isn't much of a positive result; the more we know, the bigger the mess we make of the planet, and each advance against noise, polution, inefficiencies, corruption simply leads to more negative activities that have not been reformed. So when we got computers, everyone was fascinated, and they never bothered to fix all the other problems. So if we had free non polluting energy, we'd all have money left over to spend on more timber for houses, and dang, there goes the last bit of forest. So having less noise in amplifiers and all the other gear spurred the the recording and broadcasting industries, and while musing with music, we forgot to solve other problems. Somebody rich and famous and able to go to the theatre each night of the week said in 1890, when the first phonograph was played, " Damn it George, now we'll have to put up with this rubbish being able to be heard again and again. " There was a time when an average person might have heard an orchestra about an average of 0.85 times in a lifetime, and had to put up with the noise at the local pub. For the Godly, who never went to Pubs, there was **** all else to do at night, and not many folks about, so blokes just blew out the candle and had another root, and very soon too many people were about. If only we could fix all the problems like we fixed amplifier noise, than we all decided to have less instead of more. This would be a real triumph for hu-manity, and hu-womanity. Patrick Turner. Trevor Wilson |
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#6
Posted to aus.hi-fi,rec.audio.tubes
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Tube/Valve Amp Noise
flipper wrote: On Mon, 17 Mar 2008 09:27:10 GMT, Patrick Turner wrote: Trevor Wilson wrote: "Patrick Turner" wrote in message ... SNIP More about noise and its causes is in RDH4, and because j-fets were not invented in 1953 when RDH4 was being written, I suggest interested ppl search on the net and read many books to put themselves in touch with what makes a quiet preamp. **Thanks for all that, Patrick. As always, very interesting. Just a minor nit-pick though. FETs have actually been around for a long time. A very long time. Here's a few patent references: http://v3.espacenet.com/origdoc?DB=E...d3915900a7771e http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=GB439457 Of course, neither device was commercially available. Imagine if people had paid attention to this technology back in the 1930s. Having said all that, practical FETs did not arrive until around 1958. Long after RDH4 was written. It has been said by some folks that had someone been able to make a reliable and useful and saleable j-fet or mosfet devices before the germanium transistor was invented then nobody would have bothered with germanium. The operative phrase is "had someone been able to make (it)" Germanium transistors were rather awful creatures and every real tubeman laughed at them. At the time, germanium was the only crystalline semiconductor material that could be made pure enough to work Then came the silicon variety, and nobody laughed any more, they cried instead. Everybody had known that silicon would be a better material but it was Texas Instruments discovering a way to make silicon pure enough that made them possible. People way underestimate, like generally ignore, the contribution of materials and manufacturing technology to a 'great idea'. The consecutive discoveries only became important when there was an application, There is seldom a 'shortage' of applications. The problem is usually in being able to make whatever it is. For example, almost all of the automobile's mechanical devices we consider 'modern' were tried within a decade or two of the automobile's invention. But 'automatic transmissions' made with leather belts don't last very long and turbochargers made with the crude metallurgy of the day burned up, not to mention the problem of how you keep the heads and seals on the block with that much power in the cylinder. Same kind of problem with the gasoline engine itself. People thought it would be a good idea but no one could make cylinders and pistons accurate enough to contain the explosive force and the steam engine's solution of leather seals just didn't cut it. and now developments spur applications, and applications spur development, and as a species we have learnt to develop many things just for the heck of it because a good use will come along soon enough and money can be made. The reason people 'make money' is because other people find their idea/invention useful. This is called a 'good thing'. And its called a good thing even when the result is bloody misery for many and only good for a few, like the invention of the atomic bomb. Think of the "better" purposes that the expenses wasted on arms world wide could have been spent on. One man's good idea is a devil of an idea to another. Usually good uses are defined as being initially useful to the military, so its all a sham anyway..... There are infinitely more things invented for peaceful purposes, such as Franklin's lightning rod to prevent house fires, the steam engine for pumping water out of mines, the steamboat for passenger and freight service, the telephone coming from Bell's work with the deaf, the vacuum tube triode for telephone repeater service, and the transistor coming from a search for a better telephone 'relay' switch. Wars hustled the whole inventionality along at a great rate of knots, no? Was not the repeating rifle a boon the North in the American war of Independance? Thousands more than necessary were shot because of it and because men didn't know how to resolve issues peacefully. But you make interesting points about the importance of technical feasablity. I heard that young bright scholars were talking dreamily about digital information transfer in the cafes of the 1930s, and knew a whole new world awaited them. But huge numbers of very cheap fast switches were required, and memory storage. Then WW2 got in the way a bit and many inventions were needed to fix that problem. Another 20 years passed and technology matured a tiny bit and then in 1997 the Internet became mainstream, ie, slightly more "maturity," and now we find we are still scratching on the very surface of knowledge about lots of things, and in 100 years time our wonderful technical revolution of the last century will seem like very inefficient and wasteful horse and buggy days. We may look back and think the whole deal about the Internet to be the height of imaturity and waste. But we have better dentists and doctors than in Athens in 500BC. ( Mind you, Micheal Moore has a few words to say about modern health care... ) Life was grand in 500BC, to be sure, and quite good enough in many ways, except for the brutal dentists, and the doctors who'd more likely speed your death from some minor ailment. snip of 'hate mankind' babble Quite OK with me Flipper. I find much to dislike about humanity. Don't let it bother you. Patrick Turner. |
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#7
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"Patrick Turner" wrote in message ... Was not the repeating rifle a boon the North in the American war of Independance? not really it hadn't been invented then - muskets were all the rage. Come in useful for killing indians though and all but wiping out the bison Keith |
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#8
Posted to aus.hi-fi,rec.audio.tubes
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keithr wrote: "Patrick Turner" wrote in message ... Was not the repeating rifle a boon the North in the American war of Independance? not really it hadn't been invented then - muskets were all the rage. Come in useful for killing indians though and all but wiping out the bison Easier to kill everything and think and talk later, the good ol american way! Well, if you kill everything, you don't have to talk later. Problems are so much more easily solved when you have simply blown it away. And wild bison could be replaced with cattle ranches. We had a similar policy here in Oz. We tried to get the aboriginies to breed themselves out of existance. Many horrid ways were found to discourage them. Our Govt has just publically apologized for all the crap, and number od indigenous are increasing. We have to invent the wisdom to ensure everyone gets a fair go. There are more dead kangaroos killed by the roadside than ever before. If they were bison, they'd make a bigger mess of a car when you hit one. Hitting an average roo is about like hitting an average 10 yr old kid. Grim, but country dwellers are used to the carnage of Oz wildlife. They are not inclined to double fence heights. But you are right, but wasn't it the spiral rifling in barrels and the bullet and cartridge which was faster to reload than the muzzle loader and powder was it not? We had a documentary I saw about the American Civil War shown here about 10 years ago when I may have watched it. Invented "better devices" were of great assistance to whoever won. But how many Americans die on the roads each year? So just how good is the motor car? What will americans do when oil runs out? Its better to stay at home and pipe your music through some ever so slightly noisy tubes than go out searching for an ultimate experience. But most western civilisations are afflicted by the affluenza disease where the more you get, the more you want. We are gonna affluend the whole ****ing planet. Not by tommorrow, but in a thousand years things will have to be very different indeed if our species is to survive; hint, let's genetically modify our species, and then we can live in any sort of world. First we have GM crops, then GM animals, and why the heck not GM people? If we get all the problems we see around us fixed, we'll get bored out of our minds, so ppl will think of new exciting things, like having GM kids to win gold medals at the Olympics, and then we will move right along from there..... All the rules we know now are set to be broken by the coming explosion of knowledge. Patrick Turner. Keith |
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#9
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"keithr" wrote in message ... "Patrick Turner" wrote in message ... Was not the repeating rifle a boon the North in the American war of Independance? not really it hadn't been invented then - muskets were all the rage. Come in useful for killing indians though and all but wiping out the bison **Correct. The Springfield Rifle was invented by the North, during the Civil War. It was arguably the first really mass produced item, built of sophisticated mechanical equipment. So important was this item and it's manufacturing system, that the factory was booby trapped, so complete destruction would occur, if it had any chance of falling into the hands of the South. The Springfield Rifle was credited as being, in no small part, for the fact that the North prevailed during that, very dark, time in US history. It has also left it's mark on the US psyche. Many Americans seem to think that gun owning is both sane and a right for individuals, despite the very clear wording in the 2nd Amendment. Trevor Wilson |
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#10
Posted to aus.hi-fi,rec.audio.tubes
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"Patrick Turner" wrote in message
Was not the repeating rifle a boon the North in the American war of Independance? Not really. While a practical repeating rifle had been invented and had been in volume production since about 10 years earlier, the Northern army's top brass were agin' it. Such repeating rifles as were in use were bought by the individual soldier, who had to be pretty rich when inducted, because they cost about a month's pay. In fact the Army still wasn't buying repeating rifles in volume even 10 years later, when Custer's soldiers were armed with single-shots, and the indians were armed with repeating rifles. |
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#11
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flipper wrote: On Tue, 18 Mar 2008 09:12:54 GMT, Patrick Turner wrote: flipper wrote: On Mon, 17 Mar 2008 09:27:10 GMT, Patrick Turner wrote: Trevor Wilson wrote: "Patrick Turner" wrote in message ... SNIP More about noise and its causes is in RDH4, and because j-fets were not invented in 1953 when RDH4 was being written, I suggest interested ppl search on the net and read many books to put themselves in touch with what makes a quiet preamp. **Thanks for all that, Patrick. As always, very interesting. Just a minor nit-pick though. FETs have actually been around for a long time. A very long time. Here's a few patent references: http://v3.espacenet.com/origdoc?DB=E...d3915900a7771e http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=GB439457 Of course, neither device was commercially available. Imagine if people had paid attention to this technology back in the 1930s. Having said all that, practical FETs did not arrive until around 1958. Long after RDH4 was written. It has been said by some folks that had someone been able to make a reliable and useful and saleable j-fet or mosfet devices before the germanium transistor was invented then nobody would have bothered with germanium. The operative phrase is "had someone been able to make (it)" Germanium transistors were rather awful creatures and every real tubeman laughed at them. At the time, germanium was the only crystalline semiconductor material that could be made pure enough to work Then came the silicon variety, and nobody laughed any more, they cried instead. Everybody had known that silicon would be a better material but it was Texas Instruments discovering a way to make silicon pure enough that made them possible. People way underestimate, like generally ignore, the contribution of materials and manufacturing technology to a 'great idea'. The consecutive discoveries only became important when there was an application, There is seldom a 'shortage' of applications. The problem is usually in being able to make whatever it is. For example, almost all of the automobile's mechanical devices we consider 'modern' were tried within a decade or two of the automobile's invention. But 'automatic transmissions' made with leather belts don't last very long and turbochargers made with the crude metallurgy of the day burned up, not to mention the problem of how you keep the heads and seals on the block with that much power in the cylinder. Same kind of problem with the gasoline engine itself. People thought it would be a good idea but no one could make cylinders and pistons accurate enough to contain the explosive force and the steam engine's solution of leather seals just didn't cut it. and now developments spur applications, and applications spur development, and as a species we have learnt to develop many things just for the heck of it because a good use will come along soon enough and money can be made. The reason people 'make money' is because other people find their idea/invention useful. This is called a 'good thing'. And its called a good thing even when the result is bloody misery for many and only good for a few, like the invention of the atomic bomb. The 'atom bomb' is only one incarnation of particle physics that also includes everything from x-ray machines to cancer radiation therapy to nuclear power generation. Think of the "better" purposes that the expenses wasted on arms world wide could have been spent on. Like the 'better purpose' of being enslaved? Because the Hitlers, Tojos, Stalins, Ho Chi Minhs and Maos of the world think you even sillier than I do. Hang on, the western allies were always able to outspend and out bomb the nazis or nationalists without an A bomb. Did anyone seriously consider stopping Mao? He killed about 70 million of his own countries ppl and what did we do to stop him? I get the feeling the western leaders were happy to see a Chinese leader reducing China's ""threat"" by reducing its population murderously. Anyway, atomic war knowhow was inevitable. Some things very unpleasant wait in the closits of un-utilised ideas, and then suddenly someone works it out and the closit door is opened; if not some defecting German boffins in the 30s and 40s, then most certainly by someone else, maybe Russians, Chinese if not the Russians, and so on. So we have this silly scene where trillions are spent by the tribes on sharpening their spears but nobody is game to use them. An invention is what man makes of it but 'it', the invention, is neither immoral or moral. So is invention amoral? Usually good uses are defined as being initially useful to the military, so its all a sham anyway..... There are infinitely more things invented for peaceful purposes, such as Franklin's lightning rod to prevent house fires, the steam engine for pumping water out of mines, the steamboat for passenger and freight service, the telephone coming from Bell's work with the deaf, the vacuum tube triode for telephone repeater service, and the transistor coming from a search for a better telephone 'relay' switch. Wars hustled the whole inventionality along at a great rate of knots, no? Inventions don't 'stop' during a war but that doesn't alter the fact that infinitely more are done outside of war. Gee I thought the US became very inventive in war years.... The US was the only country who had a rising standard of living during WW2. This was efficient business at work for Mr and Mrs Worker. and the US became rather High and Mighty as a result. There is good and bad involved in this process and this isn't the group where I would want to discuss it all in detail. Was not the repeating rifle a boon the North in the American war of Independance? I don't know if you're trying to make some kind of 'southern' comment or just have your American wars mixed up. The 'American war of Independence was circa 1776. The Henry repeating rifle was circa 1860. The American Civil war is what I was talking about. If you're a Northerner, the conflict beginning in 1861 was the (American) "Civil War." If you're a hard core Southerner it was the "War of Northern Aggression." If you're neutral is was the "War Between the States." Here in Oz, the war between Union North States and southern Confederates which killed a million men so stupidly is known as the American Civil War. Thousands more than necessary were shot because of it That's just plain silly. Indeed it was silly so many were shot. The war was another case of Grand Stubborness. The 'shooting' stops when one or the other, or both, side(s) have had enough of it. Till then it's 'necessary'. Its stupid until it stops. Absurd, ridiculous, and vain. The object is to have the other side decide 'first' with the least damage to yours. Lives are actually saved... yours. and because men didn't know how to resolve issues peacefully. You have a point. Things can usually be resolved 'peacefully' if you're willing to bow low enough, kneel on command, and kiss enough ass. Well, unless you get someone like Hitler who just wants 'your kind' dead to begin with. In which case dying will resolve it 'peacefully' and NAZI ovens were full of 'peaceful' Jews. A premptive strike on Germany in 1933 mighta done some good. But the means for that to be accurate enough to take out the right guys wasn't perfected. Today there are conflicts still going on with stubborns refusing to give in. And agressors continue to agress. Then the US invades Iraq because of its oil. Sure wasn't because of brocoli. Plenty worse dictators than Saddam have been left alone by the US or its allies. about 3 trillion bucks have been spent by US taxpayers and if the US left tommorow, Iraq would become a bloodbath while they sorted out amoung themselves what to do about who has the power and of course the ****ing oil. And now the US can't raise a good enough force to take on Iran. Western nation young men don't like fighting much. Anyway, I doubt the US will declare war on Iran. They will wait until Iran steps right out of line, like maybe with a nuke on Israel. Then stand well back, for the sparks will fly; it will be very unknown territory into which humanity descends IMHO. There isn't a darn thing I can do to solve the middle east problems, but if the main oil fields become radioactive, then we'll all have to get used to less oil. I've had most of my life, so whether I am right or wrong in my perceptions about what the world is coming to just does not matter one iota because I can't change it a bit, and its why I don't waste hours and hours arguing on line, and why I don't feel a need to be right about the issues. My dear old mum thinks I should attend the University Of The Third Age, and get with people my age to discuss and learn about the world. She's concerned about my lack of social life. Anyway, I don't plan to waste my time talking to anyone much about the world; I do enjoy talking to the few young customers who bring me electronic gear to fix, because they have 50 years to live, and their collective spending habits, decisions and voting habits will shape the future, not my silly old fuddy duddy lot of baby boomers. I only learn what I need to learn that's harmless and which give me an income and which I enjoy. But you make interesting points about the importance of technical feasablity. I heard that young bright scholars were talking dreamily about digital information transfer in the cafes of the 1930s, and knew a whole new world awaited them. But huge numbers of very cheap fast switches were required, and memory storage. Then WW2 got in the way a bit and many inventions were needed to fix that problem. Another 20 years passed and technology matured a tiny bit and then in 1997 the Internet became mainstream, ie, slightly more "maturity," and now we find we are still scratching on the very surface of knowledge about lots of things, and in 100 years time our wonderful technical revolution of the last century will seem like very inefficient and wasteful horse and buggy days. We may look back and think the whole deal about the Internet to be the height of imaturity and waste. Unlikely. We'll wonder how they managed with such primitive technology but admire the ingenuity and effort, like we do with the short lived Pony Express. Never underestimate the ingenuity of your ancestors. The ancient Greeks had it pretty well worked out. But we have better dentists and doctors than in Athens in 500BC. ( Mind you, Micheal Moore has a few words to say about modern health care... ) Michael Moore is a lying ass. Yeah, and whoever said Saddam had weapons of mass destruction were lying their ass off as well. Un-truth abounds. Someone lamented the fact that the horse **** was knee deep in big cities in 1890. But they were already up to their armpits in bull****. Gee, you don't have to look far, and there's another pile of bull**** trotted out as facts. Get the boys with their truck ready with their shovels and brooms... Life was grand in 500BC, to be sure, and quite good enough in many ways, except for the brutal dentists, and the doctors who'd more likely speed your death from some minor ailment. What? No 'universal heath care'? Unisys provided the care. A Greek God. You prayed he'd help, and sometimes he did. Sometimes he didn't. But the Greeks realized life wasn't permanent, no big deal if you died today rather than in 3 weeks time. Praying was being seen to be doing something. A placibo. Maybe that's another greek word; I don't know. The Romans could have been a bit worse off. Life expectancy was about 25 years, hey, that's all you need to get old enough to pork a few shielas, and die gloriously in battle, or ungloriously from a ruptured appendix. snip of 'hate mankind' babble Quite OK with me Flipper. I find much to dislike about humanity. Just remember, you 'is' one of it. Exactly. Atoms of H2O which were once in Julious Ceasar or Hitler may now form part of me. We are all one, and breathe the same air. Apparrently, 6 billion ppl breathing puts out more CO2 than does all the world airlines. In my estimation the biggest problem with 'humanity' are the members who have such a low opinion of it, because it doesn't take too many more steps before some of them decide the rest are 'in the way' and/or begin to think about 'purifying' things. So are you saying I am dangerous? Definately not. There'something else required for a Dennis the Menace dictator to get up. Sure he thinks everyone else is up **** creek in many ways, but he is hell bent on changing it all. I am quite happy to have never had children, and i see the human species as a group of slow moving lemmings slowly gathering pace as the mob heads over the cliff. But I am not conning all these available monkeys around me to change anything. Hitler was a very fine orator, he could galvanise millions to act together. George Dubbya by comparison is a dunce, but has been in power over a much more potentially powerful country than Germany ever was or could be. So now the US is bogged in Iraq, peace cannot be declared, because war wasn't declared. Look what it took to get a victory against Germany. Many flattened cities. Finally, they gave up. Too many dead bodies to step over. Dealing with Iraqis is slightly different. They don't give up so easily. They breed sons and daughters who will fight for 100 years if that's how long it takes. They've been squabbling over a lousy dusty arsole of a country for about 8,000 years. But only in recent times do they realize they have their arses pointing to lakes of oil beneath their feet. The Iraqis done nothin to the US. OK, they been a bit naughty about compliance with UN resolutions after the first gulf war where the US had the sense to quit when it did when the alternative was way too tricky. Every country is naughty. Australia even paid "trucking fee" bribes to the Saddam regime during wheat deals. There was a major scandal here about it. We went in with Dubbya in a very minor way, but had helped Saddam arm his army. So an Iraq war really didn't need to be. Oh, except for Oil, ohh farking bloody OIL; it quite bessotted a whole US regime and the multinational company elite and military. And now look at gas prices! Somebody has to pay for it all. The reasons for the war were lies, and trillions have been wasted for want of honesty and consistency. Saddam would have been toppled sooner or later from within, and Sunni rule gone from bad to worse, maybe a revolution mighta happened, and none of that would have cost the US a cent. The oil would have been always there to buy because whoever had power in Iraq needed domani. The west would have had to turn a blind eye to appalling human rights abuses. But it does anyway elsewhere. Don't worry, be happy, unreal eh! Patrick Turner. Don't let it bother you. Patrick Turner. |
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#12
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flipper wrote: On Wed, 19 Mar 2008 07:28:26 GMT, Patrick Turner wrote: flipper wrote: On Tue, 18 Mar 2008 09:12:54 GMT, Patrick Turner wrote: flipper wrote: On Mon, 17 Mar 2008 09:27:10 GMT, Patrick Turner wrote: Trevor Wilson wrote: "Patrick Turner" wrote in message ... SNIP More about noise and its causes is in RDH4, and because j-fets were not invented in 1953 when RDH4 was being written, I suggest interested ppl search on the net and read many books to put themselves in touch with what makes a quiet preamp. **Thanks for all that, Patrick. As always, very interesting. Just a minor nit-pick though. FETs have actually been around for a long time. A very long time. Here's a few patent references: http://v3.espacenet.com/origdoc?DB=E...d3915900a7771e http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=GB439457 Of course, neither device was commercially available. Imagine if people had paid attention to this technology back in the 1930s. Having said all that, practical FETs did not arrive until around 1958. Long after RDH4 was written. It has been said by some folks that had someone been able to make a reliable and useful and saleable j-fet or mosfet devices before the germanium transistor was invented then nobody would have bothered with germanium. The operative phrase is "had someone been able to make (it)" Germanium transistors were rather awful creatures and every real tubeman laughed at them. At the time, germanium was the only crystalline semiconductor material that could be made pure enough to work Then came the silicon variety, and nobody laughed any more, they cried instead. Everybody had known that silicon would be a better material but it was Texas Instruments discovering a way to make silicon pure enough that made them possible. People way underestimate, like generally ignore, the contribution of materials and manufacturing technology to a 'great idea'. The consecutive discoveries only became important when there was an application, There is seldom a 'shortage' of applications. The problem is usually in being able to make whatever it is. For example, almost all of the automobile's mechanical devices we consider 'modern' were tried within a decade or two of the automobile's invention. But 'automatic transmissions' made with leather belts don't last very long and turbochargers made with the crude metallurgy of the day burned up, not to mention the problem of how you keep the heads and seals on the block with that much power in the cylinder. Same kind of problem with the gasoline engine itself. People thought it would be a good idea but no one could make cylinders and pistons accurate enough to contain the explosive force and the steam engine's solution of leather seals just didn't cut it. and now developments spur applications, and applications spur development, and as a species we have learnt to develop many things just for the heck of it because a good use will come along soon enough and money can be made. The reason people 'make money' is because other people find their idea/invention useful. This is called a 'good thing'. And its called a good thing even when the result is bloody misery for many and only good for a few, like the invention of the atomic bomb. The 'atom bomb' is only one incarnation of particle physics that also includes everything from x-ray machines to cancer radiation therapy to nuclear power generation. Think of the "better" purposes that the expenses wasted on arms world wide could have been spent on. Like the 'better purpose' of being enslaved? Because the Hitlers, Tojos, Stalins, Ho Chi Minhs and Maos of the world think you even sillier than I do. Hang on, the western allies were always able to outspend and out bomb the nazis or nationalists without an A bomb. As usual you pull switcheros. You said "expenses wasted on arms." That's 'everything', pal. Did anyone seriously consider stopping Mao? Who are you to ask, Mr, "Arms are a waste?" Arms spending is a waste, simply because its productivity down the drain. War is waste, destroying cities and rebuilding them is waste. Nuclear war would be a monumental waste. The more time money and effort spent on arms and wars means a lower standard of living for those spending the money. And what immense sums have been spent with so little to show for it. Iraq is the relevant case of GROSS WASTE, 3 trillions so far, of YOUR money. He killed about 70 million of his own countries ppl and what did we do to stop him? The U.S. tried backing Chiang Kai-shek but wasn't prepared to segue straight from WWII into WWIII with the Soviet Union. I get the feeling the western leaders were happy to see a Chinese leader reducing China's ""threat"" by reducing its population murderously. Oh, of course you do and we can always count on you to invent the most heinous motives to everyone.. no matter how patently absurd it is. Absurd, yeah, but that's what the world is. Its absurd, in 1,001 ways. Plenty of people would like to see every muslim dead, and every chinese dead. That'd leave more world for us to enjoy. Ppl don't SAY **** like that, but its in their dark subconsious thoughts. And when the oil runs real low and greenhouse looks impossible to fix, then the dark side comes up front and a global war could very easily happen. China was not a 'threat' and, in fact, we shed a fair amount of blood aiding China in WWII, till Stalin's puppet loon you claim we were 'happy to see' took power. And a damn good case could be made we ended up in WWII as a result of refusing to provide supplies for Japan's ongoing rape of China. We helped Stalin beat the Germans, and then by 1955, Germany was back to making more steel than the UK. Winners become losers, allies become enemies, oh what fun were having..... Anyway, atomic war knowhow was inevitable. Of course it was. Some things very unpleasant wait in the closits of un-utilised ideas, and then suddenly someone works it out and the closit door is opened; if not some defecting German boffins in the 30s and 40s, then most certainly by someone else, maybe Russians, Chinese if not the Russians, and so on. So we have this silly scene where trillions are spent by the tribes on sharpening their spears but nobody is game to use them. So your 'complaint' is there aren't more wars to play with the new toys, eh? I'm being cynical. I'd much prefer no large war happens. The US might loose. In the longer term, say over the next 50 years, I reckon the US power will decline like the UK power after WW2. Don't ask me where we might be heading then. I'll be dead. An invention is what man makes of it but 'it', the invention, is neither immoral or moral. So is invention amoral? Is a rock "amoral?" Usually good uses are defined as being initially useful to the military, so its all a sham anyway..... There are infinitely more things invented for peaceful purposes, such as Franklin's lightning rod to prevent house fires, the steam engine for pumping water out of mines, the steamboat for passenger and freight service, the telephone coming from Bell's work with the deaf, the vacuum tube triode for telephone repeater service, and the transistor coming from a search for a better telephone 'relay' switch. Wars hustled the whole inventionality along at a great rate of knots, no? Inventions don't 'stop' during a war but that doesn't alter the fact that infinitely more are done outside of war. Gee I thought the US became very inventive in war years.... What is it about A B that you don't get? What is it about M N that you don't get? This is off topic BS, and I don't care what argument you make. There ain't no winners, losers. Everyone has a different idea or perception, and I can't and won't be serious about what I cannot control or affect in any way. The US was the only country who had a rising standard of living during WW2. I don't know how you come up with that but even if it's true what's the point? War's been good for the US. WW2 finally coaxed the US economy out of the lingering doldrums after the depression. Right now though, The Iraq fiasco is draining the US economy. Not by a huge amount, but certainly it is crook. No win in sight. You expect the U.S. to feel 'guilty for being incredibly productive? Or are we to feel guilty because Germany was closer to England than North America so they had a better shot at bombing it to hell and back? Probably Robert McNamara could not feel guilty about obliterating japanese cities and burning millions alive. Back then guilt wasn't publically felt. People were hardened. But could anyone propose that the US now carpet bombs all of Iraq? But killing vast numbers of unarmed ppl was the style of the allies in WW2. Hitler started it of course, and we just replied in kind and then some. But now nukes are involved, the scale of destruction is so much greater, and if the US lost 50 cities, and took out 500 from around the globe, then all economies would collapse for awhile, and its all a monumental waste. The Vietnam war was a waste. Oz lost 500 men, and for what? Should have let em turn as red as they ever wanted to. No problems. Then when the US gets its arse kicked by barefoot gooks in pyjamas they get all spiteful and won't deal with the winners, nor pay the innocents for compensation for the agent orange and landmines. The US has now sown a lot of depleted urnaium all around the ME. This will blossom into a terrible helth problem in years to come. I sure know why the US is hated so well in many places. Its also loved in a few places. Not many though. I used to get Beyshlag resistors for 10c each from an Oz disributer. Along comes some ****ing yank company and buys out the distributor, and no more small quantities of R. ****ing Beyshlag gets bought out, and the resistor price rises 400% in a year. Greed rules, OK!! I won't eat in McDonald's restaurants. Garbage food it is. This was efficient business at work for Mr and Mrs Worker. and the US became rather High and Mighty as a result. The 'high and mighty" U.S. you despise so much is who insisted the Allies defend Australia when Churchill said it wasn't strategic nor worth the effort. The US business interest in Oz was very high. The US saw that of course Oz had to be saved. Oz would bring huge profits to the US after the war. Churchill was up to his neck in one damn thing after another. We just kicked out the guy who took us into Iraq. We'd like to be really independant, and not hang off the US coat tails, and not be fed lies and BS as reasons to justify wars of fortune, which is what Iraq is all about; its about stealing oil. Gunboat diplomacy with a few gunshots. There is good and bad involved in this process and this isn't the group where I would want to discuss it all in detail. I didn't bring it up, you did. But your pedling your view anyway, and I find I can't swallow it. Was not the repeating rifle a boon the North in the American war of Independance? I don't know if you're trying to make some kind of 'southern' comment or just have your American wars mixed up. The 'American war of Independence was circa 1776. The Henry repeating rifle was circa 1860. The American Civil war is what I was talking about. If you're a Northerner, the conflict beginning in 1861 was the (American) "Civil War." If you're a hard core Southerner it was the "War of Northern Aggression." If you're neutral is was the "War Between the States." Here in Oz, the war between Union North States and southern Confederates which killed a million men so stupidly Which side was 'stupid'? The South that just wanted to be left alone or the North that wanted to keep the 'whole' Union? Both sides were stupid, stubborn, murderous, idiotic, crazy, out of hand, out of control, how else do you want me to put it? is known as the American Civil War. That's because you get your history from the side that won. We got the history from both sides of the event. Well, one side prevailed, the other didn't. The South is fulla losers who didn't like losing. Like the ppl who say the US won in Vietnam. They say that because the US killed 3 million asians, and only lost 50,000 of their own. This is stark raving madness. All those poor screaming victims, and for what reason? The whole viet war, one of the worst most grandiose mistakes ever made. Thousands more than necessary were shot because of it That's just plain silly. Indeed it was silly so many were shot. Your statement was silly. The war was another case of Grand Stubborness. Yep. all it takes is for one side or the other to bow, yield, kneel. The 'shooting' stops when one or the other, or both, side(s) have had enough of it. Till then it's 'necessary'. Its stupid until it stops. Absurd, ridiculous, and vain. If you want to be a slave then so be it but there are others who don't think freedom is so "Absurd, ridiculous, and vain." But you're 'debating' with the wrong person. For starters, go give Bin Laden a talk to and once you've got him smoking peace pipes get back to me. The object is to have the other side decide 'first' with the least damage to yours. Lives are actually saved... yours. and because men didn't know how to resolve issues peacefully. You have a point. Things can usually be resolved 'peacefully' if you're willing to bow low enough, kneel on command, and kiss enough ass. Well, unless you get someone like Hitler who just wants 'your kind' dead to begin with. In which case dying will resolve it 'peacefully' and NAZI ovens were full of 'peaceful' Jews. A premptive strike on Germany in 1933 mighta done some good. Oh? What happened to "Its stupid until it stops. Absurd, ridiculous, and vain?" Now you're talking about *starting* it. But the means for that to be accurate enough to take out the right guys wasn't perfected. Oh, "Germany" is a big enough target they could have hit it even back then. Today there are conflicts still going on with stubborns refusing to give in. And agressors continue to agress. Then the US invades Iraq because of its oil. Damn lie. Sure wasn't because of brocoli. That's right, it wasn't because of broccoli. And it wasn't because of oil either. Plenty worse dictators than Saddam have been left alone by the US or its allies. How many of them started two regional wars, attempted genocide, tried to assassinate a President, declared they were at war with the U,S. even after singing a cease fire, lobbed missiles into non combatant countries, funded terrorists, were developing WMD, and failed to comply with any of over a dozen mandatory U.N.. resolutions for 10 years? Just to mention a few 'highlights' of his illustrious reign. Gee, such a record sounds bad like like the US record. The US has always done lots of **** around the globe. Boy, and by golly the US sure has a lotta weapons of mass distruction. Nobody else is allowed to have them. Iran is big enough to get real independant, and thumb its nose at the US. It might not be good being done by Iran though, and the US response isn't good either. They spent up big setting up Saddam, then had to bring him down. They backed the rebels in Afghanistan, to make sure the Russians lost. and then they had to be removed, because of 9-11. Evil by so many people of all persuasions. Last year Afghanistan had a record harvest of drugs. The war against the Taliban could easily be lost.... The US looks so **** week, does it know what its doing? The US had a terrible record at manipulating governments and getting rid of elected leaders of countries in the 1950s and 1960s and 70s, with CIA doing all sorts of nasties. The US is just another country and the morals of its foreign policies are as questionable as many other countries' foreign policies. The US happens to be a very powerful country, because of its weapons of mass destruction. If the US didn't have these there would be little US influence around the world. Its a US century. Rome was a large power once but it faded, and empires and influences come and go. The US power cannot be forever. about 3 trillion bucks have been spent by US taxpayers Get your B.S. propaganda right. The 'claim' is it will eventually cost 3 trillion. Even a single trillion is a BS expense. Maybe it goes to 10 trillion. Its only money. The idea was to spend 5 billion on making Iraq democratic. Then the oil companies would move in and spend 20 billion to build infrastructure to exploit the vast oil reserves over the next 20 years. Oh how the money would roll in, and the US would have first bite at the cherry of the oil in Iraq. Its ****ing people could rot though. The insurgents and freedom fighters and nationalists didn't quite agree with being robbed so easy and so blind, so they've killed 4,000 US men and mained lord know how many more, while losing maybe 500,000 ppl of their own kind. 2 million have moved from the country. Splitting up the country into kurds, sunni and shiite could lead to even more blood letting because there will be losers, and the Oil wealth share is worth fighting for. So the original plan the US had didn't work out, and the US taxpayer is the big loser. Haliburton is doin OK. Besides that number being B.S. the GDP over the same time period exceeds 300 trillion, making 'the war' less than 1%. and if the US left tommorow, Iraq would become a bloodbath while they sorted out amoung themselves what to do about who has the power and of course the ****ing oil. The problem in Iraq is primarily Al Qaeda and Iran. And the millions who'd like the US to just **** off. And now the US can't raise a good enough force to take on Iran. Western nation young men don't like fighting much. Anyway, I doubt the US will declare war on Iran. They will wait until Iran steps right out of line, like maybe with a nuke on Israel. Well, of course. We just spent 60 years supporting Israel so now, just like China, we'll be 'happy' to see an ally blown to hell. Yeah, finally the Palestinians get their land back. maybe a bit radioactive, maybe it glows in the dark.... Then stand well back, for the sparks will fly; it will be very unknown territory into which humanity descends IMHO. There isn't a darn thing I can do to solve the middle east problems, but if the main oil fields become radioactive, then we'll all have to get used to less oil. Aw. come on. You can do better doom and gloom than that. Like, how about a nuke exploding the entire underground oil reserves blowing the whole planet to bits? Well Saddam tried to burn all the oil on the spot after he lost in 1991. Not enough weapons of mass destruction though. Just a few cases of dynamite. He wanted more, and I think he eventually felt foolish for wanting what he didn't have, because the US said he DID have them, but he didn't.....oh what a nice circus it was. I've had most of my life, so whether I am right or wrong in my perceptions about what the world is coming to just does not matter one iota because I can't change it a bit, and its why I don't waste hours and hours arguing on line, and why I don't feel a need to be right about the issues. You take every opportunity to spout that stuff. And you? are you not trotting out all that junk about how it makes you right all the time. Michael Moore is a lying ass. Yeah, and whoever said Saddam had weapons of mass destruction were lying their ass off as well. You need to get a dictionary and learn what words mean. The US and its allies lied to their people, ie, to you and me re weapons of mass destruction. There was not the slightest threat to the West from Iraqs WMDs. Being mistaken is not a lie but, even more to the point, the war was not to 'find stockpiles'. It was about Saddam's refusal to comply with the terms of cease fire and the over a dozen mandatory U.N. resolutions. Without which it was impossible to know if he 'had' WMD, had turned over all documentation, and had terminated the WMD programs that could be restarted in months. All ****ing bull****. Sure, Saddam's regime tried to fight its way around constraints imposed by foreign governments, If you ran a country like Iraq, you'd try to do the same under the circumstances. The US is the one with all the WMD. The whole WMD was a giant redherring of a lie. Bush wanted to get even with Saddam when his father failed to get rid of Saddam ater '91, and after 9-11 Bush wanted a ME fall guy. Saddam was the man to fall, They'd failed to find Osama in afghanistan, and even if they had won in Afghansistan, what was it they won? ****in nothin much, just an empty land with horrid people. Iraq all looked wonderful and easy and sweet and the US companies would grow fabulously wealthy when the oil began to flow cheaply. OIL was the lubricant, the glittering irresistable corrupting prize that justified all the lies and utter BS about WMD and some impossible to do idea about democracy in a few months. Its difficult to force feed democracy from the barrel of a gun. Mao tried it, he said it works, but finally China breathed a lot easier when Mao died. The US has tried the same idea in Iraq, and the results are well known. Many people try it. Here in Oz we've never neededto have a civil war. We talk about things with each other, and come to a concensus, and life goes on, without pools of blood and screams. Now China has gone all capitalist for business, communist for social control, and how long that lasts is not known, but they won't stay like it forever. Go find a transcript of Colin Powell's U.N. presentation. No where does he say Iraq "has" WMD. He points to all the things known, but unaccounted for, and how much that means he 'could' have. Then add on top if that the things that aren't known, because he won't comply. The 'lies' are from the people who scream 'liar'. Un-truth abounds. And you lap it up. I never thought Iraq had any WMD. I knew the US would wipe out Saddam's forces fast. But of course the Iraqis naturally addopted the guerilla war tactics. It ****s up a big countries army efforts far worse than fighting up front. Bog em down and pick em off, because we got no WMD, and that's how the Iraqi tries to win his war against the invader. You'd fight the same way to save the US against some invader with invincible WMDs. The story of WMD was a deliberate attempt to make the allied governments of the day be seen to be doing something good against evil, not perpetuating evil and incompetent policies. Someone lamented the fact that the horse **** was knee deep in big cities in 1890. But they were already up to their armpits in bull****. Gee, you don't have to look far, and there's another pile of bull**** trotted out as facts. You got plenty of them. snip I just plain got tired of going through the never ending B.S. The world is fulla BS. Its been trowlled on like plaster over every available surface, and there's so much of it nobody has any real answers any more. Patrick Turner. |
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#13
Posted to aus.hi-fi,rec.audio.tubes
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Tube/Valve Amp Noise
"flipper" wrote in message ... On Mon, 17 Mar 2008 07:19:59 +1100, "Trevor Wilson" wrote: "Patrick Turner" wrote in message ... SNIP More about noise and its causes is in RDH4, and because j-fets were not invented in 1953 when RDH4 was being written, I suggest interested ppl search on the net and read many books to put themselves in touch with what makes a quiet preamp. **Thanks for all that, Patrick. As always, very interesting. Just a minor nit-pick though. FETs have actually been around for a long time. A very long time. Lilienfeld's FET is not a jFET. Here's a few patent references: http://v3.espacenet.com/origdoc?DB=E...d3915900a7771e http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=GB439457 Of course, neither device was commercially available. Imagine if people had paid attention to this technology back in the 1930s. There was the not entirely trivial problem of being unable to make them. As the story goes, Shockley was unsuccessfully trying to make a field effect device (FET) like Lilienfeld's and, in investigating the problem, Bardeen and Brattain stumbled upon the point-contact bipolar transistor. You have a similar 'theory' vs 'make it' problem with lasers, the basic theory stemming from Einstein in 1917 but it took till 1960 for the first ruby laser to work. And Gabor developed the theory of holography in 1948, over a decade before there was a laser to make one with. **You're wrong. I saw a MacGyver episode which clearly showed a practical, working laser, from the 4th or 5th century. :-) Trevor Wilson |
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#14
Posted to aus.hi-fi,rec.audio.tubes
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Tube/Valve Amp Noise
On Mar 17, 4:21*am, flipper wrote:
On Mon, 17 Mar 2008 07:19:59 +1100, "Trevor Wilson" wrote: "Patrick Turner" wrote in message ... SNIP More about noise and its causes is in RDH4, and because j-fets were not invented in 1953 when RDH4 was being written, I suggest interested ppl search on the net and read many books to put themselves in touch with what makes a quiet preamp. **Thanks for all that, Patrick. As always, very interesting. Just a minor nit-pick though. FETs have actually been around for a long time. A very long time. Lilienfeld's FET is not a jFET. Here's a few patent references: http://v3.espacenet.com/origdoc?DB=E...&RPN=CA272437&... http://v3.espacenet.com/textdoc?DB=EPODOC&IDX=GB439457 Of course, neither device was commercially available. Imagine if people had paid attention to this technology back in the 1930s. There was the not entirely trivial problem of being unable to make them. As the story goes, Shockley was unsuccessfully trying to make a field effect device (FET) like Lilienfeld's and, in investigating the problem, Bardeen and Brattain stumbled upon the point-contact bipolar transistor. You have a similar 'theory' vs 'make it' problem with lasers, the basic theory stemming from Einstein in 1917 but it took till 1960 for the first ruby laser to work. And Gabor developed the theory of holography in 1948, over a decade before there was a laser to make one with. Having said all that, practical FETs did not arrive until around 1958. Long after RDH4 was written. Trevor Wilson The interesting thing is the visible acceleration between conception and practical execution. -- Andre Jute |
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