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#41
Posted to rec.audio.tubes
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No Interconnect is the Best
On Jan 19, 8:17*pm, Eeyore
wrote: Peter Wieck wrote: My take on such things based on my experience is that Euro makers such as Revox or Tandberg (B&O not so much) use very high-quality pots and switches And what audio products do Tandberg make ? What Revox products use pots (or switches carrying audio) ? They USED to use the likes of Preh parts IIRC which are reasonable but not anything special. Graham Vintage, not current... was that not obvious? Peter Wieck Wyncote, PA |
#42
Posted to rec.audio.tubes
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No Interconnect is the Best
"flipper" wrote in message ... On Sun, 20 Jan 2008 14:35:35 +0200, "Iain Churches" wrote: "Eeyore" wrote in message ... Bret Ludwig wrote: Complete agreement. No preamp, no interconnect. What's wrong with either of those exactly ? Surely, these days the preamp is superfluous. A CD player can give you 2V. That depends on the player but you should be aware that the rating is FS (full scale), the maximum voltage it can produce, and not nominal line level which, if the CD was recorded in conformance with the original specifications, would be 17dB-20dB under that level. True. Many classical CDs these days peak at -10dB. Many pop CDs are clipped at +0dBFS Iain |
#43
Posted to rec.audio.tubes
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No Interconnect is the Best
"flipper" wrote in message ... On Sun, 20 Jan 2008 20:59:31 +0200, "Iain Churches" wrote: "flipper" wrote in message . .. On Sun, 20 Jan 2008 14:35:35 +0200, "Iain Churches" wrote: "Eeyore" wrote in message ... Bret Ludwig wrote: Complete agreement. No preamp, no interconnect. What's wrong with either of those exactly ? Surely, these days the preamp is superfluous. A CD player can give you 2V. That depends on the player but you should be aware that the rating is FS (full scale), the maximum voltage it can produce, and not nominal line level which, if the CD was recorded in conformance with the original specifications, would be 17dB-20dB under that level. True. Many classical CDs these days peak at -10dB. Many pop CDs are clipped at +0dBFS Iain The problem is neither of those numbers tell you what nominal program level is so you can't estimate how 'loud' it will sound, I.E. what your nominal output power will be. Yes. That's why I use a 100k DACT on the input of the power amp, which has an input sensitivity if 1V for full power. I use no preamp. It works well. Iain |
#44
Posted to rec.audio.tubes
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No Interconnect is the Best
Peter Wieck wrote: Eeyore wrote: Peter Wieck wrote: My take on such things based on my experience is that Euro makers such as Revox or Tandberg (B&O not so much) use very high-quality pots and switches And what audio products do Tandberg make ? What Revox products use pots (or switches carrying audio) ? They USED to use the likes of Preh parts IIRC which are reasonable but not anything special. Graham Vintage, not current... was that not obvious? Not from the tense of the verb 'to use'. Graham |
#45
Posted to rec.audio.tubes
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No Interconnect is the Best
Iain Churches wrote: "flipper" wrote "Iain Churches" wrote: Surely, these days the preamp is superfluous. A CD player can give you 2V. That depends on the player but you should be aware that the rating is FS (full scale), the maximum voltage it can produce, and not nominal line level which, if the CD was recorded in conformance with the original specifications, would be 17dB-20dB under that level. Why do you think that ? I don't recall any part of the Red Book spec that requires a specific average or peak level. True. Many classical CDs these days peak at -10dB. In which case they're simply badly mastered and throwing away performance. I suspect what you say isn't true actually. Graham |
#46
Posted to rec.audio.tubes
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No Interconnect is the Best
flipper wrote: The problem is neither of those numbers tell you what nominal program level is so you can't estimate how 'loud' it will sound, I.E. what your nominal output power will be. Define 'nominal program level'. You made it up didn't you ? Graham |
#47
Posted to rec.audio.tubes
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No Interconnect is the Best
On Jan 20, 7:13*pm, Eeyore
wrote: Peter Wieck wrote: Eeyore wrote: Peter Wieck wrote: My take on such things based on my experience is that Euro makers such as Revox or Tandberg (B&O not so much) use very high-quality pots and switches And what audio products do Tandberg make ? What Revox products use pots (or switches carrying audio) ? They USED to use the likes of Preh parts IIRC which are reasonable but not anything special. Graham Vintage, not current... was that not obvious? Not from the tense of the verb 'to use'. Graham- Hide quoted text - - Show quoted text - Active use, present day.... The equipment is operating as I write - that would be active, present tense. Further - when have I _EVER_ posted on anything of commercial manufacture also of significance less than ten (10) years old? Peter Wieck Wyncote, PA |
#48
Posted to rec.audio.tubes
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No Interconnect is the Best
flipper wrote: On Mon, 21 Jan 2008 00:15:43 +0000, Eeyore wrote: Iain Churches wrote: "flipper" wrote "Iain Churches" wrote: Surely, these days the preamp is superfluous. A CD player can give you 2V. That depends on the player but you should be aware that the rating is FS (full scale), the maximum voltage it can produce, and not nominal line level which, if the CD was recorded in conformance with the original specifications, would be 17dB-20dB under that level. Why do you think that ? Basically, because it's true. I don't believe you. I don't recall any part of the Red Book spec that requires a specific average or peak level. It doesn't spec output voltage either. So? Output voltage isn't related to the CD. It's related to the hardware. The CD merely carries data. Graham |
#49
Posted to rec.audio.tubes
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No Interconnect is the Best
flipper wrote: Eeyore wrote: flipper wrote: The problem is neither of those numbers tell you what nominal program level is so you can't estimate how 'loud' it will sound, I.E. what your nominal output power will be. Define 'nominal program level'. You made it up didn't you ? You really don't know or did you figure it would be a good candidate for one of your word games? Provide a reference to 'nominal program level' in the Red Book spec or shut the **** up. Graham |
#50
Posted to rec.audio.tubes
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No Interconnect is the Best
"Iain Churches" wrote in message ti.fi... "West" wrote in message news:3iukj.9316$8A4.7230@trnddc02... "Iain Churches" wrote in message ti.fi... "West" wrote in message news:CMhkj.975$hk4.885@trnddc03... I think that I have come to a conclusion that the best interconnects are no interconnects. In my amp I have installed a 100k stereo (L-type) step Ladder attenuator with a 4 way stereo select switch. The amp now looks like an integrated amp but the preamp part, is of course, passive. Has any one else used these step attenuators with good results? I'm wondering if some of the real hi-end "botique" resistors really make an improvement. You have to use a bunch of them. I'm using Dale resistors for now. At least I know that the sound outclasses any of my interconnects. That's why I opened this post with the best is nothing. Any improvement I can make? All constructive replies are most welcomed. Thank you. Hi West. Your thinking follows on from the comment made by Morgan Jones that "no preamp is better than any preamp" but then you have to have a gain control. Fitting this to the power amp is an excellent solution. I use DACT (Danish Audio Connectors) stepped attenuators 100k stereo.They are 24 position. http://www.dact.com/html/attenuators.html If you insist on finer resolution then there is TKD P65CS available with up to 60 steps. There is a considerable difference in the price. http://www.tkd-corp.com/02_products/p_04variable_a.html For a stand alone stepped attenuator, I have been experimenting with a 1:1 audio transformer with a multi-tapped secondary. Best regards Iain Thanks Iain for the informing and kind words. At this point I am not really interested in mathematically precise attenuation, but more an analog purist approach in keeping the signal, let's say unadulterated. Thus I would endeavor to know if certain type resistors are superior than others in passing a signal. Thanks as always. Yes I understand your point of view. In my own experience, building an accurate attenuator (regardless of the quality of the resistors used) is a pretty time consuming business. A DACT stereo can be had for probably less than the cost of parts and the cost of labour to construct something similar but inferior. The mathematical accuracy is necessary during attenuation (moving stop to stop) you wish to keep the centre image rock steady. Thanks again my friend. You made me aware of something that I have never considered. The tracking between the 2 attenuators is very important for a solid center image. This is going to change my approach because I now realize that mathematical precision is not just nice to have but essential. I think I will go for the DACT. I suppose that a ladder configuration is also important vs. a serial one. I have one from a Chinese company that I use is a passive preamp. It has 4 rows of 1/4 W resistors. I bought another one cheap from a different Chinese vendor and it also claims to be a stereo ladder type but has only 2 rows of resistors. I don't understand that one. To reiterate, thanks for the heads up. We are fortunate to have you involved with RAT. (see my other question at the bottom) As to the boutique resistors, you must decide for yourself if you can see or hear any benefit in their use. A Japanese company recently sent me their catalogue of "superior non.magnetic resistors" I could find no-one who could think of a tube amp audio application in which they could be proved to be superior. However, on the otherhand, I do know a couple of bespoke guitar amp builders who use the old style carbon resistors (cracked carbon, I think they were called) in certain places in their amplifiers for their particular sound. Best regards Iain Iain, don't you need a lot of tube power to drive your Maggies? Also have you ever compared your Maggies (in the normal stereo configuration. 2 speakers) with the ESL 63 and the Martin Logans? I'm curious for your opinions in this regard and anyone else who would like to chime in. (see above for my other response to mathematical tracking) west |
#51
Posted to rec.audio.tubes
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No Interconnect is the Best
flipper wrote: Eeyore wrote: Provide a reference to 'nominal program level' in the Red Book spec Doesn't have a thing to do with 'red book' nor did I mention 'red book'. That's your straw man, not mine. or shut the **** up. Which word is it you don't understand? Nominal, program, or level? It's apparent you haven't a clue about any of them. Graham |
#52
Posted to rec.audio.tubes
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No Interconnect is the Best
flipper wrote: The CD format, however, wasn't created in a vacuum nor was it randomly picked from thin air. It was specified in light of what it was to 'replace' and be, at least as the proponents said, 'better' than, I.E. analog. And the normal analog process (U.S.) was 20dB headroom over nominal. I believe it was 18dB in the U.K. Pure nonsense. Pre-digital recording, peak audio levels went right to the very edge of tape saturation for one. Graham |
#53
Posted to rec.audio.tubes
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No Interconnect is the Best, attenuator guidlines.
West wrote: "Iain Churches" wrote in message ti.fi... "West" wrote in message news:3iukj.9316$8A4.7230@trnddc02... "Iain Churches" wrote in message ti.fi... "West" wrote in message news:CMhkj.975$hk4.885@trnddc03... I think that I have come to a conclusion that the best interconnects are no interconnects. In my amp I have installed a 100k stereo (L-type) step Ladder attenuator with a 4 way stereo select switch. The amp now looks like an integrated amp but the preamp part, is of course, passive. Has any one else used these step attenuators with good results? I'm wondering if some of the real hi-end "botique" resistors really make an improvement. You have to use a bunch of them. I'm using Dale resistors for now. At least I know that the sound outclasses any of my interconnects. That's why I opened this post with the best is nothing. Any improvement I can make? All constructive replies are most welcomed. Thank you. Hi West. Your thinking follows on from the comment made by Morgan Jones that "no preamp is better than any preamp" but then you have to have a gain control. Fitting this to the power amp is an excellent solution. I use DACT (Danish Audio Connectors) stepped attenuators 100k stereo.They are 24 position. http://www.dact.com/html/attenuators.html If you insist on finer resolution then there is TKD P65CS available with up to 60 steps. There is a considerable difference in the price. http://www.tkd-corp.com/02_products/p_04variable_a.html For a stand alone stepped attenuator, I have been experimenting with a 1:1 audio transformer with a multi-tapped secondary. Best regards Iain Thanks Iain for the informing and kind words. At this point I am not really interested in mathematically precise attenuation, but more an analog purist approach in keeping the signal, let's say unadulterated. Thus I would endeavor to know if certain type resistors are superior than others in passing a signal. Thanks as always. Yes I understand your point of view. In my own experience, building an accurate attenuator (regardless of the quality of the resistors used) is a pretty time consuming business. A DACT stereo can be had for probably less than the cost of parts and the cost of labour to construct something similar but inferior. The mathematical accuracy is necessary during attenuation (moving stop to stop) you wish to keep the centre image rock steady. Thanks again my friend. You made me aware of something that I have never considered. The tracking between the 2 attenuators is very important for a solid center image. This is going to change my approach because I now realize that mathematical precision is not just nice to have but essential. I think I will go for the DACT. I suppose that a ladder configuration is also important vs. a serial one. I have one from a Chinese company that I use is a passive preamp. It has 4 rows of 1/4 W resistors. I bought another one cheap from a different Chinese vendor and it also claims to be a stereo ladder type but has only 2 rows of resistors. I don't understand that one. To reiterate, thanks for the heads up. We are fortunate to have you involved with RAT. (see my other question at the bottom) West, you don't need anything to be more complex than it has to be. This is particularly true of audio circuitry, but you mustn't have anything simpler than it must be to achieve a flawless result beyond which any extra complexity has a countering effect. So, the DACT is a fine solution where simple single ended signal transfer is wanted, and there isn't any need to keep output resistance from the attenuator constant. SE circuitry is simply having a ground to ground connection via a shielded coax cable which is an extension of the OV rails of ther amps and one live signal inner wire whose voltage goes +ve and -ve above and below the OV level. The Rin and Rout of the attenuator is important. for tube amps, 50k is minimum if the attenuator is driven off the anode circuit of a low-µ triode. The DC to that anode should be via CCS. So the only load seen by that anode is the cap coupled 50k. 1/2 12AU7 is fine, and has Ra = 13k at about Ia = 4mA. So RL = 4 x Ra. The music will survive. The Rout of the attenuator is only a problem if it becomes too high a resistance which then allows roll off of the HF due to following cable C, following tube Miller C, stray C or low input resistance to the next stage. So assuming we'd never use less than a 50k pot or attenuator, the maximum Rout from the wiper is nearly at the -6dB position where resistance is equal above and below wiper point. So with 50k pot, plus 13k Rout of driving tube there is 63k. Half way down 63k is 31.5k, and the two halves are in parallel and hence Rout max is simply 15.75k. If there is a short interconnect to a power amp with 100pF and say 100pF power amp input C, then the -3dB with a total of 200pF is at 50kHz. if a 100k pot/attenuator was used with 200pF, the -3dB point would become too close to the audio band. If the pot was feeding a cathode follower buffer, the Cin of the CF would only be perhaps 20pF and the BW would remain fine. But a pot or attenuator is rarely ever used at the -6dB position unless the source signal was indeed feeble. More likely the 12 o clock position is used and the Rout of the pot becomes 1/10 of the pot value in parallel with the rest of the R above the wiper, and in this case with a 50k pot the R below wiper is 5k and we can ignore the remaining R of over 50k. Rout at the 12 o'clock position or -20dB spot is thus approx 5k and HF -3dB point becomes 150kHz with 200pF and way above that with a cathode follower. Its all very well asking questions about whether or not you are to use an interconnect, or an attenuator, or the darn brandname of this important thingemebob but without thinking about how and where and what impedance / resistances are involved everywhere, you are ****ing into the wind. Its the numbers that deliver the best sound, not the choice of brandname, or whether in fact you have an interconnect or not, or what type of interconnect it is. Some folks line a twisted pair made of very fine wire with a third wire included in the twist up which is connected to 0V at the preamp end only. One of the pair carries the signal with the other being the 0V line. It is a fine but fragile interconnect which is prone to noise pick up more so than a coax cable I have found, but routed away from noisy things like speaker wires and mains cables the twisted pair is a very easy and cheap audiophile doable solution. Cat 5 wires can be used for the actual wires being twisted. As to the boutique resistors, you must decide for yourself if you can see or hear any benefit in their use. A Japanese company recently sent me their catalogue of "superior non.magnetic resistors" I could find no-one who could think of a tube amp audio application in which they could be proved to be superior. However, on the otherhand, I do know a couple of bespoke guitar amp builders who use the old style carbon resistors (cracked carbon, I think they were called) in certain places in their amplifiers for their particular sound. Best regards Iain Iain, don't you need a lot of tube power to drive your Maggies? Also have you ever compared your Maggies (in the normal stereo configuration. 2 speakers) with the ESL 63 and the Martin Logans? I'm curious for your opinions in this regard and anyone else who would like to chime in. (see above for my other response to mathematical tracking) Maggies I tested here did like some power because they were relatively insensitive to many other speakers. 50 watts seemed fine, so any tube amp with 4 x EL34 or bigger will be OK. Same goes for ESL63. Martin Logan impedance curves are not to be seen anywhere and I think the ML company feels embarassed about their Z curves probably because there is a huge amount of capacitance. So 4 x KT88/KT90 are more appropriate. Something SE with such speakers needs to have good grunt ability so forget a lone 300B. But a quad of KT88 in parallel and in beam tetrode with CFB could give 48 watts, and be rather blameless.... Patrick Turner. west |
#54
Posted to rec.audio.tubes
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No Interconnect is the Best
"Iain Churches" wrote in message
ti.fi Yes. That's why I use a 100k DACT on the input of the power amp, which has an input sensitivity if 1V for full power. I use no preamp. It works well. It has been reported to me that 100K pots have enough resistance to cause excess thermal noise when used with truely clean (e.g. SS) power amps. As a rule, SS power amps have either 5 or 10 K ohm input level controls. |
#55
Posted to rec.audio.tubes
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No Interconnect is the Best
"Eeyore" wrote in
message Iain Churches wrote: True. Many classical CDs these days peak at -10dB. In which case they're simply badly mastered and throwing away performance. I suspect what you say isn't true actually. It is not unusual to see classical CDs that peak out in the 2-3 dB range, but never as much as 10 dB. I suspect that Iain has been mislead by looking at old-fashioned analog meters with their usually fairly gross needle dynamics. |
#56
Posted to rec.audio.tubes
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No Interconnect is the Best
"Eeyore" wrote in
message flipper wrote: The CD format, however, wasn't created in a vacuum nor was it randomly picked from thin air. It was specified in light of what it was to 'replace' and be, at least as the proponents said, 'better' than, I.E. analog. And the normal analog process (U.S.) was 20dB headroom over nominal. I believe it was 18dB in the U.K. While 20 dB headroom may be used for live recording, 2-4 dB is condsidered to be plenty of headroom for a recording being distributed to consumers. Pure nonsense. Pre-digital recording, peak audio levels went right to the very edge of tape saturation for one. ....and beyond. |
#57
Posted to rec.audio.tubes
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No Interconnect is the Best
"Eeyore" wrote in
message West wrote: I just checked a DACT dealer (http://diycable.com) and they want $180 for a CT2, stereo step attenuator. What do you think of that cost effectiveness? A COMPLETE waste of money. Agreed. A good regular potentiometer is more to the point, far more cost-effective, and has a very large number of steps. A good example would be the volume control on my Conrad-Johnston and Apt preamps. The one step-type attenuator that I use frequently with great pleasure are those on my 02R96. The steps are controlled by a shaft encoder's large knob with a nice dimple for twirling with my forefinger, and read out very nicely on a tastefully illuminated LCD display. |
#58
Posted to rec.audio.tubes
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No Interconnect is the Best
"flipper" wrote in message
On Mon, 21 Jan 2008 10:25:10 -0500, "Arny Krueger" wrote: "Eeyore" wrote in message flipper wrote: The CD format, however, wasn't created in a vacuum nor was it randomly picked from thin air. It was specified in light of what it was to 'replace' and be, at least as the proponents said, 'better' than, I.E. analog. And the normal analog process (U.S.) was 20dB headroom over nominal. I believe it was 18dB in the U.K. While 20 dB headroom may be used for live recording, 2-4 dB is condsidered to be plenty of headroom for a recording being distributed to consumers. http://www.ebu.ch/CMSimages/en/tec_t..._tcm6-4669.pdf "The EBU recommends that, in digital audio equipment, its Members should use coding levels for digital audio signals which correspond to an alignment level which is 18 dB2 below the maximum possible coding level of the digital system, irrespective of the total number of bits available." IOW, if you're going to align the machine, use a test signal that is 18.2 dB below FS. That's for setting up them machine. It is not a statement of the maximum levels to record program material at. Earlier in the standard, there's a clear statement that alignment level and permitted maximum level are two different things that are defined separately in the same document: " (the terms "alignment level" and "permitted maximum level" are defined in ITU-R Recommendation BS.645 [2];" |
#59
Posted to rec.audio.tubes
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No Interconnect is the Best
flipper wrote: Eeyore wrote: flipper wrote: The CD format, however, wasn't created in a vacuum nor was it randomly picked from thin air. It was specified in light of what it was to 'replace' and be, at least as the proponents said, 'better' than, I.E. analog. And the normal analog process (U.S.) was 20dB headroom over nominal. I believe it was 18dB in the U.K. Pure nonsense. You'd be able to figure it out if you'd put one or two brain cells to work. http://www.ebu.ch/CMSimages/en/tec_t..._tcm6-4669.pdf "The EBU recommends that, in digital audio equipment, its Members should use coding levels for digital audio signals which correspond to an alignment level which is 18 dB below the maximum possible coding level of the digital system, irrespective of the total number of bits available." That headroom IS NOT transferred to the **CD** you blithering IDIOT. That's typical practice in the mixing console which has wider dynamic range than a CD. The amount of stuff you only 'half know' is astonishing. Graham |
#60
Posted to rec.audio.tubes
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No Interconnect is the Best
"Arny Krueger" wrote in message . .. "Eeyore" wrote in message Iain Churches wrote: True. Many classical CDs these days peak at -10dB. In which case they're simply badly mastered and throwing away performance. I suspect what you say isn't true actually. It is not unusual to see classical CDs that peak out in the 2-3 dB range, but never as much as 10 dB. I suspect that Iain has been mislead by looking at old-fashioned analog meters with their usually fairly gross needle dynamics. Arny. See my post of yesterday. I picked out 2 CDs at random, and checked their peak level on an HHB. Iain |
#61
Posted to rec.audio.tubes
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No Interconnect is the Best
"Arny Krueger" wrote in message ... "Iain Churches" wrote in message ti.fi Yes. That's why I use a 100k DACT on the input of the power amp, which has an input sensitivity if 1V for full power. I use no preamp. It works well. It has been reported to me that 100K pots have enough resistance to cause excess thermal noise when used with truely clean (e.g. SS) power amps. As a rule, SS power amps have either 5 or 10 K ohm input level controls. The tube amp to which I refer has a SNR of 102dB, and 0.1% THD at 50W I think you will agree that is pretty "clean" The stepped attenuators replace the grid resistor. 100k is a good value. Regards Iain |
#62
Posted to rec.audio.tubes
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No Interconnect is the Best
"Eeyore" wrote in message ... True. Many classical CDs these days peak at -10dB. In which case they're simply badly mastered and throwing away performance. There are no commercial recordings existing that have a dynamic of even 80dB, so mastering to peak level is not required, except for pop music in an attempt to make it sound louder than the competition. I suspect what you say isn't true actually. I have just picked out two CDs at random: Thomas Arne, "Six overtures" and "Polish Symphonies". The first peaks at -10dB FS, the second at -9dB FS, according to the meter on my HHB CD recorder. Some tracks, in order to preserve the dynamic marked by the composer, peak at a considerably lower level. Best regards Iain |
#63
Posted to rec.audio.tubes
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No Interconnect is the Best
"flipper" wrote in message ... On Sun, 20 Jan 2008 21:36:49 +0200, "Iain Churches" wrote: Yes. That's why I use a 100k DACT on the input of the power amp, That only goes 'down', not up. which has an input sensitivity if 1V for full power. I use no preamp. It works well. Very well might. It depends a lot on what you listen to and what that "full power" value is at 1V. My main tube amp is a 50W push pull parallel hombrew. It can fill my fairly large listening room with music at a fairly serious level, with the attenuator at 1 o'clock. http://www.kolumbus.fi/iain.churches...-30%20SA01.jpg Regards Iain |
#64
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No Interconnect is the Best
"West" wrote in message
news:%fWkj.23865$8A4.18841@trnddc02... Iain, don't you need a lot of tube power to drive your Maggies? Also have you ever compared your Maggies (in the normal stereo configuration. 2 speakers) with the ESL 63 and the Martin Logans? I'm curious for your opinions in this regard and anyone else who would like to chime in. (see above for my other response to mathematical tracking) West, You must be confusing me with someone else, as unfortunately, I don't own a pair of Maggies. A pal of mine who has them has talked about critical placing, and about lack if sentivity. It's a very long time since I have heard a pair of ESLs too. They are not really to my taste. Regarding the tracking accuracy of the DACT, they promise 0.05dB error, as I recall. Best regards Iain |
#65
Posted to rec.audio.tubes
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No Interconnect is the Best, attenuation and source switch options.
.. "Patrick Turner" wrote in message ... But what I said was that even with the very nicest selection of parts, and amp not optimally set up cannot be as good as one that has been set up better. Yes indeed. People seem sometimes so concerned about silver wire between the input connectors and the selector switch that they tend to overlook that their amp has poorly matched or low emission tubes, with the bias set all over the place. IF they only were to sacrifice some maximum power. But no, marketing cowboys who now guide the design process scream "Watts, more Watts!!!!" at the apprentice engineers. Strange how the power bandwidth of tube power amps used to be quoted at 0.1% THD after Harold Leak reached this fig. Now, 1% is often used, just to add a watt or two to the power spec. When we come to SET amps, appalling loading mistakes are very common in both output stages AND driver stages. The apprentices sometimes have appalling basic knowledge of anything! The 845 amp I have just got running has exemplary measured performance for an SET amp. I gave the OPT two ways of arrangeing the secondaries in a no-waste constant current density manner with a section of either 4 ohms or 6.6 ohms. Patrick Do you have a schematic of this amp on your website? I very much want to build a good pair of SET monoblocs in the not-too-distant future. Iain |
#66
Posted to rec.audio.tubes
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No Interconnect is the Best
"Iain Churches" wrote in message
ti.fi "Arny Krueger" wrote in message ... "Iain Churches" wrote in message ti.fi Yes. That's why I use a 100k DACT on the input of the power amp, which has an input sensitivity if 1V for full power. I use no preamp. It works well. It has been reported to me that 100K pots have enough resistance to cause excess thermal noise when used with truely clean (e.g. SS) power amps. As a rule, SS power amps have either 5 or 10 K ohm input level controls. The tube amp to which I refer has a SNR of 102dB, and 0.1% THD at 50W I think you will agree that is pretty "clean" The stepped attenuators replace the grid resistor. 100k is a good value. I'll bet money that the SNR given was made with the input gain turned all the way up, and connected to the output of a signal generator that had an output impedance of 600 ohms. Redo the measurement with the control at its electrical center. |
#67
Posted to rec.audio.tubes
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No Interconnect is the Best
"flipper" wrote in message
On Mon, 21 Jan 2008 14:24:55 -0500, "Arny Krueger" wrote: "flipper" wrote in message On Mon, 21 Jan 2008 10:25:10 -0500, "Arny Krueger" wrote: "Eeyore" wrote in message flipper wrote: The CD format, however, wasn't created in a vacuum nor was it randomly picked from thin air. It was specified in light of what it was to 'replace' and be, at least as the proponents said, 'better' than, I.E. analog. And the normal analog process (U.S.) was 20dB headroom over nominal. I believe it was 18dB in the U.K. While 20 dB headroom may be used for live recording, 2-4 dB is condsidered to be plenty of headroom for a recording being distributed to consumers. http://www.ebu.ch/CMSimages/en/tec_t..._tcm6-4669.pdf "The EBU recommends that, in digital audio equipment, its Members should use coding levels for digital audio signals which correspond to an alignment level which is 18 dB2 below the maximum possible coding level of the digital system, irrespective of the total number of bits available." IOW, if you're going to align the machine, use a test signal that is 18.2 dB below FS. That's for setting up them machine. It is not a statement of the maximum levels to record program material at. Actually, it is because the avoidance of full scale clipping, as well as standardization, is the reason for it. OK Flipper, you can't read technical documents and reach reasonable conclusions. I can live with that. |
#68
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No Interconnect is the Best
"Iain Churches" wrote in message
i.fi "Arny Krueger" wrote in message . .. "Eeyore" wrote in message Iain Churches wrote: True. Many classical CDs these days peak at -10dB. In which case they're simply badly mastered and throwing away performance. I suspect what you say isn't true actually. It is not unusual to see classical CDs that peak out in the 2-3 dB range, but never as much as 10 dB. I suspect that Iain has been mislead by looking at old-fashioned analog meters with their usually fairly gross needle dynamics. Arny. See my post of yesterday. I picked out 2 CDs at random, and checked their peak level on an HHB. Iain, I've looked at several 100 commerical CDs using DAW software, over a period of over a decade. 2 CD's? Why I laugh? |
#69
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No Interconnect is the Best
"Iain Churches" wrote in message
ti.fi "Eeyore" wrote in message ... True. Many classical CDs these days peak at -10dB. In which case they're simply badly mastered and throwing away performance. There are no commercial recordings existing that have a dynamic of even 80dB, So far so good. But I've got at least one or two that come close. so mastering to peak level is not required, except for pop music in an attempt to make it sound louder than the competition. Peak levels on classical CDs pretty typically max out in the -1 to -4 dB range. I've looked at 100s of classical CDs over a period of about 12 years. My methodology is ripping with a PC and looking at the resulting .wav file with a digital editor. |
#70
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No Interconnect is the Best
Iain Churches wrote: "Eeyore" wrote True. Many classical CDs these days peak at -10dB. In which case they're simply badly mastered and throwing away performance. There are no commercial recordings existing that have a dynamic of even 80dB, so mastering to peak level is not required, except for pop music in an attempt to make it sound louder than the competition. Mastering at a lower level than necessary will simply reveal flaws in the 'replay' system. The 'bottom bits' are less accurate. I suspect what you say isn't true actually. I have just picked out two CDs at random: Thomas Arne, "Six overtures" and "Polish Symphonies". The first peaks at -10dB FS, the second at -9dB FS, according to the meter on my HHB CD recorder. Some tracks, in order to preserve the dynamic marked by the composer, peak at a considerably lower level. I'd be slightly suspicious of that meter in that case. How about transferring to your PC and examining the file with a wave editor ? Graham |
#71
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No Interconnect is the Best
"Eeyore" wrote in message ... I'd be slightly suspicious of that meter in that case. How about transferring to your PC and examining the file with a wave editor ? Whatever for? The output of the CD recorder is routed via AES/EBU to the LO1 position and meters on the Lewo console. It corresponds exactly with the level indicated by the HHB CD recorder. Iain |
#72
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No Interconnect is the Best
"Iain Churches" wrote in message
i.fi "Eeyore" wrote in message ... I'd be slightly suspicious of that meter in that case. How about transferring to your PC and examining the file with a wave editor ? Whatever for? To get a quick, accurate answer. CD transfers take place in 1/7 real time or less. A 1 hour piece thus takes a fairly predictable 9 minutes to load, with no attention required other than to start the operation. Loading a 1 hour file into a digital editor for analysis usually takes 1 minute or two. Actually scanning the whole file for a complete statistics report takes another minute or two. About 12 minutes of which at least 8 minutes can be multitasked, to get an incredibly precise report on the peak, RMS, and average maximums and minimums, and the precise points in the file where they occurred. The output of the CD recorder is routed via AES/EBU to the LO1 position and meters on the Lewo console. So you sit and watch the meters for the duration of the recording? What if you blink your eyes? That's cruel and unusual punishment for people with lives to live. It corresponds exactly with the level indicated by the HHB CD recorder. Got one of those, and no way would I trust the information about levels that I get from it for a question such as the one at hand. Such information as it provides is designed for setting levels, which one does with a goodly amount of headroom because the metering is so imprecise and recording levels are so unpredictable. |
#73
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No Interconnect is the Best
On Jan 20, 1:27*pm, "Iain Churches" wrote:
"GerryE123" wrote in message ... My SE 45 amp has a pair of built-in Goldpoint attenuators. *Of course this allows me to run my digital source directly into it. *Goldpoint and DACT are the two most popular high-quality attenuators. *Here's a link to a photo of the underside of my amp (the Goldpoints can be seen at the top): http://i27.photobucket.com/albums/c1...123/set45c.jpg Nice amp, Gerry. *Can we see a pic of the top also? Your impressions of SET, and why you chose to build one, would be of interest. best regards Iain Hi Iain: I purchased the amp from a friend who had it custom built by James Burgess in California. James is a Jeweler by trade and does meticulous work. Here's some links to photos of the top of the amp and also a schematic (the schematic will be hard to read, but could be downloaded and enlarged): http://i27.photobucket.com/albums/c1...23/blue45a.jpg http://i27.photobucket.com/albums/c1...23/blue45b.jpg http://i27.photobucket.com/albums/c1.../blueschem.jpg My impression of the amp is that it's super transparent and "natural" sounding. I find the 45 to be a bit "modern" sounding. More "neutral" sounding than "warm" (like a 300B). Of course I'm using modern 45s, but I find the same thing even with old-stock 45s. I have a SET amp because I have totally bought into the "simple-is- best" concept. Both at the system and component level. My system consists of a high quality digital source, SE 45 amp and simple, high quality open baffle speakers. Gerry |
#74
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No Interconnect is the Best
"Arny Krueger" wrote in message
. .. "Iain Churches" wrote in message ti.fi "Eeyore" wrote in message ... There are no commercial recordings existing that have a dynamic of even 80dB, So far so good. But I've got at least one or two that come close. Sorry. Close is not good enough. The statement statement stands, and comes from an article published by the BPI. It even includes info from Russian labels such as Origen. Both at Decca and RCA the two companies of which I have considerable knowledge, production discs were mastered to peak at approx 10dB above ref. of -18dBFS. You can work out the rest, Arny. I am not stating by any means that other labels may not follow different criteria. There are non-confirmists in other walks of life than just religion. I have lost count of the number of commercial CD mastering sessions in which I have taken part. Again, these may or may not be typical from a world's eye view, but -8dBFS is commonly used for classical music and pop material allowed to peak to -1dBFS. I have also (sadly) seen pop material driven badly into clippping. Regards Iain |
#75
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No Interconnect is the Best
"flipper" wrote in message ... On Tue, 22 Jan 2008 07:29:52 -0500, "Arny Krueger" wrote: "flipper" wrote in message m On Mon, 21 Jan 2008 14:24:55 -0500, "Arny Krueger" wrote: "flipper" wrote in message On Mon, 21 Jan 2008 10:25:10 -0500, "Arny Krueger" wrote: "Eeyore" wrote in message flipper wrote: The CD format, however, wasn't created in a vacuum nor was it randomly picked from thin air. It was specified in light of what it was to 'replace' and be, at least as the proponents said, 'better' than, I.E. analog. And the normal analog process (U.S.) was 20dB headroom over nominal. I believe it was 18dB in the U.K. While 20 dB headroom may be used for live recording, 2-4 dB is condsidered to be plenty of headroom for a recording being distributed to consumers. http://www.ebu.ch/CMSimages/en/tec_t..._tcm6-4669.pdf "The EBU recommends that, in digital audio equipment, its Members should use coding levels for digital audio signals which correspond to an alignment level which is 18 dB2 below the maximum possible coding level of the digital system, irrespective of the total number of bits available." IOW, if you're going to align the machine, use a test signal that is 18.2 dB below FS. That's for setting up them machine. It is not a statement of the maximum levels to record program material at. Actually, it is because the avoidance of full scale clipping, as well as standardization, is the reason for it. OK Flipper, you can't read technical documents and reach reasonable conclusions. I can live with that. That's an amusing fantasy but even if it were true it would still leave me light years ahead of your three monkeys, head in sand, snip of inconvenient evidence. You're the one with a 'reading problem'. But rather than repeat it, how about some professional mastering companies? http://www.chicagomasteringservice.com/loudness.html "In studios with both types of metering present, a point on the negative dBFS scale would be correlated with a point on the dBVU scale. Typically this is something like -20 dBFS = 0 dBVU, so that "0 dB" on a VU meter would leave approximately 20dB of headroom for signal peaks on the dBFS scale." Hi Flipper. Interesting you should mention the VU. The mastering facility where I work often has digital PPMs, a pair of analogue PPMs and VUs also. The resident engineer told me that he finds the VUs extremely useful for their indication of a close approximation of the "perceived loudness" with compressed material. This is something considered important in the domain of popular "louder is better" CD mastering. http://www.cdmasteringservices.com/dynamicrange.htm "CDs produced in 1985 had an average (RMS) level of -18dB." He's willing to "compromise" with the loudness wars at -14dB but states "For the record, I personally prefer -18db." That's pretty standard, but perhaps not universal, and the situation is *not* improving:-( Regards to all Iain |
#76
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No Interconnect is the Best
Iain Churches wrote: "flipper" wrote in message "In studios with both types of metering present, a point on the negative dBFS scale would be correlated with a point on the dBVU scale. Typically this is something like -20 dBFS = 0 dBVU, so that "0 dB" on a VU meter would leave approximately 20dB of headroom for signal peaks on the dBFS scale." All of which seems to go right over your silly little head. Hi Flipper. Interesting you should mention the VU. The mastering facility where I work often has digital PPMs, a pair of analogue PPMs and VUs also. The resident engineer told me that he finds the VUs extremely useful for their indication of a close approximation of the "perceived loudness" with compressed material. This is something considered important in the domain of popular "louder is better" CD mastering. What the hell is the point of monitoring 'perceived loudness'. Have these people not got EARS to do that ? Measureing 'loudness' with a meter makesa bout as much sense as giving a fish a bicycle and has always struck me as being about the lamest excuse you could imagine for using a backward, technically flawed method ! The metering needs to tell you something useful such as whether you're clipping and VUs most certainly haven't a hope in hell of doing that. Nor do PPMs exactly either. They're based on metering what is believed not to sound likes it's clipping, and a PPM won't register momentary clips either. To avoid 'digital clips' it's necessary to use a 'digital meter' that registers the exact amplitude of every sample. Graham |
#77
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No Interconnect is the Best
"flipper" wrote in message ... Out of curiosity, got any, say circa 1985, CDs? Last night, after sauna, I was looking at some British remastered pop CD's from that era. Jethro Tull in particular. They all seemed average around -18dBFS. In contrast, much current pop material peaks at, or close to, clipping. Regards to all Iain |
#78
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No Interconnect is the Best
wrote in message ... On Jan 20, 1:27 pm, "Iain Churches" wrote: "GerryE123" wrote in message ... My SE 45 amp has a pair of built-in Goldpoint attenuators. Of course this allows me to run my digital source directly into it. Goldpoint and DACT are the two most popular high-quality attenuators. Here's a link to a photo of the underside of my amp (the Goldpoints can be seen at the top): http://i27.photobucket.com/albums/c1...123/set45c.jpg Nice amp, Gerry. Can we see a pic of the top also? Your impressions of SET, and why you chose to build one, would be of interest. I purchased the amp from a friend who had it custom built by James Burgess in California. James is a Jeweler by trade and does meticulous work. Here's some links to photos of the top of the amp and also a schematic (the schematic will be hard to read, but could be downloaded and enlarged): http://i27.photobucket.com/albums/c1...23/blue45a.jpg http://i27.photobucket.com/albums/c1...23/blue45b.jpg http://i27.photobucket.com/albums/c1.../blueschem.jpg Hi Gerry. Thanks for those. JB has made a very good job - you must be a proud owner:-) My impression of the amp is that it's super transparent and "natural" sounding. I find the 45 to be a bit "modern" sounding. More "neutral" sounding than "warm" (like a 300B). Of course I'm using modern 45s, but I find the same thing even with old-stock 45s. It's difficult to put listening impressions into words. What do you mean by "modern" ? I have a SET amp because I have totally bought into the "simple-is-best" concept. Both at the system and component level. There is perhaps something to be said for a low parts count, as Morgan Jones says, "components that are not there cannot fail". But then SET amps traditionally have little or no NFB and so are inherently stable, not requiring step circuits to prevent them from turning into oscillators:-) Achieving unconditional stability in a PP amp is something of a stumbling block for many hombrew builders, and this may well be the reason that they choose SET for a project amp. My system consists of a high quality digital source, SE 45 amp and simple, high quality open baffle speakers. Thanks for the info - most interesting: I am thinking about doing a small survey of people who choose, use and enjoy SET systems. I am particularly interested to know what type of music they enjoy and what they think works best on their own system. I forgot to ask you this question. Best regards Iain |
#79
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No Interconnect is the Best
"Arny Krueger" wrote in message . .. The output of the CD recorder is routed via AES/EBU to the LO1 position and meters on the Lewo console. So you sit and watch the meters for the duration of the recording? What if you blink your eyes? :-))) The meter has a peak level marker, which stays in place until you cancel it, plus the possibility to assign 98 other levels into memory. It corresponds exactly with the level indicated by the HHB CD recorder. Got one of those, and no way would I trust the information about levels that I get from it for a question such as the one at hand. I knew you had. That's why I mentioned it. What you don't have is the Lewo post-production desk:-) Iain |
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No Interconnect is the Best
Iain Churches wrote: "flipper" wrote Out of curiosity, got any, say circa 1985, CDs? Last night, after sauna, I was looking at some British remastered pop CD's from that era. Jethro Tull in particular. They all seemed average around -18dBFS. In contrast, much current pop material peaks at, or close to, clipping. Yes, that's 'modern' music production for you. Go to rec.audio.pro for a discussion of it every week or two. Graham |
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