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#1
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AM receievers and tuners,1.
Gregg wrote: Solid State!!!! :-o Heretic!! ;-p Well if you don't like the solid state, then work out what each chip does, and use tubes to do what the chips do. And work out what all the LC components do as well..... The chip designs represent a no-compromise approach, and never allowing the distortions to get the better of you. Having said that, what distortions do inevitably occur with the SS approach sound bleeding awful. My tubed FM tuner and MPX decoder do manage to sound better than any chip based tuners I have tried, but there are quite a few tubes in there. Believe me its possible, but you are gonna need a few more tubes than the the guys were prepared to use in 1950. In 1950, if you'd been employed as a radio engineer at a radio making company, and you suggested that your new design required 6 tubes, not 5 tubes, you'd be immediately taken out into the back yard by the accountants, and beaten up, and then be demoted to a labourer for sweeping up, to let everyone else know that radios shall have a minimum of tubes, and to hell with notions of fidelity, and let nobody ever suggest otherwise. Its now so very easy to build better tube radio sets than ever before! It just takes knowledge and time. Patrick Turner. -- Gregg *It's probably useful, even if it can't be SPICE'd* http://geek.scorpiorising.ca |
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#2
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I saw Eniac at Moffet museum, Eric barbour was retubing
it. All those 6550s got some serious tube lust going. A big rack of fresh svetlana 6550s wow, what a sight. Patrick Turner wrote: Gregg wrote: Solid State!!!! :-o Heretic!! ;-p Well if you don't like the solid state, then work out what each chip does, and use tubes to do what the chips do. And work out what all the LC components do as well..... The chip designs represent a no-compromise approach, and never allowing the distortions to get the better of you. Having said that, what distortions do inevitably occur with the SS approach sound bleeding awful. My tubed FM tuner and MPX decoder do manage to sound better than any chip based tuners I have tried, but there are quite a few tubes in there. Believe me its possible, but you are gonna need a few more tubes than the the guys were prepared to use in 1950. In 1950, if you'd been employed as a radio engineer at a radio making company, and you suggested that your new design required 6 tubes, not 5 tubes, you'd be immediately taken out into the back yard by the accountants, and beaten up, and then be demoted to a labourer for sweeping up, to let everyone else know that radios shall have a minimum of tubes, and to hell with notions of fidelity, and let nobody ever suggest otherwise. Its now so very easy to build better tube radio sets than ever before! It just takes knowledge and time. Patrick Turner. -- Gregg *It's probably useful, even if it can't be SPICE'd* http://geek.scorpiorising.ca |
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#3
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On Thu, 24 Jun 2004 09:56:45 +1000, Patrick Turner
wrote: [snip] My tubed FM tuner and MPX decoder do manage to sound better than any chip based tuners I have tried, but there are quite a few tubes in there. [snip] Patrick Turner. If your toobed tuner and decoder sound better than the chip-based circuits you tried, it's only because that present-day commercial presentations are cheap-as-possible-****. It's almost trivial to design an SS tuner that's better than tooobz, but it would cost more than the cheap-**** SS on the market. ...Jim Thompson -- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice  480)460-2350 | || E-mail Address at Website Fax 480)460-2142 | Brass Rat || http://www.analog-innovations.com | 1962 | I love to cook with wine. Sometimes I even put it in the food. |
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#4
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Jim Thompson wrote:
Patrick Turner wrote: My tubed FM tuner and MPX decoder do manage to sound better than any chip based tuners I have tried, but there are quite a few tubes in there. If your toobed tuner and decoder sound better than the chip-based circuits you tried, it's only because that present-day commercial presentations are cheap-as-possible-****. It's almost trivial to design an SS tuner that's better than tooobz, but it would cost more than the cheap-**** SS on the market. Jim, Patrick, et al. I'm curious now with regards to SS (transistor and digital) AM tuner designs: 1) Does anyone today make a commercial SS/digital AM tuner (maybe as part of an AM/FM tuner) which is noted as being outstanding with regards to its high-fidelity audio performance? 2) Did anyone in yesteryear make such a tuner (and where schematics are available)? 3) Do schematics exist, put together by radio enthusiasts, for such a tuner? Although my primary focus is on developing a kit for a high-fidelity tube-based AM tuner, I am interested as well in modern SS/digital designs amenable to kit building. It'd be nice if the tuner would be sensitive enough for casual DXing as well (I assume it will need to have variable bandspread/selectivity controls.) Jon Noring |
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#5
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Jon Noring writes:
I'm curious now with regards to SS (transistor and digital) AM tuner designs: 1) Does anyone today make a commercial SS/digital AM tuner (maybe as part of an AM/FM tuner) which is noted as being outstanding with regards to its high-fidelity audio performance? 2) Did anyone in yesteryear make such a tuner (and where schematics are available)? 3) Do schematics exist, put together by radio enthusiasts, for such a tuner? I think they were pretty regular as construction articles in the tech rags, Popular Electronics, etc. I had a PE sub from 1964 to the dying days and remember "yet another AM detector" in lots of mags. I don't have the issues anymore. A good Public Library should have the issues. Jon-- did you ever find a low-tube-count homodyne schematic? Steve. -- Steven D. Swift, , http://www.novatech-instr.com NOVATECH INSTRUMENTS, INC. P.O. Box 55997 206.301.8986, fax 206.363.4367 Seattle, Washington 98155 USA |
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#6
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Steven Swift wrote:
Jon-- did you ever find a low-tube-count homodyne schematic? Nope. Not yet, but then the last few days I've been busy on other things, so haven't gotten back to your private replies. Was this schematic posted to one of the alt.binaries.* groups? Jon |
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#7
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"Patrick Turner" wrote in message
... Gregg wrote: Solid State!!!! :-o Heretic!! ;-p Well if you don't like the solid state, then work out what each chip does, and use tubes to do what the chips do. And work out what all the LC components do as well..... .... Its now so very easy to build better tube radio sets than ever before! It just takes knowledge and time. And Tubes. |
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#8
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scottp wrote: I saw Eniac at Moffet museum, Eric barbour was retubing it. All those 6550s got some serious tube lust going. A big rack of fresh svetlana 6550s wow, what a sight. I thought they had a lot of 12AX7 also, maybe 10,000 of them. If each 12AX7 needs 2 watts, that's 20,000 watts of heat, and it sounds like a lot until you realise its only equal to 10 x 2 kW room heaters, and if the air blown through a tubed computer was sent in to heat the rooms for the operators, there is a some savings in running costs. If $30 worth of tubes blow per day it costs 10c/KwHr, then the running costs per day are $78, based on 24 Hrs, plus all the technicians, and their tea lady. I think my hand held calculator is a better deal. But my calculator is hopeless with an audio signal. And in fact I employ the calculator to make tube amps faster. Patrick Turner. |
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#9
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Jim Thompson wrote: On Thu, 24 Jun 2004 09:56:45 +1000, Patrick Turner wrote: [snip] My tubed FM tuner and MPX decoder do manage to sound better than any chip based tuners I have tried, but there are quite a few tubes in there. [snip] Patrick Turner. If your toobed tuner and decoder sound better than the chip-based circuits you tried, it's only because that present-day commercial presentations are cheap-as-possible-****. It's almost trivial to design an SS tuner that's better than tooobz, but it would cost more than the cheap-**** SS on the market. I think there is a limit to how good radio can sound, and its because the source isn't live; its already a transmitted recording of some sort. The use of a subcarrier at 38 kHz to carry the stereo info is sub-optimal, analgous to having a digital sampling rate of only 38 kHz/second . However, some of the SS tuners I have heard are not cheap-as-possible, but were recognised as state of the art in their day. And what was that? just the usual array of chips on a board. And I found it wasn't that hard to get better sound with tubes. The cost is high, and time taken, but diy ppl who rebuild and mod an existing old set they may have bought for $100 like I did are well rewarded, plus they actually learn something. Patrick Turner. |
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#10
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On Thu, 24 Jun 2004 01:20:26 GMT, Jon Noring wrote:
Jim Thompson wrote: It's almost trivial to design an SS tuner that's better than tooobz, but it would cost more than the cheap-**** SS on the market. Stainless Steel tuner? |
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#11
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... Jim Thompson wrote: Patrick Turner wrote: My tubed FM tuner and MPX decoder do manage to sound better than any chip based tuners I have tried, but there are quite a few tubes in there. If your toobed tuner and decoder sound better than the chip-based circuits you tried, it's only because that present-day commercial presentations are cheap-as-possible-****. It's almost trivial to design an SS tuner that's better than tooobz, but it would cost more than the cheap-**** SS on the market. Jim, Patrick, et al. I'm curious now with regards to SS (transistor and digital) AM tuner designs: 1) Does anyone today make a commercial SS/digital AM tuner (maybe as part of an AM/FM tuner) which is noted as being outstanding with regards to its high-fidelity audio performance? You can't have HiFi when the station itself isn't putting out anything above 7.5 kHz. See 3rd paragraph he http://popularmechanics.com/technolo...ready_for_hdr/ 2) Did anyone in yesteryear make such a tuner (and where schematics are available)? A regular crystal radio has essentially unlimited bandwidth. That's why you can hear, at the same time, more than one station! 3) Do schematics exist, put together by radio enthusiasts, for such a tuner? They are called TRF receivers. Although my primary focus is on developing a kit for a high-fidelity tube-based AM tuner, I am interested as well in modern SS/digital designs amenable to kit building. It'd be nice if the tuner would be sensitive enough for casual DXing as well (I assume it will need to have variable bandspread/selectivity controls.) Jon Noring |
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#12
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"Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote: ... Jim Thompson wrote: Patrick Turner wrote: My tubed FM tuner and MPX decoder do manage to sound better than any chip based tuners I have tried, but there are quite a few tubes in there. If your toobed tuner and decoder sound better than the chip-based circuits you tried, it's only because that present-day commercial presentations are cheap-as-possible-****. It's almost trivial to design an SS tuner that's better than tooobz, but it would cost more than the cheap-**** SS on the market. Jim, Patrick, et al. I'm curious now with regards to SS (transistor and digital) AM tuner designs: 1) Does anyone today make a commercial SS/digital AM tuner (maybe as part of an AM/FM tuner) which is noted as being outstanding with regards to its high-fidelity audio performance? You can't have HiFi when the station itself isn't putting out anything above 7.5 kHz. See 3rd paragraph he http://popularmechanics.com/technolo...ready_for_hdr/ 2) Did anyone in yesteryear make such a tuner (and where schematics are available)? A regular crystal radio has essentially unlimited bandwidth. That's why you can hear, at the same time, more than one station! 3) Do schematics exist, put together by radio enthusiasts, for such a tuner? They are called TRF receivers. Although my primary focus is on developing a kit for a high-fidelity tube-based AM tuner, I am interested as well in modern SS/digital designs amenable to kit building. It'd be nice if the tuner would be sensitive enough for casual DXing as well (I assume it will need to have variable bandspread/selectivity controls.) Jon Noring Seems odd to see you here Watson. I always think of you as the LED Whiz!!!!! Cheers, John Stewart |
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#13
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"Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote: ... Jim Thompson wrote: Patrick Turner wrote: My tubed FM tuner and MPX decoder do manage to sound better than any chip based tuners I have tried, but there are quite a few tubes in there. If your toobed tuner and decoder sound better than the chip-based circuits you tried, it's only because that present-day commercial presentations are cheap-as-possible-****. It's almost trivial to design an SS tuner that's better than tooobz, but it would cost more than the cheap-**** SS on the market. Jim, Patrick, et al. I'm curious now with regards to SS (transistor and digital) AM tuner designs: 1) Does anyone today make a commercial SS/digital AM tuner (maybe as part of an AM/FM tuner) which is noted as being outstanding with regards to its high-fidelity audio performance? You can't have HiFi when the station itself isn't putting out anything above 7.5 kHz. See 3rd paragraph he http://popularmechanics.com/technolo...ready_for_hdr/ Gee, what a lot I had to try to download to see whatever it was.... so I gave up. But anyway, rarely do radio stations have not have "anything above 7.5 kHz". If they do have a filter which rolls off the modulation with a -3 dB pole at 7.5 kHz, there is some benefit in having a tone control in the receiver which will lift the treble a bit, and you might squeeze a bandwidth of 9 kHz out of the set, depending on the nature of the tone control boost, which shouldn't have any effect below 2 kHz. Anyway, 7.5 kHz of audio bw sounds far far better than 2 kHz, which is all you get with so many radios. 2) Did anyone in yesteryear make such a tuner (and where schematics are available)? A regular crystal radio has essentially unlimited bandwidth. That's why you can hear, at the same time, more than one station! It has a very wide pass band if the Q of the coil used is low. But a good crystal set has a high Q tuned circuit, perhaps 100 at 1,000 kHz, so the RF bw is 10 kHz, so you get 5 kHz of audio. The audio bw is near half that at 550 kHz and near twice that 1,700 kHz, for the same Q. Stations of equal power about 100 kHz away from the wanted station are going to be heard in the background. We have 7 stations on the AM band where I am and some are less than 100 kHz apart. Crystal sets with one tuning circuit do not gurantee good audio, and they are so non selective they'd be dead useless to me. 3) Do schematics exist, put together by radio enthusiasts, for such a tuner? They are called TRF receivers. I beg to differ. Last week I posted about a 1/2 dozen viable designs of radio sets, one was a TRF, with high Q double tuned circuits, using solid state amplification, the rest were superhets and synchrodynes. I suggest some of thse sets we designed by very serious radio enthusiasts. There has always been a debate about TRF vs Superhet. Its been going on since 1930. Patrick Turner. |
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#14
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The Real Andy wrote:
On Thu, 24 Jun 2004 01:20:26 GMT, Jon Noring wrote: Jim Thompson wrote: It's almost trivial to design an SS tuner that's better than tooobz, but it would cost more than the cheap-**** SS on the market. Stainless Steel tuner? Squalid State.... :-) Anyway, in the RF and IF sections of the FM portions of the tuner, before the FM signal is demodulated, it shouldn't make any sonic difference SS or tubes. All the audio information in an FM signal is essentially carried in the timing of the carrier's zero crossings. Oh, there are other issues such as intermod problems in the FM front end that tubes tend to handle better than SS, but careful design should take care of that. Where you'd want the tubes to take over would likely be at the FM demodulator and the stereo decoder. As for AM, that is more of an "analog" signal system than FM is. FM is almost "digital" in the sense that you can distort the hell out of the signal, aka limiting, and not damage at all the demodulated audio. |
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#15
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"Patrick Turner" wrote in message ... "Watson A.Name - \"Watt Sun, the Dark Remover\"" wrote: ... Jim Thompson wrote: Patrick Turner wrote: My tubed FM tuner and MPX decoder do manage to sound better than any chip based tuners I have tried, but there are quite a few tubes in there. If your toobed tuner and decoder sound better than the chip-based circuits you tried, it's only because that present-day commercial presentations are cheap-as-possible-****. It's almost trivial to design an SS tuner that's better than tooobz, but it would cost more than the cheap-**** SS on the market. Jim, Patrick, et al. I'm curious now with regards to SS (transistor and digital) AM tuner designs: 1) Does anyone today make a commercial SS/digital AM tuner (maybe as part of an AM/FM tuner) which is noted as being outstanding with regards to its high-fidelity audio performance? You can't have HiFi when the station itself isn't putting out anything above 7.5 kHz. See 3rd paragraph he http://popularmechanics.com/technolo...ready_for_hdr/ Gee, what a lot I had to try to download to see whatever it was.... so I gave up. But anyway, rarely do radio stations have not have "anything above 7.5 kHz". If they do have a filter which rolls off the modulation with a -3 dB pole at 7.5 kHz, there is some benefit in having a tone control in the receiver which will lift the treble a bit, and you might squeeze a bandwidth of 9 kHz out of the set, depending on the nature of the tone control boost, which shouldn't have any effect below 2 kHz. Anyway, 7.5 kHz of audio bw sounds far far better than 2 kHz, which is all you get with so many radios. It's my understanding, that for the U.S. anyway, the _law_ says that the bandwidth has to be restricted to less than 10 kHz. See the FCC regulations at http://frwebgate.access.gpo.gov/cgi-...47&PART=73&SEC TION=44&YEAR=2000&TYPE=TEXT Since the skirts of the bandwidth can be only so steep, the bandwidth starts to rolloff at 7 or 8 kHz. 2) Did anyone in yesteryear make such a tuner (and where schematics are available)? A regular crystal radio has essentially unlimited bandwidth. That's why you can hear, at the same time, more than one station! It has a very wide pass band if the Q of the coil used is low. But a good crystal set has a high Q tuned circuit, perhaps 100 at 1,000 kHz, so the RF bw is 10 kHz, so you get 5 kHz of audio. The audio bw is near half that at 550 kHz and near twice that 1,700 kHz, for the same Q. Stations of equal power about 100 kHz away from the wanted station are going to be heard in the background. We have 7 stations on the AM band where I am and some are less than 100 kHz apart. Crystal sets with one tuning circuit do not gurantee good audio, and they are so non selective they'd be dead useless to me. 3) Do schematics exist, put together by radio enthusiasts, for such a tuner? They are called TRF receivers. I beg to differ. Last week I posted about a 1/2 dozen viable designs of radio sets, one was a TRF, with high Q double tuned circuits, using solid state amplification, the rest were superhets and synchrodynes. I suggest some of thse sets we designed by very serious radio enthusiasts. There has always been a debate about TRF vs Superhet. Its been going on since 1930. Patrick Turner. |
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