The article appeared in the 1948 March issue of Audio Engineering, unfortunately, the copies found online are all missing the relevant pages, so if anyone has the complete article, could you please send me a copy?
TIA,
jaz
TIA,
jaz
This is not what you actually look for, but since these two articles from RCA Ham Tips are dealing with 6AS7G amplifiers and are from the same era, I dare to attach these here.
I have actually built one (modified) amplifier based on the first article.
I have actually built one (modified) amplifier based on the first article.
I was very satisfied with it's performance.
Attached the schematic, which is drawn with LTSpice, but the results given are measured values of the prototype without GNFB.
10 W @ 1 kHz with 0.25 % THD is a good value.
I also have LTSpice model if you need.
Attached the schematic, which is drawn with LTSpice, but the results given are measured values of the prototype without GNFB.
10 W @ 1 kHz with 0.25 % THD is a good value.
I also have LTSpice model if you need.
Attachments
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Pages 20-23 are missing from the scans but the complete article can be found in the (reprinted) AUDIO ANTHOLOGY Volume One (pages 5 to 8) and followed by a second 6AS7G amp ("General Purpose 6AS7G Amplifier", pages 10-14) also designed by C.G McProud. Should be floating somewhere on the web but If you can't find it I could scan the missing pages from the original book I own.
The key component is 6SN7 driver stage.
It biased to generate considerable 3rd harmonic distortion, up to 4 % at full drive, which then cancels out the distortion generated by 6AS7G PP stage.
It biased to generate considerable 3rd harmonic distortion, up to 4 % at full drive, which then cancels out the distortion generated by 6AS7G PP stage.
Hi,
Here's the 1948 article by McProud.
In 1949 he did a 2-part article in the same magazine, the 'Compact 6AS7G Amplifier for Residence Audio Systems'
I have that too if anyone's interested.
rgds,
/tri-comp
Here's the 1948 article by McProud.
In 1949 he did a 2-part article in the same magazine, the 'Compact 6AS7G Amplifier for Residence Audio Systems'
I have that too if anyone's interested.
rgds,
/tri-comp
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Thanks! Really appreciated you taking the time to scan these articles. Would you have the original March 1948 article, i.e., the one with the missing pages online.
I actually got a copy of the whole March issue and here's what the editor says about the 6AS7G project.
I'm SO happy that I have a stash of these tubes for a future build !
I'm SO happy that I have a stash of these tubes for a future build !
Some time ago, a member discovered this valuable website. I think you will find all the articles you need and much more!
Documenting the History of Radio TV and FM broadcasting
Documenting the History of Radio TV and FM broadcasting
Hi,
As I use lots of those in OTL amps I'm quite familiar with this tube and absolutely love it.
It's low anode impedance relaxes the demand on the OTP so you can expect excellent bass and highs.
Of the lot I prefer the sound of the 6080 over the NOS 6AS7G with the possible exception of Sovtek's version which sounds much like the 6080.
One little amp that sounds quite impressive on high efficiency systyems (a la Lowther etc) is the Italian Triodino. I think it was using ITA Megaherz iron.
Cheers, 😉
As I use lots of those in OTL amps I'm quite familiar with this tube and absolutely love it.
It's low anode impedance relaxes the demand on the OTP so you can expect excellent bass and highs.
Of the lot I prefer the sound of the 6080 over the NOS 6AS7G with the possible exception of Sovtek's version which sounds much like the 6080.
One little amp that sounds quite impressive on high efficiency systyems (a la Lowther etc) is the Italian Triodino. I think it was using ITA Megaherz iron.
Cheers, 😉
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