Hi RSK,
I'm not commenting on your choice of amp because I can't remember it clearly.
I will say that often one product sounds great! .... until you hear something that actually does sound great!
My GF has a system she paid a lot of money for and she was convinced it was an extremely good system. Then I replaced parts of it one piece at a time, some components she had never heard of before. Let's just say that one thing she does have is an extremely good ear and sense of good sound. She is currently still amazed at how good the new stuff sounds, and it isn't even as good as it could be. She fought me on upgrades initially.
So you see. It's all a matter of perspective. I have noticed that often equipment is accepted as "great" based on reputation alone, and not self personal critical assessment. That's what makes the high end audio business go round and round. Often a great story trumps actual performance.
-Chris
I'm not commenting on your choice of amp because I can't remember it clearly.
I will say that often one product sounds great! .... until you hear something that actually does sound great!
My GF has a system she paid a lot of money for and she was convinced it was an extremely good system. Then I replaced parts of it one piece at a time, some components she had never heard of before. Let's just say that one thing she does have is an extremely good ear and sense of good sound. She is currently still amazed at how good the new stuff sounds, and it isn't even as good as it could be. She fought me on upgrades initially.
So you see. It's all a matter of perspective. I have noticed that often equipment is accepted as "great" based on reputation alone, and not self personal critical assessment. That's what makes the high end audio business go round and round. Often a great story trumps actual performance.
-Chris
the datasheet of this early version of 2N3055 in this databook from first link you will find on page 291.
I guess, first announcement and advertisement of RCA's 2N3055 must to find in this magazine archived as PDF files under
https://worldradiohistory.com/Archive-All-Audio/Audio-Magazine.htm
probably between 1962 and 1964.
Who know the associated issue ?
Did you follow up on the reference I posted a while back?
Here in the UK the first advert I have uncovered can be found on the Worldradiohistory web site, UK section.
Industrial Electronics, January 1965. Advert page 29 is page 67 in the pdf.
So I expect the US adverts to precede this by about 6m-a year
Here in the UK the first advert I have uncovered can be found on the Worldradiohistory web site, UK section.
Industrial Electronics, January 1965. Advert page 29 is page 67 in the pdf.
So I expect the US adverts to precede this by about 6m-a year
The Audio Innovations Alto
What a s... design
Burned PCB around the transistors that had a very small heatsink
What a s... design
Burned PCB around the transistors that had a very small heatsink
And no mention of audio amplifiers!
Supports the idea that the 2N3055 was developed for power supplies, mainly.
But RCA did well out of amplifiers...until they didn't.
And the data code is 64, I believe.
Supports the idea that the 2N3055 was developed for power supplies, mainly.
But RCA did well out of amplifiers...until they didn't.
And the data code is 64, I believe.
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Just had a look at some web refs.
Seems the 35 is a quasi.
It is possible to reduce crossover distortion to quite low levels in a quasi, if the output is inclusive in the Miller compensation. I'm wondering if they've done something like that and operating in Class B (which would push the compensation/crossover distortion reduction a little too much) to keep the heatsink size small. Too small, perhaps, but it is also possible someone overloaded it.
Seems the 35 is a quasi.
It is possible to reduce crossover distortion to quite low levels in a quasi, if the output is inclusive in the Miller compensation. I'm wondering if they've done something like that and operating in Class B (which would push the compensation/crossover distortion reduction a little too much) to keep the heatsink size small. Too small, perhaps, but it is also possible someone overloaded it.
https://www.diyaudio.com/community/threads/audio-innovations-alto.144893/
The first models used a circuit similar to the JLH1996 with Darlington output (class AB). Perhaps someone wanted to increase the quiescent current (class A)))
Attachments
"The black and the chrome versions are totally diffren amplifiers. The older one uses a single end psu and capacitor coupling for the speaker outputs.. the later chrome version uses a dual rail psu and no speaker coupling cap!
in 1964 nobody ever thought one would be making audio amplifiers big enough to use 2N3055’s out of anything but…. Tubes. We already had the 6550, a pair of which would make more reliable watts than a pair (or two) of 2N3055 running at 60 volts. And you wouldn’t dare run those old ones higher like you “can” today. In those days, transformers didn’t go for stupid money like they do today (They now dominate the cost of any product).
Are you sure about that? Sixty years ago anything was much cheaper than today, if we restrict to the amount of money one had to pay. But the mean income also was much less. For a real comparison we need to take inflation into account, of course. An example: In 1963 at the Oktoberfest at Munich one had to pay DM 2,20 for a »Maß« (=about 1 litre of beer). This year the public is charged about € 15 (depending from where and which beer you're drinking), about 13 times the money of 1963.
Best regards!
I am not sure that alcohol drinking (or sigarette smoking) constitute accurate inflation indicators as they involve health-related regulations.
Specialty items with limited markets (such as tube audio output transformers) are not accurate inflation indicators either. They tend to go up faster than the norm. When everything had them it was different.
Even with modern SS amps the iron is on the expensive side, often costing as much as the rest of the BOM.
Even with modern SS amps the iron is on the expensive side, often costing as much as the rest of the BOM.
I remember that in the sixties the legendary VOX AC30 guitar amp had a price tag about 2000DM - while the Volkswagen Beetle was about 4500 DM.
The Siemens "Klangschatulle" (tube radio) was about 300DM in the fifties, like the average month salary of simple craftsmen.
An example how different markets develop.
The Siemens "Klangschatulle" (tube radio) was about 300DM in the fifties, like the average month salary of simple craftsmen.
An example how different markets develop.
The first ad that I can find for a 2N3055 appeared in the Feb 28, 1964 issue of Electronics magazine. It is located on the last page (64) (also known as the 4th cover) in the following link: https://worldradiohistory.com/Archive-Electronics/60s/64/Electronics-1964-02-28.pdf
NOTE: BTW, I could not find an ad for a 2N3055 in Electronic Design magazine around this time period (1964).
NOTE: BTW, I could not find an ad for a 2N3055 in Electronic Design magazine around this time period (1964).
yes - at this time most solid state power amplifier stages use germanium transistors like e. g. AD149, AD155, AD161/162 or AD133.
It may only have been used as an output stage for power amplifiers from the 2nd generation of the 2N3055 onwards.
Interesting to know would be, from what brand the first ss amp introduced with 2N3055 in the output stage.
Here an early 2N3055 RCA advertisement as PDF-attachment (thank you very much for the advice in post #517):
2nd generation? As far as I know the RCA-2N3055 was always a "hometaxial" device as RCA called it. Plenty of amplifiers used it by 1970, or European look-alikes (BDY20, BD130 etc). The Quad 303 was introduced in 1968 or thereabouts. The second gen was really from about 1978 when the epi version came out. I suspect ONsemi are now making it on something like a Gen 4. RCA published loads of circuits using the 2N3055 or similar devices (usually under the 40xxx banner). Many companies built amps using RCA circuits as a baseline.
Yes, the semi-fabs generated uses for their products in their manuals. I made so much stuff from the RCA tube manuals, then transistors. Their app notes were also used to showcase new products and still are.
I still have my old manuals, including leather-bound Motorola manuals.
I still have my old manuals, including leather-bound Motorola manuals.