early solid state amp design

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JR.
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early solid state amp design

Post by JR. »

early design article by Jack Sondermeyer circa 1966

https://pdf.yt/d/51PM6w1n7kJHzRJC (Wayne you may want to grab a copy of the PDF from that link).

We recently lost Jack Sondermeyer 1939-2015 father of the CS800 and much much more. I worked with him for 15 years at Peavey. He was a talented design engineer and good people. RIP

The article is far from modern design and looks like the early stuff when they were mostly dropping transistors in place of tubes in old boilerplate designs.

JR
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ricardo
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Re: early solid state amp design

Post by ricardo »

I remember a RCA application booklet, probably a little after this one, which had stuff right up to the 70W LTP i/P fully complementary O/P stage that was so common in the 70's & 80's. It was my first Bible for amp design cos it had detailed discussions of H/S requirements and how to design VI current limiting.

The supa devices in those days were Motorola MJ802/4502 but the circuits I played with were RCA from that application booklet. Also did fun stuff like re-winding mains transformers & dyeing Aluminium heatsinks black with Dylon hair dye :ugeek:

I was still in school.
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JR.
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Re: early solid state amp design

Post by JR. »

Jack knew his stuff and it was a luxury while working there for me to be able to walk in his office and pick his brain about amp design. When I took over the mixer engineering department I inherited many of his amp designs used inside powered mixers, so in the course of supporting those products I got to ask him a bunch of questions. Jack educated me about secondary breakdown, and he had specified several sets of fully complementary power transistors from Motorola.So new amp designs generally just picked output pairs from his menu.

Jack and I used to lead a class during Peavey dealer seminars where we discussed modern technology used in new products for sound reinforcement applications. At the beginning of each session I used to introduce Jack and say "He has forgotten more about amp design than I ever knew". I was teasing Jack about being older than me, but I was only half kidding about how much more than me he knew about amp design.

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mediatechnology
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Re: early solid state amp design

Post by mediatechnology »

John - Thanks for posting this. I snagged the pdf.
vintagedesign
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Re: early solid state amp design

Post by vintagedesign »

Still have the light bulb test circuit on my bench that was descibed in the CS800 manual. Think I put it together back in 1978.
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JR.
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Re: early solid state amp design

Post by JR. »

vintagedesign wrote:Still have the light bulb test circuit on my bench that was descibed in the CS800 manual. Think I put it together back in 1978.
Yes, the light bulb in series with the line cord was handy for current limiting during repairs and troubleshooting.

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emrr
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Re: early solid state amp design

Post by emrr »

I recognize those basic amp circuits from various early RCA SS broadcast equipment. Thanks for posting.
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