Watts really were bigger in the 70’s…

by Stephen Hobley on January 11, 2011

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From time to time I like to check out the local Goodwill store – mainly the electronics to see if there’s anything worth salvaging and re-purposing. I keep a look out for TVs, radios and speakers but once in a while you can snag a real bargain.

I just bought this amp for $10 – it’s a Technics 7300 circa. 1978. Originally I got it for the massive heat sinks on the MOSFETs at the back, but after a little online research it turns out that it’s a something of a classic amp. (There’s one for sale on E-bay at the time of writing for $150)

I finally managed to download the service  manual after some digging around (As an aside – I really hate those other websites that advertise “free service manuals” and then make you jump through all kinds of stupid hoops to get them). After cleaning up the contacts and running a few quick tests I hooked up my speakers and tried it out. It’s rated at 40W per channel, but it actually packs much more of a punch than my modern amplifier allegedly rated at 100W. (Behold! The power of marketing). It has great bass response and minimal distortion for an amp so old.

It would probably benefit from being “re-capped”, but it seems to be working just fine.

So I probably won’t be stripping it down after all – in fact I’m pretty happy where it is right now.

While I was there I also found these two excellent electronics books –

“Electronic circuits – Discrete and Integrated” by Donald L. Schilling and Charles Belove
and “How To Design and Build Electronic Instrumentation” by Joseph J. Carr

Both are jam-packed full of circuits for doing all kinds of wild and crazy things…

[The title of this post was shamelessly stolen from an article here – about the exact same amplifier]

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{ 4 comments… read them below or add one }

Michael January 12, 2011 at 11:46 pm

Very nice find! I got into vintage audio a few years ago… looking for robot scrap parts and found myself a very heavy receiver that had a lot more punch than the 60W it was rated for… an HK680i.

Are you a member of AudioKarma ? Great resource for vintage audio. In the last few years I’ve gone through a pile of 70’s and 80’s gear–receivers, speakers, turntables, cassette decks–straining our storage space and annoying my wife 🙂 only to arrive at a real nice sounding main system and living room system. 🙂

clicclic January 30, 2011 at 5:05 pm

That receiver looks totally retro sweet. Nice score!

sl-1200mk2 April 2, 2011 at 4:44 pm

Great find! Reminds me of the systems bought in the PX in Germany back in the mid 80’s. Just because it’s new doesn’t mean it’s better. Just my humble opinion.

Morris April 15, 2014 at 5:07 am

Please I will like to have books for Electronics cricket book.
Regards
Morris

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