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Old 24th July 2002, 12:10 AM   #1
The one and only
 
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Cool My first amp

By way of encouraging you lurking DIYers, I present
a photo of the very first amplifier I built from scratch
by myself.

It was gathering dust in my storage racks (think of the
warehouse at the end of Raiders of the Lost Ark), and
I've been meaning to rehabilitate it.
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File Type: jpg mvc-004f.jpg (63.2 KB, 6757 views)
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Old 24th July 2002, 12:14 AM   #2
The one and only
 
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Here's another shot, this time closer view of
board construction.

This was made about 1972. It delivered 60 watts per
channel and constituted a first effort at keeping a
follower stage always forward biased (a predecessor
to dynamic bias)

Tomorrow I'll see about a schematic.
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Old 24th July 2002, 01:15 AM   #3
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Quote:
Originally posted by Nelson Pass
This was made about 1972
I was still in high school... looks like the top would be kinda tricky to put on.

Thanx for the pics.

dave
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Old 24th July 2002, 03:30 AM   #4
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Location: Columbia, SC
I remember when I finally got up the courage to simply throw away all my 10 and 20% carbon composition resistors and commit to (<i>gasp!</i>) 5% from then on. Now I've gotten so used to 2% that I can't bring myself to throw them away, even though the 1% Dales cost me less to buy. Somewhere along the way I lost my affinity for the 10% parts and confess to flinching when I see a silver tolerance band. I'm not sure when I became such a snob...looks as though I'll have to sit myself down and give myself a good talking to for the simple reason that a lot of fine amps were built using pretty vague values.
I managed to work this same sort of creeping snobbery into a scene in one of my stories once upon a time. It's subtle; you never notice it creeping up on you, but the realization is sudden.
What's the pot for? Input level, bias, or feedback?
For what it's worth, I think my first circuit was a crossover, the guts of which I happened to come across in the bottom of a box the other day.

Grey
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Old 24th July 2002, 02:07 PM   #5
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Default Re: My first amp

Originally posted by Nelson Pass
Quote:
It was gathering dust in my storage racks (think of the warehouse at the end of Raiders of the Lost Ark) ....
Nelson ..... does this mean you really do have the holy grail ?

cheers, mark

PS: If you ever need help cleaning it out .... I'm sure we could find you a couple of helpers !!!
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Old 24th July 2002, 02:22 PM   #6
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Yes, I like this idea of the Passcam.

The board looks a lot like that of a set of Ark amps I own of that period, pre Jurasic if I recall (aka Phase Linear 700B and 400.)

It looks quite industrial and very American in construction compared to the Japanese (plastic ) amps of the day

Those spring loaded heatsinks were quite popular then as per the carbon power resistors.

regards

macka
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Old 24th July 2002, 03:09 PM   #7
SteveG is offline SteveG  United States
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Quote:
I was still in high school...
That's ok, I wasn't even born yet! Shoot, my parents weren't even out of high school!
Nelson,
Thanks for showing us your human side once in a while... even still, it looks a lot more ambitious than the power supply I build in the pan of an old spring reverb, haha. And, it is a whole lot nicer than the mic preamp I tried to build out of a couple transistors and an op-amp (man, did that ever suck!)
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Old 24th July 2002, 07:45 PM   #8
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My lord! It has been a loooooooong time since I have seen 10% resistors!


Gabe
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Old 24th July 2002, 08:18 PM   #9
FBJ is offline FBJ  United States
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In 1972 I was dancing to disco on my sister's JC Penney AM/FM recevier with built in 8 track. And I could not imagine a better system ( back then).
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Old 24th July 2002, 08:21 PM   #10
JoeBob is offline JoeBob  Canada
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Damn, your first was prettier than my first... For a first project, the construction dones't look bad at all. My first amp got dismantled shortly after it was built (it looked pretty bad).
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