Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: tdvt on February 20, 2024, 01:12:44 pm
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A friend I had built a Reverb Champ for asked if I knew anything about stereo amps, which I do not. Nor have I really thought much about them, other than checking out the newer Magnatone stereo stuff on YT a while back.
But that got me wondering more about it; from just using two amps to an all-out 2-pre/2-pwr amp custom.
Are there any builds out there, or experiences using them, that anyone wants to share?
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Try to read this thread, may be you can find something of your interest
https://el34world.com/Forum/index.php?topic=29296.0
Franco
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guitar or audio?
Ampeg's Super Echo twin comes to mind for guitar
for audio, i've built a few mono-blocks. did a stereo but it weighed ~60 pounds, gutted it, re-purposed the good stuff
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A friend ... asked if I knew anything about stereo amps ...
But that got me wondering more about it; from just using two amps to an all-out 2-pre/2-pwr amp custom. ...
On another forum, people point out that an original lightweight Princeton Reverb of the 1960s might run you $3600, while a Twin Reverb from the same era might not sell at $1200. The difference is no one wants to schlep the big amps any more, so the price of small vintage amps has gone way up.
If it's for guitar, don't put "stereo anything" into a single cabinet. You can be pretty sure the customer will gripe at the unexpected weight & bulk.
And I've owned an Ampeg Super Echo Twin. After the novelty of "Trem 1 into Trem 2" wore off, I sold it. Because like everyone else, it just seemed to heavy to want to mess with 2 amps in 1 box.
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Try to read this thread, may be you can find something of your interest
https://el34world.com/Forum/index.php?topic=29296.0 (https://el34world.com/Forum/index.php?topic=29296.0)
Franco
Thanks Franco, I somehow missed that thread, as I always search here first.
guitar or audio?
Ampeg's Super Echo twin comes to mind for guitar
for audio, i've built a few mono-blocks. did a stereo but it weighed ~60 pounds, gutted it, re-purposed the good stuff
For guitar.
I am thinking he has some pedals with stereo outs that could be sent to separate speakers/amps. Didn't know about the Ampeg, will take a look.
Looking at the new Magnatone, it is mono up until the trem/vib circuit then splits to to pwr amps/speakers.
Saw another vintage amp (maybe a Valco?) that split the reverb off the main signal path & gave the wet signal it's own pwr amp/speaker.
Seems there have been lots of variations tried over the years.
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The difference is no one wants to schlep the big amps any more
Agreed, I am one of those guys.
Just using two small amps makes the most sense logistically, but there is something intriguing about a purpose-built stereo unit.
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And I've owned an Ampeg Super Echo Twin. After the novelty of "Trem 1 into Trem 2" wore off, I sold it. Because like everyone else, it just seemed to heavy to want to mess with 2 amps in 1 box.
The Super Echo Twin schematic makes my head hurt
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:l2:
you should try n work on one! small ask chassis, wires everywhere
This guy gets my gratitude for his re-draw
https://el34world.com/charts/Schematics/files/Ampeg/Ampeg_echotwin.gif
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Been thinking of a build for this stereo amp. Someone left this at the dump for me. Chassis is only 12.5" x 7" running 12ax7s and PP 25L6s. It's pretty light weight too. 2/3rds of that schematic are already gone.
Any good Ideas?
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the schematic is mostly "readable"
take a hi-rez, have your favorite "office" store print it in B&W hi-contrast, 14X17 or 16X20
while you wait buy a real nice mechanical pencil, a 6-pack of quality thin-tipped highlighters
pour or roll your favorite substance
touch-up the schematic with the pencil
decide your "color palate" RED = B+, green = Ground..... (make note so you don't forget:)
"trace" POWER, SIGNAL, GROUND
take the finished schematic to your favorite framing shop, walla, wall art
Any good Ideas?
:undecided:
OR, find the "S2" plug, looking for Left channel, right channel, solder up a 1/8" stereo jack, plug in a line-level audio source, enjoy
:icon_biggrin:
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OR, find the "S2" plug, looking for Left channel, right channel, solder up a 1/8" stereo jack, plug in a line-level audio source, enjoy
:icon_biggrin:
Ha Ha, this! Probably the smart thing to do. The wall art is cool though, love that it was right on the back panel.
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In a stereo amp you want two different outputs. So you need two output stages. That could be two champs. But where does your different input signal come from? What would you like to add to it?
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Our friend TIMBO has experience with stereo guitar amps, do a search in the forum using Stereo and TIMBO as author
Franco