Amplifier for....amplifiers?

Help Support GroupDIY:


Well-known member
Sep 22, 2014
Without a big backstory, I'm interested in building an amp that would boost the output of an existing speaker amp.

The idea is that instead of the added componentry, complexity and suboptimal gain structure of attenuating a 15-30W signal down to line level for input to a larger amplifier, only to boost it back up again to 60-120W, this "amp booster" would simply take the roughly 15-30 watts from an existing amp's speaker outputs and triple (or quadruple?) attenuation + redundant amplification needed. Just a simple, smaller "booster amp" with a high-wattage 2-8 ohm input stage.

I'd need something that would run on 12vdc or less.

Does such a thing exist? If not, can anyone recommend a methodology for creating such a thing? Or perhaps some chips or transistors off which to create an input, buffer and amp stage? Spank ya vary mooch!!!


abbey road d enfer

Well-known member
Jan 22, 2008
Producing 60+W from a 12V source requires either an output transformer (bulky and expensive) or converting the 12V to a higher voltage via DC/DC boost converter.
A amp with gain of 2-3 is not easier and does not take more components than a standard amp with gain of 20-30.
A pair of those
And a module such as this one
would get you going.

You could also use that
Beware that the power rating may be seriously inflated...
I'm afraid it's not very much DIY.


Well-known member
Jul 31, 2008
Buy a couple of 805 tubes and wind a input transformer that will step up the output voltage from your 15-30W amp to the tube grids. You will also need a output transformer, but that one you can probably buy. Use 12V for the heaters and a dc-dc converter to get the 1000V you'll need for the 805 plates. With few watts of driving power a push pull pair of 805 tubes will easily make 120W. Simple and optimal.

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