Adding gain to this buffer....

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I found this simple buffer schematic here on the forum and would like to know the proper way to add a small amount of gain.....

An externally hosted image should be here but it was not working when we last tested it.


Can the standard method of gain for a non-inverting configuration work, or are there other things that need to be considered?

An externally hosted image should be here but it was not working when we last tested it.
 
Thank you Jan.

Yes, only a gain of around 2 or 3.

I am planning to add this buffer to an amp that has a passive volume control. The amp is Tripath TA2022 based and I would like to lower it's gain and add some to the buffer instead.

Is there a huge difference between running an OPA2134 at +/-12v instead of +/-15v? I have a boat load of positive and negative 12v regulators, but no 15v.
 
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Be careful because the opamps at the input stage of the Tripath amp are powered by a single 5V rail. We have no idea what the specs of the opamps internal to the chip are, so it would probably be a good idea to make sure the maximum possible input voltage is below 5V peak to peak (biased around 2.5V of course).
 
theAnonymous1 said:


The Tripath amp is kind of noisy with the recommended gain. I've tried lowering the gain and it also lowered the noise, but then it doesn't play as loud (duh).

Adding gain to the buffer isn't a good solution for this?
explained like this, then it begins to make sense.
It's worth trying sending a higher level signal to the amp. But now you need more headroom. +-18V supplies for 12Vac gets back 3.5db of headroom ref 6db of gain. You still lose out but much better than +-12V supplies.
 
BWRX said:
Be careful because the opamps at the input stage of the Tripath amp are powered by a single 5V rail. We have no idea what the specs of the opamps internal to the chip are, so it would probably be a good idea to make sure the maximum possible input voltage is below 5V peak to peak (biased around 2.5V of course).

:eek:

So your saying the 2.5Vrms coming out of my DAC is probably as much as it can take anyway?

AndrewT said:
explained like this, then it begins to make sense.
It's worth trying sending a higher level signal to the amp. But now you need more headroom. +-18V supplies for 12Vac gets back 3.5db of headroom ref 6db of gain. You still lose out but much better than +-12V supplies.

Hey, I can pop some OPA551 in the sockets and and run them off the +/-30v regulated rails of the amp. I know, bad idea.... but talk about headroom.:smash:
 
theAnonymous1 said:
The Tripath amp is kind of noisy with the recommended gain. I've tried lowering the gain and it also lowered the noise, but then it doesn't play as loud (duh).

Ah, ok.

Adding gain to the buffer isn't a good solution for this?

I guess that depends on whether you can achieve the gain in the buffer with less noise than you'd have with the gain in the Tripath. If you can, then yeah, you'd be ahead of the game there.

se
 
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