Transistor Preamp

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My version of simple "blameless" pre-amp. Not tested!
Maybe it better to add DC Offset adjustment.

THD at 20kHz should be 0.002978%

Bimo, are R4 and R37 2K ohm trimmers?

I assume the trimmers are for DC offset?

Also, can one use 220uF caps in place of all the 100uF caps?
I notice you used 5mm LS for the 100uF caps and most of the lower voltage ones I've found have 2.5-3.5mm LS.

Thanks.
 
Some people asked about top quality pre-amp with SE input and balanced output (XLR). This is the way I would do it:
1) Take Damir's GainWire, mentioned in the previous post (it can also drive the headphones);
2) Add some input selector and volume pot at the input.
3) Add the balanced line driver at the output - that's the way I see it (attached).

That's it. Pro-grade pre-amp.

P.S. This driver stage will also work perfectly with my AmpliWire line stage, mentioned earlier in the thread - >HERE<
 

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Last edited:
Some people asked about top quality pre-amp with SE input and balanced output (XLR). This is the way I would do it:
1) Take Damir's GainWire, mentioned in the previous post (it can also drive the headphones);
2) Add some input selector and volume pot at the input.
3) Add the balanced line driver at the output - that's the way I see it (attached).

That's it. Pro-grade pre-amp.

P.S. This driver stage will also work perfectly with my AmpliWire line stage, mentioned earlier in the thread - >HERE<

Thanks, Valery.

Ahh so we have to resort to an IC op amp for balanced driver ? I don't have a problem as the OPA2134 is one of my favorites and currently the output driver on my DAC.

Simple enough circuit though.
 
Thanks, Valery.

Ahh so we have to resort to an IC op amp for balanced driver ? I don't have a problem as the OPA2134 is one of my favorites and currently the output driver on my DAC.

Simple enough circuit though.

It's also possible to use any discrete differential line stage circuit as an opamp in the balanced driver, but to my taste ... it would be a kind of ... paranoia 😛
OPA2134 at unity gain - excellent wire with gain 😎
A lot of professional mixing equipment is based on opamps, sometimes even less sophisticated, than this one.

Oops! A "typo" mistake on schematic in post #231. Please use the one, attached here.
 

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