Great River output pot

Hi everybody,
I'd like to add an output pot attenuator to my great river MP2 and I thought this could be done as follows:


can anyone confirm (or not!) if it is right?
10K log, is that a good value for the pot?

Best,
Mattia.

the pic wouldn't load so can't see where you mean ,
but for sure a question for the designer
, you don't want to be changing the output impedance
[ as the pot would do ] and not sure there
is much to be gained with an output level
It's one of the great things about this preamp , you just set the level
and it sounds great , if you are not happy ,
change [ or move ] the mic .

Yeah, i'm all for experimenting, but I trust that Dan has considered these things and left them out on purpose.

thank you guys,
I'll follow your suggestions!

Mattia.

As shown, you should not try to drive the output transformer with this configuration. You need to maintain the low impedance connection between the output amplifier and the transformer primary. There doesn't appear to be a good place to put an output level control in the circuit as its an operational topology. If you need to attenuate the output, consider using an adjustable pad, after the output transformer.

The pic wouldn't load on my computer , but burdij's advice
sounds quite reasonable , in fact if you had some davin pots
or the attenuation network , make it as a separate ,
patchable unit to use with other things when needed .

regards Greg

You can sure add a pot where you show it, but be advised that like burdij has said, you won't be able to drive a transformer off the wiper, the driving impedance will be far to high, and very load dependant as to the sound.

What's your reason to do this?

If it is to "get a sound" by driving the preamp harder, and then attenuating the output to fit your A-D input range, well, you're not going to get the results you want, because this preamp sounds pretty much the same right up until it clips, then it gets ugly instantly. That's one of the reasons the rail voltage is fairly high, you just don't get close to clipping that way.

If what you want is a continuously controllable gain (within reason), you'd be better off putting a 2K pot wired as a rheostat with a 750 ohm resistor in place of the feedback resistor, or maybe 2K and 1.5K to give you a little up and a little down from the switch gain setting.

Brilliant.
thank you very much Dan, the main reason was,in fact, that I wished to drive the preamp harder while having a low level output before the AD stage.
I guess this ain't the right preamp for this..
thank you everybody!
Best,
Mattia.