Help: W492eq input and output gain!

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Hi Folks!

I just putted this question in the w492 topic but it is a bit old so I start a new one. I want to add input and output gain to this cool project but I'm quite new in electronics so not sure how to do that. Here are the schems http://www.groupdiy.com/index.php?topic=28332.0
To do that, shall I put pots instead of the feedback resistors in the opamps of the ballancing and deballancing stages?
Any help is welcome.

Thanks to all

 

[AUDIO-ON]

Any help with this?

Thanks

 

[signalflow]

I don't think ill be able to help you, but I am curious as to why you want to do this?  Are you not able to control the level from the device you are sending from?

-Casey

 

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Thanks for the reply... I'm feel a bit stupid
I'm learning now electronics and so forgot about the basics...

 

[RuudNL]

To change the sensitivity of the input, you could make R3 (10K) variable. Changing it to 20K will give 6 dB more sensitivity, 5 K will give 6 dB less. To do it properly, you should vary R3 and R4 at the same time with a dual pot. My only objection to the given input schematic is that both legs of the input have a different impedance; the -input has an impedance of 20K, but the +input has an impedance of 30K (R2+R4).
Changing the gain of the output stage is more complicated if you would keep a balanced output. You can't simply change the value of R43 (5.1 K) If you are only interested in an unbalanced output, you could vary the value of R50 (5.1 K) and use the - output.
Or you could add an extra inverting amplifier stage (fixed gain 1x) after the -output to have a variable balanced output. This would then be the new +output.