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In the Forum: Melquiades Amplifier
In the Thread: Planning my DSET
Post Subject: FixedPosted by anthony on: 7/28/2020
Thanks Romy,

It is now fixed.  I have left Channel B the same apart from adding a 390k positive bias resistor on the positive signal line (between C1 and R5) connected to the 14k resistor that also connects to Channel C and F.  A 402k would have been used had it been on hand.

The solution came about by thinking about simple things that Romy could have transcribed when preparing the schematic, and it worked right away.  The beauty of this solution is that changing the attenuation for Channel B (R4) will not alter the bias voltage by much and also there is much less drop across that resistor from the negative signal line.  

Now, all the channels can be set to about -4.3V bias so it is working.

Regards,

Anthony

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