How to bypass volume pot?

Tom-Huffman · 5718

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Offline Tom-Huffman

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on: December 13, 2013, 03:25:47 AM
Do I jump it with a wire or is a resistor required?  I require NO attenuation. If a resistor is needed what is the value and what quality is best?

Also I do not need a 2 input selector since I use it as a power amp.  Is there any sonic improvement bypassing the selector switch?



Offline Grainger49

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Reply #1 on: December 13, 2013, 04:04:26 AM
There has to be a "load" for your source.  Otherwise it sees the grid of the tube.  So a resistor on each channel from the selector switch output to ground would do it.

The value can be 100k, 50k or 20k Ohms.  I think 50k is a good compromise.



Offline Paul Birkeland

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Reply #2 on: December 13, 2013, 04:55:31 AM
When you turn the control all the way up, it becomes a pair of 100K resistors. I would keep the selector switch - this maintains flexibility and resale value for less sonic degradation than you would get between an RCA plug and jack.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Grainger49

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Reply #3 on: December 13, 2013, 10:20:36 AM
I think Paul is saying that the pot turned wide open is like taking it from the circuit.  I'm not positive but this is how I read his post.



Offline Paul Birkeland

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Reply #4 on: December 13, 2013, 10:27:43 AM
Exactly!

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man


Offline Tom-Huffman

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Reply #5 on: December 13, 2013, 03:44:02 PM
So just to make sure, a 100K resistor hard wired between #1 and #2 terminals on  the pot for each channel will be FULL volume?



Offline Paul Birkeland

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Reply #6 on: December 14, 2013, 07:23:15 AM
So just to make sure, a 100K resistor hard wired between #1 and #2 terminals on  the pot for each channel will be FULL volume?

You can substitute resistors for the volume pot.  If you turn the pot all the way up, you will make it into a pair of 100K resistors. 

If you start putting resistors across pot terminals, you will change the behavior of the pot, but not in any real useful way.

Paul "PB" Birkeland

Bottlehead Grunt & The Repro Man