Foreplay : unbalanced volume control

[choff]

I have a vintage Foreplay (II?) built back in 2003.  It has always had a slight offbalanced sound between the left and right pots (with the left being stronger and having sound at 7pm position while the right will have none).  I then installed the Sweet whispers a few years back and this actually made the difference even more noticable with the stepping effect. 

I've always done my best to ignore the problem as it is slight but lately have been eager to try to get it corrected.  Any ideas on sourcing out a fix to this issue?  Thanks.

 

[Grainger49]

Have you swapped the tubes to see if it follows the tube?  Same thing for swapping inputs and outputs, one at a time, to see if it is the Foreplay for sure?

By the way, I have a FP 2 and my volume controls are never exactly matched.  But then each recording has a different point for a centered vocalist in my system.  If I HAD to have my vocalist in the center I would adjust the volume controls for each disk, possibly each song. 

I'm pretty sure it is not the system but my system showing me the lack of dead center that is recorded on each disk/LP.

That is not to minimize your wish for a balanced system.  Have you looked into remote volume and balance controls?  It would save you a lot of jumping up, walking across the room, adjusting, returning to your listening seat, and finding that it still isn't balanced.  Yes, I used to do that but then got old and lazy.

 

[choff]

I have swapped tubes many times and have had it running to different amps and always have the same issue.  Again,  the left side always starts with volume before the right side at the lowest setting no matter what the source or recording. 

Didn't know you could do a remote volume control with a Foreplay....that would be nice.

 

[Grainger49]

Ok, what you are describing is that the right and left channel mono pots do not track exactly the same.  (I forgot you said you had the Sweet Whispers)  The worst part of a volume control is usually the lowest part or where it starts.  You can replace them with a higher priced pot pretty easily.  I would suggest a pair of Alps 50k mono pots from Mouser.  (You don't need this as PJ says below the SW are 1% and should track perfectly, well better than you and I can hear.)

IIRC, and I may not, Bent Audio had a couple at VSAC 2008 that had balance functions.  Try Bentaudio.com.

 

[Paul Joppa]

It seems likely that there is an error in the Sweet Whispers wiring or the series resistor if you are using the -20dB version. Check the resistance to ground at each switch terminal, comparing side to side.

If they are identical (they are 1% resistors) then as long as you are there, also check the circuit resistances as described in the manual. If they are also correct, better fire it up and check all the voltages. These checks are to make sure there are no side to side differences in the circuit.