balanced volume control

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
How can I make a volume control with one pot (or attenuator?) for both channels of bosoz running balanced (now im using two 5k stereo pots of not so good quality)?
I searched forum but I didnt found answer to this question or It was there and I didnt interpreted it right so im sorry if that has been talked before.
 
Instead of placing the pot between output and ground (4 needed) place the pot between positve and negative output of ea balanced channel (2 needed), so one stereo pot would work. This way, depending on impedance of the pot, positive and negative output will cancel each other without conecting to ground. You can find this setup in Pass D1 DAC.
 
You can use Peter's idea but be aware that it can change the character of the circuit. Look at the original BoSoZ article. The distortion is related to gain, and using a pot between the two sides of the circuit changes the gain.

On my BoSoZ I used a four-deck stepped attenuator from GoldPoint.
 
Peter,

Is that option for a stereo pot in the BOSOZ schematic as well? I seem to remember that being built in to the design.

Any idea on what resistance value to put there? Any pro/cons to doing it this way?

I am thinking now of getting an Electroswitch 4-pole 23 position switch and making a 5-10 kOhm attenuator and putting it at the output, seeing as all the IC-based pots have built-in opamps, or require an opamp.
 
jwb said:
You can use Peter's idea but be aware that it can change the character of the circuit. Look at the original BoSoZ article. The distortion is related to gain, and using a pot between the two sides of the circuit changes the gain.

On my BoSoZ I used a four-deck stepped attenuator from GoldPoint.

The gain pot is the separate pot. The pots I'm talking about are at the output.
 
Is that option for a stereo pot in the BOSOZ schematic as well? I seem to remember th

I don't think it was discussed in the original article. What I'm suggesting here is a quite clever way of using single stereo pot to control balanced stereo output. I can only see pros (since pots don't even have to be matched perfectly) and none of the cons. Yet, this method is not very popular with DIYers, anybody knows why?:scratch2:
 
The one and only
Joined 2001
Paid Member
We used a pot across the balanced output in the
DAC, as described by Peter. It works fine except that
it won't give you absolute zero volume. There is always
some residual output at minimum.

By the way, we bought a pile of those Electroswitch 23
position switches and regretted it. I have boxes of them
if anybody wants to make me an offer.


:bawling:
 
Peter:

Instead of placing the pot between output and ground (4 needed) place the pot between positve and negative output of ea balanced channel (2 needed), so one stereo pot would work. This way, depending on impedance of the pot, positive and negative output will cancel each other without conecting to ground. You can find this setup in Pass D1 DAC.

Is this what you mean?
 

Attachments

  • pot.jpg
    pot.jpg
    44 KB · Views: 3,060
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.