BOSOZ Balanced volume control revisited

[kennethrl]

I was searching the past postings about volume controls and pots locations. In posting #72 the attached drawing was given. I am interested in connecting a pot in the "C" position. However, I am confused exactly how to connect it? Is the connection being shown,is it in parallel or in series?

[jh6you]

Your question is the most difficult one I have ever read here.
Anyhow, Fig.3 on the original article, Balanced Zen Line Stage, in www.passdiy.com answers clearly. There is one pot on the + input side and another on the – input side for one channel. The same will apply for the other channel. So, total four pots for both channels. And, the four look like arranged in parallel.

Regards
jh

[wuffwaff]

Hi,

the balanced pot is connected between the two points shown as a variable resistor (very straightforward).

If you want to use one I would think about position C. This has the advantage that noise is also recuced when you reduce the volume control. I´ve used one just like that for my X-BOSOZ.
It may be neccessary to use a stepped control with resistors because you need very low values and most pots (for stereo) are not matched enough in this area.

William

[Hattori Hanzo]

I suggest you re-read the original BOSOZ paper and look at fig. 3.

Neither of your marked positions represent the original proposed method. Position "A" will work perfectly though but you have to find the right values for all resistive parts of the output network.

[wuffwaff]

just looked at he pic again,

read my C for an A.(at the output)

William

[Fox]

Hi,

I have experimented a lot with various volume control options for the BOSOZ (passdiy) including option C. With option C there was some hiss audible, which was absent when the gates of the MOSFETs were not connected.

Just my 2 cents.

Fox

[kennethrl]

Originally posted by wuffwaff
just looked at he pic again,

read my C for an A.(at the output)

William

Thanks for the replies.... I don't understand the above posting.

So do most people agree that C position would be best for a pot?

[wuffwaff]

No,

the pot should be between the two outputs with two series resistors (around 1k).

There´s a thread somewhere about this that was started by me (X-BOSOZ)

If I find it I´ll post it.

William

here it is: (the last post with the schematic)

X-BOSOZ first tests