Separate Left & Right Volume Controls

sure, if you want better channel seperation and/or like to have the option of adjusting left/right volume without adding a seperate ballance control. Besides you get a few more types (of pots) to chose from.
The only hastle is adjusting the volume with the two channels following properly. It requires the two pots mechanically linked, no big deal, but adds a bit in building complexity.
Hello PTL60,

I had a power amp with Alps laser trimmed stepped 21 position vol pots on front panel.
The attenuation was 0dB at full clockwise rotation (with CDP connected directly this gave only momentary and inaudible clip),
coming down in 1 dB steps to -20 dB, then mute.
This provided a stunningly transparent system, with the volume level perfectly settable and repeatable in 1 dB steps.
Separate infinitely variable pots are a straight out pain, but a pair of stepped attenuators works great ! :)
The big advantage here is that you have close matching of L&R gains, and this is quite critical for correct imaging.
It is too hard to set the gains easily with L&R pots, and most dual pots give pretty lousy L/R channel matching.

Hope this helps you,
Regards, Eric.

BTW - despite what some old textbooks say, a level change of 1 dB is perfectly clearly audible.
Hello PTL60,

Thanks for the info. I've heard about stepped attenuators, but aren't they quite expensive?
The ALPS stepped vol pots are not too expensive, but yes some DIY attenuators using high quality rotary switches and Holco or Vishay resistors can end up pretty pricey .
Of course this comes down to a value judgement, regarding your audio system.
I do not have much experience with rotary switch stepped attenuators, so other constructors on this forum may have some better knowlege and comments on these.
The key factor in all of this is close channel matching, and this is the only proper way to get it.

Hope this helps,
Regards, Eric.


2002-01-07 6:02 pm
Hey Eric,

Do you have a source/model number for the Alps? I didn't think they made these any more. I used some maybe 20 years ago, and if suitable values are available at a good price could be useful for a couple of projects I have running.