[DecibleDude]

 possible? If I wanted the gain pot to be stepped in order to maintain precise channel balance is that something that could be done without changing the sonic attributes of the preamp, which are already exemplary. I can foresee a possible problem with the remote control working on it, but are there other things that would make this impractical? If it is possible is it something AVA could do. I can live with things as they are, but being a stickler for precise channel balance it would be nice to know that the option is there even if I don't ever bother to do it.

[DecibleDude]

 I have a second question. How is it possible to have 140 views and not a single reply?

[glynnw]

Thinking along the same vein, I am having a preamp modified by changing the volume control to a Tortuga unit.  Great sound, remote volume and balance.

[SteveFord]

Now you're up to 214 views!

I'd contact AVA, if they're not interested send a PM to AVnerdguy, he's pretty familiar with AVA gear.

[Mithat]

Hi,

Jim and the rest of the crew have been tied down with Axpona since Thursday. Please don't consider what follows regarding the level of support AVA can offer as an official reply. It's just a stopgap one until someone else can tell you something definitive.

A potentiometer with detents (i.e., steps) from the same or similar family of potentiometers will track no better or worse than one without -- which is what I think you're after. The mechanism that adds the physical stops is independent of what that does the electronic potentiometering. Swapping out the Vision SLR's continuous motorized pot for an equivalent one that has detents will only get you repeatable positions, not an upgrade in tracking specs.

What it sounds like you're looking for is either a precision stepped attenuator or a specialized potentiometer that guarantees the level or tracking precision you feel you need. Electronically, a specialized potentiometer or a stepped attenuator configured as a potentiometer with the same resistance as the original shouldn't impact the Vision SLR's performance.

However, physically making such a swap in a Vision SLR or Fet Valve CFR would be close to impossible without custom PCBs or similar work, assuming there's enough clearance to accommodate the replacement part. The situation in our the RB chassis is a little better, making it not impossible but just very impractical.

In either case, I don't think this kind of "custom shop" service is something AVA is able to offer at present. That said, I'll let Jim or someone else give the final word once they've recovered from their Axpona adventures.

-Mithat

[DecibleDude]

Thank you for the reply. I suspected it might not be practical, but wanted to find out just to be sure, because for me this less than exact channel balance is the preamps only weak point. Of course it's far from the only preamp using this type of pot, but having a touch of ocd it bugs me if I can detect a volume imbalance between the two channels.  Luckily at higher volumes it's not detectable and I typically play fairly loud.

[jimava]

Thanks for the question, and Mithat for answering in our absence. We had a marathon weekend and are just getting back online and dug out. Yes to Mithat's response. Each of our offerings is engineered to work with the components we specify, and modifications, nearly at any price, are not feasible for our operation at this time.

Thanks
Jim

[peter4jc]

Thank you for the reply. I suspected it might not be practical, but wanted to find out just to be sure, because for me this less than exact channel balance is the preamps only weak point. Of course it's far from the only preamp using this type of pot, but having a touch of ocd it bugs me if I can detect a volume imbalance between the two channels.  Luckily at higher volumes it's not detectable and I typically play fairly loud.

Help my ignorance, please... you're saying the volume control is affecting channel balance?

[DecibleDude]

Help my ignorance, please... you're saying the volume control is affecting channel balance?

 Yes, even though the pot used is a good quality one of it's type it doesn't maintain precise channel balance and can be off a couple or more db's. There are other kinds that do maintain more exact balance between the channels. It's usually only noticeable at low listening levels, but still annoying for some folks like me.

[peter4jc]

Interesting... thanks for clarifying.  I've never heard of that.

But I can relate to channel imbalance.  When I stream the L/R is perfect.  When I listen to vinyl, it's off just enough to drive me batty if I let it.  I think it's a combination of cartridge imbalance (within spec, but still) and that much orchestral music has more on the left.

[Dart87]

My preamp has a fine balance adjustment in it's phono preamp settings.  The manual refers to small cartridge imbalance being a common condition.

[DecibleDude]

My preamp has a fine balance adjustment in it's phono preamp settings.  The manual refers to small cartridge imbalance being a common condition.

 Yeah, back in the early eighties I had an APT Holman preamp which had that feature and in fact I think it was the first preamp to have it. In practice it was a pain though because it would seem to migrate from the balance I set to something else. Eventually I asked the company to remove the feature which they did without reservations, and I was happier not having to constantly readjust the cartridge balance. I suspect it might have been vibration that caused it to go out as I played my Rock music very loud in those days as one does in their Twenties.

[Tone Depth]

My early preamps all had a balance control knob, I used it to approximate balance based on where I was sitting relative to the speakers. Unless you are listening in mono, it is difficult to discern a balanced stereo signal reaching your ears from your left and right speakers.