Tribute Inductive Volume Control and other TVCs

[luvdunhill]

I'm sorta intrigued by this unit:



anyone know much about it?

Also, anyone heard the AVC TVC units from Diy HiFi (i.e. Django, etc.)

50/50% Permalloy Core Autoformer 28 step (Pair) | Diy HiFi Supply

Of course there is the S&B, Sowter, and Jensen (and probably Lundahl) .. any others to consider? This would be used in conjunction with an active preamp. What is the general consensus of TVC used in this type of situation?

[n_maher]

For me it would still come back to not being satisfied with or willing to risk 28 steps, especially at that cost ($270).

[luvdunhill]

for me, it depends on how the steps are spaced, not necessarily the number of steps... ~2dB may not be enough resolution, granted.

check out the back of the pic posted.

[n_maher]

Originally Posted by luvdunhill

for me, it depends on how the steps are spaced, not necessarily the number of steps... ~2dB may not be enough resolution, granted.

check out the back of the pic posted.

They would appear to be 3db steps for the pictured unit and also only have 24 steps (using the typical elma switch). And my experience with 3db steps leads me to believe I'd be rather unhappy with the level of choice provided regardless of how good it sounded.

[spritzer]

RK50 FTW!!!

[luvdunhill]

Originally Posted by n_maher

They would appear to be 3db steps for the pictured unit and also only have 24 steps (using the typical elma switch). And my experience with 3db steps leads me to believe I'd be rather unhappy with the level of choice provided regardless of how good it sounded.

My hottest source is 2v. I'd assume that the (mostly) 2dB steps on this baby with a 2v source is different "feeling" than having a 5v source...

I'm surprised there aren't more TVC/AVC proponents around here

[deepak]

Originally Posted by luvdunhill

My hottest source is 2v. I'd assume that the (mostly) 2dB steps on this baby with a 2v source is different "feeling" than having a 5v source...

I'm surprised there aren't more TVC/AVC proponents around here

I think a couple of people here tried or owned the Promitheus TVC. I wouldn't mind hearing a good one in a speaker system.

[n_maher]

Originally Posted by luvdunhill

My hottest source is 2v. I'd assume that the (mostly) 2dB steps on this baby with a 2v source is different "feeling" than having a 5v source...

It all depends on the application really, my problem with steppers has always been that they've been on headphone amps designed to drive vastly different loads. That's a bad application in my opinion. In a speaker amp I suppose it would be possible to tailor the gain (assuming it's adjustable in the design) such that you'd have plenty of adjustment. But again with some tube speaker amps (highish gain) I'd be hesitant to invest in one prior to testing the amp with a traditional pot to see where the listening sweet spot was.

[luvdunhill]

Originally Posted by deepak

I think a couple of people here tried or owned the Promitheus TVC. I wouldn't mind hearing a good one in a speaker system.

Do you know what transformer he uses? Assuming it's the same guy at DiyA, he's a nice guy ..perhaps he'd tell me

[luvdunhill]

Originally Posted by n_maher

It all depends on the application really, my problem with steppers has always been that they've been on headphone amps designed to drive vastly different loads. That's a bad application in my opinion. In a speaker amp I suppose it would be possible to tailor the gain (assuming it's adjustable in the design) such that you'd have plenty of adjustment. But again with some tube speaker amps (highish gain) I'd be hesitant to invest in one prior to testing the amp with a traditional pot to see where the listening sweet spot was.

I think 2dB inductive attenuation is much finer than resistive attenuation, but I have nothing to back that claim up other than voodoo magic.

[deepak]

Originally Posted by luvdunhill

Do you know what transformer he uses? Assuming it's the same guy at DiyA, he's a nice guy ..perhaps he'd tell me

I don't know. aerius might, I think he was one of the first people to mention them around here. It might be the Bent Audio one and not the Prometheus.

[aerius]

I haven't heard the Prometheus or DIY Hifi transformers yet, and I don't know anyone around here who has one. I've heard the S&B TX102, a Dave Slagle AVC, and a couple Tribute AVC's. Tribute & Slagle will both do custom jobs, if you need different spacing between steps, inductance values or whatnot, they can do it.

My personal favourite is the Tribute followed by the Slagle, the Tribute sounds like it has a wider bandwidth, more details, more speed, more goodness. Kinda like hearing DHT's for the first time but not quite that dramatic, but it's the same idea. The Slagle is no slouch itself, the difference between it and the S&B is the same as going from the Tribute to the Slagle.

I don't know how much of a difference you'd notice on a typical headphone system, most of the listening was done on a custom open baffle speaker rig using Lowther and Beyma drivers with a Heil tweeter.

[luvdunhill]

Originally Posted by aerius

I haven't heard the Prometheus or DIY Hifi transformers yet, and I don't know anyone around here who has one. I've heard the S&B TX102, a Dave Slagle AVC, and a couple Tribute AVC's. Tribute & Slagle will both do custom jobs, if you need different spacing between steps, inductance values or whatnot, they can do it.

My personal favourite is the Tribute followed by the Slagle, the Tribute sounds like it has a wider bandwidth, more details, more speed, more goodness. Kinda like hearing DHT's for the first time but not quite that dramatic, but it's the same idea. The Slagle is no slouch itself, the difference between it and the S&B is the same as going from the Tribute to the Slagle.

I don't know how much of a difference you'd notice on a typical headphone system, most of the listening was done on a custom open baffle speaker rig using Lowther and Beyma drivers with a Heil tweeter.

Thanks! were the AVCs wired for gain, or were they used passively, or in front of a preamplifier? I cannot seem to find pricing on the Tributes, so I've e-mailed them...

[aerius]

They were used passively in front of the power amps. It was source(s) ---> AVC box ---> power amps ---> speakers.

[luvdunhill]

Originally Posted by aerius

They were used passively in front of the power amps. It was source(s) ---> AVC box ---> power amps ---> speakers.

Any reason a TVC couldn't be used between a preamp and the amplifier itself? Kinda backwards thinking I suppose ... but it solves the SE -> Balanced problem that AVCs have to deal with...

[Fing]

I have a Promitheus TVC (Reference C-Core) but haven't really done much listening on it since its in my speaker system. First blush impression is that its not a good match with my existing system - a bit subdued and boring.

I need a better source and speakers but headphones suck all my cash.

[luvdunhill]

Originally Posted by Fing

I have a Promitheus TVC (Reference C-Core) but haven't really done much listening on it since its in my speaker system. First blush impression is that its not a good match with my existing system - a bit subdued and boring.

I need a better source and speakers but headphones suck all my cash.

Fing:

Are you looking to sell your TVC? I might be interested Although, I contacted Nickolas and he's willing to sell me the balanced TVCs naked for DIY use

[aerius]

Originally Posted by luvdunhill

Any reason a TVC couldn't be used between a preamp and the amplifier itself? Kinda backwards thinking I suppose ... but it solves the SE -> Balanced problem that AVCs have to deal with...

Possible signal overload depending on the output of the preamp. The Tribute is spec'd for 6V RMS and I don't know what the specs are for other inductive volume controls, so it's possible the output from a preamp can overload them.

[luvdunhill]

Originally Posted by aerius

Possible signal overload depending on the output of the preamp. The Tribute is spec'd for 6V RMS and I don't know what the specs are for other inductive volume controls, so it's possible the output from a preamp can overload them.

I thought about that, I think that's a limitation to the AVC approach but not the the TVC approach. However, I found a 50/50% Permalloy and Z11 core that would not have the same saturation issues as a 100% Permalloy unit. I have an e-mail off to the manufacturer, so we'll see what he says. Since my power amp has no voltage gain, I think I may very well run into this issue.

[aerius]

Both AVC and TVCs will run into saturation issues, as I understand it it's a function of the core material and not the single vs. dual windings. That's why 100% permalloy is found only in small signal applications and not in output transformers.