vvr3 unit question

[toskrlec]

Hi, I would like to build in vvr3 from Hallamplificatin in my express, have someone any experience with some issues or reliability problems with unit, is it smart to bulid bypass switch, so if unit fails you can bypass it ?

Thanks

[UR12]

Personally, I have them in my 2 channel inspired amps (Rocket/Liverpool) that gets played 4 - 5 hours continous every Sunday for the last 2 years without a failure. I have also installed them in a few Expresses over the last couple of years and have never had any reported problems. Of course you may consider my opinion a little biased but it is what it is. I install them in every amp I build.

If you wanted to install a bypass switch there should be no problem with that either.

Dana Hall
Hall Amplification

[Structo]

Isn't the VVR essentially out of the circuit when the pot is turned all the way up?

[Gargoyle]

I had one installed in my Express Clone, liked it so much I have one going in my DC30 Clone.....

[Gargoyle]

oops double post

[Structo]

Did you scale the whole amp or just the PA?

[Gargoyle]

I scaled the whole amp on the Wreck.
I don't know anywhere near as much as you guys regarding amplifiers, and I may be way of base, but I figure by scaling the whole amp it kinda maintains the status quo in terms of pre/power interaction.
Cheers Mick

[rfgordon]

I just put my first VVR3 on a baby Trainwreck Rocket I'm building for a guy. At first I scaled the whole amp, but didn't like how it really lost its high end. So then I just scaled the PI and the duet of EL84s.

One thing to keep in mind if you scale the PI/power tubes, as you dial back the VVR, the HT will increase on the other preamp tubes by 10 to 20 volts, due to the reduction in current draw on the power supply. In the case of this amp, that's a good thing, since an increasing preamp plate voltage improves high end response, which makes the amp maintain clarity as the power is dialed back.

The amp is going to a strat player whose wife constangly nags him about playing too loud....

[Structo]

Interesting, that makes sense about the top end.
Same kind of principle behind a treble bleed on a guitar volume pot.
Maintain the high end as you turn down.

As for the wife, I think she will still be annoyed.

[rfgordon]

>> "As for the wife, I think she will still be annoyed."

No doubt--particularly when he pays off the balance he owes me!

Sometimes I feel like a crack dealer--enabling other peoples G.A.S. In this case, I haven't even delivered this amp yet, and the guy's already talking about having me build another one!

[KellyBass]

I recently installed one on an express clone I built for a local player. I ended up scaling the whole amp. The few minutes I got to spend with the amp before he carted it off to a gig, I was very impressed with it. He did call later and tell me that his volume knob is a little scratchy, so I guess I've got a little DC coming back. I'll just install the grid cap at some point.

I think the hardest part was eductating the player about it's use..."Hey!, this isn't a volume pot"!

[Gargoyle]

I can understand the "losing the topend" thing. I found this does happen when scaling the VVR right down. However I don't use it below half way so hadn't really experienced it much.

[Tonegeek]

I adapted a VVR to my 18 watt BN kit (EDIT: other way round actually, I adapted the amp to accept the VVR). I tried scaling the whole amp but the best sound was obtained just scaling the power amp. it helps to also use a post PI master in this application as it gets buzzy as you turn down the wattage without also limiting the drive out of the PI. I love it.

[Structo]

Would a bright cap across the VVR pot help with the loss of treble?
Or is that strictly a power supply mod and no effect on the signal?

If so, maybe a bright cap somewhere in the path would help preserve the highs.

[UR12]

Would a bright cap across the VVR pot help with the loss of treble?
Or is that strictly a power supply mod and no effect on the signal?

If so, maybe a bright cap somewhere in the path would help preserve the highs.

Strictly power supply.....no signal