vvr on my Blackstar

[andrewt]

Hello all, new member here (a different Andrew than the other Andrew asking about a vvr); I just found out about the Hall vvr and this forum seemed to have the most discussion/knowledgeable people.

I'm considering installing a vvr in my Blackstar HT-5. (I know this forum is mostly about custom amps, but hopefully you can humor me) I just have basic electronics knowledge, but I think I'm up to the job after my experience getting a 1935 Hammond model A running.

I play guitar in pit orchestras for musical theatre, so I need to be able to change volume instantly while I'm playing, without losing my tone. I think my ideal solution would be a FluxTone speaker, but that's way out of my budget.

Is it possible to operate the VVR via a foot controller, like a volume pedal? How would this be done? I assume you wouldn't the B+ voltage going through a footswitch, right?

I emailed Hall about this as well.

[Reeltarded]

Hey! All amps are fair game here.

No go on a foot controller unless you use a motorized pot, me thinks. Spendy and not always nice for very long.

Here is a terrible idea I would never mention; volume pedal in your loop.

Dunno..

[John_P_WI]

You might want to email Kevin O Connor. Check out his website @ Londonpower.com A few years ago he had a power scaling kit that you could use an expression pedal with, I don't see that kit any more but his new SV kits only have 60 V on the pots. Send him an email and ask if it will work.... You will have to scale the whole amp IF you use a foot pedal, otherwise you will overdrive the output too much.

[andrewt]

Thanks guys. I have thought about putting a volume pedal in the loop, but I normally have the clean channel cranked (perfect volume for my situation) and I'd like to keep that compressed sound (just on the brink of distortion since I swapped the preamp tube for a 12AT7) when I have to play softer. I also believe I remember reading that the FX loop in my amp is serial (or parallel, forget which) and therefore a volume pedal wouldn't give the desired effect--does that sound right?

I saw one of the Fluxtone videos on youtube and they have an optional foot controller; I wonder how that works...

I've seen the London Power website, and I'll send Kevin an email; I wouldn't mind paying more for something foot controllable.

[xtian]

The Hall VVR does not "instantly" change volume, FYI, because of the reservoir caps. When I twist my VVR knob quickly, the volume changes level much more slowly, over two to three seconds as the filter caps charge or discharge.

[andrewt]

The Hall VVR does not "instantly" change volume, FYI, because of the reservoir caps. When I twist my VVR knob quickly, the volume changes level much more slowly, over two to three seconds as the filter caps charge or discharge.

Good to know! Have you any idea if the London Power unit behaves similarly?

[xtian]

No.

[John_P_WI]

The Newer London Power boards do not suffer the lag, I have used them in channel switching applications from no scale to scale mode, although I have not scaled the whole amp in this application, only the power tubes. I also used a voltage clamp on the PI and Pre to maintain a constant voltage and to limit tonal change. Once again, this was not a "whole" scaled amp. I believe Kevin's TUT 6 details the newer (a few years ago) power scaling circuits.

[Structo]

How about a volume pedal in the loop.

Does your amp clean up if you ride the guitar volume?

[andrewt]

The Newer London Power boards do not suffer the lag, I have used them in channel switching applications from no scale to scale mode, although I have not scaled the whole amp in this application, only the power tubes. I also used a voltage clamp on the PI and Pre to maintain a constant voltage and to limit tonal change. Once again, this was not a "whole" scaled amp. I believe Kevin's TUT 6 details the newer (a few years ago) power scaling circuits.

Interesting... I'd like to know more about your channel switching setup--how did it work?

Structo--I have it setup now so that if you dime the clean channel it's just at the edge of breakup (which is the sound I'd like to preserve) and I use the overdrive channel for distortion. If your thought was to use the guitar volume to control distortion, I'm often required to switch from clean to distortion with no time in between, which is why something foot controlled works best.

[John_P_WI]

It was possible to have the the "older" SB kits controlled with 2 pots and a mechanical relay, allowing the settings to be channel selectable. I am sure there is a simpler way defeat the power scaling for a "scaled" and no scaled option, but I have no experience with his NEW "SV" kits and don't feel that I should comment on their operation. I would expect that Kevin's new kits are even more flexible as he is the master of "options" and switching would be a simple option.

Edit: Looking at his site the new SV kits are flexible too:

I would encourage you to read here:

http://www.londonpower.com/catalog/index.php?cPath=7

And ask Kevin directly.....

[Richie]

The Hall VVR does not "instantly" change volume, FYI, because of the reservoir caps. When I twist my VVR knob quickly, the volume changes level much more slowly, over two to three seconds as the filter caps charge or discharge.

Good to know! Have you any idea if the London Power unit behaves similarly?

I don't think any of them,whatever kind was intended for useing like a foot operated on the fly master volume type thing.
Most all of these change the voltage of the tube or tubes and maybe bias too depending on how thats all set up.Or to set the level of volume needed or wanting to use.
I could be wrong, but i think they are more like an attenuator would be, to set it at the volume you want to use.
I just don't know how happy tubes would be in voltages changing like that.
I guess like a tremolo..
I just don't see how the tubes could react to something that fast.