Dana's VVR questions

[iknowjohnny]

i have a schematic for this and i'm going to put one together this week hopefully. But i saw something that suggested this will not work for amps over somewhere around 35 watts. Not sure what that would matter, as i would think it's the B+ voltage that matters. in any case, i have a cathode biased 2xEL34 amp and i want to know whether i can use this VVR with it. I also want to know how i would wire it differently if i wanted only the PA to be regulated. i tried to access the SEwatt forum but all of those forums are down for the last few days. Any help/suggestions would be appreciated.

[UR12]

Friggin server debug error again, double post.

[UR12]

i have a schematic for this and i'm going to put one together this week hopefully. But i saw something that suggested this will not work for amps over somewhere around 35 watts. Not sure what that would matter, as i would think it's the B+ voltage that matters. in any case, i have a cathode biased 2xEL34 amp and i want to know whether i can use this VVR with it. I also want to know how i would wire it differently if i wanted only the PA to be regulated. i tried to access the SEwatt forum but all of those forums are down for the last few days. Any help/suggestions would be appreciated.

Yes to everything. Yes you can use it on amps up to 50 watts. We have actually installed on on an amp with an extra heatsink putting out 60+ watts but I don't recomend it. I think wat you read was that amps over 35 eatts MAY need an extra heat sink. The VVR can be used to regulate the voltage on the whole amp , just the power tubes or anything in between. You need to add a couple of diodes if you just regulate the power tubes to keep the regulated section isolated from the unregulated section.

[iknowjohnny]

Thanks. I guess i would try the entire amp scenario at first since i'm not sure how to implement the power section only. Maybe that will be fine as is, tho i figured for a amp with a high gain pre the PA scaling only would be best. In any case, could you tell me if the schematic below is correct? and also, would simply adding a SPST switch to short the B+ in and B+ out wires together be the right way to bypass the VVR entirely? Stupid question, i know. But i don't like taking the chance i may have spaced when i determined how to do something that deals with B+ power !

[img:378:353]http://i24.photobucket.com/albums/c39/dazco/VVR.jpg[/img]

[FunkyE9th]

I've seen it with a 6V zener. Actually, I use a 6.5V zener. It's supposed to set the current limiting. I'm guessing it was increased to a 12V zener to cover a wider range of amps?...more current before you hit the threshold of the zener and the FET shuts off?