VVR Issue

[HeeBGB]

Ok so I installed a VVR into my rocket combo build last night. Did the checkout with just the rectifier tube in place. Looks good. 410VDC coming off the rectifier. About 408 from the VVR board with the VVR pot all the way up. With the VVR pot all the way down I get about 42VDC. Perfect!......until I install the power tubes. Max voltage at this point is now about 270. The VVR is stock and works with the power tubes pulled. It was late and I haven't had the chance to go any further. Gonna get to it either tonight or over the weekend.

Any ideas? The VVR is installed before the standby switch

[martin manning]

The first thing I'd do is find out whether the voltage drop is occuring before or after the VVR.

[xtian]

Which VVR? Hall, London, other?

[matt h]

(deleted)

[Colossal]

Assuming the Hall type (only because I know nothing about KOC's design, but it's probably the same), I do believe (and am happy to be wrong) the VVR needs to be placed downstream of a filter cap. Anyway, the primary ct, the recto diodes, and the first filter cap ground all need to be upstream of the VVR for it to function.

Definitely. There needs to be a cap in front of the VVR.

[HeeBGB]

OK Had to work late tonight. Just got a chance to look it over a bit. I removed the VVR and the issue still happens so I must have done something else. It will have to wait for the weekend. I will keep you all posted on what I find. This WAS a working amp before I tried the VVR install.

[sliberty]

And I am sure that it will be a working amp again soon. Good catch. Its always best to know what to look at so that you don't spin your wheels.