steve_k
New member
I didn't realize how much a few volts AC input would affect DC output. When I got my Naked delivered and plugged in, popped a fuse, plated a tube and was stumped. Was back and forth with Dave and he kept saying it had to be the power supply a I was checking all the pinout voltages and everything seemed to be there, just high on pin #3. I was getting 520V at the plates and that particular trannie shouldn't be getting that much. I should have been seeing around 480-490V. We are on US current over here, but a little elevated. It runs anywhere from 117V-128V and it may be a result of the Hz being somewhat unsteady. Anyway, I always use a Furman voltage regulator and thought it was keeping me at a constant 110V like the little meter said in front. Whoa....not so. Got the multimeter out and decided to see what that thing was regulating at and it was just as bad as wall current. Sheeeeit.
Anyway, bounced down to an electrical supply place and got an industrial strength, high capacity voltage regulator/frequency stabilizer and put wall current to it. Checked it with the DMM and got a steady 110V AC coming out of it with loads of current capacity. Running the Furman into it now and basically using the Furman for a power strip in the rack, when used. Plugging everything in through a Furman power strip on the pedal board now and out to the regulator.
Now, I got to go back and re-bias several amps. Been biasing against excess PV due to high input voltages. 10-15V AC on the input side will get you 20-30, almost 2:1 on the output side to the plates. I think this is why I was having a hell of a time with JJ's and popping them fuckers like popcorn. SED's seemed to be the only 34 that I could keep in an amp.
So............lesson learned. Don't trust the pretty little light meter on your Furman. Confirm the supply voltage with a DMM if you can. Be aware that a few volts variance input will give almost double that on the DC output. Depending on the amp/tube/bias scheme, this could turn frustrating. And, with thousands of bucks worth of amps, investing in a good industrial regulator/stabilizer is warranted. Especially for those of us living overseas or other places with dodgy electrical works.
Thanks again Dave for staying on it that weekend. Spot on dude.
Steve
Anyway, bounced down to an electrical supply place and got an industrial strength, high capacity voltage regulator/frequency stabilizer and put wall current to it. Checked it with the DMM and got a steady 110V AC coming out of it with loads of current capacity. Running the Furman into it now and basically using the Furman for a power strip in the rack, when used. Plugging everything in through a Furman power strip on the pedal board now and out to the regulator.
Now, I got to go back and re-bias several amps. Been biasing against excess PV due to high input voltages. 10-15V AC on the input side will get you 20-30, almost 2:1 on the output side to the plates. I think this is why I was having a hell of a time with JJ's and popping them fuckers like popcorn. SED's seemed to be the only 34 that I could keep in an amp.
So............lesson learned. Don't trust the pretty little light meter on your Furman. Confirm the supply voltage with a DMM if you can. Be aware that a few volts variance input will give almost double that on the DC output. Depending on the amp/tube/bias scheme, this could turn frustrating. And, with thousands of bucks worth of amps, investing in a good industrial regulator/stabilizer is warranted. Especially for those of us living overseas or other places with dodgy electrical works.
Thanks again Dave for staying on it that weekend. Spot on dude.
Steve
