reswot
Active member
- Joined
- Jan 22, 2004
- Messages
- 3,295
Hey, all...
I built a BF Vibrolux Reverb clone last week and am having a couple of issues with it.
It (mostly works) and sounds good, but there are two issues. The first is that it's just not as loud as it should be. It's not as loud as my blackfaced 70 Deluxe Reverb, but close. The second is that the vibrato doesn't work.
I've checked all of the voltages from the schematic and layout and, except for one tube (the vibrato tube), they check out within spec -- just a few volts higher than the schematic, due to higher wall voltages. The only discrepancies are on the plates of V5: the schematic shows 350v on pin 1 and 405v on pin 6. I get 360 on pin 6 and 415 on pin 1. I actually don't under stand how the voltages could be what the schematic says, as both plates are fed by the same B+, and pin 6 is fed from a 10M resistor and pin 1 is fed from a 220K resistor; I would expect that voltage would be dropped more at pin 6, correct?
Besides that, the voltages are correct everywhere.
I can see the light flashing on and off in the roach, so I don't suspect that's the problem. I'm getting continuity at all of my connections. I've changed the vibrato tube several times (a new Tung-Sol, two NOS GEs, and one old RCA longplate); none made a difference. Besides the light, I can sometimes hear a faint thump when I switch on the vibrato. The footswitch is turning on the circuit.
Any advice on where to look?
I built a BF Vibrolux Reverb clone last week and am having a couple of issues with it.
It (mostly works) and sounds good, but there are two issues. The first is that it's just not as loud as it should be. It's not as loud as my blackfaced 70 Deluxe Reverb, but close. The second is that the vibrato doesn't work.
I've checked all of the voltages from the schematic and layout and, except for one tube (the vibrato tube), they check out within spec -- just a few volts higher than the schematic, due to higher wall voltages. The only discrepancies are on the plates of V5: the schematic shows 350v on pin 1 and 405v on pin 6. I get 360 on pin 6 and 415 on pin 1. I actually don't under stand how the voltages could be what the schematic says, as both plates are fed by the same B+, and pin 6 is fed from a 10M resistor and pin 1 is fed from a 220K resistor; I would expect that voltage would be dropped more at pin 6, correct?
Besides that, the voltages are correct everywhere.
I can see the light flashing on and off in the roach, so I don't suspect that's the problem. I'm getting continuity at all of my connections. I've changed the vibrato tube several times (a new Tung-Sol, two NOS GEs, and one old RCA longplate); none made a difference. Besides the light, I can sometimes hear a faint thump when I switch on the vibrato. The footswitch is turning on the circuit.
Any advice on where to look?
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