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Amp with Batteries in it?
- Thread starter Jimbo165
- Start date
The only thing that comes to mind is that the batteries are a work-around for one of the tube voltages.
RX cut-off bias maybe? No idea why the batteries. The batteries would not be able to power the filaments at all due to current and 36 volts is not high enough for the plates although there were tubes made that would run with 12 volts on the plates. I know it has SO-239 jacks on it but it does not really look like it was meant for RF. Audio maybe? What kind of tubes are in it and can we see more pictures of the other side?
Dont feel bad I did the same thing at first glance until I looked to the far left and seen 4 x 9 Volt batteries.......
36 volts is an odd voltage to run the coils on the relays, most are 12.
I have seen 36 volt relays in a industral forklift chargers but not any in an amp.
maybe it is RX cutoff, can not tell were the wires are going.....but it sure looks like.......
Damn it the 36 volt transformer took a crap and I do not want to replace it.......need to sell this thing.
I know, i will wire 4x 9 volts in series ...... I know they wont last long but it will be sold by then
73
Jeff
I have seen 36 volt relays in a industral forklift chargers but not any in an amp.
maybe it is RX cutoff, can not tell were the wires are going.....but it sure looks like.......
Damn it the 36 volt transformer took a crap and I do not want to replace it.......need to sell this thing.
I know, i will wire 4x 9 volts in series ...... I know they wont last long but it will be sold by then
73
Jeff
Think you hit the nail on the head. This I have seen before. Most likely an add on circuit.
Looks like too many hands have been inside this amp. The batteries were probably installed because there was no negative bias supply in the amp. The amp is grid driven but bias is applied through the cathode. Notice the three yellow cathode bypass caps on a pins 2? They have all been arced over with black marks on them because the cathode was allowed to float well below DC ground when someone connected the purple bias wire to pin 1 rather than pin 2.
The batteries are not needed here and do not have a low enough internal impedance to stabilize the bias voltage anyhow. The zener or a zener with a transistor buffer is a much better way to establish cathode bias here. Bad news is if the voltage on pins 2 was enough to arc the caps, it could have easily damaged the tubes too.
The batteries are not needed here and do not have a low enough internal impedance to stabilize the bias voltage anyhow. The zener or a zener with a transistor buffer is a much better way to establish cathode bias here. Bad news is if the voltage on pins 2 was enough to arc the caps, it could have easily damaged the tubes too.
Did you mean your "other" left? I'm confused.
I WAS STANDING ON MY HEAD!! GEEZE!! LMAO!!
Ok so the upper right I beleive it was without looking again but if Im wrong then hook me to a vehicle emergency jumper pack that should straighten me out today
I WAS STANDING ON MY HEAD!! GEEZE!! LMAO!!
Ok so the upper right I beleive it was without looking again but if Im wrong then hook me to a vehicle emergency jumper pack that should straighten me out today
Forget the jump starter pack. This is more like it.
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