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I recently picked up a chassis with iron and a couple tubes on it.
There was a 5Y3GT recto tube , a 6J5 metal octal tube and 2 metal can 6SC7's.
Where there were two missing tubes, the sockets were labled 6L6.
Any how, the PT had this what looked like a broken tube socket on top.
At home after removal I concluded it was the remanants of a switch and likely a primary voltage selector.
The cloth leads on this transformer was in awful shape and the insulation would split and fall of when the leads were manipulated.
I removed the bells from the tranny and carefully peeled back the varnish soaked silk tape to expose the connections from the transformer to the leads and replaced the leads with new leads.
After that I replaced the silk tape and varnished them back into place and after that I applied a coat of epoxy as strain relief for the leads.
Reassemled now, I felt safe enough to put some power to the tranny and take my readings. (see attached chart)
These measurments are under no load.
*EDIT* the RED B+ readings were taken to the RED/YELLOW CT wire.
How much of a drop in voltage can I expect to see when I put this under load?
I was hoping to build something with a couple 12AX7's (one as a pre amp the other as a PI) and a couple 6L6GT's in push pull. I'd also like to get about 35 or 40 watts of power.
I know now this might not be possible as the B+ is about 50v too low when the primary tap is selected at the number 5 tap, but if the 1 or 2 tap is selected this might be possible if the heater windings didn't read so high.
Is there a practical way of lowering the heater voltage if I select the higher 1 or 2 tap?
My other quandery...
This chassis had a 5Y3GT recto and powered 3 octal preamp tubes and a pair of 6L6's. This seems woefully inadequate. I would expect to see something more in the line of a 5U4GA
If not, could I use a 5Y3GT to power the amp I would like to use this in with 2 12AX7's and 2 6L6GT's?
There was a 5Y3GT recto tube , a 6J5 metal octal tube and 2 metal can 6SC7's.
Where there were two missing tubes, the sockets were labled 6L6.
Any how, the PT had this what looked like a broken tube socket on top.
At home after removal I concluded it was the remanants of a switch and likely a primary voltage selector.
The cloth leads on this transformer was in awful shape and the insulation would split and fall of when the leads were manipulated.
I removed the bells from the tranny and carefully peeled back the varnish soaked silk tape to expose the connections from the transformer to the leads and replaced the leads with new leads.
After that I replaced the silk tape and varnished them back into place and after that I applied a coat of epoxy as strain relief for the leads.
Reassemled now, I felt safe enough to put some power to the tranny and take my readings. (see attached chart)
These measurments are under no load.
*EDIT* the RED B+ readings were taken to the RED/YELLOW CT wire.
How much of a drop in voltage can I expect to see when I put this under load?
I was hoping to build something with a couple 12AX7's (one as a pre amp the other as a PI) and a couple 6L6GT's in push pull. I'd also like to get about 35 or 40 watts of power.
I know now this might not be possible as the B+ is about 50v too low when the primary tap is selected at the number 5 tap, but if the 1 or 2 tap is selected this might be possible if the heater windings didn't read so high.
Is there a practical way of lowering the heater voltage if I select the higher 1 or 2 tap?
My other quandery...
This chassis had a 5Y3GT recto and powered 3 octal preamp tubes and a pair of 6L6's. This seems woefully inadequate. I would expect to see something more in the line of a 5U4GA
If not, could I use a 5Y3GT to power the amp I would like to use this in with 2 12AX7's and 2 6L6GT's?
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