=265 * 390 / 325
=318
That is what I get.
Are you going to replace all of the capacitors at the higher voltage rating?
Will there be any resistors that need replacing with higher power dissipation ratings?
Will the output transformer be able to handle the increase in power?
Are the output tubes able to handle the increased voltage/power?
Are the interstage tubes going to operate at a higher voltage as well?
Just asking in case you have not thought about it.
=318
That is what I get.
Are you going to replace all of the capacitors at the higher voltage rating?
Will there be any resistors that need replacing with higher power dissipation ratings?
Will the output transformer be able to handle the increase in power?
Are the output tubes able to handle the increased voltage/power?
Are the interstage tubes going to operate at a higher voltage as well?
Just asking in case you have not thought about it.
First of all, it would be good to know your amp.
Do you want to increase B+, but leave the power tubes' bias idle current the same? That simplifies things a bit.
The rectification is full wave with centre tap. 265 VAC gives 375 Vpeak, and you get 325 VDC.
So 50 volts are lost in the way. If you made an (awfully) crude assumption that idle current is same, and so will be the losses of the new transformer, then you need 390+50=440 Vpeak, which means about 310-0-310.
The above is absolutely incorrect in absolute terms. But gives you a rough estimate in case you want to buy an off-the-shelf, existing model of power transformer.
If you want real calculations, tell us the amp (at least the power tubes), measure mains when B+ is 325 VDC, estimate the regulation of the new transformer (ask the manufacturer, in other terms), give information on the VA rating of the old one etc.
Do you want to increase B+, but leave the power tubes' bias idle current the same? That simplifies things a bit.
The rectification is full wave with centre tap. 265 VAC gives 375 Vpeak, and you get 325 VDC.
So 50 volts are lost in the way. If you made an (awfully) crude assumption that idle current is same, and so will be the losses of the new transformer, then you need 390+50=440 Vpeak, which means about 310-0-310.
The above is absolutely incorrect in absolute terms. But gives you a rough estimate in case you want to buy an off-the-shelf, existing model of power transformer.
If you want real calculations, tell us the amp (at least the power tubes), measure mains when B+ is 325 VDC, estimate the regulation of the new transformer (ask the manufacturer, in other terms), give information on the VA rating of the old one etc.
It's a trainwreck guitar amp. I currently have a 265-0-265 pt in the circuit all b+ voltages are low. I have 325 on output b+ and want 390. I had a 320-0-320 pt and voltages were to high by 25 vdc. I'm thinking 300?
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Guitar amp threads should be posted to Instruments and Amps forum. This thread moved.
It's a clone and I attempted dropping resistors and zeners with unfavorble results.
I actually like the distortion on a lower voltage but can't get as much clean as I want and more annoying is a buzz in my speaker follow higher notes particularly a and b notes on g and b strings. Must be high freq osc less noticeable on higher strings. I'm still playing with dress leads I can post a pic under the hood? Perhaps someone here can chime in and notice something
Why not just use the 320-0-320? 25V in my opinion would be close enough. Bias it properly and the amp should run fine. If you have an oscillation coming in because of a resistor in the supply then the amp has other problems and won't be running optimally no matter what voltage you use. You need to fix that first.
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