If PSUD won't dance for you, PSpice, LTspice or regular spice will.
Just place two inductors, L1 and L2 along with a 'K' spice directive: K1 L1 L2 0.999
This makes a transformer with a coupling coefficient between primary and secondary of 0.999 (99.9 %).
Include the DCR of all the components - including both the primary DCR and secondary DCR of the transformer.
~Tom
Just place two inductors, L1 and L2 along with a 'K' spice directive: K1 L1 L2 0.999
This makes a transformer with a coupling coefficient between primary and secondary of 0.999 (99.9 %).
Include the DCR of all the components - including both the primary DCR and secondary DCR of the transformer.
~Tom
well the best thing is to increase regulation. about another 100Uf or so in the power supply would work nicely. but regardless of how stiff you make the power supply, it supposed to sag slightly without inducing power supply noise.
like this power supply : this is for 4 6l6's and 4 12ax7's the 2H choke was deleted in final design that mesa boogie uses.
Copyrighted schematic deleted by Moderation
Last edited:
Sorry, moderator deleted my schematic. I'll have to make one instead of posting my originals ( even though they settled on a different design).
O.k. with using public domain knowledge, we'll walk you through the designing phase. So give me a few minutes as I will have to setup some sort of flicker accoun
O.k. with using public domain knowledge, we'll walk you through the designing phase. So give me a few minutes as I will have to setup some sort of flicker accoun
Several people suggested it, did you provide us the DC resistance of the power transformer windings? From your report, your AC voltage at the transformer was dropping considerably. If that voltage drops, then so will the resultinbg rectified and filtered DC. You can consider the resistance of the winding to be in series with it and causing voltage drop with current flow.
now everyone is talking about the transformer.
If it is to spec. as you stated 372-0-372. now what you need to do first when ever you using a transformer for the first time, you will need to measure the total secondary. This means from ct to voltage taps. note any differences. (this should be done with a true RMS DMM). remember to fuse the primary.
for example:
now take that measurement, say its 371 on one of them and 372 on the other. you will need to use the smaller no.
so take that and we are going to get the peak value. but we will use the smaller number: 371 x 1.414
If we live in a perfect world, this power supply would put out 524.6V so that means we need caps that can handle this no problem. so using the 80% safety margin factor, we need caps that are rated for 655.75 VDC.
so now we see our main cap ratings. now rectification. I like using the 6A10 diode because of the inrush current handling and low forward junction drop. one diode per voltage side and of course, ground the ct.
next, the caps:
as stated above, we take into account the margin. now I will select from my parts supplier some 330Uf @400V. around $6ea I get 4 of them.
next the schematic
If it is to spec. as you stated 372-0-372. now what you need to do first when ever you using a transformer for the first time, you will need to measure the total secondary. This means from ct to voltage taps. note any differences. (this should be done with a true RMS DMM). remember to fuse the primary.
for example:
now take that measurement, say its 371 on one of them and 372 on the other. you will need to use the smaller no.
so take that and we are going to get the peak value. but we will use the smaller number: 371 x 1.414
If we live in a perfect world, this power supply would put out 524.6V so that means we need caps that can handle this no problem. so using the 80% safety margin factor, we need caps that are rated for 655.75 VDC.
so now we see our main cap ratings. now rectification. I like using the 6A10 diode because of the inrush current handling and low forward junction drop. one diode per voltage side and of course, ground the ct.
next, the caps:
as stated above, we take into account the margin. now I will select from my parts supplier some 330Uf @400V. around $6ea I get 4 of them.
next the schematic
now with your meter set it to ac measure the AC voltage at the output of the rectifier. if this is more than 5mV add more caps.
but in reality your voltage should sag slightly during operation.
its only bad when your power supply can not recover fast enough
as the output tubes conduct they form a resistance that is in series with the output trans. (pri) resistance and parallel to the power supply transformer's (sec) resistance. Any voltage measurement along the points would be measuring that point of the voltage divider network.
but in reality your voltage should sag slightly during operation.
its only bad when your power supply can not recover fast enough
as the output tubes conduct they form a resistance that is in series with the output trans. (pri) resistance and parallel to the power supply transformer's (sec) resistance. Any voltage measurement along the points would be measuring that point of the voltage divider network.
No, was dropping only 10-12 volts. After the rectification DC dropping about 60v.
The AC output from the transformer will be "flat-topped" since the filter cap is charging only at the peak. Current waveform has perhaps 3:1 peak-to RMS "form factor" - NOT 1.4 like a sine wave! PEAK voltage sags much more under load than RMS. And PEAK voltage is what determines output voltage. Larger first cap will help a little (average output is increased by half the amount the P-P ripple decreases).
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