I have received one transformer for DHT preamp with tube rectification, but are not perfectly symmetrical 204 0 200.
1 Is right
2 reduce with resistor the 204 to 200
3 use only one secondary 0 - 200 with hybrid rectification
1 Is right
2 reduce with resistor the 204 to 200
3 use only one secondary 0 - 200 with hybrid rectification
1/ May well be within tolerance.
2/ Resistors are a poor choice given that operating conditions and current draw can change.
3/ Why not just try it and see how it works. Measure the voltage under load in normal use. You could add very low value resistor to both as a means of measuring volt drop and hence calculate if the currents are equal.
I would imagine that different characteristics between each rectifier would more than swamp any small difference in open circuit transformer voltage.
I doubt you have a problem in practice.
2/ Resistors are a poor choice given that operating conditions and current draw can change.
3/ Why not just try it and see how it works. Measure the voltage under load in normal use. You could add very low value resistor to both as a means of measuring volt drop and hence calculate if the currents are equal.
I would imagine that different characteristics between each rectifier would more than swamp any small difference in open circuit transformer voltage.
I doubt you have a problem in practice.
This shuldn't be a problem , only a little more ripple . But if the 2 diodes inside the tube are not "matched pair" the result should be far worse . As nobody is complaining about this probably it is a non issue .
It may have been intentionally designed that way, to give the same voltage between the two halves under load. The higher voltage side will probably have a higher resistance (and leakage inductance, both a result of the outer 1/2 of the coil being physically larger). Could also somebody miscounted the turns but that still wouldn’t be the end of the world.
It could also be the result of shorted turns, but if that is the case it would draw a bunch of current and run hot just sitting without a load. Plug it in, let it run for an hour and if it doesn’t heat up more than it should it’s fine.
It could also be the result of shorted turns, but if that is the case it would draw a bunch of current and run hot just sitting without a load. Plug it in, let it run for an hour and if it doesn’t heat up more than it should it’s fine.
Go ahead and use that transformer.
If that is the only problem with the transformer, consider yourself lucky and blessed (many complain about hot transformers, noisy transformers, fit and finish, etc.)
The 60Hz ripple will increase very slightly.
The 120Hz ripple will change very little, if at all.
For those on 50Hz power mains, the ripple frequencies are 50Hz and 100Hz.
If ripple is a problem, you probably did not have enough filtering in the first place.
If that is the only problem with the transformer, consider yourself lucky and blessed (many complain about hot transformers, noisy transformers, fit and finish, etc.)
The 60Hz ripple will increase very slightly.
The 120Hz ripple will change very little, if at all.
For those on 50Hz power mains, the ripple frequencies are 50Hz and 100Hz.
If ripple is a problem, you probably did not have enough filtering in the first place.
if i were you, i will use the winding with lower dc resistance, for hybrid rectification, traffo utilization is about 30% better that way...reason being the secondary current flows for the full 360 degrees of the electrical cycle...
i do not use the FWCT circuit since i make my own power traffos, heating is also lesser...
i do not use the FWCT circuit since i make my own power traffos, heating is also lesser...
