There was a long Thread discussing a noisy transformer.
The Member did eventually cure the noise by repeatedly dipping and drying the toroid. But it tooks weeks of effort because he did not have the correct "varnish", nor the correct Vac Vac procedure.
The Member did eventually cure the noise by repeatedly dipping and drying the toroid. But it tooks weeks of effort because he did not have the correct "varnish", nor the correct Vac Vac procedure.
a sign of overloading?, toroids are seldom dipped in varnish like EI's...
if you can separate the secondaries in two and use two bridge rectifiers,
that may help, bussing can also be caused when the center tap is not exactly where it should be....
so when specifying a toroid, get one that has a bifilar wound secondaries...
fyi, i wind my traffos for ss amps with bifilar secondaries...
if you can separate the secondaries in two and use two bridge rectifiers,
that may help, bussing can also be caused when the center tap is not exactly where it should be....
so when specifying a toroid, get one that has a bifilar wound secondaries...
fyi, i wind my traffos for ss amps with bifilar secondaries...
If it helps, for a toroid i used the same as in the build guide, the 45v Antek 800VA
It is not noisy and doesn't vibrate with 2 badger boards. It is only bolted to the bottom chassis plate with the thin rubber pad it comes with. It turns on kind of hard so i put a soft start in it to stop the lights dimming when i turn it on and lessen the speaker thump.
It is not noisy and doesn't vibrate with 2 badger boards. It is only bolted to the bottom chassis plate with the thin rubber pad it comes with. It turns on kind of hard so i put a soft start in it to stop the lights dimming when i turn it on and lessen the speaker thump.
I bought a power switch for the front of my badger amp and am not sure how to power the red LED in the switch...
The data sheet (link to digikey) says it has a forward voltage drop of 1.9VDC and max of 3VDC so i understand i need at least 2v or more to power it but how much is too much? Do you typically need to implement current limiting resistors to switch LEDs?
Can i just break apart a 9vdc wall wart and mount that in my amp and wire it straight in to the LED?
Thanks
The data sheet (link to digikey) says it has a forward voltage drop of 1.9VDC and max of 3VDC so i understand i need at least 2v or more to power it but how much is too much? Do you typically need to implement current limiting resistors to switch LEDs?
Can i just break apart a 9vdc wall wart and mount that in my amp and wire it straight in to the LED?
Thanks
if you have e.g. 12VDC available, then use an appropriate current limiting resistor.
R=(12-2)V/20mA=500ohm
Power=I*I*R= 200mW
I used a similar switch for a boombox project and works great. LED Power Logo Switch -Blue_Latching
20mA is probably too much for an indicator LED.
Try 25% first (5mA) and see how bright that is.
Try 25% first (5mA) and see how bright that is.
Thank you so much. I visited their site and see they do not normally ship to Switzerland. Will contact them by e-mail ...
Did build a mains DC blocker as per Mains DC and Transformers but it does not help much. Anyway I know DC offset is not very important when we draw a substantial current from the TX (my case) so I mechanically decoupled the TX from the amp enclosure and that helped.
They shipped to me (Zurich/Switzerland) just recently, and I was surprised their price was not over the top.
Did you use ESP Figure 8?
And at least double, or even quadruple the capacitor values?
A pair of back to back 10mF capacitors have an impedance at 50Hz of ~0.6ohms
Pass 1Aac through that and you will get 0.6Vac across the capacitors if the waveform is sine like.
That would be ~0.9Vpk across the caps and thus the dual parallel diodes would have ~0.45Vpk across each of them and should not pass any significant current.
The 1Aac of sinewave would be equivalent to the transformer passing 230VA to the rectifier.
You might be better using a pair of back to back 22mF caps for a big transformer. Or maybe a bank of 10off 4m7 to give similar capacitance. You don't want the diodes turning ON for normal loading.
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600mA of amplifier bias is only a small portion of the maximum continuous rating of the transformer.
Maybe that is the problem... I used two 9mF caps connected in series + to + and bypassed by four diodes in anti parallel.
2series diodes in each direction allows voltages upto ~1Vpk to not pass through the diodes. With 9mF+9mF giving ~4m5F you get an AC waveform upto 0.9Aac into your transformer.
Even at 600mA bias and quiescent when the music is silent (drawing ~60W to 100W from the PSU), I'd expect the diodes are not passing and the DC blocker should be effective.
I don't have the mathematical abilities to analyse the spiky charging pulses and what they do in passing THROUGH the caps to know what actually happens with non sinusoidal waveforms. I can't recall ever seeing a Forum expert discussing this type of analysis.
Even at 600mA bias and quiescent when the music is silent (drawing ~60W to 100W from the PSU), I'd expect the diodes are not passing and the DC blocker should be effective.
I don't have the mathematical abilities to analyse the spiky charging pulses and what they do in passing THROUGH the caps to know what actually happens with non sinusoidal waveforms. I can't recall ever seeing a Forum expert discussing this type of analysis.
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