on the thread
http://www.diyaudio.com/forums/powe...d-transformers-what-right-17.html#post4305992
are to find new observations concerning the remove of unwanted hum.
http://www.diyaudio.com/forums/powe...d-transformers-what-right-17.html#post4305992
are to find new observations concerning the remove of unwanted hum.
I'm sure you know it
Z = 1/(2*pi*f*C)=> 1/(2*3,14*50*470e-6) = 339 ohm.
In my world you'll need > 4700 uF More is better.
The choice of the capacitor size is a trade off between physical size, how high sound from the speakers you must have in order to hide the transformer hum. Normally you will only need current through the caps up to a couple of watts out. You can have huge caps but it will not serve any purpose. For a true class A amp you will need bigger caps since you have a high idle current.
This is an old threat, and I did read it all.
I have a Roland musical instrument keyboard that buzzed like crazy. Today I decided to try to fix it as easy as possible.
Not many seemes to notice Nelson Pass idea in the start of the thread.
I have respect Nelson a lot, and opted for that solution. Just a thermistor seriel in the live
power line, and the buzzing was gone.
Best regards
Arthur.
I have a Roland musical instrument keyboard that buzzed like crazy. Today I decided to try to fix it as easy as possible.
Not many seemes to notice Nelson Pass idea in the start of the thread.
I have respect Nelson a lot, and opted for that solution. Just a thermistor seriel in the live
power line, and the buzzing was gone.
Best regards
Arthur.
Maybe the perfect specs for the thermistor are not so obvious...I tried them on a couple of isolation Tx and they helped significantly, not to total silence but anyway they reduced audible noise and improved sound quality (noise floor, detail retrieval, dynamics...etc) to an extent higher than anticipated. As if the attached power supplies were happier now
I plan to test with higher values until I find the optimal for my environment.
Cheers,
M.
check out the interview between reviewer for The Absolute Sound and Mr. James Bongiorno, developer for SAE, SUMO and some other company - go to
https://www.diyaudio.com/forums/pow...bar-mains-dc-mains-voltage-2.html#post6455330
https://www.diyaudio.com/forums/pow...bar-mains-dc-mains-voltage-2.html#post6455330
Hi guys. I was hoping to get some help.
I have recently noticed the transformers in all of my amps humming. Some louder than others but everyone is noisy. I thought to check what in the house had changed and found that two humidifiers we have running for the winter are the cause of the problem. I tried adding power line filters to the humidifiers but no difference. I than reversed the phase of one of the units and my amps transformers are quiet as long as both humidifiers are turned on. I’m not so sure this is a great solution.
My question is how to stop the dc from going back into the wall from the humidifiers or if it’s ok to run one unit out of phase.
Thanks for reading my long winded post.
I have recently noticed the transformers in all of my amps humming. Some louder than others but everyone is noisy. I thought to check what in the house had changed and found that two humidifiers we have running for the winter are the cause of the problem. I tried adding power line filters to the humidifiers but no difference. I than reversed the phase of one of the units and my amps transformers are quiet as long as both humidifiers are turned on. I’m not so sure this is a great solution.
My question is how to stop the dc from going back into the wall from the humidifiers or if it’s ok to run one unit out of phase.
Thanks for reading my long winded post.
Both humidifiers unplugged and the transformers are quiet. Doesn’t matter where in the house I plug them in the humidifiers or the amps. My audio equipment is on a dedicated circuit.
I think the main problem is that US has no(?) EMC regulations so you can these "polluters". In Europe you are not allowed to sell devices over a certain EMC emission level. You could use my DCT03 which is capable of 12 amps and connect as many amps you want with the restriction to current consumption.