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Improving transformer hum

The thing that puzzles me having just read the ESP article, is that my buzzing trffos are a pair of 225VA toroids (dual mono amp) and he mentions that smaller (<500VA) toroids should be fine with DC offset. So why are mine still buzzing?
 
Some of it is plain unavoidable from transformer action - look-up 'magnetostriction'. How much it results in annoyance depends on exactly how (well) the transformer was wound, encapsulated, overdesigned on core size, mounted etc. Potting is nice for small transformers to minimise the sonic effect, but not always available/affordable!
 
Mine have potted centres. They came from Airlink transformers but weren't specified for audio. I'll try some mechanical decoupling and see if that helps. I should as its not a major issue, more a minor niggle. I can only hear the buzzing when I'm right up close with my ear.
 
Gents, mains filtering is not for me, I have tried a lot of expensive and cheap, juts kills dynamics to a greater or lesser extent

Check this out http://www.acoustica.org.uk/

Glad my mains install hits the spot here too ;) won't stop the hum, but sounds very good !

13 32A lines with 6mm from board to unit
 
These are not really filters in the traditional sense. Will cost a pound ninety nine to build and try... thought this was the diy forum?
 
Been looking for info on handling transformer noise without using the DC blocker method and haven't found much info to be honest. The search brought me back to this old thread.

For the last couple of days I have been pondering the possibility of potting my traffos in resin provided I can find suitable cans for them.

The question is, will potting the trafo actually stop it buzzing internally? Or is it the case that the resin compound and the can effectively damp the resonances in the traffo?

On the subject of cans I need to find something that will take a 110x55mm traffo and be no taller than about 58mm and be not much bigger in diameter than the traffo because space is limited in my amp. I was thinking of using cooking pans. Obviously I'd have to modify them a bit. Take off the handles and cut them down to the right height.

I have some mu-metal sheet to line the inside of the can too which should help with regard to stray field. And on that note would an aluminium can be better than a steel one?
 
Just make a bocker, if it is good and safe enough for Bryston, it is good and safe enough for you....
 
IWC Doppel said:
Gents, mains filtering is not for me, I have tried a lot of expensive and cheap, juts kills dynamics to a greater or lesser extent
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But better mains can do wonders. I swear by a dedicated mains with 10 gauge wiring. I'm running 5 Naim transformers with little to no hum. Money better spent than on power conditioning IMHO.

IWC Doppel said:
I sit close to 4 Naims 135's and 2 250's
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IWC Doppel said:
Hoping it will be 6 x 135's and 1 x 250 shortly :)
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Sounds like you're driving 'briks. An alternative is to access each driver individually and run 6 x 250s. :D Or 6 x stereo HackerNAPs. :D:D:D
 
I love a dedicated spur but were renting so its not possible.

Any opinions on the DIY potting and encapsulating please?
 
the hum of my main power amp definitely reduced after i had the house rewired. Now i suffer hum very occasionally.
 
what I prefer is a very simple 240volt set of components. I prefer a fuse and iec part screwed to the back plate. This eliminates a set of connections the diy person can bugger up and you can't pull the cord and disconnect a live cable. soldered cables directly to the transformer if possible with heat shrink covering all connections. If using a chocolate connector then cover it up. pretty much as ESP audio suggest. With few live components the diy person is less likely to lean on or contact the dangerous stuff with a probe etc. Also connect a good earth to any metal cases with a screwed and lock-nutted fixing. The fixing shouldn't be a box screw.
 
flashgo said:
But better mains can do wonders. I swear by a dedicated mains with 10 gauge wiring. I'm running 5 Naim transformers with little to no hum. Money better spent than on power conditioning IMHO.



Sounds like you're driving 'briks. An alternative is to access each driver individually and run 6 x 250s. :D Or 6 x stereo HackerNAPs. :D:D:D
Click to expand...

I am currently running 7 x 135's 4 driving Sonus Faber Extremas, one for the center channel (Cremona), 2 for the rears (Elector Amators).

My mains consists of a separate consumer unit to the room fed by a dedicated 35mm sq line direct from the incomer. Then I use 13 32A lines with minimum of 6mmsq through to each unit using oyaide IEC's. So each 135 is fed from a separate line from the consumer unit all have equal length earthing to the consumer unit
 
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