S22 transformer questions

If you stack the two boxes you will get transformer buzz with sensitive cans. I can hear hum with a pair of IEMs, sensitivity is something like 115 dB @ 1mW. The hum disappears if the boxes are moved so they sit side by side. Less sensitive cans like my hd600 and lcd2 I hear no hum even when stacked. I imagine you will have no problem with speakers as they are much less sensitive than even the hardest to drive headphones.

Using a single trafo to power both power supplies should be fine.

Probably best asking this on the official AMB forum - Ti Kan responds personally to a fair proportion of queries (and who better to ask about the amp and PSU than the guy who designed them?)

Aluminum provides NO shielding from EMF. Spend the extra $10, get the shielded transformers. 

If your worried enough about crosstalk to use 2 s22's why not solve the problem from the start and use 2 transformers too?

So much of this stems from the myth that toroids dont leak EMF :(
 

Quote:

Originally Posted by bcg27 

If you stack the two boxes you will get transformer buzz with sensitive cans. I can hear hum with a pair of IEMs, sensitivity is something like 115 dB @ 1mW. The hum disappears if the boxes are moved so they sit side by side. 

 

Buy some mu-metal foil and line the lid and floor of the various boxes. Just make sure not to short anything :)

McMaster Carr sells it for about $21/ft (4"wide) with an adhesive backing that is very easy to install in aluminum cases. You may be able to find a better deal elsewhere, but everyone loves McMaster Carr.

You can experiment with it before you install it by just putting a piece between the cases. When it works the effect is startling.

Aluminum can shield against electromagnetic interference (aka radio frequency interference). But it doesn't really help much against magnetic fields.

Quote:

Originally Posted by nikongod 

Buy some mu-metal foil and line the lid and floor of the various boxes. Just make sure not to short anything :)

 

McMaster Carr sells it for about $21/ft (4"wide) with an adhesive backing that is very easy to install in aluminum cases. You may be able to find a better deal elsewhere, but everyone loves McMaster Carr.

 

You can experiment with it before you install it by just putting a piece between the cases. When it works the effect is startling.

Thanks for the suggestion, I might pick some up my next mcmaster order to try out, although it is rather expensive. Would probably end up spending a couple hundred to cover 3 12x12 par metal boxes. Unless you just need it above the toroid? That would be a much smaller area to cover. 

I would start with just above the toroid with a bit of overhang. 

Do you have a steel tray (like a cookie baking tray) you can put between the cases for a moment? Mu metal is a bunch better, but that should give you a quick idea if its worth pursuing further.