Home SET Asylum

Single Ended Triodes (SETs), the ultimate tube lovers dream.

RE: Ground Loops and Isolation Transformers.......................

Hi,

I'm an electrician, I hope to help, and you're not going to hell(*)

I havent read all the replies, someone else has probably said the same, but who knows, and in any event it all gets archived for the searcher in the future, so its not a waste of time - although the same might not be said for reading through all the posts :-)

Isolation transformer, just forget that for a while - they're good in certain applications but if you're free of signal common loops you wont need one to solve any problems related to mains hum fundamental or its second harmonic. Balanced power - yes.

Dont know where you are, in Australia the standard known as AS3000 stipulates that any metal chassis enclosure for use with mains connected gear needs to be 'earthed'. Needs to be a bolt with split washer, or two self tapping screws (not one) and use either a single bolt with a crimp lug, or two self tapping screws with a double eyed lug. Good luck with the double eyed, lug they dont make them, but they certainly could - would be a hit with the solar install guys :-). Use a bolt.

If its a wooden enclosure, have a direct connection with any 'iron' to earth - physically. More lugs, the bolts will likely be there.

The idea is that under fault condition, there needs to be a return current path to the main switch board in order for the circuit protection to operate. Fix this first. Or not, but be aware that its not safe and the insurance, or not, wont cover xyz et al.

Once you've fixed that, change your ground/earthing arrangement, Cheater plugs are called as such for a reason.

Options for signal common (ie. return of secondary winding of the power/filament/heater transformers) are flexible. You dont need to reference them hard to the chassis (mains earth), you can float them, or go with say 2M2 in parallel with an MOV etc.

If you have an ground loop, find it. All the frustration associated with the search will be rewarded with some interest (as you interpret this to be - it all ends well).

* not literally and for this, although if it catches you out before you've made amendments YMMV. (as you interpret this to be - it doesnt always end well).


Sincerely,
Shane









This post is made possible by the generous support of people like you and our sponsors:
  VH Audio  


Follow Ups Full Thread
Follow Ups
  • RE: Ground Loops and Isolation Transformers....................... - shane. 10/20/1301:32:25 10/20/13 (0)

FAQ

Post a Message!

Forgot Password?
Moniker (Username):
Password (Optional):
  Remember my Moniker & Password  (What's this?)    Eat Me
E-Mail (Optional):
Subject:
Message:   (Posts are subject to Content Rules)
Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:  Automagically notify you when someone responds.