Trichord / Ben Duncan Isolation Transformer Q

Hi

Normally frequent diyaudio.com (I know...), but came across the forum whilst googling for info on the Ben Duncan Pure Power isolation transformer, which appears to be the same as the Trichord isolation transformer.

A question - do these transformers output balanced AC i.e. 120 / -120V or do they have an accessible centre tap so they can be wired to do so?

Ta

Nyal

 

So nobody replied ..................

The way I see these things is that the approach you get the ac in with a 1:1 and ac out the ground doesn't go through the trans. The crud cant transfere across the windings

As for the balanced approach there must be some one who knows more about this ?

 

Thanks for the reply...any1 with a BD power conditioner care to help me?

 

I've got a Trichord. I don't remember seeing any central tap wire inside. I can't get to it to have a look at the moment as it's installed in a cabinet.

 

The B/Duncan/Trichord/Moth units are all Identical, they have no centre tap.
They can be ordered in step down or step-up formats. Wm

 

Thanks for the info, interesting that none of them have facility to create a balanced connection given the significant increase in Common Mode Rejection that this approach provides. I am not convinced with using a toriod design as a non-balanced isolation tx due to the wide bandwith. A EI would be much better in this instance due to the lower capacative coupling between windings.

Does any1 know a UK supplier of isolation transformers with centre tap?

 

Torriod's couple with the mains far better then a EI, implimenation is the key

 

Wadia-Meister

by what do you mean when you say "couple" with the mains?

and i would be grateful if you could explain a bit more about what you mean about implementation

 

Also in an awful lot of cases of electrial isolation in instrmentations and circuits requiring 'Zero' mains interference, torriodial transformers are used due to the very nature, yes they couple better to ac than E-I core however E-I with pass through mains interference as well, though the torrodial being more sensitive will let interference through easier UNLESS it's dual wound opposite windings to cancel the interference out.
Daul opposed wound transformers IF you are going the Iso-route are far better (imho) than the EI or Frame style (Alot of Big names use this method of mains isolation) for isolation in an AUDIO enviroment.
Though personally I don't use isolation trasnformers any more. Wm

 

Yeah I agree - am not convinced by EI isolation transformers in theory. Torodial transformers produce less reactive current, hence a wide band torodial wired to produce balanced ac (+120V / -120V) a la equitech would seem to be the best solution unless:

1) all equipment can be supplied from one centre tapped EI
2) multiple spurs are wired back to the distro for each centre tapped EI

I hear equitech have a UK distributor...that seems like my next port of call. BTW WM are u using any mains 'conditioning' devices now?

 

Zodiac,

I've run, BPT's 3.5's, Trichords, PS Audio, Furutech,Equitech,Chang light speed, Isotek, Nordost, Richard Grey,Shunyata (both old and new Hydra's, custom built programmable mains regeneration units up to 50 kva
I Have had a Eqiptec unit in the past
BTW I don't believe in transformers of any kind for Audio mains conditioning, I have tried something similar to this a few years back, with mixed results, though I've heard favourable reports on these units. Wm

 

If you don't mind me asking are you currently using any filter based mains conditioning device?

What were the pros and cons of using isolation txs? Did you try running only parts of the system off the isolation txs e.g. digital rather than the whole caboodle?

 

Zodiac,
I used to run 2 Balanced style mains conditioners, one .5kw unit dedicated just for the transport/dac/dvd (I had modded both of them)
And a seperate 1kw unit for just the power amp (Digital Class T)
The units offered more clean resolving power, better groove and bass control on the amp.
The digital improved the openiness and detail and added a more fuild sound.
Both units were purchased by forum memebers here Technobear and MartinC if you PM them, I'm sure they would give a personal insight it to what/how it works for them.
Both units worked well, I personally found other units were more to my taste.
I personally run an Audio Magic Transendence, which I've further enhanced.
hope that helps Wm

 

What WM said