Anyone know of a US source for ESL toroids?

[CharlieM]

Hi everyone,
I've been searching in vain for some reasonably priced toroidal transformers suitable for ESL's. I can't spring for those expensive Piltrons or Aplimos. I did find sources in Europe but all either didn't have an English language website or didn't respond to my emails, or wouldn't sell and ship to the US. Does anyone here know someone here in the US might get hold of some inexpensive 50VA 230V x 6V toroidal transformers?
much obliged, Charlie

[Few]

This post won't help you Charlie, I just want to add my voice to yours. I've had similar trouble coming up with a source. Looking forward to hearing from others who have had more success!

Few

[CharlieM]

Sorry to hear that, Few.
I'm hoping that some enterprising member from across the pond (with easy access to 230V x 6V European toroids) will see an opportunity here to both further the cause and pocket a few $$ for their trouble.

[jackinnj]

Look at http://www.antekinc.com/index.php

[CharlieM]

Thanks, thanks, thanks, [Jack?] jackinnj !!

The 50VA 6V's shown there look promising. Would you happen to have tried those out already?

Few,
Have a look... what do you think?

[Coreyk78]

I've used Antek toroids several times and had good results, good prices too.

[jackinnj]

Originally Posted by CharlieM

Thanks, thanks, thanks, [Jack?] jackinnj !!

The 50VA 6V's shown there look promising. Would you happen to have tried those out already?

Few,
Have a look... what do you think?

I haven't tried the 50VA --- I've used the much larger ones.

John has tube "output" transformers now -- 20W, 40W, 70W and 100W

[Few]

My transformer expertise is limited, Charlie, so I wouldn't want anyone to make a choice based on my recommendation. Are you planning on using multiple transformers or can you get away with a low turns ratio?

Few

[CharlieM]

Few,

Your knowledge of transformers can't be as limited as mine. I recall one of Calvin's threads reported favorable results using pairs of inexpensive 50VA 230v/6v toroids from some German company, which he wired up with the primarys in parallel and the secondaries in series:

new Trannies

I'm thinking these AN-Tek 50VA 230V/6V's might work out, even though they have dual primaries and secondaries [two 115v windings and two 6v windings). I think the trannys described in Calvin's thread used single 230V and single 6v windings.

If I've got it right, each AN-Tek tranny would need its two 115v windings series connected to form a single 230v winding and only one of the 6v windings would be used. A pair of these would then be wired together with their 6v primaries in parallel and 230v secondaries in series to power each speaker.

Coreyk,
How did you wire yours up?

[Calvin]

Hi,

I think the trannys described in Calvin's thread used single 230V and single 6v windings.

That is right. While the primary-to-secondary insulation is usually designed to withstand several kVs the insulation between the secondary windings can be as low as 500V. And keep in mind that insulation values fall with rising frequency. Trannies are tested with low-freq signals. For audio bandwidth I suggest to calculate with just half of the datasheet value. So, as long as you don´t know how the individual transformer sections are wound and insulated the use of two equal "1prim-1sec-winding trannies" is the easiest way to get good and safe results. You can profit from the increased flashover treshold. While a single tranny might be safe to 3.5kV -i.e 1.2kVrms- in case the sec-sec-flashover treshold is at least of the same value as the prim-sec value. The double-stacked trannies would be good for 7kV -i.e. 2.4kVrms- under the same conditions.
Unfortunately there doesn´t seem to be a sec-sec-value given in the Antek datasheets, just a prim-sec-value. You might clear up that point before order.
Oh, some last hints.....these trannies are only good for Hybrids. The primary inductance defines the low-freq limit. With standard power toroids the inductance is too small for fullrange usage, but enough for hybrids from ~100Hz on. Higher wattage types feature larger inductance values (and lower losses). So the lower You intend to play the panel the bigger the tranny will be. Because of the low losses, those trannies will transform the capacity of the panel very immediate to the amp. High values of phaseshift will occur that stress the amp more than the lesser phaseshift of a worse and lossier tranny.

jauu
Calvin