Looking for an E core transformer with dual 100 Vac secondaries

[Uunderhill]

I have a tube preamp design that requires a + Ve and and - Ve supply rail .

I was hoping to find a E core transformer with the following specs

• North American use ( 120 Vac primaries )
• something in the ball park of Dual 90 Vac or 100 Vac secondaries
• 50 VA to 80 VA
• use with full bridge rectifier
• buy from a North American vendor

With a passive supply , this would give something in the order of + / - 126 Vdc or +/- 140 Vdc rails .

So far I've had no luck finding such a beast . But the Hydro voltage in Japan is 100 Vac ( 50 Hz or 60 Hz ) .
Does anyone know of a North American to Japan voltage conversion transformer that would fit the bill ?


Thanks

 

[Uunderhill]

To add, Hammond has the model 185D230 .
https://www.hammfg.com/electronics/transformers/power/185

If the primaries are wired for 230 Vac , yet used in North America ,
this will give dual secondary voltages of 60 Vac , which will give + / - 83 Vdc rails .
But this is probably a touch low for a 6922 ( e88cc ) or 6dj8 ( ecc88 ) .
.

 

[ErikdeBest]

Something like this? 2x 110V secondaries, a bit on the high side, but you can shave off some voltage in the PS.
https://www.mouser.ch/ProductDetail/Triad-Magnetics/VPS230-350?qs=Fg5d7evCuampJb4iXfKS4A==

 

[Uunderhill]

Erik ,

Thanks for pointing out the Triad Transformer , but it provides the same configuration as the Hammond 185D230 .
Dual 2 x 117 Vac primaries and dual 2 x 117 Vac secondaries .

You would think that a transformer that converts North American 117 Vac to Japan's 100 Vac ,
and has dual 100 Vac secondaries , could be easily obtained .... but no .
.

 

[ErikdeBest]

Yes, you are right about it being the same as the Hammond you mentioned yourself, sorry 🙂 I am just a happy Triad (and Hammond) customer, putting their nicely priced off the shelf products to good use and willing to spread the word 🙂

Just looked around at Mouser and found this https://www.mouser.ch/ProductDetail/Hammond-Manufacturing/167H200?qs=2EywpuXRhvpMcqNm%2B7tnEg== It has a 200V winding with CT. Using it with a single bridge will give you about +-140VDC: But at 174VA it is quite overdimensioned (which apart from weight is rarely a disadvantage). There is also the 363AX with 200VCT, but underdimensioned at 32VA (and more expensive than its bigger brother).

​

 

[Uunderhill]

Looks like these are listed as " International transformers " or " multipurpose international transformers "
Bel makes a transformer that matches the specs above .... except the smallest one in the series is 200 VA .

https://www.mouser.ca/datasheet/2/643/ds_st_mpi_series-1633427.pdf

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