[sdiy] Tube question 1: transformers

[René Schmitz]

Hi again,

> I found that output and PSU transformers for tubes
> are quite expensive, arround 70 EUR.
 >
> Is this shameless abuse, or justified pricing
> for low volume production?

The production is not mechanized, and involves many
manufacturing steps, as the windings are "interspaced"
(verschachtelt). Thus the labor cost is dominating the price I think.
But this doesn't mean you could wind your own for that price. Simply 
because you can't get the materials in the small volumes you need. So 
you end up buying a whole spool of wire, costing you more than the 
transformer if you buy it.

Still I think for what you're after you should try one of those ELA 
transformers. The inductivity would be ok, just these aren't 
interspaced. (It will maybe only go to 10kHz, but what the heck, the 
speaker won't reproduce that anyway.) A smaller core will faster 
saturate, since that is what you're after it doesn't make sense to use a 
bigger core one to avoid that. (I think you won't be able to saturate 
the usual HiFi transformers with that EL95 tubes, because there is not 
enough current.)

Cheers,
  René


-- 
uzs159 at uni-bonn.de
http://www.uni-bonn.de/~uzs159