WTB: 5V Filament transformer

[DMills]

Hi all,
I have just been looking at setting up that ALC 909 I bought, and have noticed that the current power supply if fitted with a single secondary winding filament transformer with the cathode current injected at one end.

This is making me twitchy as that tends to be a bad thing for tube life, so I am looking or a suitable transformer with a centre tapped secondary that can handle a few hundred VA and 30A injected into the centre tap.....

Either 5V or 6.3V centre tapped would do, with a 230ish primary.
Anyone got something that would suit before I order a custom build?

Regards, Dan.

[300EVIL]

Why not just wind your own? A small microwave oven transformer would probably do just fine with the HV secondary cut off and a couple of turns with 10Ga.

[DMills]

Pretty much my exact fall back plan, but if someone had something with the useful +-5 & 10% taps on the primary it would have saved some dicking around.

The nice thing about maggie transformers for this use is that they have a magnetic shunt built in which provides some inherent current limiting (The cathode is **VERY** low impedance when cold).

Regards, Dan.

[Things]

If you are thinking about rewinding a microwave transformer, be aware that it is a VERY time consuming process, and quite hard. If you damage the primary, all that work has gone to waste (Thats what happened after my 5 hours trying to strip one )

Although, they can be had for almost nothing so if you don't find anything, it could be the way to go

[dave]

Hey Dan,

I would speak to Florian at ABSee laser. He used to sell a lot of these ALC909 / Lexcel 88 combos, and had a custom filament transformer wound up IIRC.. http://www.absee-laser.com/


Dave