Radford STA 12 Rebuild

[snowman_al]

Hi Everyone,
I'm new to posting on Aos so please treat me kindly. And I hope I have chosen the right place to post... So here goes.

As a long time fan of Radford, I recently acquired a very sad STA12.
This one had suffered more than most. Clearly in the past it had had the reservoir/smoothing cap explode. There was sticky residue and flakes of paper and foil under everything. I guess that was the start of 'someone' fixing it up and 'modifying' it. Triode connected outputs and shared cathode bias resistor, components dangling on bits of wire and so on.
Then it had clearly been dropped and the transformer chassis badly bent together with the outer frame.

Only one thing to do, a total rebuild. This is where I am to so far, the is chassis stripped, cleaned and straightened:-




I'm missing a few parts, especially an output transformer, so please look out I will be on the scrounge!
Alan

[brian2957]

Hi Alan , welcome to AOS . I'll be watching this thread with interest

Enjoy the forum

[spendorman]

Very interesting. I shall be following too.

I wonder if Radford Revival can help.

I'm a long time owner of an STA25 III, probably more than 40 years.

[walpurgis]

I wonder if Radford Revival can help.

That idea crossed my mind. I'd expect they'd have some spare parts and could possibly match the enamel too for touching in purposes.

[snowman_al]

Guy's thanks for the Radford Revival tip, and Will says, ''rarer than hens teeth!''
My best bet will be a pair of later T2063s, anyway I've put a Wanted Ad up just in case.

[spendorman]

Rare, yes, but I would have thought an STA20 was even rarer. I just happen to know someone that owns one! (not me).

[walpurgis]

It's worth keeping an eye on ebay. There may be a compatible transformer from a non Radford design, although obviously an original would be desirable.

[spendorman]

Circuit diagram here:

http://www.audiomisc.co.uk/HFN/Radfo.../circuits.html

[Firebottle]

Welcome to AoS from another Alan

Great start to your project. Good luck with the hunt for a transformer.

[spendorman]

There is a lot of interesting info here by Jim Lesurf: http://www.audiomisc.co.uk/HFN/Radford/revisited.html