Radford STA25 rebuild pics

[Arkless Electronics]

As promised in the main Radford STA25 thread... and in spite of the memory I have of definitely having posted this before about 2 years ago... It ain't here now!

This was it when I received it and had just started to take it apart. It has new boards from Radford Revival but has been messed about with to the extent that it had to be stripped and start again. There are wiring errors and electrolytic caps the wrong way round amongst all sorts of other problems.

A bit later...

Original wiring to OPT's which had to be re-done.

This was a particularly fiddly bit.... rewiring of the speaker impedance switches... unusually complicated as the Radford uses all the windings simultaneously at each setting to give best usage of the available winding area and lowest copper losses etc . It also switches in a different feedback network for each impedance.

Self explanatory really...

Rewired OPT's

And various stages of reassembly etc culminating in last photo of completed amplifier with various new capacitors, resistors and all board faults repaired plus all rewiring etc completed.

 

[Tony L]

and in spite of the memory I have of definitely having posted this before about 2 years ago... It ain't here now!

I’d have remembered it if you had as I always read classic room restorations! It wasn’t here on pfm for sure.

 

[Arkless Electronics]

I’d have remembered it if you had as I always read classic room restorations! It wasn’t here on pfm for sure.

Yeah I guess you're right... I came to the same conclusion but it's one of those "weird ones" as I actually remember posting it!... False memory I guess... It was up on AOS, and not that long before I moved here, and as it was a big job with great results I remember deciding that it should be here as well and thinking "bollox I'll have to do this again from scratch..."
I'll blame it on age...

 

[Stunsworth]

Thanks Jez, there's certainly a big difference between the 'before' and 'after' photographs <grin>.

One question, I'm assuming the two main boards are left and right channels. Why does the board on the left have an extra capacitor? It looks like there may be other differences too - a bit like those 'spot the difference' puzzles they used to have in comics.

 

[Arkless Electronics]

Thanks Jez, there's certainly a big difference between the 'before' and 'after' photographs <grin>.

One question, I'm assuming the two main boards are left and right channels. Why does the board on the left have an extra capacitor? It looks like there may be other differences too - a bit like those 'spot the difference' puzzles they used to have in comics.

It was while ago but IIRC it's the supply for a Radford pre-amp.

 

[Stunsworth]

It was while ago but IIRC it's the supply for a Radford pre-amp.

Thanks Jez.

 

[Johnjo]

You posted this thread on AoS Jez, I remember it.

 

[Rug Doc]

How cool is that. Thanks for sharing Jez

So, if I were to buy one of these...., how much would it cost.... nope, must stop buying stuff... Not going there. lol