Radford STA15 or SET?

[Tweedle-Dee]

I have the offer of a Radford STA15 (mk?) that is rather tatty and unused for a long time, but reported to be working fine. The valves have lost all markings, so are unknown. My question is whether this would really be as good as a modern SET 300B DIY amp that I've also been offered? Is the Radford really as good as people say?

Importatnly for me being a bit uninformed with current values, what price, roughly, might the Radford be worth given the description above?

Any advice would be most appreciated as I would need to move fast if I decide to go for the Radford - at the back of my mind I do have reliability concerns, perhaps unfounded given reported reliability by others.

I'd be using either of the above with vintage Alnico 15 Ohm high sensitivity speakers and possiblilty Decca Kelly ribbons.

Many thanks,
TD

[John]

Send the Radford to me
On a serious note Everytime I heard one I really liked them

[The Grand Wazoo]

Is the Radford really as good as people say?

Yes!

My question is whether this would really be as good as a modern SET 300B DIY amp that I've also been offered?

Only you can decide that, I'm afraid.

You have worries about reliability, but if the Radford is working properly, then I'd be more concerned about the reliability of a DIY amp. There are many competent DIY'ers out there of course, but do you know for sure if the maker of this amp is one of them?

The valves in an STA15 are:
EF86, ECF82, 6U8, GZ34 & EL34

The STA12 (which was kind of an STA15 Mk I) is different:
EF86, ECC83, GZ34, EL34

[Tweedle-Dee]

Thanks Guys,

I'll update in due course...

[lurcher]

It all depends on the speakers and the SET. I know of SET's that better Radfords on all fronts, and I know of 300b SET's that are better, but only if the speakers allow them to be. If the speakers are less suitable the Radford will be a better choice, but then again there are speakers that the Radford will not work with also.

Also, not all 300b amps are at all equal, modern (whatever that means) or not.

[Tweedle-Dee]

Hi guys,
Well, I've listened to the Radford and it was lovely - through a pair of Ditton 66s as well! Overall the sound was detailed and natural. I had a concern in that all of the valves on one side glowed a fair bit less than the other. Is that normal, or does it suggest some possible issues. The EL34s did seem to be different left to right, so might this have contributed?

Thanks,
TD.

[DSJR]

If the amp hasn't had a service in some years, then it WILL be necessary, I can assure you. Once done, I think these old Radfords were about as good as transformer coupled valve amps get when used within their power - those transformers are legendary. Amps like this will never lose value tbh, whereas the "SET lot" are rather marginalised, no matter how great these amps are claimed to be into hugely efficient speakers. No offence, but hopefully you'll understand where I'm coming from.

[spendorman]

I have a single ended EL34 amp that works quite through Tannoy HPD315's, provided that nothing above lowish levels are used, and then it all goes to pot, especially the bass. On the other hand, my Radford STA25 III is about as good at lowish levels, but has bags of power and can blow the windows out on the Tannoys!

It might be that the STA15 has some odd output valves in it, or needs a service.

My STA25 III was bought second hand about 35 years ago, utterly reliable. Nothing has been replaced, except trying some alternative output valves. The original Mullard EL34's are still fine.

Bear in mind that the STA15 has 28 Watts RMS per channel, STA25 is 36 Watts RMS per channel.

[spendorman]

Thinking about the differing brightness of the glowing valve heaters, most probably due to the valves themselves as all the heaters are likely to be driven off the same 6.3V AC supply, which I guess is pretty stiff.

I was forgetting the GZ34, that would be a separate 5V supply for the heater.

[The Grand Wazoo]

Stupid question, but sometimes stupid ones are the best ones:
You say the valves glow with different brightness. Were you looking at them from the same relative angles? The bases are possibly not aligned so that from a given position, you're seeing the same part of a valve on the left as on the right.