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A DIY Radford STA25 restoration

wd40addict said:
When I compared my STA15 to a friend's Stereo 20 the Radford was comfortably ahead.
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I'm not going to get drawn into an in-depth comparison yet but I can already say that it's going to be a close call between my Leak ST20 and my Radford STA25. Based on my initial impressions they're fairly evenly matched overall.

We're talking about 40-60 year old amps here and condition is everything. All it would take is a knackered valve, a dried out cap or an out of spec resistor to easily swing the result one way or another.

Both of mine are fully rebuilt so it's a reasonably fair contest but if anything the Leak has a slight advantage because it is running a selection of the crème de la crème of NOS valves.

Both are lovely, which is all that really matters to me.
 
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JTC said:
I would love to hear it. If only to (a) appreciate your sterling restoration efforts and (b) to get the chance to listen to one ahead of buying my own (which, as you will no doubt be aware, I am a bit nervous about as I've never spent that much money on a totally unheard bit of equipment before). But very glad it's sounding great. I'm also interested in a comparison against things I have heard, just for context. But that's difficult; the Venn diagram of 'amps I have heard/owned' and 'amps others have compared against a Radford' being very small, and subjective too..... anyway, I sort of wish I just had to pay my money for mine now to get it 'committed' and be done with it :)
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I don't think you can go far wrong with the RR STA25. The STA25 is almost universally praised and in my brief experience with it I'd say that it is a very neutral sounding amp, so unless you have strong preferences for a particular kind of sound you probably like it.
 
Mike P said:
We're talking about 40-60 year old amps here and condition is everything. All it would take is a knackered valve, a dried out caps or an out of spec resistors to easily swing the result one way or another.
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Totally agree, would still be interesting to hear your thoughts.
 
Both the Leak and the Radford are competent designs with no serious corner cutting
Something like it new these days would be very expensive, the transformers are massive.
 
Has anyone compared a similar condition STA15 against the 25? I’m guessing the difference is really valve vs. solid state rectification, though I’ve no idea if there are other significant changes. Curious as to how they differ sonically?
 
Tony L said:
Has anyone compared a similar condition STA15 against the 25? I’m guessing the difference is really valve vs. solid state rectification, though I’ve no idea if there are other significant changes. Curious as to how they differ sonically?
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The two are more similar than different so in my experience there's not a huge difference - the 25 has more headroom of course. The STA15 is more user friendly in that it biases itself via cathode bias, which is harder to achieve with fixed bias hence the manual pots / test points (but entirely possible, I have working prototypes for such systems)

Dan K said:
Surely less gain = less noise

Which one has the valve rectifier?
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The STA15 uses the valve rectifier (a GZ34), the (closed loop) gains on both are identical - apart from the power supply, biasing arrangements and a slightly different turns ratio on the OPTs the circuits are the same.
 
What's the current wait like on the RR STAs? (I'm in the queue btw, just curious whether I need to start digging the pennies out the back of the sofa etc.)??
 
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