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da2222
06-12-2011, 17:38
Hi Guys

I may be able to pick up a pair of Radford mark II monos in very good condition. Can anyone tell me if there are significant differences between this model and the mark III? How are they sound wise compared to the sta15 and sta35 (I would have to buy them blind). Given I have been used to a modern 845 integrated am I likely to be underwhelmed by the sound of this vintage set up?!! I listen to all types of music...

Thanks!

spendorman
06-12-2011, 18:00
Can't really answer your question, but would imagine them to be very good. Suspect a lot of Bulgin connectors on them, make sure that you get the plugs.

I love my STA25 III, bought second hand about 35 years ago, never needed any parts replaced. Sounds wonderful.

It's the STA 25 here:

http://www.adventuresinhifiaudio.com/03/07/2010/a-history-of-radford-electronics/

The Grand Wazoo
06-12-2011, 18:27
I know the sound of the STA15 very well & it's thought by some as being the best sounding of the stereo Radfords. You get valve rectification which was done away with in 1965 in the later models like the 25 & 35 from Series III onwards. Although the Series III STA & MA15's were rectified with a GZ34, the Mk 1 & 2 used the EZ81.
All of the valve Radfords are perhaps the least 'vintage' sounding of all the vintage British amps.
The monos give you the benefits that any monoblock amp will give you over it's stereo equivalent - achieved from independant power supplies & absolute separation between channels.

I've been lusting after a pair of MA15's for a very long time - grab 'em if you can!

Barry
06-12-2011, 21:42
Would concur with Chris regarding the rectifier valve used by the monoblock MA15s.

I would only add to make absolutely sure the phase splitter is an ECF82. The use of a triode pentode valve for the phase splitter was a real inovation by Radford (suggested by Dr Bailey, consultant to Radford at the time). This, along with Arthur Radford's skill at transformer design, is what make the Radford designs stand head and shoulders above other British valve amp designs of that period. If it doesn't use an ECF82 but uses an ECC83, then it is no better than the (capable) Mullard 5-20 design, on which it is based.

Don't worry about the Bulgin connectors: they are readily available on eBay.