Radford STA25 service UK

aquapiranha · 3rd October 2008, 08:50 PM

Hi guys. A chap has asked me where in the UK he can have his STA25 serviced, and I am sure there is some among you who know the best people for the job!

All help greatly appreciated.

Thanks.

bigwill · 3rd October 2008, 08:52 PM

Mail me, I'm off to bed now but I may be able to help in the morning.

Me and my father have lots of original Radford parts and skills to repair.

My address is poopduck at gmail dot com

bigwill · 3rd October 2008, 08:56 PM

Mail me at

poopduck

at

gmail

dot

com

Excuse the stupid email address, it's temporary and I'd rather not post my primary one on a public forum

aquapiranha · 3rd October 2008, 08:58 PM

wont let me mail you? the guy says this.. " I had the output valve bias
voltages checked and they were a good way out"...

Not sure what thuis means, I am no expert!

Thanks..

aquapiranha · 3rd October 2008, 08:59 PM

Quote:

Originally posted by bigwill
Mail me at

poopduck

at

gmail

dot

com

Excuse the stupid email address, it's temporary and I'd rather not post my primary one on a public forum

OOPS! was typing when you posted...

coolmaster · 4th October 2008, 06:33 AM

Quote:

Originally posted by aquapiranha
wont let me mail you? the guy says this.. " I had the output valve bias
voltages checked and they were a good way out"...
Not sure what thuis means, I am no expert!
Thanks..

Likely the bias resistors or capacitors have aged. Happens to old amplifiers which may still have it original resistors and caps.
Old resistors change value, old capacitors dry out and these impair the performance in varying degrees.Don't worry...easily tackled if nothing else is wrong.

barretter · 4th October 2008, 08:35 AM

The STA25 has variable fixed bias. There are test points and potentiometer shafts, accessible through a hole near the test points, which can be varied with a screwdriver. Has your friend tried this? They can go off quite a way over time.

aquapiranha · 6th October 2008, 10:49 AM

Quote:

Originally posted by barretter
The STA25 has variable fixed bias. There are test points and potentiometer shafts, accessible through a hole near the test points, which can be varied with a screwdriver. Has your friend tried this? They can go off quite a way over time.

I will pass on the info thanks. I assume like most amps it is a case of measuring from the "-" speaker terminal and the measure point? do you know what the measurement should be?

Many thanks, Steve

andyjevans · 6th October 2008, 11:05 AM

One thing you might like to know is that the Radford ST25 will soon be made again. Peter J Comeau has bought the name and will be re-manufacturing.

www.radfordaudio.co.uk

barretter · 6th October 2008, 11:10 AM

One of the test points is at chassis/ground (Radford uses the chassis for ground) level and the other is positive. The potentiomters should be adjusted until you get a reading of 2V (I think it says this on a plaque near the test points). There are two adjustments for each channel. I found it easier to attach the ground lead of a multimeter to the chassis with a crocodile clip whilst poking the positive lead into the appropriate socket and adjusting the pot with a screwdriver.

3rd October 2008, 08:50 PM	#1
aquapiranha diyAudio Member Join Date: Jul 2007	Radford STA25 service UK Hi guys. A chap has asked me where in the UK he can have his STA25 serviced, and I am sure there is some among you who know the best people for the job! All help greatly appreciated. Thanks.

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3rd October 2008, 08:52 PM	#2
bigwill diyAudio Member Join Date: Dec 2004 Location: UK	Mail me, I'm off to bed now but I may be able to help in the morning. Me and my father have lots of original Radford parts and skills to repair. My address is poopduck at gmail dot com

3rd October 2008, 08:56 PM	#3
bigwill diyAudio Member Join Date: Dec 2004 Location: UK	Mail me at poopduck at gmail dot com Excuse the stupid email address, it's temporary and I'd rather not post my primary one on a public forum

3rd October 2008, 08:58 PM	#4
aquapiranha diyAudio Member Join Date: Jul 2007	wont let me mail you? the guy says this.. " I had the output valve bias voltages checked and they were a good way out"... Not sure what thuis means, I am no expert! Thanks..

4th October 2008, 08:35 AM	#7
barretter diyAudio Member Join Date: Apr 2003 Location: West Yorkshire, UK.	The STA25 has variable fixed bias. There are test points and potentiometer shafts, accessible through a hole near the test points, which can be varied with a screwdriver. Has your friend tried this? They can go off quite a way over time.

6th October 2008, 11:05 AM	#9
andyjevans diyAudio Member Join Date: Sep 2003 Location: London	One thing you might like to know is that the Radford ST25 will soon be made again. Peter J Comeau has bought the name and will be re-manufacturing. www.radfordaudio.co.uk

6th October 2008, 11:10 AM	#10
barretter diyAudio Member Join Date: Apr 2003 Location: West Yorkshire, UK.	One of the test points is at chassis/ground (Radford uses the chassis for ground) level and the other is positive. The potentiomters should be adjusted until you get a reading of 2V (I think it says this on a plaque near the test points). There are two adjustments for each channel. I found it easier to attach the ground lead of a multimeter to the chassis with a crocodile clip whilst poking the positive lead into the appropriate socket and adjusting the pot with a screwdriver.

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