Go Back   Home > Forums > >

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Radford STA25 service UK
Radford STA25 service UK
Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools
Old 3rd October 2008, 09:50 PM   #1
aquapiranha is offline aquapiranha  United Kingdom
diyAudio Member
 
aquapiranha's Avatar
 
Join Date: Jul 2007
Default 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.
  Reply With Quote
Old 3rd October 2008, 09:52 PM   #2
bigwill is offline bigwill  United Kingdom
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

  Reply With Quote
Old 3rd October 2008, 09:56 PM   #3
bigwill is offline bigwill  United Kingdom
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
  Reply With Quote
Old 3rd October 2008, 09:58 PM   #4
aquapiranha is offline aquapiranha  United Kingdom
diyAudio Member
 
aquapiranha's Avatar
 
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..
  Reply With Quote
Old 3rd October 2008, 09:59 PM   #5
aquapiranha is offline aquapiranha  United Kingdom
diyAudio Member
 
aquapiranha's Avatar
 
Join Date: Jul 2007
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...
  Reply With Quote
Old 4th October 2008, 07:33 AM   #6
coolmaster is offline coolmaster
diyAudio Member
 
Join Date: Jul 2005
Location: MY
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.
  Reply With Quote
Old 4th October 2008, 09:35 AM   #7
barretter is offline barretter  United Kingdom
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.
  Reply With Quote
Old 6th October 2008, 11:49 AM   #8
aquapiranha is offline aquapiranha  United Kingdom
diyAudio Member
 
aquapiranha's Avatar
 
Join Date: Jul 2007
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
  Reply With Quote
Old 6th October 2008, 12:05 PM   #9
andyjevans is online now andyjevans  United Kingdom
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
  Reply With Quote
Old 6th October 2008, 12:10 PM   #10
barretter is offline barretter  United Kingdom
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.
  Reply With Quote

Reply


Radford STA25 service UKHide this!Advertise here!
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Radford ZD 50 and ZD 100 schematic anyone ? phase_accurate Solid State 9 20th February 2009 12:16 PM
Radford STA-15 questions patrickamory Tubes / Valves 17 24th November 2007 05:21 PM
Need help with a Radford HD 250 amplifier gaetan8888 Solid State 2 4th July 2007 06:59 PM
Wanted Radford MA-15 spoke Tubes / Valves 6 14th June 2007 04:29 AM
Radford STA25 Gram Tubes / Valves 4 15th August 2003 10:32 PM


New To Site? Need Help?

All times are GMT. The time now is 10:26 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.79%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki