Welcome to Solid State Guitar Amp Forum | DIY Guitar Amplifiers. Please login or sign up.

December 09, 2023, 10:38:00 AM

Login with username, password and session length


McGregor V4S Amplifier

Started by arpotts99, March 10, 2023, 08:33:16 AM

Previous topic - Next topic


Good afternoon all,

I'm new to this forum so if I make any mistakes, please forgive me.

I'm restoring (or trying to) a McGregor V4S PA amp. So far-so good. I have managed to solve a couple of problems but I have been thwarted by a lack of information on these amplifiers.
I contacted McGregor UK who said that it is not their policy to give out or sell service info (or indeed a circuit diagram). Does anybody out there have a schematic for this amp please.

Many thanks,



Your profile gives no clues what country you are from. I know that in some country's there is a Right To Repair Law, but I don't know the details. Even if your country doesn't have such a law, you might be able to obtain service info from someone in a country that does.


Hi Loudthud,

Many thanks for your reply. I'm located in the UK but I haven't worked out how to show my location yet as I'm new to all this.

There seems to be distinct lack of information on the internet about some electronic products - particularly vintage amplifiers (1970's to 1980's). Why do some manufacturers behave in this way, after all a disclosing information about a 40 odd year old amplifier is hardly going to lose them any business!

Anyway, the project is going well and after some repairs to broken/corroded tracks on the pre-amp board and replacement of some of the pots, I now have a working amp.

Many thanks,




This isn't an amp I'm familiar with.  Any pictures or videos would be much appreciated!
Life is what you make it.
Still rockin' the Dean Markley K-20X