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25 quid an hour? or 45 quid all inclusive?
rip off? better off without a service?
fucking r and b and bruce milars.

[General Ermintrude]

groove tubes make an in-line meter for biasing the valves yourself. i think it costs about a hundred quid

[Rob Karloff]

A good electrical engineer who knows their valves should know what you're talking about and be able to do it. However :

You need to know what current flow the amp should have through the valves. Most manufacturers won't tell you this, and neither will the guitar shop techs.

You need to know how to alter the resistors or trim pot to achieve the right setting. Marshall et al will also not tell you which trim pot to use, or where it is.

On an amp that costs circ. £800 upwards and a set of new valves that set you back £50+, is £30 or £40 for doing the job worth risking on doing it yourself....?

unfortunetaly, there arnt any trim pots inside the amp, none that i can see anyway