What I do…
With a degree in electronic engineering, forty years experience designing, building and repairing electronic equipment and a well equipped workbench, I service and repair valve and transistor amplifiers, effects and P.A. equipment.
Initial diagnosis will cost a maximum of £30 (if the diagnosis is simple I will charge you less, unlike most workshops who charge a flat fee). Once we know what the problem is I will quote you a price for carrying out the work. I aim to turn every job around within 7-10 days, but sometimes it can take longer to source hard to find parts.
Some common problems:
- If your amp goes bang, makes smoke or is completely dead, it’s probably the main transformer blown (assuming you’ve already checked the fuses!) but some further investigation will be needed to find out what caused it to blow.
- Output valves have a limited life and need changing every year or two to maintain output power and quality. This isn’t quite as simple as just plugging in a new pair/set, the bias needs to be adjusted to match the new valves and ensure you get the best sound and maximum life expectancy from them.
- Capacitors have a lifespan of about 35 years, and on vintage equipment leaky valves can cause a variety of symptoms.
- Contacts and potentiometers get worn or dirty, causing all sorts of crackle, pops and hum.
- If the amp is completely dead it is probably the power supply blown. As with valve amps, the main culprit is the transformer.
- If the amp lights up but there is no sound, or no sound from one channel, it is likely to be the output transistors.