The date for the free valve clinic will be the 14th April, here is a quote from Johns Hifi Exchange
“Saturday 14th April we will be have a free “Check Out Your Tube Amp” clinic for all customers.
open to all – you don’t need to be a regular customer or even have bought the item from us.
Our tech will be on hand to give your amp a run over as follows:
1. Check bias current in output tubes..a good sign an amp is healthy
2. Check output tube life, performance and matching
3. Check amp for even frequency response, noise, distortion and, if you are brave, maximum power output.
4. Preamps can be tested for RIAA phono accuracy.
If you buy tubes on the day we will bias your amp free of charge.
Note- tests will be performed on power or integrated amps using up to four octal output tubes only – EL34/6CA7, 6550, KT88, KT66 and 6L6GC. This includes ALL Leak, Quad, Radford, Pre 1980 McIntosh, Marantz, Dynaco and most chinese amps except SET models. No direct heated triode amps and no amps with more than four output tubes due to time constraints. (If unsure ask in advance)”