• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

tube id book

I am looking for a book that can help me identify different bands of tubes from a fake. mostly the 12a- 7 and 6922 type tubes. When i am at home its easy to compare an example that I have with a picture, sometimes it works when in doubt I don't buy. The prices have gone so high in the last year I am seeing a lot of re marked tubes that dont match in construction up to the nos. Any thing out there to help with date codes? Thanks