Vacuum tube ! And Warnings


To all out there who have Vacuum tube Amplifiers .
my friend just bought his first tube amp , it came with EL34 power tubes he wanted to get a bit more punch . He ordered on EBay  6550s I told him I would assist in fine tuning the bias.
he plugged them in we turned it on and a huge transient goes through one of the speakers and a surge through one tube . I shut it down waited 5 minutes then turn it on bias has a built in meter ,I checked they were over 90 +milliamperes maxed the meter. should be around 50. I removed them , he is sending back.the story here is many Ebay sellers don’t even test them they just get them from Russia and state as a match quad ,and runin for 24 hours . Never buy from anyone that doesnot  personally check them .
viva tubes, and upscale Audio are good , Jim mc Shane is good.
for vintage tubes, Brent Jesse recording, and Vintage tube services   I recommend. 
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Showing 1 response by jnovak

A couple of years ago I bought a PS Audio BK preamp (the latest one) from a seller here on Audiogon. He replaced the stock tubes with two tubes he bought from The Tube Monger. The seller claimed that the preamp sounded MUCH better with the new tubes, He also provided the original factory tubes. The distortion coming out of the preamp was so bad I couldn't get an output to my computer to produce an undistorted wave file! I sent the tubes to PS Audio who checked them and told me to throw them out. I reinstalled the factory tubes and the preamp performed perfectly. I'd say that the seller was a "tube roller wannabe". If the preamp had tubes that PS Audio felt were excellent and reviewers agreed, why mess with perfection. Joe