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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. 
128x128audioman58

Showing 5 responses by audioman58

audioman58's avatar
audioman58 OP
3,913 posts
 
I was just making a point nothing more
i have been using tubes for over 40 years 
and owned a Audio store I know how to bias tubes. My point was a lot of eBay sellers don’t even check the tubes they just 
go by what the mfg state I later checked
with a textronics tester 2 tubes were at over 100 most ma meters go to under 90.
that is why you buy tubes that should be within range under 70 ma for sure
6550-kt88 50-60ma is the norm
audioman58's avatar
audioman58 OP
3,913 posts
 
It is a custom canary amp
audioman58's avatar
audioman58 OP
3,913 posts
 
The amp in question can take el34- kt 150s
audioman58's avatar
audioman58 OP
3,913 posts
 
hello Jond  the amp can take anything from El-34,  KT-88-6550 kt120,kt150s
audioman58's avatar
audioman58 OP
3,913 posts
 
my friend bought them ,and told me after he had them in his possession.
i told him ,he is sending them back 
pronto tommorow ,it was a very valuable lesson learned and luckily no damage .
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