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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. 
audioman58
stereo5's avatar
stereo5
6,533 posts
 
I have had 2 bad experiences on eBay. Not for tubes, but for other audio equipment.  In one case, it was an Acrolink cable that never materialized after waiting 9 months.  The other was on an amp that arrived broken (not from shipping) and had a very hard time getting a refund.  Too many amateurs selling on eBay so now I avoid at all costs. 
birdscantrow
19 posts
 
agree with Stereo5 on why would anybody buy tubes off of Ebay ?   

if you knew your friend was going to get tubes, why not suggest getting them from a tube dealer that would have the tubes matched / tested ???

there was another thread recently about someone getting tubes from Ebay and they are all shocked that they were junk.    duh.....
geoffkait's avatar
geoffkait
23,365 posts
 
“Not for tubes.” There it is! 🤗
audioman58's avatar
audioman58 OP
4,306 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 .
big_greg
6,711 posts
 
Saying that every tube seller on ebay is bad is a bit of a head scratcher. I bought two matched quads of KT120’s back in October from ebay for my Rogue Audio monoblocks and no issues whatsoever.

I just biased my amps today and the tubes in one amp had not drifted at all, and in the other amp, a couple of tubes were just a hair off. That particular seller has about 19000 transactions and 100% feedback. I would keep an eye on those numbers when considering making ANY purchase from ebay.

I’ve bought tubes from Brent Jessee and a couple have had had issues. That doesn’t make him a bad seller. He arranged to get me new ones pronto and was super helpful when I had questions about the best tubes for my gear, listening preferences, and budget. I recommend him highly.

I’ve also had issues with Sophia Electric tubes. Same thing, they got me new ones quickly and were easy to deal with. I’d also recommend them.

I don’t know how the other seller would have responded if I had problems, since I haven’t.

Exercise common sense and good judgment when buying from ebay, the same as you should when making any online purchase. Don’t lump all sellers into one bucket because of a couple of bad ones.


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