Newproduction power tubes: Reliablity

@stereo5 

haha stereo, you beat me to saying that

mozart

is there a question in your post?

chinese tubes have historically had a reputation for cheap manufacture and poor qc - back 10-15 years ago they were truly grim

russian makes have had their problems too

in both cases, quality has improved a lot... 

the chinese in general are state of the art in making things cheap, run on the hairy edge, and have failures... they have value engineered the world's supply of most everything, but such is way of capitalism and commoditzation

russian makes still have some soviet military mindset, make things more to last, thicker glass, more solid metal structures inside

this being said, the chinese and russians now also very much understand there is a good size market for quality - so in tube making, they have responded with higher qc, higher quality materials, made premium products as a result and of course they charge accordingly... that is good for us pursuing this hobby/activity

still, i buy from known sources who do secondary testing, i do not trust factory testing in and of itself yet - i won't buy from cheapest ebay sellers without a long reputation

as mentioned, when a power tube fails there is often secondary damage to associated equipment... so it is not just about the seller of the tube taking the tube back - they won't fixed your damaged amp...

@glupson

i may have stated that point a bit too strongly... not to be too scary about this -- more appropriately: when a power tube fails, depending on how it fails and depending on the amp, there may be some ancillary damage -- would be a more accurate statement

like everything else, there is a learning curve and knowledge to using tube power amps
-- turn tube bias down when installing fresh tubes, then bias up gradually after 10-15 minutes idling (if the amp is manually biased)
-- be watchful when first powering up, for abnormal/inconsistent glow amongst the tube set (helps to lower the room lighting to see this obviously)
-- listen for any crackling, hissing or anything sounding abnormal at the amp or through the speakers - things may settle down if this appears initially
-- roughly note operating hours on power tube set over time

all the above is less critical (but should still be practiced) if the tubes have been pre-burned and tested by the retailer - good sources do this, sometimes for a small extra charge, it is worth paying for it for peace of mind

different amps have different protection circuits... primaluna among the best in this respect... the famous brand is audio research whose lovely, expensive amps do not have protection circuitry for the output tube, and so some (usually relatively minor) damage can result if a tube blows badly -- very fixable by a tech but still a pain to deal with (thusly, ARC tube amp users learn to be conservative in terms of replacing power tube sets pre-emptively and carefully noting the operating hours)

@johnss

good post

what amp(s) are you running your kt88s on? curious to know... i have a number of kt88 amps - several audio research and a primaluna - hearing the different sound profiles of the various compatible tubes is fun to experience

as for mozartfan... you are being kind... i would think even mozart himself would reject some of the close minded and narrow thinking expressed  :(

Sovtek makes their tubes in the old Reflektor plant in Saratov... EH is one of their marketing brands, so current 6922’s labeled Sovtek are the same tube as sold by EH

if you want a better sounding 6922 you should look at USA or Dutch Amperexes or Tesla old Yugoslav production ’labelled’ 32... otherwise seek true old stock (not current Sovtek owned brand) Mullard 6922 equivalents called E88CC