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  3. 162685-132884

TUBE BIAS, socket to me!

BIAS: (I'm starting from zero understanding) 

I have never measured/adjusted bias in the 3 tube amps, 3 tube receivers, and 2 tube preamps I have acquired over 47 years. I just switched my current Cayin from 6550's to KT88's. Adjust bias? Adjusters inside, scary electrocution warnings. I could pay someone else to do it, i.e. Steve at VAS 1 hr away in NJ, soooo, 

What really counts? (personally I don't care about either heat or life, but would like to understand)

Heat?
Life?
Output stays Matched when adjusted?
Acoustic Performance?
_________?

Over the years, fronts off, bottoms off, I hose em down with contact cleaner/lubricant, compressed air, all controls and switchers, any adjusters, swish full spin back and forth. Kill any spiders, look for, replace the rare burnt resistor. 
Then leave any adjusters (whatever they are) in the middle position, button it back up.

Two tube testers, my big hickock always agrees with small portable one, test strength, shorts, matched strength old and newly purchased. Large collection of NOS, used. Often used test essentially same strength as new ones.

When they go, it's usually a short.
elliottbnewcombjr
oldhvymec
5,101 posts
 
OP, there is one thing for sure. You know it's done, BETTER than most because you did it.  That has always been my position..

Saying that, I have backed off a bit on the self imposed brain surgery (s).
YES practice makes perfect.. Any volunteers? I'm getting close, not seeing double anymore, or less..:-)

Happy Happy...

Regards
elliottbnewcombjr OP
5,304 posts
 
oldhvymec

It's hard to adjust bias with vision problems they tell me.
sokogear
1,093 posts
 
Is it really worth all this fuss? Can't you find a solid state amp that sounds as good or better, or are tubes less expensive for a given sound quality?

Don't shoot me - I am a vinyl guy, so certainly willing to go through some inconvenience for top SQ, but ever since I was in a room with tubes that got so hot a fan had to be installed (ruining the sound of the stereo), I never considered them.

I like to think I am open minded. Convince me why I should change my Plinius 8200MKII integrated amp to a tube one.
lewm
12,909 posts
 
Sokogear, It's a personal decision based on your own listening to music. One cannot say for sure exactly which tube amplifier you might prefer to your Plinius SS one.  There are many types of tube amplifier, just as there are a few different standard topologies for SS.  You would have to put in the work yourself.  But since you have already stated your bias for SS, it might not be fruitful.  It's not anyone else's job to convince you of anything.
sokogear
1,093 posts
 
Thanks Lewm. I am hoping to hear from people who have tried or use both and their reasons for choosing tubes over SS. There was a similar discussion on analogue vs. digital and it was interesting to hear both sides opinions.
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