Question about bias resistors

[Mr.Death]

I plan on biasing my Traynor yba3  myself with the 1 ohm bias resistor attached from pin 8 to ground. Question is do I need to have a resistor on all 4 tubes or can I just put a resistor on one tube and use that as my bias point of adjustment? The tubes are a matched set. Will having a resistor on just one tube mess up that tubes bias and have it hotter than the rest? Thanks.

[thetragichero]

i find it best to have one on each side to check that each half is biased close. matched doesn't always mean matched after running in the amp for awhile

[Mr.Death]

for all 4 tubes? 8 points to read?

Question was is it fine to just use one tube to check the bias? Only attaching one 1 ohm resistor to one tube. Not all 4 (or 8).
Thanks

[66Strat]

If you assign a resistor to each tub cathode, it will provide the ability to mix and match tubes to achieve the best side to side balance.

[Mr.Death]

Its kinda tough to get at some of the tubes to get a resistor in place, why I ask is it cool to just use 1 tube to read from.

[66Strat]

You can use one tube to bias the amp; but you will only know the current draw for that one tube.  A work around would be to alternate each tube in that tube socket to measure the current draw for each tube, and then mix and match tubes accordingly.

[acheld]

is it cool to just use 1 tube to read from ?

No.    Of course, that depends on your definition of "cool."

If you're going to install resistors to assist biasing, the minimum would be two resistors, one for each pair of tubes.   It is not uncommon to see large differences in tube performance, and using only one tube (of four) to bias your amp will miss this.   Better to use one resistor for each tube pair, at a minimum.   

I've never worked on a yba3, but the internet image of the interior suggests there is plenty of room to do this.

[Mr.Death]

is it cool to just use 1 tube to read from ?

I've never worked on a yba3, but the internet image of the interior suggests there is plenty of room to do this.

My eyes aging and my hands are not so steady. lol. Maybe easy for some...

[Mr.Death]

Maybe Ill just buy the probe.

[66Strat]

Maybe Ill just buy the probe.

Or, hire a tech.

[Mr.Death]

Never!!! I just recapped and modded my yba. People told me to take it to a tech for that but I refuse to pay someone to do something I can do myself. Like that with most things in life. Pay NO-ONE to do stuff you can do yourself!!! I'm sure I could add the 4 resistors to all 4 tubes if I really took my time ....just wanted to know if 1 tube would suffice.

[thetragichero]

for all 4 tubes? 8 points to read?

Question was is it fine to just use one tube to check the bias? Only attaching one 1 ohm resistor to one tube. Not all 4 (or 8).
Thanks

I'm curious about what sort of dual cathode power tubes you might have that would take 8 cathode resistors

[glass54]

It appears YBA3 can come with 6CA7, 7027 and possibly other output tubes.
So 4 tubes, 1R0 on each one on pin 8. Can it be simpler? Avoids removing 4 output tubes, one at a time to use "the probe".
(Always pin 8 on 6CA7, EL34 and 7027)
My thoughts 
Regards
Mirek

[acheld]

eyes aging and my hands are not so steady. lol.

Oh man, I know all about that!    

[PRR]

...YBA3 can come with 6CA7, 7027 and possibly other output tubes.
(Always pin 8 on 6CA7, EL34 and 7027)

6CA7 is a US-branded EL34. (Some were different internally but bodged to work-alike.)

7027 is a hi-spec 6L6GC with extra grid pins in unexpected places to 'force you' to use 7027.

Aside from the 7027 cheap-trick, OCTAL power tube pinouts are standardized. Heater always 2 and 7, cathode always pin 8.

[Lectroid]

My eyes aging and my hands are not so steady. lol. Maybe easy for some...

I resemble that remark!     

[sluckey]

Aside from the 7027 cheap-trick, OCTAL power tube pinouts are standardized. Heater always 2 and 7, cathode always pin 8.

Here's another non-conformist...