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Need CL help

#21
If the bias on each triplet is proper (point above cutoff) they combine properly at the OT. You can not maximize bias to three different tubes on one side (as in replacing "pairs"). If it was a critical "HiFi" application then an interactive output balance control should be used (is the original SVT did). Matched sextet prefered yes, absolutely necessary, in an MI amp no. You would be hard pressed to hear any small crossover notch distortion from a bass amp.
 
#22
svt's DO work in a push pull system. but 3 power tubes push and 3 tubes pull, unlike most tube amps where each power tube is paired with another for push pull. so you get 3 that match on each side, then you set the bias FOR EACH SET OF 3 SEPARATELY. so all you need to do is get two sets of 3 that match each other within their own sets. once the bias is set properly, each triplet set can be non-matching and it won't matter.

but if it makes you feel better to replace them all, have at it. not my money.


Jimmy M.
 
#24
Had me trippin' there for a minute Mark.


Now, since I have been looking all over the internet this morning trying to be thorough, I have seen a lot of information about blown grid resistors and diodes etc.. I really can't afford to pay a tech to even bias this thing so I am hoping at the most, a matched sextuplet of tubes and the bias lights on back will have me back in shape. I'd like to get by with 3. Taking it to a tech is definitely something that will have to wait. What are the odds that something else popped as well.
 
#26
Floyd Eye said:
Had me trippin' there for a minute Mark.


Now, since I have been looking all over the internet this morning trying to be thorough, I have seen a lot of information about blown grid resistors and diodes etc.. I really can't afford to pay a tech to even bias this thing so I am hoping at the most, a matched sextuplet of tubes and the bias lights on back will have me back in shape. I'd like to get by with 3. Taking it to a tech is definitely something that will have to wait. What are the odds that something else popped as well.
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Since this happened at power on and not under full operating conditions chances are you won't have further troubles. No guarantees, but the odds are in your favor!

Alex1984 said:
I have no idea what you guys were talking about, but B-String is an amp guru, and I've yet to see him proven wrong on here.
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Thank you ;)
 
#30
I think I'll go ahead and order 6 matched tubes. I can get 6 new Sovteks for $191.50 or I can get 6 matched Winged Cs with 800 hours on them from some dude on Ebay for $150. I'd like to get the Winged Cs but I don't know about buying them used. The guy has 100% positive feedback though.
 
#31
Used tubes are always a gamble new production or old production. IMHO if they were $75 to $100 max I might say worth the gamble. I'd go new set with a warranty to cover any possible new tube failures.
800 hours from a well cared for amp should have plenty of life left but.........to many unknowns at that price.
 
#32
Mark Reccord said:
Yeah, there are 3 "push" tubes and 3 "pull" ones, just like in any push-pull amp with 6 output tubes. You can indeed bias the amp properly with 3 different matched pairs but good luck doing it with 3 matched tubes on one side and 3 matched but different ones on the other.

There's a reason the vendors sell matched pairs and not matched triplets. :)
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You *match* parallel-connected tubes so you don't get current runaway. You *balance* drive to push-pull stages in some amps with adjustments. They are two different things, and the second does not apply to SVTs in general since the drive levels are fixed in the power amp. This discussion has been had many times before. You match tubes in threes for SVTs.

The only reason you can't buy triplets is that distributors found that people would buy sextets instead. You can save money and buy a quad, and have a new spare to boot. :hmm:

You could always prove us all wrong by putting three different brands of matched pairs in your SVT-CL and having it bias up with no issues. ;)
 
#33
okcrum said:
You *match* parallel-connected tubes so you don't get current runaway. You *balance* drive to push-pull stages in some amps with adjustments. They are two different things, and the second does not apply to SVTs in general since the drive levels are fixed in the power amp. This discussion has been had many times before. You match tubes in threes for SVTs.

The only reason you can't buy triplets is that distributors found that people would buy sextets instead. You can save money and buy a quad, and have a new spare to boot. :hmm:

You could always prove us all wrong by putting three different brands of matched pairs in your SVT-CL and having it bias up with no issues. ;)
Click to expand...

I understand how it works, just had a temporary lapse. No CL for me thanks, I'll stick to the real thing. ;)
 

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