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Tube Amp Questions

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(@the-dali)
Noble Member
Joined: 18 years ago
Posts: 1409
Topic starter  

Sorry - I put this in the recording section by accident...

Hello everyone... well I know a lot about guitars and next to nothing about amplifiers. I bought a Traynor YCV40T which was running pretty well, but recently the sound hasn't been that good and now it actually seems to "fart" or "belch" when hitting the low strings. I took a look at the tubes and it seems like only one is working... but I don't know. It just doesn't sound right.

The setup for this amp is:

Preamp Tube - 3x 12AX7WA Dual Triodes (Russia)
Power Amp Tube - 2x 6L6GB Beam Power Tubes (Russia)

I assume that the two large tubes I can easily see and touch are the Power Amp tubes. I think only one is working because I only see one light up.

The other three tubes are inside a housing that I can't easily get to (the others you can get to without taking the amp apart). Is it easy enough for me to order two new Power Amp tubes and replace them? Is that the source of the issue, or should I have someone (a tech) look at the whole amp? I can't really see the three pre-amp tubes so I don't know if they are all working or not.

Plus, I bought this second-hand so I don't know the last time the amp was serviced. The Power Amp tubes appear to be the original tubes (the name matches the ones in the book).

I know some of you are real tube Amp geeks/gurus ... what do you think I should do? Ahh... part of me just wants to go back to Solid State...

Thanks!

-=- Steve

"If the moon were made of ribs, would you eat it?"


   
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(@ricochet)
Illustrious Member
Joined: 21 years ago
Posts: 7833
 

If one of the 6L6s isn't glowing, you've definitely got a problem. Replace both of them.

I don't know whether that Traynor amp is one with adjustable bias that has to be set. If so, you'll need to take it to a tech to get that done, or learn the procedure and buy the necessary equipment. Sounds like you would rather get it done. However, if that amp has "cathode bias" or nonadjustable fixed bias, it's a simple plug and play operation, rather like changing light bulbs.

(Why players without a full time gear support staff on salary want to buy amps that require adjustment by a technically knowledgeable person to change tubes is beyond my comprehension, but they've been doing it since the early '60s. One of those things the audiophiles infected us with.)

"A cheerful heart is good medicine."


   
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(@the-dali)
Noble Member
Joined: 18 years ago
Posts: 1409
Topic starter  

A couple of additional questions...

Can you replace the Power Tubes without replacing the 3 pre-amp tubes?

Is the biasing for the pre-amp tubes, or all the tubes? I thought I read somewhere that the biasing was specifically for the pre-amp tubes.

Any suggestions on the tubes? I went to eurotubes.com and found that there are like 100,000 types ranging from $10 Electro-Harmonix tubes (per tube) to $100 specialized tubes...

-=- Steve

"If the moon were made of ribs, would you eat it?"


   
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(@racetruck1)
Honorable Member
Joined: 18 years ago
Posts: 518
 

No, you don't have to replace the pre amp tubes with the power tubes. Usually there is no biasing on the 12AX7 preamp tubes either.

Try swapping the 6L6GB tubes in thier sockets and see if the original non glowing tube is still not glowing, if it is, then the heater is bad, just replace both power tubes.

I always rebias the amp when retubing, I think that it is just good practice and extends the life of the power tubes and prevents any damage.

Every used tube amp I get gets a good going over, theres no way to know if theres an existing problem within the amp, any good amp tech can do this for a reasonable amount. He (or she) will check things like capacitors, power resistors and biasing. Sorta like giving your car a good tune-up! Well worth the money in performance and peace of mind.

Tube selection can be intimdating, opinions are like a******s, everyones got one, I have customers who demand vintage NOS (new, original stock) tubes that can run obscene amounts of money and others that say generic, Russian or Chinese tubes are fine. I personally have a hard time hearing it myself! Sovtek 6L6GC will run you about $10 to $15 each at GC and I have had no problems using them. 12AX7,s run about $5 to $7 each, it won,t hurt to put them in either but It may not be necessary.

One last warning, THERE BE LIGHTNING INSIDE ANY TUBE AMP!!! High voltage lives here! 350 to 400V at the power tubes and capacitors that can hold a charge after the amp is unplugged!

If you are unsure about ANYTHING inside, don't do it! get someone else that knows what they are doing do it! Biasing does require that you play around with this kind of stuff and proper safety proceedures MUST be followed to do it safely!

I think that it is well worth the added effort to own a tube amp, there is a good reason for them to still exist. The sound of them beats the crap out of any solid state amp by a large margin. JMHO.

By the way.

Welcome to the dark side! :twisted:

When I die, I want to go peacefully in my sleep like my grandfather, not screaming......
like the passengers in his car.


   
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(@ricochet)
Illustrious Member
Joined: 21 years ago
Posts: 7833
 

I buy the cheapest tubes available and keep spares on hand always. Works fine for me.

For all the fuss made over tube types and brands, really that's one of the lesser factors in the tones you hear. They're just one link in a long sonic chain, and the differences as Racetruck said tend to be fairly subtle. Not only that, but they're not consistent with the same tubes in different amps as the tubes are operating within a circuit with other components interacting with them, not alone. Personally, when I use different tubes and they sound a little different, I say "They sound a little different. Cool." And I go right on playing. I have no patience with people with fixed ideas of "tone." Some people like Bob make a very good living catering to those notions, while I roll my eyes in derision. I'm glad I don't have to make my living that way.

"A cheerful heart is good medicine."


   
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(@the-dali)
Noble Member
Joined: 18 years ago
Posts: 1409
Topic starter  

Thanks - I'm going to try to bring it to a local tech for a full check-up. Like I said, I bought her used about a year ago so it is probably a good idea to have the amp checked out altogether.

Ric - I'm on board with the "sonic qualities" of materials. I believe most of it is simple hype. From the type of wood in a guitar to the solid versus laminate argument to the USA versus import pickups to the cable that you use to the type of strings to the amp (solid state versus tube) to the type of speaker in the amp to the electrical system you are using for power... there is so much that influences the sound of the guitar, and to pigeon-hole yourself with a specific type of anything for "your tone" is simple-minded.

With that said, the Traynor amp sounds GREAT and I hope we can get it fixed without too much cash outlay.

-=- Steve

"If the moon were made of ribs, would you eat it?"


   
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(@hyperborea)
Prominent Member
Joined: 17 years ago
Posts: 827
 

It's my understanding that all the new Traynor tube amps (i.e. 90's and on) are all cathode biased and don't need anything done when replacing the power tubes. You can find links to the owner's manual and the service manual here - http://www.traynoramps.com/products.asp?type=3&cat=63&id=252

On page 4 of the owner's manual it says:
This amplifier features Yorkville's auto-balancing / auto-matching tube biasing technology. As a result, when the time comes to replace the tubes in your Yorkville amplifier, there is no need to pay a premium for a matched set – nor does the bias need to be adjusted when you use a different brand. We make no claims as to which brands of tubes might sound best, but with auto-balancing / auto-matching, you are free to experiment without any need for concern that the amplifier or tubes will be distressed. Please note that auto-balancing / auto matching cannot fully compensate for different types of tubes - 6L6/5881s versus 6CA7/EL34s, for example.

Pop music is about stealing pocket money from children. - Ian Anderson


   
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(@the-dali)
Noble Member
Joined: 18 years ago
Posts: 1409
Topic starter  

Well, I brought the amp to a GREAT local tech and asked him to look over the entire amp since I had bought it used and didn't know the history. He had it for a week and said that the only issue was the one bad power tube. Overall he thought it was in great condition and REALLY loved the sound.

I decided to re-tube the whole thing, so we put in JJ Tubes for the pre-amp and power tubes. I'm still working them in, but it sounds fantastic.

$110 out the door, so not too bad! I really do recommend that people check out these Traynor amps... good sounding amp (made in Canada) for under $500 with Celestians.

Later.

-=- Steve

"If the moon were made of ribs, would you eat it?"


   
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(@ricochet)
Illustrious Member
Joined: 21 years ago
Posts: 7833
 

Sounds great!

"A cheerful heart is good medicine."


   
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