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Do I need matched tubes?
Old 7th December 2009
  #1
80425 ๐ŸŽ™๏ธ
Guest
Do I need matched tubes?

I have a Peavey Ultra 410...Been noticing some crackling in certain channels as of late so I checked the tubes... & yep I need some new ones.

I understand the pre-amp tubes are the cause of my particular problem so I'm just going to swap all four of those guys out & replace them with new 12ax7a/Ecc 83's. I'm planning on going with Sovtek 12AX7WA...They've been in there for as long as I can remember.

Now I figure I might as well replace the amp tubes as well & get those two Chinese 6l6gc's out especially cause the signs of wear are evident, I.e Brown print, but does the replacement pair need to be matched, or is that something that only pertains to separate amp heads? Or choice a choice of color...much like the endless debate of gold platted tips,high gain or soft gain tubes...


Thanks for your help!
Old 7th December 2009
  #2
Registered User
 
๐ŸŽง 10 years
Quote:
Originally Posted by Mr_headphones โžก๏ธ
I have a Peavey Ultra 410...Been noticing some crackling in certain channels as of late so I checked the tubes... & yep I need some new ones.

I understand the pre-amp tubes are the cause of my particular problem so I'm just going to swap all four of those guys out & replace them with new 12ax7a/Ecc 83's.

Now I figure I might as well replace the amp tubes as well & get those two Chinese 6l6gc's out, but does the replacement pair need to be matched, or is that something that only pertains to separate amp heads?


Thanks for your help!
I assume it's a push pull amp so yes the 6l6s should be matched.
tubedepot.com sells them matched.
Old 7th December 2009 | Show parent
  #3
80425 ๐ŸŽ™๏ธ
Guest
Not exactly sure how to know for sure if its a push pull any explanation for such?

Old 8th December 2009 | Show parent
  #4
Registered User
 
1 Review written
๐ŸŽง 10 years
Most guitar amps over 20 watts are push/pull.
Old 12th December 2009 | Show parent
  #5
Registered User
 
๐ŸŽง 10 years
No Matching needed in guitar amps. The straight Dope

In a high powered circuit like the Ampeg SVT, yes definitely there must be two matched trios to balance. In a Hi Fi amp, yes definitely if there is no bias and AC balance adjustment to compensate for unmatched tubes. In any tube guitar amp up to 4 power tubes run at rated plate voltage it is not needed. That includes the original Marshall Major 200w. Fender, Marshall,Vox,Traynor,Etc Etc. did not match their tubes. That is why Fender tried the bias balance circuit in Silverface amps, and part of the reason they sounded more sterile than Blackface amps. Unmatched power tubes add to the character of guitar tone, historically. YOU DO NOT NEED MATCHED TUBES AND IT MAY WELL MAKE YOUR GUITAR AMP SOUND WORSE TO YOU.
Old 12th December 2009 | Show parent
  #6
Registered User
 
๐ŸŽง 10 years
Although

Extremely unmatched tubes (one near dead) can allow amplifier hum to increase through the speakers, as well as lower the power output of your amp. This is because the push pull power section cancels exterior/interior hum just like any balanced signal circuit. Oh yeah, swap around your AX7s until you get the best sound for you. This can have a major difference on tone, gain,response etc. It seems to be finding which tube is best for the first position. Power tubes don't react the same because they are all parallel together anyway, and not in series like the preamp tubes.
Old 13th December 2009 | Show parent
  #7
Gear Guru
 
kafka's Avatar
 
๐ŸŽง 15 years
"Need" is a funny word. Until the `80s, nobody had ever heard of matched tubes because there weren't any. Groove Tubes was a new thing, and although Boogie was selecting and matching their tubes, they were just doing so to support their own products. When we needed new tubes, we just went up to Radio Shack and got the right ones, and that was it. Typically we didn't even change them until they failed. As far as matching goes, the advice was to use the same brand, and to change pairs at the same time. By the `90s, matched pairs and quads had become de rigueur.

Well, having played guitar since well before we had matched tubes, I can tell you that it certainly is possible, and many fine and great sounding albums have been recorded with unmatched, old, and worn out tubes. However, after switching to matched tubes some time ago, I don't know why someone would bother not to. It costs $2 or $3 more per set to match them, and I can't say I've ever met someone who thought that unmatched tubes sounded better. But as the last guy said, hey, unmatched tubes (or old worn out tubes, or dead strings, or 60 cycle hum, or whatever) just may be your bag.

I personally would look for something other than a pair of Chinese power tubes. I haven't tried many, but the few I've had were unreliable and sounded pretty flat. Of new productions, I like the Tung-Sol 6l6GC reissues and the Groove Tubes black plates. Sylvanias, Phillips, RCA, and GE are all great NOS tubes. NOS tubes are a world of their own and can be pricey, so talk to a tube dealer before you pay too much for something you may not like.

As far as 12ax7's go, I have a shoebox full of old ones (preamps tubes essentially last forever. not exactly, but close). When I'm not happy with my sound, I just dig out the box and just swap them around until it sounds right. I'll use one that has matched sections for the phase inverter on some of my amps that need it (all but two), but the rest are just a question of taste. I could end up with a vintage Mullard, or a cheap Russian, or some unlabeled thing.
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