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Topic: Tube time |
gary darr
From:
Somewhere out in Texas
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Posted 10 Sep 2001 6:33 pm |
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I use a Peavy Classic 50 four ten combo for my guitar amp and its starting to get a little distorted on the clean channel. I suspect its probably time for new tubes considering it still has the origional tubes in it from 94. From my understanding Peavey uses Ruby tubes for their amps and I just wondered if any one has tried other tubes in this type of amp, the sound I'm looking for is loud and clean. this amp uses the EL-84 power tubes and 12AX7 pre amp. Is it the pre amp tubes that give the clean vs dirty sound or is it the power tubes ? any input certainly appreciated
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sho-bud,session 500,american standard strat,shecter tele,peavy classic 50
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Michael Holland
From:
Nashville, Tennessee, USA
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Posted 11 Sep 2001 5:52 am
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Hi Gary,
Your power tubes do wear out with use. The pre-amp tubes shouldn't need to be replaced unless you want to experiment with different manufacturers' tubes to get different sounds. I use Mesa Maverick amps for guitar and they also use 12AX7 pre-amp and EL84 power tubes. I just got a new matched quad of Tesla JJ EL84s from Triode Electronics and they sound great. The site also has some good resource and info pages.
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Emmons Push Pull S10 | Peavey Session 400 | '52 Fender Lap Steel | Goodrich L120 & Matchbox
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Mike Brown
From:
Meridian, Mississippi USA
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Posted 11 Sep 2001 11:03 am
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We recommend that you change tubes about every six months if you play the amp several hours per day. There is no "official" time limit as tubes(just like tires) are an expendable part, ie; the more you use them, the more that they wear. We do advise that you change your preamp tubes in addition to your power amp tubes for the same reasoning.
We presently use Sovtek tubes in our products. Our engineers have worked closely with Sovtek and have specified characteristics in a tube that provide maximum performance and longevity. The specific models that we use are the 12AX7EH(low microphonic) in the first position and the 6BQ5/EL84's in the power amp, which are made in Russia. There are questionable claims made by some marketing companies that certain tubes are "matched" and appear to be "better" than others. Well, these tubes may be "matched" when you install them, but just like tires or speakers, they do wear over time, thus changing their performance characteristics. At this point, they are no longer matched.
We have designed and manufactured tube amplifiers since the early '70's and presently have over 20 models in our product line. Lynard Skynard and the Nitty Gritty Dirt Band were some of the first artists who use our tube models and still do today. If you recall, Skynard used our Mace amplifiers. As a matter of fact, guitarist Gary Rossington still uses the original Mace amplifiers in live concerts.
Mike Brown
Peavey Electronics Corporation |
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Bobby Lee
From:
Cloverdale, California, USA
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Posted 11 Sep 2001 8:44 pm
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I never change my tubes unless they get noisy or microphonic. Of course, I also know how to use the standby switch. I don't turn the amp on unless standby is off, and I let the amp come up to full power before swiching standby on. I turn standby off a few seconds before I turn the amp off. I think that most tube wear comes from not using the standby switch properly.
As long as I'm getting a sound I like, why should I change my tubes?
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 Bobby Lee - email: quasar@b0b.com - gigs - CDs
Sierra Session 12 (E9), Williams 400X (E7, D6), Sierra Olympic 12 (F Diatonic)
Sierra Laptop 8 (D13), Fender Stringmaster (E13, A6) |
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Jack Stoner
From:
Kansas City, MO
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Posted 12 Sep 2001 2:21 am
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| When I was doing amp repair, I made a lot of money replacing good tubes simply because the customer wanted them replaced. I had people bring in Twin Reverb's for complete retubings. Tubes do deteriorate over time but the time will vary. |
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Ron Whitworth
From:
Yuma,Ariz.USA Yeah they say it's a DRY heat !!
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Posted 12 Sep 2001 3:09 am
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| My take on this as i use & own several tube amps..DO follow B0b's suggestion to the letter as he stated above!!.Mr. Leo Fender certainly knew what he was doing when he put the "standby" switch on his tube amps..It is a real shame as B0b & Jack are saying that most folks just don't know how to use them properly..Listen to what Jack said also-the voice of experiance from these 2 men..Ron [This message was edited by Ron Whitworth on 12 September 2001 at 04:19 AM.] |
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Jeff A. Smith
From:
Angola,Ind. U.S.A.
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Posted 12 Sep 2001 3:07 pm
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Gary-
You asked whether it is the preamp or power amp tubes that provide the clean or dirty sound. Both stages contribute to the total distortion, but in a different way.
I also understand that preamp tubes need to be replaced less often than power amp tubes.
When Mike Brown refers above to matched sets of power tubes, (only power tubes are matched,) he may be referring in part to the "Groove Tubes" line. Not only are these power tubes matched to produce a balanced output, but they are matched according to characteristics that provide very different distortion levels. The sets are marked either "H" for "hard", or "S" for "soft". The H series tubes will break up later, as volume is increased. There are numbers following the letters, for example: "H-9". I don't remember off hand if a higher number means more distortion or less. Normally discount catalogs don't list what the ratings are, but you can ask what they have over the phone.
There are also characteristic differences depending on where the tubes are manufactured, something else that Groove Tubes offers a selection regarding.
Another advantage of finding a rated set of matching tubes that you like is, you theoretically will not have to re-bias the amp whenever you change power tubes. Proper biasing is extremely important for getting the right sound out of an amp.
Groove tubes generally cost significantly more, but these advantages might make them worth considering for you. |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 12 Sep 2001 5:38 pm
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Tubes either burn out, or they wear out.
Burn out is caused more by cycling on/off than by hours used. Just like a light bulb, tubes most always burn out when power is first applied, and seldom while already operating.
Tube "wear out" stems from a few different problems. Loosening elements (which cause microphonics, or sometimes "shorts") are caused by vibration of the tube...either in transporting the amp, or the repeated vibration from the speaker. Tube "weakening" comes from constant use under heavy loads. The coating on the cathode (which emits the electrons) gradually breaks down due to heat from the filament and use. This weakening exhibits itself by a general loss of gain.
Use of the standby switch (which usually just cuts off plate voltage to the final stages) actually does little to preserve the tubes. It does nothing to prevent loosening elements, or prevent filament burn-out. And it does very little to prevent wear-out, since this problem is caused more by heat and high loads, than it is by idling (no-signal) currents and voltages. I find that using the standby switch, especially on Fender amps, is hard on the speaker, and other components, as well. If you hear a loud "thump", or "snap" from the speaker when turning the standby switch "on" or "off", that indicates a voltage surge...which doesn't help anything! The only real asset of the standby switch is it lets you shut the amp down, without shutting it off. We know repeated on/off cycling is hard on the amp. But, to keep the amp "on and quiet" between sets, it's quite convenient. However, a better idea might be just to turn the volume down.
Want to preserve your tubes? (And the rest of your amp, as well?) Install a small fan that circulates air directly on the power tube section of the chassis. This is especially helpful on amps (most of 'em) that mount tubes upside-down.
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gary darr
From:
Somewhere out in Texas
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Posted 12 Sep 2001 6:26 pm
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Thanks for the input so far guys,I did fail to mention on my original post that this amp is not used daily since 94, but I do gig with it once or twice a month.The classic 50 is allready equipt with cooling fan as Donny suggested and I'm sure that does help with tube longevity, it just seems to my ears (OR HEARING AID) that the clean channel is breaking up a little too fast. I guess the older I get, the more I want my guitar to sound loud and proud like my steel ha ha
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sho-bud,session 500,american standard strat,shecter tele,peavy classic 50
[This message was edited by gary darr on 12 September 2001 at 08:29 PM.] |
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Doug Earnest
From:
Branson, MO USA
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Posted 13 Sep 2001 8:49 am
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I'm curious about sources and brands of tubes. My new Cyber Twin had a bad preamp tube (it made a rattling sound, through the amplifier and also the tube itself rattled after I removed it). I knew it was equipped with Groove Tubes. I called a some stores in the area. One didn't have Grooves, but he did have Sovtek 12ax7wa. This was the correct number, but I kept looking for Grooves. Finally MARS music had new Fender tubes so I went there. Fender box, stamped Fender and Groove Tubes right on the tube - right over Sovtek 12ax7wa. One of these tubes failed soon after, same symptoms.
What other brands / sources would be good to try for the best clean sound? I don't have too much faith in these Sovteks. Other than the crappy tubes I really like the Cyber Twin, BTW.
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Doug Earnest
Zum2000U12,Sierra12,Sho-Bud ProII D10 |
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Hamilton Barnard
From:
Oro Valley, Arizona (deceased)
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Posted 13 Sep 2001 2:26 pm
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JJ/Teslas are a well respected tube with the rock 'n rollers, having good tone AND reliablility. They can be purchased on-line or possibly from an amp tech.
Groove Tube doesn't and never has made a tube. They buy them from suppliers, put them in their tester, then paint their name on them. And I have no idea what their tester is.
We tried a brand-new set of their GT-KT66s (almost $100 for the pair) in an old Marshall. The 'matched pair' were almost 10mA apart in plate current. *LOL*
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My Marshalls.
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 13 Sep 2001 4:10 pm
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| Gary, as a rule, I have found that weak coupling capacitors cause the most distortion-type problems in tube amps. Since they are relatively cheap to replace, it's often the first suggestion I make to someone who has no test equipment (such as an o-scope) to precisely track down the distortion. Re-tubing is becoming a very expensive proposition, and as Bobby says, should only be done when it's really needed. I often got several years of use out of U.S.-made tubes, but most imports aren't as good as the old RCA and GE brands. Still, if you're going to do this as a "maintenance item", I'd replace the power tubes every 1-2 years, and the preamp/driver tubes every 4-5 years. |
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Michael Holland
From:
Nashville, Tennessee, USA
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Posted 14 Sep 2001 11:25 am
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Tube resources links page.
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Emmons Push Pull S10 | Peavey Session 400 | '52 Fender Lap Steel | Goodrich L120 & Matchbox
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Michael Frede
From:
Sonoita, AZ, USA
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Posted 17 Sep 2001 4:48 pm
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| When the master vol. is turned down and the preamp level is advanced,saturation occurs primarily in the preamp section.When the master is all the way up,advancing the preamp control will eventually cause saturation in the power amp section.These settings produce two very different types of distortion,and saturation in the PA in combination w/the output transformer produces an abundance of even-order harmonics and is very musical IMHO. |
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Len Amaral
From:
Rehoboth,MA 02769
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Posted 17 Sep 2001 5:24 pm
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| Sovtek tubes seemed to be quite good when I was using tube amps. The driver preamp tube usually will be the first to give you trouble in the preamp section. This tube is usually the first tube next to the power tube. |
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Bobby Lee
From:
Cloverdale, California, USA
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Posted 17 Sep 2001 5:44 pm
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I don't hear a "thump" when I switch my standby switch on. Maybe Mesa/Boogies are wired differently from other tube amps.
I bought my current Mesa Maverick combo amp about 8 years ago. I still don't feel a need to change tubes - it sounds as good today as when I bought it. I've used it at least once or twice a week for as long as I've had it.
Yes, it has a fan.
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Bobby Lee - email: quasar@b0b.com - gigs - CDs
Sierra Session 12 (E9), Williams 400X (E7, D6), Sierra Olympic 12 (F Diatonic)
Sierra Laptop 8 (D13), Fender Stringmaster (E13, A6) |
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gary darr
From:
Somewhere out in Texas
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Posted 17 Sep 2001 6:27 pm
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I finally tried some new EL-84's in my amp,the place that I bought them from only had the Sovtek quad set in red. These break up or distort more readlily than the blue sets. Verdict is in, the reds definatly not for country or clean guitar work. I have to wait another week or so when they get some blue ones in and I'll update on my findings
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sho-bud,session 500,american standard strat,shecter tele,peavy classic 50
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Mark Cohen
From:
Calabasas, CA, USA
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Posted 17 Sep 2001 10:02 pm
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| Gary: I'm sorry - entering late as I did. That was a Classic 50, as in 50 watts? I find it very hard to play undistorted in front of a trap set with such a small amp. Sure, tubes wear out, but you might just be pushing this amp a bit too hard. |
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gary darr
From:
Somewhere out in Texas
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Posted 18 Sep 2001 10:46 am
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Yes Mark, the amp is a 50 watt'er however I'm playing in a duet situation at present and we use a drum machine thats mostly out front on the mains.I have played this amp a few years now and I have a pretty good feel of what it can produce,I think I just made a bad choice in the power tube .BTW this is my six string guitar amp, not my steel
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sho-bud,session 500,american standard strat,shecter tele,peavy classic 50
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gary darr
From:
Somewhere out in Texas
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Posted 23 Oct 2001 7:06 pm
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| I finally got my my second set of sovtek tubes after a long wait and what a difference they were from the first I tried.The blue coded (cleanest)ones are the ones for me. They don't do heavy metal but they sure sound good for anything from clean county to Eric Clapton kinda blues tones. I just wanted to update and thank everyone for the great input and links you provided, best regards........Gary |
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