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Topic: Replacement tubes |
Harold Dye
From:
Cullman, Alabama, USA
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Posted 13 Jan 2005 5:30 pm |
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When replacing tubes in an amp (Fender or Music Man)Which ones(brands) are best to use?
I know there are different manafacturers of tubes but are some better for amps used for steel as opposed to an amp used for 6 string guitar. Will a different make of tube give a different sound in an amp, or is a good quality tube as good as any other? I have heard of Groove tubes...what are they, and how do they compare to other tubes? |
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Harold Dye
From:
Cullman, Alabama, USA
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Posted 13 Jan 2005 5:33 pm
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| Sorry about the spelling in the above post...it was just a slip of the finger... |
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jim milewski
From:
stowe, vermont
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Bob Metzger
From:
Waltham (Boston), MA, USA
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Posted 13 Jan 2005 11:38 pm
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Tubes are a deep subject with almost everyone having lots of opinions all over the spectrum. But here goes:
Tubes do vary with the different manufacturers but I think setting the bias for power tubes will have alot to do with the sound you get. A guitarist after a distorted sound might set his bias differently than a steel player looking for a clean sound, even with the same type of amp. Whenever you get new tubes, check your bias (or have your tech do it). It's important, maybe the most important thing.
Some tube types are known to be brighter and others darker. If I had a very bright amp, I might use tubes known to be a bit darker in sound, to help balance the sound somewhat. Or vice versa. This is part of the art of tube usage and selection.
Also there are tubes that are direct drop in replacements, with no modifications at all. For example, if your amp uses 6L6 tubes, you could consider using 5881, 7581A, KT66 as well. Each of these tube types has their own set of electronic characteristics and sound, and could be beneficial, depending on the sound you're after.
Groove tubes aren't really a tube type/make but more, a biasing or transconductance system allowing the user to get similar characteristics with each (power) tube change. Lets say you found a particular type of 6L6, for example, that you liked alot from Groove Tube. And when you retubed your amp (hopefully, several years later) you may not be able to get that very same type of 6L6 again (it may not be available anymore) but their numbering system would ensure that the new tubes will have characteristics similar to the old tubes. Groove Tubes merely buys, tests and relabels tubes, according to their own specs and system. At least, this is what they have done in the past. I've heard Aspen is involved in some deals in Russia/Europe. Stay tuned to see what develops.
If all this nuance confuses you, find a reputable seller of tubes who knows what your application is and can steer you toward the right product. Someone like Lord Valve. Keep in mind you're probably after a clean sound (if you're using these tubes in an amp for Steel Guitar) and you'll be looking for matched tubes, which helps to get the most clean power from your amp.
Bob Metzger[This message was edited by Bob Metzger on 13 January 2005 at 11:47 PM.] |
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Billy Murdoch
From:
Glasgow, Scotland, U.K.
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Posted 14 Jan 2005 2:23 am
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Harold,
I hope you do'nt mind me butting in on your thread,I have a somewhat similar query on tubes.
I purchased an amp which has 6L6 output tubes fitted,the original tubes were EL34.
I cannot find out if the previous owner had the amp biased when the 6L6 tubes were fitted.
My question is...If biasing has not been done could I be damaging the amp or is biasing done to alter the tone only.
Thanks
Billy |
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Tony Prior
From:
Charlotte NC
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Posted 14 Jan 2005 3:16 am
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ok my 1 cent..thats half of 2 cents..
Unless you know why..replace tubes with the same type, not necessarily the same brand but for sure the same type.
Pre amp tube swapping or substituting will color the front end..harsh, bright, gain , edge etc...swapping power tubes with the wrong ones or different ones without knowing why it was done will most likely cause a decrease in overall output gain. It's not a damage thing..
Tube Amps are designed to work with the tubes that it came with. Circuits and settings are designed for a specific type of tube for efficient operation.
You can buy a matched set of Sovtek 6L6's for your Fender amps for less than $30..Groove Tubes matched will be probably closer to $70..Is there a difference?..I'm sure some would argue there is..the only difference I can see is $40...oh..and bragging rights I suppose...
Once you're on the bandstand, under the lights with the rest of the CrXX on stage..and with single coil pickups...the only real test for the amp is..does it come on ? and does sound come out....? after that the rest is downhill...
t[This message was edited by Tony Prior on 14 January 2005 at 03:18 AM.] |
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Mark Metdker
From:
North Central Texas, USA
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Posted 14 Jan 2005 5:09 am
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Hi Harold. I'm not a tube expert by any means, but to answer your question, I use Groove Tubes and think they work just fine. In fact, I broke a tube in my Hot Rod Deluxe this week, went down to Guitar Center and bought a replacement Groove Tube...sounds great.
------------------
Zum U-12 w/True Tone pickup
G&L guitars
Peavey Nashville 112
Band Pics
http://community.webshots.com/album/176544894AuXSmi
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Dennis Detweiler
From:
Solon, Iowa, US
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Posted 14 Jan 2005 6:58 am
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JJ Tesla EL84 power tubes. Sovtek 12AXLPS. Electro-Harmonix 12AT7. I purchased these tubes for my Peavey 50/50 head after hours of surveying tubes for clean power and warm tone. Purchased through thetubestore.com
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Dave Grafe
From:
Hudson River Valley NY
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Posted 14 Jan 2005 9:43 am
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While there is often a noticeable difference in the performance of tubes from various manufacturers I will leave the discussion of which tubes work best to those who hold stronger opinions than myself. However, I DO have a very important note for those wishing to experiment with bias adjustments and such:
BE VERY CAREFUL WHEN POKING AROUND INSIDE YOUR AMP! THE PLATE CONDENSERS OF TUBE AMPS WILL HOLD A CHARGE OF 250 TO 450 VOLTS INDEFINITELY. ACCIDENTAL CONTACT WITH THE PLATE VOLTAGE PINS OF A TUBE SOCKET WILL SEND YOU ACROSS THE ROOM LIKE A KICK FROM A HORSE AND YOU WON'T LIKE THE TASTE IN YOUR MOUTH WHEN YOU COME TO, EITHER.
This point is in all caps because it is SO important, this jolt is nothing to fool around with, it can even kill some folks. If you don't have a pin-out chart for the tubes you are fooling with get one or better yet, take it to a competent technician who has experience with tube amps. If you do have a pin-out chart be absolutely certain to ground out the plate voltage before you stick your fingers, screwdriver, or anything else in there.
Take it from "a competent technician who has experience with tube amps" who has been there more than once, it's not a fun place to go.
------------------
 Dave Grafe - email: dg@pdxaudio.com
Production
Pickin', etc.
1978 ShoBud Pro I E9, 1960 Les Paul (SG) Deluxe, 1963 Precision Bass, 1954 Gibson LGO, 1897 Washburn Hawaiian Steel Conversion
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Bob Metzger
From:
Waltham (Boston), MA, USA
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Posted 14 Jan 2005 10:42 am
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Billy,
I believe you can use 6L6 tubes in a EL 34 circuit but I would error on the side of an ounce of prevention by having a tech monitor these tubes in the circuit by checking vital voltages, ect. However, I should include, the opposite is not true:
EL 34s are not a direct drop in replacement for 6L6 tubes. EL 34 tubes requires a higher filament amperage, which your power transformer (the most expensive part in most amps) may not be able to provide. In other words, you can potentially hurt your power tranny by using EL 34 tubes in a 6L6 designed amp. But an experienced tech can also set up an amp to use EL 34 tubes perfectly safely.
Also, the tube sockets for certain 6L6 designs must be rewired internally to accomodate EL 34 tubes. Some designs will work, other need this rewiring. This is tech stuff and don't do it unless you know what you're doing.
Biasing is not a static number but a window of operating conditions that controls how the tube works in the circuit. If the amp sounds fine to you and the plates of the tubes aren't glowing red, you're probably fine. If I bought a new amp with tubes other than the one specified by the manufacturer, would I check how the bias is set? You bet.
Would you buy an expensive set of four tires for your car and not have them balanced? It's kind like throwing some of your money away because you'll then probably have to buy new tires again sooner than you should have if they were originally balanced. Just like tubes.
Within an amp's biasing window, you can set the bias for cleaner operation or for more overdriven operation, depending what you're trying to do. Once outside of normal operating conditions of a tube, you can shorten tube life drastically (tubes are expensive) or burn out a tube and possibly take out some related/adjacent parts, like screen grid resistors, if the bias setting is really out of range. You can also set bias so out of range that the amp will sound thin and sterile and you won't get all that good sound you paid for with those tubes. My advice - to everybody - have your bias checked when you replace tubes. I do this free for my regulars and $20 for walk-ins. Anyone who tries to tell you that this is some sort of difficult,expensive, arcane operation.... Well, then it's time for a new tech!
Bob Metzger[This message was edited by Bob Metzger on 14 January 2005 at 10:51 AM.] |
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Billy Murdoch
From:
Glasgow, Scotland, U.K.
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Posted 14 Jan 2005 6:22 pm
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Bob,
many thanks for your informative reply,
Your mention of the amp sounding good and the tubes not glowing red was mentioned to me this evening by our lead guitarist who is quite well informed.
I tried the amp out tonight for the first time and I was pleasantly surprised by the tone I got both on steel and six stringer,I wish my dear Wife was strong enough to carry a '64 vibroverb.
Best wishes
Billy |
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Harold Dye
From:
Cullman, Alabama, USA
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Posted 14 Jan 2005 7:51 pm
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| Many thanks for the responses. I just purchased a new amp (old Music Man head) and before I bought the owner said it had new matched Groove tubes.It came late yesterday and from what I can tell it is working great with a nice clean mellow tone. I will have a tech check the bias just to be safe. This thing is in near pristine condition cosmetically and I believe it's a keeper. I am not familiar with different tubes and when he told me about the Groove tubes I didn't know what they would do to the tone. I can't tell much difference between it and my older MM head....just more power |
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Bob Metzger
From:
Waltham (Boston), MA, USA
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Posted 15 Jan 2005 9:27 am
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| I know, Billy, my wife is always saying to me, "Can't we take that Champ amp to the gig instead!!" |
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