Now that I've got tubes, which ones do I use?

[getuhgrip]

Just got a JCM602. First tube amp for me. Do different types of tubes give different performance in terms of tone?
Do different types or brands last longer?
How can they be tested at home?
The distortion from this amp is good and thick, but can different tubes produce a more "fuzzy" signal?
This thing's got slovteks in it now; EL34s & 12AX7s.
-Thanks

[Emeric]

Well, I did post something to this but it timed out and said I was not allowed to log in or something.

Anyway. From what I've found it's mostly hype. I've used Groove tubes, Mesa Boogie products... Certainly they are different... prices. If you can get a different sound, and more importantly, perceive it than great. Most differences I've found are very black and white. i.e. functional, or not. I'm sure the tone freaks will disagree. YMMVVMAD

[Wide Awake]

I don't know if one brand lasts longer than another. Power tubes will not last as long as preamp tubes, therefore they should be replaced more often. I've read that if you use an amp everyday, they will last 1 to 2 years. A lot depends on how hard you drive the tubes.

Check out www.tubestore.com There is some decent information on tubes there.

[getuhgrip]

This amp will never leave the basement and though the gain gets maxed, the volume stays relatively low. I came up with the tone question based on some comments I saw on Harmony Central. A few folks eluded to tonal variations by virtue of tube type. If one tube goes out, do ya loose the signal completely...or does it work progressively?

[dragonworks]

If you want the specs on any of those tubes I can go in my tube book and get them for ya. If one power tube goes the amp should still perform at a lower volume with more distortion. Ususally there are two or four power tubes in a push pull configuration. In the preamp section it is usually 1 12ax7 per channel for preamplification and if one of those goes that channel probably will not work.

[getuhgrip]

'ppreciate it DW, but I was really just curious. Just like any other new toy, I'm just trying to determine what the "hotrod mods" are if any. I just took the power cord off my ol' ladies hair dryer and fitted it with a 1/4 plug. Didn't do a thing!
Thanks

[schwa]

There's almost as much info out there about tubes as the amps themselves, partially becauset ey are also the province of high end audio fans. There's a good newsgoup (do a search on "tubes") where those folks get together to discuss what's going on. I haven't been connected to it recently but here's a few points of interest.

American and Western European tubes are usually hailed as best. None of these manufacturers still make tubes. Some companies are (were) GE, RCA, Synvania, Mullard (UK) Telefunken, & Siemens.

These good tube can still be found but are rare, and sold as New Old Stock (NOS), often at a serious premium.

The best place to find good tubes cheap are TV repair places. People stopped buying them in the '70's, but sometimes they have stuff in the back room.

Marshalls usually use El-34's which is a British type tube. They did use 6881s for a while in the 80's when no good el-34's were available.

Most regard the Mullard el-34 as the best ever, the last I checked these were going for over $300 a pair (NOS).

The best one available today (according to many) is the Svletlana (Russian). When these first became available, it was a relief to marshall owners, as things got pretty bad for a while.

THe yugos still make el-34s, Sovtek, and I think the Chinese make e-34's, but from what i've heard the Svets are the way to go for replacements.

12ax7's don't need replacement as often, but have a profound effect on the sound. Once when I had my Bassman serviced, the tech sat with me and we "taste tested" a bunch of tubes. I picked RCA's.

Check out the tube newsgroup - there's a buch of stuff out there. And watch out for Lord Valve, he's their Sonusman - there to shut up anyone who spouts anything untrue.

[dragonworks]

A tube is designed to run with a certain plate voltage, grid voltages, bias voltage. If these are not correct the tube will not perform correctly. You cant hot rod tubes because of this. How would you go about it? More plate voltage etc, the tubes are not designed for this. How would you accomplish this hot rodding? Go into the tube circuits and change resistors and caps and adjust the bias voltage, I dont think so. If you put a so called hot rod tube in your amp it is still operating at the same voltages etc as the one you replaced.
For anyone who needs to know the el-34 has a direct replacement 6CA7/EL34. The 6CA7 is the same tube.

[getuhgrip]

Oh, I wasn't talkin' about milling the heads or opening up the combustion chambers....I meant after-market bolt-on stuff like a hot cam and headers!
Seriously, I think I misinturpreted some stuff I read, in that output power could be boosted with "hotter" tubes, or tone and distortion could be manipulated via tube selection. I'm really just learning about this thing and as always, I'm curious about what works and what doesn't. When I was a kid, I made a pickup mount in metal shop that carried a pickup over the TOP, sandwiching the strings between two humbuckers! Made a bunch of noise, but looked really cool! 25 years later I'm still a tinkerer but less adventurous!
Anyway, I appreciate the education on tubes. Understanding how something works allows you to troubleshoot problems and sometimes spawns creative ideas
-Thanks all

[vox]

Changing tubes definately has a dramatic effect on an amp's sound, I retubed my Marshall with PM (Whirlwind) tubes and it got a lot louder and cleaner sounding (probably more efficient tubes), I then changed to some old RCA tubes that someone had lying around and the output of the amp dropped a lot but became very warm and slightly 'mushy' (not bad for bluesy stuff).

Some tube manufacturers rate their tubes according to 'hardness',
Groove Tubes does I think.

Before you go and start yanking out tubes talk to a tube amp service guy, I am 99% sure that you can just stick any 12ax7 in your preamp sockets without any adjustments (I did it), but if you change power tubes some amps need to be 're-biased'. Ask someone who knows for sure before you start 'Modding'.

[lazyboy]

I have a Fender deluxe reverb II (one of the Paul Rivera designs). Recently, I read that it has a fixed bias. Presumably I can just yank out old power tubes and stick some new ones in? 6L6's if my memory serves me.

I'm thinking of tinkering a little bit with the amp. Anybody ever try any of those Dan Torres mod kits? Or Weber speakers? They're the rage over at fenderforums.

[someone else]

The Pre-amp tubes have a direct relationship to guitar tone, and the 'Old' ones are definately better than the 'New'... As for the Power tubes, the most commonly known name is 'Groove Tube' These are merely 'Sovtek' tubes that have been rated, and are usually sold in 'Balanced' pairs.... Rated from the 'dirtiest' sound, to the 'Cleanest' The higher the number, the 'Cleaner' the sound, and the opposite, the lower, the 'Dirtier'
If you have tried out any premium 'Vintage 'amps, and you like the sound, check the Power tubes, the pre-amp tubes, and the speakers, these three things have more to do with the over-all sound than almost anything else..... the facts are that the older amps had a way of 'Toning' a guitars sound, as much as the name on the guitar,IE: Gibson vs Rickenbacher vs Fender vs Whatever.....
As far as aquiring 'older' tubes, if you can afford the $$$$ go for it, you won't be sorry....!!!!!
Or, better yet, look for the 'old' amps that still have the original tubes in them, as long as they weren't fried....Most of all...... have fun with it...
By the way, I personally am leaning towards the 'Mullard' tubes for their 'Warmth'
Thats what the British made 'VOX' amps used, and they are without a doubt, one of the warmest tones available in any tube amps....

[S8-N]

Someone once told me that all brands of 12AX7's were made at the same plant... I dont know if it is true, but I have always used Groove tubes and replaced them every two years or so... you will hear a noticeable improvement over the old tubes.
MY preamp came with Peavy tubes and I replaced them with Groove tubes, but they LOOK identical except for the logo's.

[someone else]

As I stated earlier in this thread, 'Groove ' tubes are just russian made Sovtek tubes that have been tested, and rated numbering from 1 thru 10. The higher the number, the cleaner,(sharper, harsher, however you want to say it) the sound, and the lower the number, the fuzzier, dirtier the sound. If, in replacing your tubes every 2 years, you have never checked the rating numbers, you probably have been replacing with different rated tubes if you are getting a noticably different sound. Check the rating numbers on the original package. I'll bet you a set of Grooves that the numbers are different every time you have replaced them...!! I believe that Groove Tubes is the only name to put the 'Rating' numbers on the package, I don't know of any others that do this.... Anyone else???
As far as all the 12ax7s being made in one place, I don't think that is a true statement either, as of current info that I have, all 'tube' manufacturing in the world is now done in either China or Russia.
The actual manufacturing process is environmentally very dirty, and these two countries are lacking in controls for their environments, so my advice is to seek out 'Old' tube stock, and not keep contributing to the pollution in the countries involved in producing the 'new' tubes...
There are still tons of the old stuff left, and there is no need for us , as caring people, to contribute to the polution in countries that don't care....
Having said all that, I have looked at the 'Groove Tubes' in the peavey amp I am going to trade on a Trace Elliot, and feel bad that I didn't check before this.....
Oh well, next time....

[psmith66]

Just had my JCM800 serviced by a local amp tech guy. He has a flawless reputation and does work for basically everyone in this area. He cleaned the pots, checked the bias and replaced the EL34's (one was getting bad - he said it was better to replace both instead of mixing). He recommended Sylvania and charged me $15 each. He said he has had nothing but trouble with Groove tubes. Also, he doesn't think either the power tubes or the preamp tubes make much difference with respect to quality of sound per brand. Personally, I wouldn't be able to comment as I haven't tried different tubes myself.

[someone else]

Originally posted by psmith66
Just had my JCM800 serviced by a local amp tech guy. He has a flawless reputation and does work for basically everyone in this area. He cleaned the pots, checked the bias and replaced the EL34's (one was getting bad - he said it was better to replace both instead of mixing). He recommended Sylvania and charged me $15 each. He said he has had nothing but trouble with Groove tubes. Also, he doesn't think either the power tubes or the preamp tubes make much difference with respect to quality of sound per brand. Personally, I wouldn't be able to comment as I haven't tried different tubes myself.

He is WRONG, WRONG, WRONG, about the different tubes not having an effect on tone,..... just ask any serious professional who has tried, or uses an amp outfitted with the 'Mullard' tubes I mentioned earlier. And as for Groove tubes, he is correct, even tho they are rated, that is no guarantee of quality. He did give you a fair price on the Sylvania EL34s, but I whole heartedly recommend that you try to find some 'Old' stock tubes, the next time you are gonna replace any of them....

[psmith66]

Actually, he wasn't a "real" guitar player and perhaps doesn't understand the nuances of tone. Perhaps I should get some tubes in the 1-3 range to see if they actually will help the distortion kick in a little quicker at lower volumes.

[someone else]

psmith66
Also try using a miss-matched set, such as a 1, and a 3, this combo will give you a slightly distorted sound right off the bat, and will only increase at higher volumes...