Re-tubing opinions

[Manicompression]

Hey guys, Just kinda want some opinions about stuff. So heres the scoop, I have a Mesa Dual Rec 3 channel that ive owned for a bit over 2 years. I really enjoy the tone I get from the thing, so its not so much that Im unhappy as much as its been a couple years and I want to try something new for fun. Im running everything stock, 6l6s and such. Ive kind of decided to just buy my new tubes from Mesa so I dont have to worry about biasing or durability or learning chinese. I liked the sound of the Stilleto when I played that at guitar center, so Im thinking EL34's could be cool,
the EL34 STR-450 is a nos Slemens EL34 that Im thinking would be good, It is descibed as having bell like clarity and being "tonefull" whatever the hell kind of description that is,
and then maybe some of these 5U4G coke bottle tubes, they are described as being slightly less saggy, but with a lesser life expectancy
Does anybody have any experience with these ?
Would I be doing myself a disservice to not check something else out ?
Is running an EL34 a bad move for a high gain metal dude, note, that I do like my clean channel to be clean, and my distortions bass heavy but organic sounding. Also, How big of a difference can I expect from changing the different sets of tubes? Which makes more of a difference ?
Sorry for the long post, I just wanted to be clear. Thanks for any and all input.

 

[pifos_2]

You'll get some info about your amp, the sound and the variety of tubes here : http://www.eurotubes.com/

Also, 4 EL34's for your amp will only cost you around 100 bucks. So what I would do is to buy some, and listen if you like it. If you're not, well, at least you have back-up tubes....

 

[Manicompression]

Hey thanks PIFOS 2, that link was surpisingly helpfull, I have seen other people drop it before but i just figured it was a place to order tubes from if you lived in Europe, but there is a pretty cool wealth of info on there about the possibilitys. Im still open for more info though on which tubes make the most tonal difference, and interested to know what you guys have to say about the mesa / Siemens el34s or the 5U4gs. And yes I agree the end outcome of this tube journey is that Im gonna have some backup tubes no matter what, which is never a bad thing. BTW I really like your tunes, rock out man!!!

 

[Omega_Void]

Is running an EL34 a bad move for a high gain metal dude, note, that I do like my clean channel to be clean, and my distortions bass heavy but organic sounding. Also, How big of a difference can I expect from changing the different sets of tubes? Which makes more of a difference ?

EL34 does not have so much low end as 6L6 types. Also lacks the top end. Does however have more of a bark due to higher inherent distortion. IMHO good for rawk, not so good for metal.

Consider KT66 tubes - they have an EL34 type bark in the mids but the good top and bottom end of 6L6.

And make sure whoever re-biases your amp knows what they're doing.

 

[Manicompression]

Mesa's have this fixed bias thing going on, so if I wanted to try something drastic I would need a good tech to do the work, lucky for me I have a mesa certified guy who's also done good work for me about 25 minutes away, so not too big a problem there. But still, I dont know if I feel like doing anything that would require a rebiasing, as its not like Im that dissatisfied with how it sounds now, and dont feel that drastic measures are called for or that mesa has designed there product in an uncool manner. Thanks for the info on these KT66 tubes though OMEGA VOID. Do you or anybody else have specific experience with changing the 6l6 oreintation of the mesa to that of a el34 or even this KT66, if so did it record better, what did you gain what did you lose, how big was the difference? Ive used the search but most mesa tube talk boils down to "what did testament use" or "what would andy do" which is fine, helpfull, and cool but I didnt catch anything less subjective.

 

[::XeS::]

I'm going to buy a set of JJ KT77...they seem to have deep lowend.

 

[Metaltastic]

Manic, I'm pretty sure Omega_Void was referring to KT77's, cuz KT66's are much more like 6L6's while KT77's are more of the "best-of-both-worlds" between 6L6 & EL34. I gotta say, I really love the JJ KT77's (from eurotubes) in my jSX; I let a friend borrow it for a show this weekend, mostly so I could hear it from an audience perspective, and HOLY GOD, it brought a tear to my eye; the power in the mids just made it so full and powerful, and annihilated the other guitarist's Crate Solid State half stack (cuz that's so hard to do and all ). And EL34's are definitely NOT only for rock, unless you wanna claim that a Bogner Uberschall, Framus Cobra, any VHT, etc. isn't a metal amp!

Honestly, I'm finding that I'm starting to think 6L6's are kinda...boring, because of the lack of mid-range snarl/character. But this is only a recent development on my part, so it may change...

 

[Metaltastic]

Oh, and KT77's are a direct swap for EL34's, so literally all you would have to do is flip the switch to EL34 and stick 'em in...and as for losing gain, since pretty much all of the gain in a modern amp comes from the preamp (hence why the effects loop is between pre and power amp), the type of power tubes isn't gonna have any effect on the gain.

EDIT: Here's the source of my info http://mesaboogie.com/manuals/2chRecto.pdf on direct swappability

 

[Manicompression]

Thanks Metaltastic for your impressions on your retube and for drowning out a Crate in a world where too many still exist. So these KT77's sound like a pretty good call. How long have you had them in there? they seem to hold up pretty well? Anyone else have any different experiences to share ? Off to work I go now, ughhhhhhh.

 

[::XeS::]

I just ordered a set of KT77...next week I'll post some comparison clips..I hope

 

[KeithRT99]

not to hijack your thread, but does a fixed bias mean i can just drop tubes in without biasing and it's all cool? That euro tubes site had a KT77/6l6c split kit for 5150s and it got me thinking.

 

[JBroll]

In a sense... it means that no matter what you do, you don't get to bias things.

Jeff

 

[Manicompression]

looking forward to hearing those clips XES, yeah the fixed bias thing is kind of and advantage or a disadvantage depending on how you look at it, Any other opinions on my situation ?

 

[Omega_Void]

The non-adjustable bias in Mesa amps means that replacement tubes have to have specific DC characteristics. Not all tubes even of the correct type will be correctly biased. That's why you invalidate your warranty if you put any other make than Mesa tubes in the amp. Tubes with unmatched DC characteristics will put some strain on the amp, and tubes far off from what Mesa has decided are ideal may run too hot (bad for the tubes) or too cold (bad for the sound). At least one article (by a guy who sells tubes, mind!) expressed the opinion that Mesa's biasing was set too cold anyway. I seem to recall Mr Sneap saying a while back his new Recto didn't sound so cool, but later posted it was fine once he'd put a set of Svetlanas in it, which could be read as corroborative.

Point of technical terminology - fixed bias doesn't mean the bias is not adjustable.

Fixed bias amps bias the power tubes by applying a negative DC voltage to the grid, to make it negative with respect to the cathode which sits at zero volts. No current passes the bias circuit so the bias remains fixed whatever signal is in the audio path - hence the name. Fixed bias is often adjustable, since this can be achieved with low-power trimpots.

The most common alternative is cathode bias (AKA self-bias), where the grid is made negative with respect to the cathode by raising the cathode to a positive voltage. This is done with a big power resistor at the cathode. Since the tube draws more current when a bigger signal is passed, this means that the louder you play the more current passes the resistor, so more voltage is dropped. The bias point therefore moves hotter - the bias in a cathode biased amp is not fixed to a particular voltage. Cathode-biased amps are not often adjustable-bias as this requires high-power wirewound trimpots which are expensive, but the way the bias reacts to the current drawn is somewhat self-correcting so a whole range of tubes can be used equally happily in a well-designed cathode-biased amp.

You may well get away with not re-biasing. If the plates in the tube go red, switch off immediately, they're too hot and will damage stuff if you keep running them 'til they melt. If the sound has a shedload of crossover distortion they're biased too cold. This is harmless to your amp, but sounds terrrible.

@Metaltasic: I'm pretty sure it was KT66 I heard, but it was a while ago. KT77 I can't comment on, I've not knowingly heard them. And I didn't actually say EL34s were no good for metal, I said in my OPINION they were less ideal for metal than 6L6 type. That sort of issue is always really just subjective.

 

[Metaltastic]

Of course you're right, you did make clear that it was your opinion before, and these things certainly are subjective indeed! And thanks for the info on fixed- vs. self-bias, really informative stuff!