power tube questions..installation, etc

[shreder75]

hey guys..this came up in a thread way down below but It hought I'd give it another thread..

my new tube amp has a quartet of 6L6s in it..and I do like the sound but have gotten interested in maybe switching them out to make the tone more 'mine' and maybe a little crunchier..

now, I know tone depends on alotta things...the amp, the player, the guitar, the pickup, etc, etc...but I hear alotta good things about EL34s..that they can be crunchier and punchier....which to me, wouldn't be a b ad thing....think nuno, early vh and george lynch and that's the type of tone I've always been looking for...

anywho, how hard it is to change these things? I've heard alotta things about biasing and having to re bias an amp when you put in new power tubes...is this hard? do you need a tech to do it? could a gear idiot like myself do it? does my amp even need it?

any info would help....and as an aside, I hear good thinsg about the Groove Tube EL34's...oh, as far as they go..when I look on musician's friend, they come in different 'hardnesses'? what's that all about?

thanks in advance!

 

[Curly]

Re: power tube questions..installation, etc

most amps require rewiring the tube sockets to use EL 34s

 

[grams]

Re: power tube questions..installation, etc

first of all:
EL34 are normally asociated with a "british tone" because most marshalls have EL34. So if you're looking for a marshall crunch EL34's might help you...

Both 6L6 and EL34 use the same octet socket but draw different current. To swap in EL34's instead of 6L6's, you would have to rebias the poweramp. you'd (normally) "only" have to change the cathode resistor so the EL34's is running with the correct current (the resistor value must generally be lowered if going from 6L6 to EL34, because they draw more current).
If you don't have a schematic and not much experience with tube biasing I'd recommend you not to do it by yourself. Any tube-experienced technician should be able to do the trick without problems.

 

[shreder75]

Re: power tube questions..installation, etc

hmm..what if I were to just swap out the 6L6's I have now with other 6L6's? I saw the name on the pre amp tube...electro harmonix I think...so the power tubes are probably the same..IW as lookin' at the groove tube site and the 6L6-S power tubes sound pretty good...that would just be a straight swap, no?

 

[Edgecrusher]

Re: power tube questions..installation, etc

Most amps need to be rebiased when you swap tubes. Some amps that are cathode biased are said to be self biasing but even they need adjustment sometimes. To get the best tone and life out of the tubes have it rebiased.

 

[StrykeBack]

Re: power tube questions..installation, etc

I have some JJ el 34s in my ashdown peacemaker that replaced the stock electroharmonix. It made the amp stop being so sterile and high pitched whine to it in the upper frequencies that bugged. bob at eurotubes can pick out a set in the "hardness" or higher gain or lower gain depending on what you want. Hit him up with some questions.

I've got my rectoverb head on the way now :32: It's coming with 6l6s but I can toss the el34s from my ashdown in (i think) and just flipt the bias switch from 6l6 to 34 and be good to go.

el 34 is definitley a more marshall tone. Break up easier I beleive as well.

 

[shreder75]

Re: power tube questions..installation, etc

so is that what hardness means? cause on musicians friend, the 6l6-s groove tubes they had came in different hardnesses...

would I still have to have it rebiased even if I just put in different brand tubes of the same type? (I.E. switching the 6l6's I have now for a different brand of 6l6's)

 

[Edgecrusher]

Re: power tube questions..installation, etc

so is that what hardness means? cause on musicians friend, the 6l6-s groove tubes they had came in different hardnesses...

would I still have to have it rebiased even if I just put in different brand tubes of the same type? (I.E. switching the 6l6's I have now for a different brand of 6l6's)

The hardness denotes whether or not the tubes will push into distortion easily or not. I wouldnt go too nuts and go too far to one extreme or the other until you have your rig pegged as to what you want. Early break up tubes can get mushy pretty easy.

You still need to rebias even is you swap 6L6's from the manufacturers lot. Tubes have some amount of variance even ones made right next to each other on the assembly line.


I have done business with Bob at Eurotubes before. He is a great guy very knowledgable I have nothing but respect for him. But he is a JJ dealer. There is nothing wrong with JJ's though if you looking to try some different things why limit yourself to just one brand. Yes there are different hardness's available in the JJ's but they will still share sonic charicteristics of all JJ's. (Bob has a rebuttal for this. I spoke with him on the phone about maybe trying various tube brands) An example is right now my Mesa MKIV has a pair of Tung Sol 5881's in it and a pair of GE 7581's. Essentially both are from the 6L6 family but they are very different not just psyically but also sonically. In my MKIV they compliment each other very well. There are lots of tubes to try both new and NOS. I would find someone who deals in them all and work with them to help find what set you need to help you achieve the sound in you hear in your head. Just my 10 cents