#1
As the title says, I need new power tubes for my Marshall 6101LM. It's a '90 model with 4 6L6/5881's in it. I have some Harma 6L6STR ones in there at the moment, but they are over 8 years old & have had a lot of use, it's done 18 gigs so far this year alone, plus practice sessions. Definately sounding pretty flat & not as lively as it used to be. I can't change valve type without extensive mods, so the same type will be needed. I'm in the UK, playing in a covers band, just not sure of which make would be best for the money. I can't afford NOS tubes, looking to re-tube for £100 or less, most NOS stuff is £70+ each!

Sorry if I rambled on, just looking for recommendations

Thanks people
My Gear:- A guitar, a guitar lead, a guitar amplifier. Or sometimes just an acoustic guitar!
#2
Get some JJ 6l6's, they are decent and not extremely expensive.

For the preamp new Mullard 12ax7's are nice in V1, JJ ecc803 are a nice tube also. I would stick a Sovtek 12ax7LPS in the PI position

www.watfordvalves.com gets a good rep from your side of the pond
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
#3
Thanks Rob, it's just the power valves needed. I've got an original Mullard 12at7 in V1 to drop the gain & stop the clean channel breaking up. The last set came from Watford valves, so I might have to just take a flyer on a set.
My Gear:- A guitar, a guitar lead, a guitar amplifier. Or sometimes just an acoustic guitar!
#4
Quote by anguskilminster
Thanks Rob, it's just the power valves needed. I've got an original Mullard 12at7 in V1 to drop the gain & stop the clean channel breaking up. The last set came from Watford valves, so I might have to just take a flyer on a set.


Hey! I have the head and was thinking of putting in JJs myself, but was wondering whether there were tonal differences between 6L6 and 5881 (I heard they are slightly different.. correct?). Mine still has the 5881.

Also, when does your clean channel break up? Mine stays clean even with the channel volume at 8/9. Maybe the previous owner put in a lower gain tube already, I should really look into that
#5
Quote by lxar
Hey! I have the head and was thinking of putting in JJs myself, but was wondering whether there were tonal differences between 6L6 and 5881 (I heard they are slightly different.. correct?). Mine still has the 5881.

Also, when does your clean channel break up? Mine stays clean even with the channel volume at 8/9. Maybe the previous owner put in a lower gain tube already, I should really look into that


Yes 5881 is interchangeable with 6l6 and KT66 (if they will fit in your amp)

EDIT yes 5881 are a little different than a 6l6 because a true 5881 can't handle plate voltages as high as a 6l6 can.
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
Last edited by Robbgnarly at Aug 17, 2014,
#6
Rob, do EL34's handle higher plate voltage than 6L6's? I'm not sure that these amps will take KT66's, I had mine serviced at Marshall in 2006 & they said 6L6/5881 & similar were ok, but other types of octal tubes would mean mods, which , as the pcb's are stacked and have computer chips in for MIDI switching, means I can't find someone to do any more that re-bias new tubes!
Ixar, my clean channel breaks up fairly early as I have a high output pick-up in my guitar, a Seymour Duncan Invader, which some people here hate, but I like it! The SD Jazz in the neck stays clean almost all the way up, so it's definately the bridge pup crunching it up!
My Gear:- A guitar, a guitar lead, a guitar amplifier. Or sometimes just an acoustic guitar!
#7
In order to use EL34 type tube, you would need to change the screen resistors and possibly some other parts (I'm not an amp Guru ) but it can be done.

You are fine using any 6l6 tube in that amp, I don't want you to think you can not. If KT 66 will fit they are a great tube, but a set of JJ 6l6 would be just fine

Roll the volume of the guitar back some when using the bridge pickup and it will stay cleaner longer
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate
Last edited by Robbgnarly at Aug 18, 2014,
#8
Quote by anguskilminster
Rob, do EL34's handle higher plate voltage than 6L6's? I'm not sure that these amps will take KT66's, I had mine serviced at Marshall in 2006 & they said 6L6/5881 & similar were ok, but other types of octal tubes would mean mods, which , as the pcb's are stacked and have computer chips in for MIDI switching, means I can't find someone to do any more that re-bias new tubes!
Ixar, my clean channel breaks up fairly early as I have a high output pick-up in my guitar, a Seymour Duncan Invader, which some people here hate, but I like it! The SD Jazz in the neck stays clean almost all the way up, so it's definately the bridge pup crunching it up!


Hi, I looked around for info on changing tubes to EL34.. from what I've been told and I've found it's a pretty easy mod and there is a suggested list of changes written by Marshall itself. I personally didn't do it because I'm pretty happy with the current 5881, but also because I read that switching to EL34 can under unlucky circumstances lead to damage to the channel switching system (midi, but looks like it controls everything). Don't know if that's true though, has anyone heard about this before?

Here's the mod info:
http://home.myfairpoint.net/vze1u14s/sitebuildercontent/sitebuilderfiles/5881el34conversion.pdf

Beware, the tables are for EL34->5881, so you have to swap the new/old values.

Nice about the pickups! Do you like the lead channel with those? Quite a few people say it's too fizzy, but with my SD '59 on my strat I get acceptable results.
#9
I'm sticking to 6L6's, I got rid of the original 5881's in '06. I keep the channel volumes at about half & just use them to balance out volume jumps between channels. The 12AT7 in V1 really keeps it clean with the Invader in the bridge. Thanks for the help Rob

The lead channel took me a while to dial in, I prefer the crunch channel on mode 3, but as I can't change to that from mode 2 from the footswitch, I kept toggling between the 2 until I got as close as I could to mode 3 on the crunch channel. Mine has the gain boost button and a button to turn the mid pot into a contour pot, which gives a more scooped tone than just taking out the mids. I don't use either of these & use a Bad Monkey as a means of tightening the lead channel up, works for me

On topic, I might take a punt on some new Tung Sol's, specifically these :- http://www.watfordvalves.com/product_detail.asp?id=3148
Thoughts?
My Gear:- A guitar, a guitar lead, a guitar amplifier. Or sometimes just an acoustic guitar!
#10
I've used the Tung Sol5881 re-issue and I really like them they had a grind that I did not get with regular 6L6's. the 6L6 STR I have not used, but they get a pretty good review
2002 PRS CE22
2013 G&L ASAT Deluxe
2009 Epiphone G-400 (SH-4)
Marshall JCM2000 DSL100
Krank 1980 Jr 20watt
Krank Rev 4x12 (eminence V12)
GFS Greenie/Digitech Bad Monkey
Morley Bad Horsie 2
MXR Smart Gate