#1
My hot rod deluxe groove tube are dying. it came w/ 6l6's. Would it sound better or worse or just diff. if i got it rebiased and put in el-34's?

should i go for groove tubes again or try jj's or svetlana's?
#2
It would sound more Marshally. You'd probably lose the great cleans. As for brands, it depends what sound you want. JJs are good tubes, primarily for harder rock sounds. Groove Tubes suck. SEKs are supposed to be really good. Check out www.tubestore.com for reviews and ratings of a few different brands. You could also shoot an email to Doug at Doug's tubes to get his opinion and to Bob at Eurotubes.com to see what kind of JJs he'd recommend for you.
Hi, I'm Peter
#3
Can you just rebias a 6L6 amp to EL-34? I always thought that couldn't be done due to the wiring of the amps and power abilities of the tubes.
the lesser known of the 4
#4
My Mesa/Boogie can take either EL34s or 6L6s (or 2 of each) without rebiasing (since it's hardwired). I think the problem is if you tried to go from a 6L6 or EL34 to an EL84. I may be wrong.
Hi, I'm Peter
#5
Quote by Dirk Gently
My Mesa/Boogie can take either EL34s or 6L6s (or 2 of each) without rebiasing (since it's hardwired). I think the problem is if you tried to go from a 6L6 or EL34 to an EL84. I may be wrong.



I didn't know Fender did that too, I think in Marshalls and some other amps, you can't just rebias it and make it work, some of the electronics would have to be changed. I'm also not sure though.
the lesser known of the 4
#6
Well, like I said, I could be very wrong. I think a quick email to any of those places I've mentioned above should straighten that out, given the huge popularity of Fender amps.
Hi, I'm Peter
#7
it doest mean that if its handwired, it can take el34's or 6l6's...
anyway, contact a tech just to be sure about what you are planning to do.
i havent tried switching tube types...
Quote by tubab0y
Look at it this way- everyone rags on air guitar here because everyone can play guitar. If we were on a lawn mower forum, air guitar would be okay and they would ridicule air mowing.


#8
Quote by km-r
it doest mean that if its handwired, it can take el34's or 6l6's...
anyway, contact a tech just to be sure about what you are planning to do.
i havent tried switching tube types...

I said it was haRdwired bias - you can't adjust it unless you custom install a trim pot. But most 6L6-equipped Boogies can take 6L6s, EL34s, or 6V6s without any modification to the amp or changes to any settings.
Hi, I'm Peter
#9
Quote by Dirk Gently
I said it was haRdwired bias - you can't adjust it unless you custom install a trim pot. But most 6L6-equipped Boogies can take 6L6s, EL34s, or 6V6s without any modification to the amp or changes to any settings.


I would not bet on 6V6 in such a high power amp without at least a few modifications... Their maximum power dissipation is 12 Watts VS 30 Watts for the 6L6, so just putting them with the 6L6/EL34 bias setting would probably give the plate a really bad day... The 6V6 are also meant to be run with higher output transformer impedance than 6L6, so again I would not try...

The only option I see would be running the 6V6 in push-pull parallel instead of a push-pull of 6L6/EL34, but that would require two more sockets and a good modification to the power stage's design.
#10
Quote by Xp Sim
I would not bet on 6V6 in such a high power amp without at least a few modifications...

This is according to the Mesa/Boogie Mark IV manual, which you can reference here:
http://www.mesaboogie.com/manuals/Mark%204.pdf
Those of you who recall the great sounds of old Fender Deluxes will be delighted to know that four 6V6's can also be used in the Mark IV...but, ONLY when TWEED and SIMUL CLASS are selected.

The wonderful thing about Mark IVs is that you can change their total power amp wattage. So, again, 6V6s without rebiasing. And note that you can also run 6L6s and EL34s with the same power amp settings. Yes, Randall Smith is a genius.
Hi, I'm Peter
#11
Didn't mean to start a great debate Dirk, I was really just curious. That feature on Mesa's is genious though.
the lesser known of the 4
#12
Interesting ! But they also say that without the switches in the good position, the strain on the tube is far exceed the specifications... I guess these switches (especially the "Tweed" one) simply modifies the bias (otherwise, how could a 6V6 withstand a such high power dissipation at idle, I ask myself !) in some way or alter the circuitry (adding resistors in series to drop some [a hundred or so] Volts).

But, even so, this is a good idea from Mesa, because the 6V6s are kinda forgotten these days in modern-era tube guitar amps...

Didn't mean to start a great debate Dirk, I was really just curious. That feature on Mesa's is genious though.


Didn't mean to start either, it was just a warning for people not to start putting 6V6 in their guitar amp (to reduce output power or something like that) if they didn't know what they were doing ! To reduce power, there is a better and simple way : remove a few power tubes (on class A amps only, otherwise serious clipping will occur if you remove a odd number of tubes on a Class AB), by the way.
#13
Don't go and plug in EL34's until you know enough about your amp.

EL34's need pin 1 grounded(6l6 pin 1 isn't connected) and they need more heater current, which could be a strain on the power transformer. And of course, they need to be rebiased.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#14
Quote by That_Pink_Queen
Don't go and plug in EL34's until you know enough about your amp.

EL34's need pin 1 grounded(6l6 pin 1 isn't connected) and they need more heater current, which could be a strain on the power transformer. And of course, they need to be rebiased.

See? I told you I could be very wrong
Hi, I'm Peter