What EL34's do you recommend for a 1978 JMP 2204

[Kapo_Polenton]

I have a moded 2204 and I used for years the RFTs EL34's...

Very classic sound...I recently changed the EL34's for 6550(NP TADs)...

Will not go back to EL34's...

I've owned a lot of JMP and JCM800's... all with EL34's and NEVER kept them for more than a few months. A few years ago I got a 1980 JMP with GE 6550's. I'm going on close to 4 years with it. I'd never buy one with EL34's again. Nope!

Interesting, I "modded" ( resistor or two) mine to take EL34's..maybe I should go back to 6550? What diff do you guys hear?

 

[glip22]

I have a moded 2204 and I used for years the RFTs EL34's...

Very classic sound...I recently changed the EL34's for 6550(NP TADs)...

Will not go back to EL34's...

I've owned a lot of JMP and JCM800's... all with EL34's and NEVER kept them for more than a few months. A few years ago I got a 1980 JMP with GE 6550's. I'm going on close to 4 years with it. I'd never buy one with EL34's again. Nope!

Interesting, I "modded" ( resistor or two) mine to take EL34's..maybe I should go back to 6550? What diff do you guys hear?

Marshalls were never designed to run 6550's as you know. Only used because they were more reliable when Marshall kept having warranty issues with EL34's back then.The OT impedance is for EL34 at approx 1.9k. 6550's need much more I think to be optimized.
They do offer a different tone but they are not optimized in the circuit.
You will not get more output from them regardless they are rated for higher maximum plate dissipation at 30 watts. Bias them the same as you would a 25 watt tube in a Marshall designed for EL34. You can go a little higher but you hit diminishing returns fast

 

[Racerxrated]

I have a moded 2204 and I used for years the RFTs EL34's...

Very classic sound...I recently changed the EL34's for 6550(NP TADs)...

Will not go back to EL34's...

I've owned a lot of JMP and JCM800's... all with EL34's and NEVER kept them for more than a few months. A few years ago I got a 1980 JMP with GE 6550's. I'm going on close to 4 years with it. I'd never buy one with EL34's again. Nope!

Interesting, I "modded" ( resistor or two) mine to take EL34's..maybe I should go back to 6550? What diff do you guys hear?

Marshalls were never designed to run 6550's as you know. Only used because they were more reliable when Marshall kept having warranty issues with EL34's back then.The OT impedance is for EL34 at approx 1.9k. 6550's need much more I think to be optimized.
They do offer a different tone but they are not optimized in the circuit.
You will not get more output from them regardless they are rated for higher maximum plate dissipation at 30 watts. Bias them the same as you would a 25 watt tube in a Marshall designed for EL34. You can go a little higher but you hit diminishing returns fast

When it comes to Marshalls I love 34s..UNLESS we are talking about an amp that came with GE 6550s. They destroy every other 6550 including the Winged Cs. Too bad they are stupid expensive now. My 83 2203 came with GEs. It will stay 6550.
As Gary said, bias them like they are EL34s. 30-40ma and you are set.

 

[braintheory]

I have a moded 2204 and I used for years the RFTs EL34's...

Very classic sound...I recently changed the EL34's for 6550(NP TADs)...

Will not go back to EL34's...

I've owned a lot of JMP and JCM800's... all with EL34's and NEVER kept them for more than a few months. A few years ago I got a 1980 JMP with GE 6550's. I'm going on close to 4 years with it. I'd never buy one with EL34's again. Nope!

Interesting, I "modded" ( resistor or two) mine to take EL34's..maybe I should go back to 6550? What diff do you guys hear?

Marshalls were never designed to run 6550's as you know. Only used because they were more reliable when Marshall kept having warranty issues with EL34's back then.The OT impedance is for EL34 at approx 1.9k. 6550's need much more I think to be optimized.
They do offer a different tone but they are not optimized in the circuit.
You will not get more output from them regardless they are rated for higher maximum plate dissipation at 30 watts. Bias them the same as you would a 25 watt tube in a Marshall designed for EL34. You can go a little higher but you hit diminishing returns fast

When it comes to Marshalls I love 34s..UNLESS we are talking about an amp that came with GE 6550s. They destroy every other 6550 including the Winged Cs. Too bad they are stupid expensive now. My 83 2203 came with GEs. It will stay 6550.
As Gary said, bias them like they are EL34s. 30-40ma and you are set.

I agree. Maybe if I tried GE 6550’s I’d change my mind, but I’ve always been an EL34 guy. In all the amps I’ve tried them in vs 6550’s or KT88’s, I find EL34’s to be a lot more musical, complex, more mids and growl, just more inspiring to me vs the more sterile, but I guess more robust and big 6550 tone. I also consistently preferred 6L6’s vs 6550’s when I tried the same amps compared with them

Tubes are one area I’ve not too experienced in yet, but I’m getting the sense that it’ll be like speakers in that the higher powered tubes seem like they’ll be bigger and more robust sounding, but less toneful vs smaller tubes like EL34’s, EL84’s, 6V6’s, etc. I guess I’m also an EL84 and 6V6 guy since the Vox’s are in my top 5 favorites and also Jim Kelley being a 6v6 amp. Never liked yet any KT77’s, 66’s, or 6CA7’s as much as EL34’s thus far