Difference in JTM45 and 1987x RI's w/ EL-34's

DirtyChains

Member
Messages
167
I have a 1990 JTM45 RI that I am thinking of putting EL-34's in place of the 5881's currently in the amp. My question is, is there much of a difference between the 2 amps tone wise other than wattage and headroom? I have listened to many 1959 amps (original and RI's) but I have never sat down and played a 1987 to compare with the JTM.

My understanding is my amp has the good Drake transformers (saw them when I removed the chassis) and is more than capable of running the EL-34's with no mods. Is that correct?
 

retro

Silver Supporting Member
Messages
1,814
I changed all my Tranny's for more headroom before I switched to
EL-34's.

Hopefully someone will pipe in here with more tech help on tranny's.

If you are asking no mods at all besides the tranny's, I had to change one bias resistor and I changed the value on my sockets also.


There was a large change in tone with EL34's for me. I tried a few new EL-34's and did not like them at all. Terrible IMO.

Did however really like a pair of NOS EL34's. Really changed the character of the amp in a good way.

But long story short due to a faulty NOS tube I had to switch back to my original bias and ended up loving TAD short bottle 6l6WGC's too much.
 

4styx

Member
Messages
1,268
For the amp you have,try some Sylvania Fat Boys(big bottle 6CA7's) and don't look back!They're amazing with a tube rectifier amp.
 

stratton

Member
Messages
1,080
I have a 1990 JTM45 RI that I am thinking of putting EL-34's in place of the 5881's currently in the amp. My question is, is there much of a difference between the 2 amps tone wise other than wattage and headroom? I have listened to many 1959 amps (original and RI's) but I have never sat down and played a 1987 to compare with the JTM.

My understanding is my amp has the good Drake transformers (saw them when I removed the chassis) and is more than capable of running the EL-34's with no mods. Is that correct?


I'm by NO means a Marshall expert, but I owned an RI JTM45 and felt it had a good bit of Fender feel and sound to it, a sort of roundness and bigger bottom. The 1987 is more aggressive sounding: Tighter, brighter, louder, and all Marshall.
 

DirtyChains

Member
Messages
167
Thanks for the info guys! It was my understanding the JTM-45 RI did not need any mods to run EL-34's due to the pot having enough turns to bias correctly. I was also told the circuits in the RI amps were not that different from the 1987X RI amps-sans the tube rectifier. Did I get the wrong information?

Any help is appreciated and more tone comments as well as tech responses would be greatly appreciated!
 




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