2. amps-preamps
  3. 128910-78314

KT-88 vs. EL34

Hi. I have a modified Jolida 502 amp (not my main amp) currently using KT-88s and formerly the similar 6550s. Some have suggested that this unit will sound even better, power hit aside, modifying to accept EL-34s. The mod is easy. Anyone find this to be true or is it just another myth? Thanks in advance, Andy8400.

andy8400

Showing 2 responses by bdp24

bdp24's avatar
bdp24
9,412 posts
 
Modjeski designed his RM-9 specifically for use with the EL34 (four per channel for 100w/per in the Mk.1, 125/per in the Mk.2), his RM-200 for the KT88 (two per channel for 100w/per at 8 ohms, more at 4!). But the 200 can also be run with KT-120’s (though not the KT-150---the transformers get too hot at the required plate voltages).
bdp24's avatar
bdp24
9,412 posts
 

Roger Modjeski of Music Reference and RAM Tube Works had for quite a while a forum on AudioCircle. On it he discussed tube amplifier design, tubes themselves, and the relationship between tube circuits and the performance characteristics of specific tube types---how the two are interrelated. The Music Reference Forum is no longer active (Roger has moved his business from Santa Barbara in Southern California to the Berkeley/Oakland area in Northern California, where he designs and builds amps, an ESL loudspeaker, and a subwoofer. He also teaches a course in amplifier design.), but remains readable on the AC site.

There is a LOT of information about tube circuits and tubes on the old Audiocircle MR Forum, well worth your time to peruse. Roger invented computer tube testing and matching, and is the world’s foremost authority on vacuum tubes. He’s not easy to reach by phone, but if you do you may be able to get a lot of your questions answered straight from the horses mouth.

More to discover