doomsdaymachine
Active Member
- Joined
- Nov 5, 2011
- Messages
- 169
- Reaction score
- 107
I finally had a chance to do some extensive testing of a few different power tubes in the JVM205H, and thought I would post my findings, for those interested...
My volume was at 10:00 on the master, and 10:00 on the channel, which is pretty darn loud! I biased them all the same, at 37mV. Seems just about right, for all. Keep in mind, I play from older Gary Moore hard rock, to heavier 80's thrash, and Drop-D, chunky rhythms. I like a searing lead tone, thick with harmonics, and sustain for days, (but, who doesn't)??
I only utilize 3 channels/modes on the JVM - clean green, and orange & red on the OD's. I boost both OD's, with a Wylde OD - It's THE BEST I've found for boosting a Marshall, boutique or not! I've tried them all..
First up - JJ E34L's: NICE midrange, and good "EL34" sound, with a bit more THUMP, than other EL34's.. I dialed in good tones, NICE 80's/90's Mercyful Fate tones, but after some time, I just didn't find it "TIGHT" in the bottom end. It was more, but I found it "muffled", to some degree. Could be dialed out, but they just didn't "wow" me..
Next, EH 6CA7'S: Immediately, I thought, "BIGGER" tone than the E34L's. Certainly more highs, not as pronounced in the mids, but surely brighter, & clearer than the JJ E34L's. NICE thump! More bass? It's close, but I did find it clearer. These were a step up in tone, to the E34L's, but they have some high end, I found apparent. I like them well enough to keep them for spares, but still no "wow".
Next, the stock =C= SED's: I started experimenting right away, when I got the amp, but never really spent a whole lot of time, and was never really extensive about it. But, putting these back in, and biasing up to 37mV, (I think stock, I tested them at 26mV), these really sound good. Clear as a bell, nice punch, nice mids, nice aggression, but a tad bright. SWEET harmonics. Tighter bass than the E34L's, but not as warm. These do have some "wow" factor, biased up a little warmer I do like them, and have no problem keeping them in there!
Last - JJ KT77's: These are said to have an extended low end, as well as highs. They're also said to have LESS bass than E34L's, and not as aggressive. I BEG TO DIFFER. They have less mids, yes. Extended highs? I'd say clearer is more accurate. Extended bass? More than the SED's, more than the 6CA7's, and TIGHTER than the E34L's. I find it plenty aggressive, and MEAN AS HELL. If you're a metal guy -THESE ARE FOR YOU. I'm extremely pleased with them. They make my JVM sound "pissed off", for lack of a better description. Harmonics are abundant, chunky rhythm tones are tight & aggressive, and for me, these have that "wow", in spades. They will STAY IN!! The SED's would be my go-to back-ups, 6CA7's my third choice, and E34L's, may last. They ALL are more than adequate replacements, but the KT77's are the shit, for my JVM. They kick all sorts of ass!
My volume was at 10:00 on the master, and 10:00 on the channel, which is pretty darn loud! I biased them all the same, at 37mV. Seems just about right, for all. Keep in mind, I play from older Gary Moore hard rock, to heavier 80's thrash, and Drop-D, chunky rhythms. I like a searing lead tone, thick with harmonics, and sustain for days, (but, who doesn't)??
I only utilize 3 channels/modes on the JVM - clean green, and orange & red on the OD's. I boost both OD's, with a Wylde OD - It's THE BEST I've found for boosting a Marshall, boutique or not! I've tried them all..
First up - JJ E34L's: NICE midrange, and good "EL34" sound, with a bit more THUMP, than other EL34's.. I dialed in good tones, NICE 80's/90's Mercyful Fate tones, but after some time, I just didn't find it "TIGHT" in the bottom end. It was more, but I found it "muffled", to some degree. Could be dialed out, but they just didn't "wow" me..
Next, EH 6CA7'S: Immediately, I thought, "BIGGER" tone than the E34L's. Certainly more highs, not as pronounced in the mids, but surely brighter, & clearer than the JJ E34L's. NICE thump! More bass? It's close, but I did find it clearer. These were a step up in tone, to the E34L's, but they have some high end, I found apparent. I like them well enough to keep them for spares, but still no "wow".
Next, the stock =C= SED's: I started experimenting right away, when I got the amp, but never really spent a whole lot of time, and was never really extensive about it. But, putting these back in, and biasing up to 37mV, (I think stock, I tested them at 26mV), these really sound good. Clear as a bell, nice punch, nice mids, nice aggression, but a tad bright. SWEET harmonics. Tighter bass than the E34L's, but not as warm. These do have some "wow" factor, biased up a little warmer I do like them, and have no problem keeping them in there!
Last - JJ KT77's: These are said to have an extended low end, as well as highs. They're also said to have LESS bass than E34L's, and not as aggressive. I BEG TO DIFFER. They have less mids, yes. Extended highs? I'd say clearer is more accurate. Extended bass? More than the SED's, more than the 6CA7's, and TIGHTER than the E34L's. I find it plenty aggressive, and MEAN AS HELL. If you're a metal guy -THESE ARE FOR YOU. I'm extremely pleased with them. They make my JVM sound "pissed off", for lack of a better description. Harmonics are abundant, chunky rhythm tones are tight & aggressive, and for me, these have that "wow", in spades. They will STAY IN!! The SED's would be my go-to back-ups, 6CA7's my third choice, and E34L's, may last. They ALL are more than adequate replacements, but the KT77's are the shit, for my JVM. They kick all sorts of ass!
over high-gain overdrive a-la death-metal sounds 
...although I do occasionally dail up to that for a few riffs...just because I can. 
