Evolution of the Sozo's/JTM45 upgrade kit first impressions

jtm-45/dr504 · Post by **jtm-45/dr504** » Fri Feb 17, 2006 3:56 pm

Well, I got the upgrade kit very quickly (cool!), and spent about four hours being very careful and meticulous with the population of the board and the installation. For the most part, the instructions are fairly clear, but I had to refer to the JTM45 amp kit instructions a couple of times to clarify some things, and I had to ask a question here on the board about the placement of a resistor. So, a few issues could be addressed with that.

It fired up perfectly without a hitch, and after initial testing and tube installation/biasing (the Valve Arts biased within 1ma of each other) I fired the amp up through my Weber MASS (it was late) and gave a listen. As I've read from other posts on this board, the amp almost seemed way too fizzy in the top end, moreso than it was before, but I'm assuming that will go away within the first three hours or so as I've heard. Some of that may be to the differences between the Valve Arts and the Groove Tubes I had installed previously. Time will tell. I'm also using the JJ's with the kit as well, instead of the EI/EH/JAN Philips smorgasbord that was in there previously.

The amp seems to have more gain in the 7-10 range on the volume knob than it did previously(JJ's?), which is interesting. What it that seems to do is make about 7 be the perfect spot for volume knob clean to dirty operation, which seems to be better than it was. No ghosting or anything with the ruduced filtering, and I'm only using one side of the 16x16 cap can, just to see if I liked it. So far, a great amp made even better! Thank you George!

SoZo · Post by **SoZo** » Sat Feb 18, 2006 8:44 pm

The SoZo Capacitors do give a good gain push and are very alive. I get the perfect gain on 7 with a JTM45. If you need help tweeking it I am working on my own JTM45 now and can give you some of the tricks I have had sucess with...

jtm-45/dr504 · Post by **jtm-45/dr504** » Sat Feb 18, 2006 9:34 pm

Yes, they are very alive. I still have yet to test the amp in a band situation, but it's already smoothed out quite a bit in the small amount of time I've had to play the amp. The amp has more gain than it did at 7 previously, but still gets to the same beautiful clean at about 6 on the guitar. Nice.

John, by all means share your findings. Right now, though, the amp finally gets fat and mean on the strat bridge pickup the way I've always wished it did on its own.

SoZo · Post by **SoZo** » Sun Feb 19, 2006 10:14 am

Let me know what board parts you are using or a picture can help...

jtm-45/dr504 · Post by **jtm-45/dr504** » Sun Feb 19, 2006 6:28 pm

I'll try to post a picture of the installed board soon.

I just finished a thirty minute session with the amp right after work (no else home yet!) and it has really smoothed out now. Amazing. The JTM-45 is an amp that I think a lot of people wish their amps sounded like, but they just haven't tried one. Super fat, and smooth like a tube screamer (now, with the sozos!) with enough gain and tonal range to do Zeppelin, Free, Hendrix, Cream, EVH, or anything, really.

I play in a modern rock band that has a classic rock feel, and the JTM serves me well. I've always used pedals into the amp set 'on the edge', but I'm going to try using the amp dynamically with my MASS to help tame it a bit, and a couple pedals just for solo boosts.

People always talk about how '45s love humbuckers (and it's true), but IMO, it's also the perfect strat amp. I read where George said the JTM45/100 was the first amp he'd found that sounded perfect on his bridge pickup and the neck pickup as well, and that's true with my JTM and my strat.

jtm-45/dr504 · Post by **jtm-45/dr504** » Sun Feb 19, 2006 11:45 pm

Also, after some CD player burn in time this evening, I checked the bias on the tubes. I originally biased to 39 on one, 41 on the other, and they had drifted to 32 and 34! Cranking the bias back up while carefully watching the meter, though, I got them back to almost 39 and 41 again. Interesting.

grumpy · Post by **grumpy** » Mon Feb 20, 2006 2:36 am

jtm-45/dr504 wrote: People always talk about how '45s love humbuckers (and it's true), but IMO, it's also the perfect strat amp.

Well, I'm with you! I use a strat pretty much all the time and I love my JTM's. I think I'm an odd one out here ,because I play pretty clean apart from solo's. The JTM has a fantastic clean tone for my taste. I run mine on around 7 and guitar vol about 6 to 6.5 for lovely crisp spanky, bluesy cleans that sound good with all the P/U's and turn her up varying degrees from there. I actually find I don't need more than that in some rooms, In acoustically dead rooms I use a pedal sometimes to get me a little extra drive. JTM's.....I love 'em!
Grumpy

jtm-45/dr504 · Post by **jtm-45/dr504** » Mon Feb 20, 2006 7:37 pm

Well there you go. Others just have yet to discover our secret.

mah84 · Post by **mah84** » Mon Feb 20, 2006 9:32 pm

Regarding the JTM/strat combo, you've just gotta look to Hendrix. He had that beautiful cleanish sparkly sound with a gritty edge for his chordal work. That is one of the most beautiful sounds i've ever heard -i'll never get sick of it.

grumpy · Post by **grumpy** » Tue Feb 21, 2006 8:54 am

Too True!! Hendrix's clean tones are monstrous!!I just love the way you can change the tonal response by changing your attack of the strings with the Strat/JTM combo. Just got home from a gig tonight, my JTM made me smile again! Honestly, it just seems to sound great in every room. Magic mate..bloody magic...just like a bought one!
Grumpy

PS. Are the Aussies gonna kick some arse in the World Cup?..Oh yes they are!!!!

BashCoder · Post by **BashCoder** » Tue Feb 21, 2006 9:03 am

Abso-freaking-lutely! We're waaay off the Sozo topic now, but while we're here: Sometimes (when I'm accidentally playing a phrase really well) my SRV Strat/JTM45 combo seems like it could conjure Hendrix's ghost.