JCM600...what I think

[8eezrule]

I've put my new(to me) amp through it's paces. After recieving it I spent a couple eve'nings dialing it in. The fan I ordered for it was too big and had to send it back for a smaller one. But till I get it I'm using a small desktop fan aimed at the back to help cooling. I went and jammed with some friends with it last night, running it through a Crate 4x12 loaded with 2 Celestion g12t75's and 2 vintage 30's. The amp has 2 Celestion Heritage speakers in it, and not g12t75s as I was lead to believe, not a deal breaker. It's got 2 EHX el34 power tubes and some unbranded(no markings at all) 12ax7 preamp tubes. We were playing a mix of 80's hairmetal, 80's thrash, southern rock, and classic rock. This amp did it all wonderfully! I'm talking about 3+ hours of jamming. Between beers and bs'ing I left the amp on standby, no overheating or loss of power or tone. Both efx loops work, I used the parallel with a jumper for a gain boost, which I found out also affects the clean channel. I think some new tubes may be in order though, the amp sounds VERY mid rangey. I had too turn the presence all the way down to tame it. Gonna get 2 Mullard el34's and some Mullard or Tungsol 12ax7 and I think she'll sound how I want. Other than that bass, mids, and highs all sound good, depending on eq setting. For the hairmetal and thrash I did use a combination of Boss sd1, dod yjm308, and ehx lpb1 along with a mxr super comp with a little chorus for added thickness. For the southern rock and classic rock, just the amp either in the clean channel with the volume around 6-8 or the gain channel with the gain set around 4-6. Settings depended on song, and later on in the night how many beers I had. Overall I'm very happy with this buy. I maybe coulda talked them down from 499.99, but didn't feel like haggeling, not when shipping was free, no sales tax was added, and I have a 30 return.

 

[JOLLY]

Glad to hear that it worked out for you

 

[beaubrummels]

FWIW Midrangy is what almost every Marshall I've ever played through sounds like. Changing tubes won't change that basic signature, but it might sweeten it some, if you can find some good NOS glass at all. Different speakers also go a ways to smoothing the sound. If it's got Heritage speakers, that might be the best sound you can get with Celestion to tame midrange. Changing from EHX to recent issue Mullard or TungSol won't changing much because they are roughly the same tube. https://www.ehx.com/tubes/

To even my JCM900 out, I normally have to set EQs something along these lines:

 

[jeremy]

master on 10 eh? good for you! mkiii or slx?

i think all the jcm 30/60/600 models came with those heritage speakers. not bad, but not my favorite. i ended up with a g12-65 in my jtm30

 

[beaubrummels]

master on 10 eh? good for you! mkiii or slx?

i think all the jcm 30/60/600 models came with those heritage speakers. not bad, but not my favorite. i ended up with a g12-65 in my jtm30

Yeah I keep the master on 10 to get close to a NMV Marshall, I only use the input gain to set level and distortion. That one in the picture is an SL-X head.

 

[8eezrule]

I know Marshall's signature sound is midrange heavy, and thats what I am going for, wrong description on my part, the mid range on my amp right now is pretty harsh, almost brittle sounding. The Mullards will smooth that out. At least on my old Lee Jackson Crate Stealth(which was just a hot rodded jcm800 clone) they seemed to warm the midrange. I ran all Mullards in that amp. Really warm and creamy gain tones.

 

[xxxplorer]

I've really never had different brand tubes change the inherent character of an amp enough to chase it. Especially at gig volumes and with a band. As long as the tube works and isn't noisy I just use it lol.

 

[Mincer]

I've really never had different brand tubes change the inherent character of an amp enough to chase it. Especially at gig volumes and with a band. As long as the tube works and isn't noisy I just use it lol.

I did, on a Mesa Blue Angel. I tried new JJs and early 2000s Groove Tubes, but none sound as good as the stock Mesas.

 

[Securb]

I am happy to hear you are gelling with the amp. That amp is a beast and, like you said, very flexible. I went with all Mullard glass in my Marshall a few years ago and would not use anything else in that amp.