#1
Yep thats right, finally got that JCM 900 50 Watt 1x12 combo i've been after for so long:








yeah the guy packed it really really well






I jizzed when i saw it for the record



And there she is all at home

I want to give thanks to all the people who helped me on this long search:
pychokiller98, StephenRettie, SurfinWithSatch, al112987, Gutch220, georgakis187 and all the others, I can't remember them all

Now there are your pics, and i would be working on clips, but there's a problem.

The amp is:
-very very quiet, the master for the channel b (overdrive) is on 5 and its at bedroom levels
-there is no sustain, the volume keeps dropping out
-its crackling a little bit as well

my first guess is a blown power tube?
its hard to get to the tubes without taking off the back panel, which i really don't want to do so i can't check

also the guy i bought it from mentioned he didn't know how old the tubes are, which makes me believe there's a blown tube

anyway thanks to you all, and somebody help, i really really want to play this badboy the right way
Quote by progbass
right Metallica is a given. Personally I like to pretend the bus exploded and killed them all in '86.

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Last edited by acdclandon at Feb 10, 2009,
#3
Quote by mcrfobtai
Wow, that;s awsome. sounds like a power tube problem. What do they look like when turned on?



thanks man, looks like their both lit up, but one is really dim compared to the other
Quote by progbass
right Metallica is a given. Personally I like to pretend the bus exploded and killed them all in '86.

GUITAR PEDALS FOR SALE
#7
Congrats, while the dimness doesn't necessarily mean it's blown, the volume and sustain problems do sound like a bad power tube.
I don't give a shit if you listen to me or not
#8
Quote by mcrfobtai
Probably blown


alright thanks man
Quote by progbass
right Metallica is a given. Personally I like to pretend the bus exploded and killed them all in '86.

GUITAR PEDALS FOR SALE
#10
Quote by Kevin Saale
Congrats, while the dimness doesn't necessarily mean it's blown, the volume and sustain problems do sound like a bad power tube.


hmm alright thats 3 for 3

thanks by the way

so what do you recommend for replacing?

i'm pretty set on JJ 6L6's, or i guess EL 34's if i want to go that route, but i mean i've heard people say get them online? my only issue is i can't replace them (first tube amp) and i kinda want to play it somewhat quickly lol
Quote by progbass
right Metallica is a given. Personally I like to pretend the bus exploded and killed them all in '86.

GUITAR PEDALS FOR SALE
#11
I'm not sure you can change El34's for 6l6's. I don't think the pins and draw are the same. Although some amps are designed to do it, I don't think the 900 is
#12
Congrats man, glad I could help!

I also had similar problems when I first got my 4102, same as you the guy didn't know how long the tubes had been in for (he had the amp for 4 years and said it still had the same tubes from the first owner) I had to play it on the 100watt setting at just over half volume to hear it properly.
Sounds like the power tubes are near death, maybe the preamp aswell. My advice is to take it to an amp tech though, I did and he changed the tubes but also checked the circuit board and something had blown on the circuit board. He replaced what had blown with parts from a Framus Cobra (he had them lying around so decided to use em, lucky me lol) and I also had him mod the amp so it could take EL34s rather than 6L6 (just my personal preference), I got it back and it was a completely different animal! I'm still finding new things out about this amp which I didn't know before for instance I've recently found an awesome tone with some EQing and adding my TS9 on top to give it that extra bite. So take it to an amp tech and let them give it a full servicing so you can get the most out of it and SCREAM!!!


EDIT: Just noticed you said you're thinking about putting EL34's in it. In my opinion it gives the amp more balls, however it will need to be modded to take them like I had mine, it'll cost ya a bit but not too much. For my full service with all the replaced parts and the mod it cost a total of £180 but from what I remember it was like £40 just for the normal service, then the mod + tubes about £80 or £90 and the rest on replacing parts of the blown circuit board (+ the labour of course). I could be way off with my guesses there but I think it was something like that.

EDIT 2: I just remembered the mod cost me a little more than it would have usually because the guy had to spend twice as long doing it as Marshall had sent him the plans the wrong way around (changing a EL34 amp to take 6L6 rather than the way I wanted)
Gear:
Epiphone SG Standard - Natural Wood Finish + SD Alnico Pro 2 Bridge Pickup
Epiphone Les Paul Standard - Limited Edition Green
Ibanez S470
Blackstar HT-100 Head
Harley Benton 2x12 Vintage 30's
Vox AC4TV
Vox VT15
Last edited by SurfinWithSatch at Feb 10, 2009,
#13
Quote by mcrfobtai
I'm not sure you can change El34's for 6l6's. I don't think the pins and draw are the same. Although some amps are designed to do it, I don't think the 900 is


the first couple of years it ran with el34's, than after that with 5881's (basically 6L6's) so i think with an adjustment it should be able to

Quote by SurfinWithSatch
Congrats man, glad I could help!

I also had similar problems when I first got my 4102, same as you the guy didn't know how long the tubes had been in for (he had the amp for 4 years and said it still had the same tubes from the first owner) I had to play it on the 100watt setting at just over half volume to hear it properly.
Sounds like the power tubes are near death, maybe the preamp aswell. My advice is to take it to an amp tech though, I did and he changed the tubes but also checked the circuit board and something had blown on the circuit board. He replaced what had blown with parts from a Framus Cobra (he had them lying around so decided to use em, lucky me lol) and I also had him mod the amp so it could take EL34s rather than 6L6 (just my personal preference), I got it back and it was a completely different animal! I'm still finding new things out about this amp which I didn't know before for instance I've recently found an awesome tone with some EQing and adding my TS9 on top to give it that extra bite. So take it to an amp tech and let them give it a full servicing so you can get the most out of it and SCREAM!!!


thanks man you helped me a lot in my search

alright i think thats what i'll do, i'll be sure to mention that something might need to be adjusted in it to make it work properly and such
Quote by progbass
right Metallica is a given. Personally I like to pretend the bus exploded and killed them all in '86.

GUITAR PEDALS FOR SALE
#15
I would go for Electro Harmonix el-34 and Tung-sol 12ax7.
My Gear
Guitars:
-Gibson Les Paul Studio
-Ibanez "lawsuit" Les Paul
-Ibanez S470
-PRS SE Custom

Amp:
Marshall TSL100
Marshall 1960a cab

Effects:
Dunlop 535q wah
Visual Sound Liquid Chorus

Pickups:
Guitarforce
MHD
#16
I like JJ's in the power and Tungsols in the Pre. EHX tubes aren't all that great imo. Plus the dark JJ's balance out the brighter tungsols nicely
#17
tungsols in all of the pre slots are usually TOO bright and harsh... maybe something different in the PI to smooth it out a bit
My gear:
PRS SE custom
~!~--Peavey XXX super 40 EFX --~!~
Peavey VK 112

===WGS Vet30
===JJ power tubes

---Pedals:
-ISP Decimator
-Digitech Bad Monkey
-Crybaby wah
-Korg Pitchblack
-Danelectro FnC EQ
#18
i see what you guys are saying, the 900 is a very bright amp to start with, so i might go with JJ's in the preamp, because i've heard their main problem is being too dark?
Quote by progbass
right Metallica is a given. Personally I like to pretend the bus exploded and killed them all in '86.

GUITAR PEDALS FOR SALE
#19
so i'm going today (my school was canceled because of snow ) to my local music store to replace the tubes, and i think i'm gonna get them all replaced just for a good fresh start

as stated the amp is very bright to begin with, so i think going for a bright tube might be too much. also, the tungsols aren't able to run in the cathode followerer stage? What is that?

I think if they jj's i'll go both with JJ 12ax7's and JJ 6L6's, plus the possiblity of looking at the amp and making sure it will run them correctly

If not JJ's than i guess Tongsols will work nicely
Quote by progbass
right Metallica is a given. Personally I like to pretend the bus exploded and killed them all in '86.

GUITAR PEDALS FOR SALE
#21
Quote by 311ZOSOVHJH
The thing is with preamps, they don't all have to be the same. I actually would get a variety of preamps and swap them around as you see fit.


Congrats btw



sweet, i'll try out the mesa tube sometime as well

oh and thanks man, its been a long time coming


So I when today, just got back, turns out to get the 6L6's in they'll have to take out the chassis which will unfortunately add to the cost, oh well, worth it right?

also it won't be done til saturday at the earliest, and more likely tuesday or wednesday

oh well, i'll get clips up when i get it though
Quote by progbass
right Metallica is a given. Personally I like to pretend the bus exploded and killed them all in '86.

GUITAR PEDALS FOR SALE