JCM900 Combo 2x12 100w: sell or upgrade?

Emopunk

New member
So.. I have this amp from the end of the nineties. It served me well. It's still good sounding, but I always was bothered by his weight.
That is why I am considering selling it to get maybe a 50w head (I think I would love a JVM205h) + 2x12 cabinet. I mainly play rock, alternative, punk rock. One other option would be maybe to upgrade the combo I have with some Celestion Vintage speakers, to improve its sound (altough I realize it would become heavier!). So I am really willing to hear your best advices on what to do. I play in a band and occasionally we may gig into some pubs and places like that. Any good advice will be welcome, thanks!!
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

If you can get a good trade in, or have no emotional attachment to it, then trade it off. If not, upgrade it, you might be surprised by the new tones.

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Re: JCM900 Combo 2x12 100w: sell or upgrade?

If you can get a good trade in, or have no emotional attachment to it, then trade it off. If not, upgrade it, you might be surprised by the new tones.

Sent from my SCL22 using Tapatalk

That's for sure a good point. What should be my priorities in case I decide upgrading it? Speakers?
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

Speakers comes to mind first, however if you are happy with your tone, then skip it.

Next up are tubes. If you are gigging occasionally, you may wanna keep some handy

A maybe would be to Google for mods (if there are any, and if they are relevant)

My gut instinct is kicking in and saying don't sell. An amp like that is the perfect fit for your genre. My two cents


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Re: JCM900 Combo 2x12 100w: sell or upgrade?

Speakers comes to mind first, however if you are happy with your tone, then skip it.

Next up are tubes. If you are gigging occasionally, you may wanna keep some handy

A maybe would be to Google for mods (if there are any, and if they are relevant)

My gut instinct is kicking in and saying don't sell. An amp like that is the perfect fit for your genre. My two cents


Sent from my SCL22 using Tapatalk

Do you find it reasonable if I would substitute one of the two 75s with a vintage 30?
Could they work well together and give a deeper tone?
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

Celestion' website has some suggestions for matching speakers I believe. Check it out. From speaker types to ohms

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Re: JCM900 Combo 2x12 100w: sell or upgrade?

Celestion' website has some suggestions for matching speakers I believe. Check it out. From speaker types to ohms

Sent from my SCL22 using Tapatalk

Wow, I didn't know that I am going to see right now! :headbang:
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

It's here

http://celestion.com/upgrade/

Your speaker combo is listed under the mix it up section

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Yes, it's true. It seems they're actually a good match. Another thing I could plan to do is changing the valves. At the moment I have Soviet 5881. Should I consider a swap?
Thanks for all the good infos!
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

I'm not a knowledgeable tube guy, but yeah if they are old and have been used and abused gig after gig. If you want to try different brands then try to Google and find a tube comparison chart or similar info. It will help you determine which tube characteristics suits your needs.

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Re: JCM900 Combo 2x12 100w: sell or upgrade?

Good.. I see they sell around 125 euro each, here. Good price? It looks like the substitution is quite easy and I could do it by myself, am I correct?

At the current conversion rate that comes out to $143USD which is $2 cheaper than the average retail price here. It's really easy to do your self, just make sure you put the same ohm rating in as the one you take out
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

As far as tubes go, the preamp tubes on these don't change the sound quite as much as with a lot of other amps, but you will hear a difference. All I've tried in my 50w 900 head were the stock Marshall labeled pre's and Sovtek 5881s that came in it, and a set of Tung-Sol 12AX7 gold pins and a set of Tung-Sol 5881s. The change really helped it out
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

I rehearse at a place that gives me a choice of Marshall heads including DSL, Jubilee, 800 and 900. I always go for the 900. The clean/crunch channel with pedals sounds the best of the lot.
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

As far as tubes go, the preamp tubes on these don't change the sound quite as much as with a lot of other amps, but you will hear a difference. All I've tried in my 50w 900 head were the stock Marshall labeled pre's and Sovtek 5881s that came in it, and a set of Tung-Sol 12AX7 gold pins and a set of Tung-Sol 5881s. The change really helped it out

So I understand that you changed both pre and final valves with Tung-Sol models? Did you need to make adjustments to the circuitry or is it a simple swap? What kind of improvement did you notice?
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

Ehm.. I know it may sound stupid question to some of you but.. Do I need 8Ω or 16Ω Vintage 30 speaker for my 100w 4102 combo? :eek13:
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

So I understand that you changed both pre and final valves with Tung-Sol models? Did you need to make adjustments to the circuitry or is it a simple swap? What kind of improvement did you notice?
You can technically change both preamp and poweramp tubes yourself, but you should have it rebiased by a tech after changing power tubes.

Ehm.. I know it may sound stupid question to some of you but.. Do I need 8Ω or 16Ω Vintage 30 speaker for my 100w 4102 combo? :eek13:
According to the JCM900 owner's manual I found here, the combos have output transformers with 8 and 4 ohm taps. Your combo is a 2x12, and a pair of 16ohm speakers in parallel would yield 8 ohms, so you'd need a 16 ohm Vintage 30.
 
Re: JCM900 Combo 2x12 100w: sell or upgrade?

Keep it. It is a good amp and also one of the last marshalls to come out of england. A head and 2x12 is just as much of a PITA to carry as a 2x12 combo. Just get a folding trolley.
A fresh set of tubes is always good for re-energizing your amp, but a speaker swap would be cool too. Chuck in a set of jjs in the power section for bottomn end and EH in the preamp slots for low noise/high gain and a gutsy and aggressive midrange. I used a 900 100w head for many years and also owned a 900MKIII master volume 100w combo. This tube combo was great for both, but really...you could put any fresh set of tubes in there, bias them up properly and have a great rocking sound.
I'm guessing you have a pair of g12T75s in there at the moment. They are quite mid scoopy and heavy on the bass and high trebles. They are ok but far from my favourite voice in the celestion range. Very 80s hair metal sounding.
I would recommend a pair of creamback g12m speakers. They will give you that classic midrangey 60s era tone and the other advantage is that they are not very efficient, which means you can run your amp a bit louder on the volume control than you normally would with the speakers you have in there. A pair of creambacks g12ms will be able to handle the 100watts of your amp no problems. They will give a warmer, woodier more vintage vibe to your amp. Nice. The tonality that springs to mind is Eric Claptons "cream" era tone. Nice singing midrange. Your amp, with its two channels and maybe a nice fuzzface and you will be rocking with the best of them.
The other speaker worth looking at is the creamback g12H. These are also fine as a pair with your 100w amp. They have a much stronger low end and a much more present top end than the g12m, much more defined over all. However, they are also a lot louder, so in a club you will not be able to push your amp as hard without upsetting the punters, the soundguy/your bandmates. The tone of these guys is wide open...think along the lines more of Jimi Hendrix "band of gypsies". Big, bold, open and loud.
The last one to look at is a bit unusual for marshall amps but a really good sounding option is to go for a pair of speakers from eminence. Either get a pair of texas heats to soak up your 100watts without breaking a sweat and giving you a really thick tone with no flab. These guys are great for taming the output of big amps and smoothing off the tops. Ive been running a texas heat with a marshall for a while and its just great. Muscular sounding across all the frequency spectrum and never harsh or buzzy. If not a pair of those, then go for one texas heat and one private jack. The private jack is voiced something like the g12m celestion so youll get a groovy, complex tone by running the texas on one side and the private jack on the other...bear in mind tho that the private jack is only rated for 50 watts. This is fine as you are running it in a pair with another speaker, so even a pair of 50 watt speakers will be ok with your 100 watt amp, but it will be working closer to its limits so you will get some of that famous "cone cry" of the 60s. However, one speaker running like that, sitting next to the 150watt texas heat and youll get the best of both worlds. One will be loose and spongy (and just plain cool) and the other will be powering out the low end like it doesnt care. It is a sound ive used in the studio and run mics on both speakers to get a really great stereo spread. Sound engineers love it. For live...just mic the texas.
Ok...so that's 4 speaker options that are all nicer than what you have there:
1. 2 x creamback g12ms
2. 2 x creamback g12hs
3. 2 x texas heats
4. 1 x texas heat 1x private jack
Hope this info is useful
Keep your amp, its cool ;)....maybe a bit of armor all on the tolex and possibly some shoe nugget and your amp will be looking great too and you will remember why you liked the amp in the first place.
 
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Re: JCM900 Combo 2x12 100w: sell or upgrade?

I'll never get why 900s seem to be so hated, it's nice to see other people who like them as much as I do. I like V30's with these amps because they have a more pronounced mid range compared to t75s, and since channel b has a different voicing hard wired into it that scoops the mids the speakers help balance it out a little. I run mine through a v30 and M65 creamback sounds great. As for my choice in tubes, I mainly went with Tung-Sol because I've had good experiences with them, and unlike I've read in online reviews of their 12ax7s, I've never had one go bad prematurely in almost 10 years of using them. Also I read a few comparisons online and nearly all of them rated their 5881s as one of the best modern production 5881s on the market, closest to vintage sounding. Overall the effect they had on the amp was more chime/sparkle on channel A but without getting shrill or "ice picky" and they smoothed out some of the fizziness on channel B and get nice and fat with smooth breakup at higher volume.
Ps yes I did re-bias it after changing power tubes. I don't remember the exact numbers, but it came out about 73% dissipation
 
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