JCM 900 4101 Combo - Incoming

JMP

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I’ve never owned or played a Marshall. I know….it’s crazy. But I absolutely love all the Classic tones many many people have made with Marshalls. I found a used 1991 JCM 900 4101 Combo locally and grabbed it. Got it cheap because it needs a fair bit of work to be functional. It’s currently at a local tech being resurrected. I’m very much looking forward to playing it.

@cherrysunburst00 - thanks for the Marshall inspiration!

Anyone else have one of these?
 

Deftone

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@Deftone is a H U G E 900 fan!
True. I use a lot of pedals though, so YMMV.
I’ve never owned or played a Marshall. I know….it’s crazy. But I absolutely love all the Classic tones many many people have made with Marshalls. I found a used 1991 JCM 900 4101 Combo locally and grabbed it. Got it cheap because it needs a fair bit of work to be functional. It’s currently at a local tech being resurrected. I’m very much looking forward to playing it.

@cherrysunburst00 - thanks for the Marshall inspiration!

Anyone else have one of these?

I actually borrowed a 4101 many years ago and loved it. I currently have JCM900 4500 Hi Gain Dual Reverb and an SL-X 2500.

JCM900 Hi Gain Dual Reverbs were likely designed for Metal, so some people find them a bit harsh for rock and blues. An EQ in the loop helps sometimes.

Congratulations and HNAD!
 
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JMP

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True. I use a lot of pedals though, so YMMV.


I actually borrowed a 4101 many years ago and loved it. I currently have JCM900 4500 Hi Gain Dual Reverb and an SL-X 2500.

JCM900 Hi Gain Dual Reverbs were likely designed for Metal, so some people find them a bit harsh for rock and blues. An EQ in the loop helps sometimes.

Congratulations and HNAD!
Thanks for the info. There’s gotta be plenty of Classic Marshall tones in the JCM 900. That said, a 100 watt combo is definitely going to be a challenging beast for my bedroom and garage rock excursions.

Congratulations on the retirement. I’m 44 and we’re DINKs too….hoping to retire at 55ish too.
 

Deftone

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Thanks for the info. There’s gotta be plenty of Classic Marshall tones in the JCM 900. That said, a 100 watt combo is definitely going to be a challenging beast for my bedroom and garage rock excursions.

Congratulations on the retirement. I’m 44 and we’re DINKs too….hoping to retire at 55ish too.
Thanks.

I always have a Distortion pedal in front, so I use the volume on the pedal to control the beast. Volume box in the loop my help too.

There's also a half power switch on back.

I just went and played mine...I do love that amp.
 

Gridlock

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Congratulations, Welcome to the Marshall club.

I used a 100 watt JCM900 half stack and a 50 watt JCM900 combo in a band for years. I’m debating on picking up a 900 2100 MKIII head for sale at my favorite music store. Definitely would prefer a combo.
 
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Deftone

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I just drank a lot of beer https://www.moonrakerbrewing.com/ so I cant remember which channel is which right now but one channel is dark like my Mesa Solo Rec and the other channel is straight up JCM800...like my JCM800.

FWIW I have the JCM800 2204 & 2205, as well as the JCM900 4500 & 2500 (SL-X) I keep thinking I'm going to keep two and sell the other two but every time I play one I think "oh fuck that, I'm not selling this one."
 

JMP

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I’m guessing it’ll be at least a few weeks before the amp is up and running and I have it in my possession. There are a few well regarded amp techs locally (Western MA) and both said they have been unable to meet demand. I can be patient!

That said, the preliminary diagnosis indicated the following- broken solder joints on a few power tube sockets , two of the four power tubes are totally cooked (the other two still function, but are not healthy), a bunch of the electrolytic capacitors are dead. These items will need to be addressed, then the tech can power up the amp and check everything else.

It’s all good! When the repairs are done, the amp will probably be better than new be good to go for a very long time.
 

Deftone

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I’m guessing it’ll be at least a few weeks before the amp is up and running and I have it in my possession. There are a few well regarded amp techs locally (Western MA) and both said they have been unable to meet demand. I can be patient!

That said, the preliminary diagnosis indicated the following- broken solder joints on a few power tube sockets , two of the four power tubes are totally cooked (the other two still function, but are not healthy), a bunch of the electrolytic capacitors are dead. These items will need to be addressed, then the tech can power up the amp and check everything else.

It’s all good! When the repairs are done, the amp will probably be better than new be good to go for a very long time.
I took 3 of 4 of my Marshall's to a tech for service/ tune up right off. The 4th had just been to a tech before I got it. It's a good idea with older tube amps, IMHO.
 

Deftone

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I’ve always been into Fender amps. Exploring Marshall tones will be a shit ton o fun!
Been playing my 900HGDR quite a bit lately, since your thread started. It's going through a 1960 A 4x12 with V30's. I have an A/B box so I'm switching back and forth with the Mesa Single Rec, then combining the two. Sounds awesome.
 

JMP

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Update: amp is repaired and I’m getting it tomorrow. The tech wanted to keep it powered up and running all afternoon just to ensure there’s no issues and to let the new tubes settle in, tweak the bias if needed.

The amp was pretty mangled apparently. But now it’s functioning better than new I am told.

I’ll update the thread this weekend after I’ve had a little quality time with the amp.
 

pirate19

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Not the same amp, but I love my my 1990 JCM900 MkIII 50W head. Classic Marshall tones, then can use the "Gain Sensitivity" knob if I want thicker/higher gain. The low power switch on back really comes in handy. Happy New Amp Day, hope you enjoy
 

Deftone

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Update: amp is repaired and I’m getting it tomorrow. The tech wanted to keep it powered up and running all afternoon just to ensure there’s no issues and to let the new tubes settle in, tweak the bias if needed.

The amp was pretty mangled apparently. But now it’s functioning better than new I am told.

I’ll update the thread this weekend after I’ve had a little quality time with the amp.
It will be better than new. I think mass production at Marshall may have resulted in some inconsistent quality at times. You'll be getting yours tuned to peak performance. Looking forward to hearing about it.
 

JMP

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I picked up the amp mid day. It’s clear to me the tech knows his stuff and he clearly did a very thorough rehab of my amp. I’ll post a thorough break down of repairs later. But, I was able to spend a quick 30 minutes playing it and it’s a totally different animal as compared to my Deluxe Reverb (I’m sure everyone knows this!). My initial low-volume so as not to scare my old dog impression is…AWESOME! Holy crunch!

Another observation, which the tech noted, is that the amp runs hot. He says every JCM 900 combo he’s encountered runs hot - 100 watts, big transformers, and lots of tubes in a small package = heat.
865C1B11-A376-487A-8636-56FE37D8FB8A.jpeg
 
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