Voodoo Amps Marshall JCM 900 4100 Dual Reverb Mod

OK, let me start off by saying that when I first got this amp, it absolutely sucked. Marshalls with 5881/6l6 tubes sound like garbage imho. I almost wanted to sell it, but I heard about voodoo for many years. So I decided to give them a shot. This thing is awesome now! Absolutely amazing! i have a 5150 block head, ampeg vl, and have owned a TSL100 marshall, xxx, jsx, etc. This is by far my favorite amp. I went with the standar mod, which totally cleaned up the amp (much quieter) the clean channel can actually be clean, and the gain channel has so much gain and balls. I also went with the el34 mod for my amp since it came with the 5881 power tubes. Much better! Yes the amp definitely sounds good at low volume, but its a Marshall, and this thing is SICK at high volumes. When the tubes get hot its amazing!!

As stated before, the tone on this thing totally sucked when i got it. Think 5150 crunch channel with all lows, and no mids and bad tubes, and thats exactly what this thing sounded like. It was dead sounding. I called voodoo, and they explained what the mod would do to my amp, and we went from there. The Svetlana el34 tubes they put in with the EL34 mod are amazing! nice bottom end. They installed some high gain ruby tubes with the mod they did, but I later switched to Tungsol high gain 12ax7's. This thing sings now. Every note cuts through crystal clear. I dont even know how to explain how good this thing sounds!! I would recommend the standard mod and EL34 mod to everyone!

OK at this point, Im sure everyone is like "10's all the way so far??" but its true. My amp is constantly being moved to and from practice, shows, studios, etc. This thing can seriously handle every ounce of beating I have given it. I have never had any trouble with it, the mods have held tight, and all I can say is I am 100% satisfied with the outcome of my amp.

The people at Voodoo are extremely helpful and very knowledgeable when it comes to amps. Ive called and spoke with numerous people about different heads I have wanted to have modded and they always help me as much as they can. Also, when I sent my amp in, there were a few issues with it that needed to be worked out, and they called me immediately and discussed it with me. These guys are absolutely amazing.

All I can say is their customer service is awesome, their mods are awesome (at least for this particular amp) and I couldnt be happier. So if you have a 4100 jcm 900 that you are unhappy with, DO NOT sell it, get it modified. I promise you will be very glad you did. The standard mod is not expensive at all, and neither is the EL34 mod. The most expensive part about the EL34 mod, is the tubes, and I assure you, it is well worth it, every single penny. But don't take my word for it, try it yourself.

Before the Mod the Amp was pretty stale. I couldn't go from one sound to another at all, it was all blah. I would turn the Mids all the way down and it still sounded noisy as hell, turn the treble down and still noisy as hell. No matter what knob I turned the sound seemed to stay the same. That is definately not the case anymore. When I turn a knob I hear the change in sound immediately. The Global control is a Godsend and the Bass Push/Pull knob is amazing. Not only does the amp sound better, but I can get more than one sound out of it. I can play metal, punk, even the clean sounds are great!

The sound is superb. I will be fiddling with this amp for a while to find out what settings are perfect on it though, because there are so many sounds to choose from. The bass push/pull is great and the global is even better. The only knob that doesn't seem that have as much power to change the sound as it used to is the presence knob. Another thing, DAMN this amp is LOUD. I don't remember this amp being so loud, a tube must have been broken or something when I sent it in because this thing crushes now. What Voodoo says about you being able to play at the master volume at 1 is right on the money. I can play at low volumes and still like the sound that is coming out of the amp, I think the amp sounds better at 3, but its waay to loud to play past 2 even.

Wouldn't know yet, I assume that it is reliable since it's not broken right now. All my tubes were changed, and my filter caps were replaced. I kept the old transformer though. Hopefully it will last me a long time and I don't see any reason that it wouldn't. I would gig without a backup.

Disregard my post about the customer service as it was because of a misunderstanding on my part, Trace went out of his way to make me happy after hearing my concerns. Definately much better than I had previously posted.

Overall this is now a great amp, when it used to be a terrible amp. Kind of on the expensive side, but that's also because I basically had the entire thing serviced with the new filter caps, power and preamp tubes. If I had to do it all over again, I probably would. If someone steals it I will hunt them down like a dirty dog and probably try out their Witchdoctor or Hex amps, cause if they can make my JCM900 sound this good, I wonder what they can do when they start from scratch. Amp good, customer support, a little under mediocre.

I hated it since day one. It never had enough articulation, balls or depth. But hey, I had bought it for a good deal in a full stack and the cabinets were a different story. This amp basically had 2 channels, a clean crunch, and lead. Duel reverb, one for each channel, and an effects loop.
Fast forward to 2004. I?m surfin? the web one day. I punched in modified Marshalls and accidentally found Voodoo Amps. I went to the sight and was pretty much in awe. Could all this stuff be true? So I decided to call Trace.
Talking to this dude seemed too good to be true; that he could make this deficient amp I detested into the amp of my dreams. We talked for approximately 45 minutes. We spoke of the Plexis of yore as well as the modern gain amps. We came to a conclusion; to build a modern high gain Plexi of yore. Was this even possible? You bet your ass!
After the mod my almost three channel amp was now a single channel with no foot switching capability; but I didn?t care. We chose the hex mod for the pre-amp. The out-put section is a totally different story. We went with Mercury Magnetics, ?68 Plexi transformer. So I figured, if I?m going to have it ?modded,? might as well go with a new Mercury Magnetics Power transformer also. Swap the stock 5881?s, for EL34?s, put in a tube buffer effects loop? And Walla! There you have my dream amp!

I?ve had this amp for five months now and I?m still finding new sounds. I?m into players like Lynch and DeMartini and this amp delivers that in spades. But Gary Moore, Michael Schenker, John Sykes and Jake E. Lee live in there too. I do the brutal mode with about mid gain, with a modified tube screamer, and get the most killer Lynch tone you can imagine.
Switch to savage mode and this thing has more usable gain than I?ll ever need in my life. My one channel monster has more versatility than the stock ?footswitchable? 2 channel dud that I originally bought. This screams, moans, cries and sings! I?ve been trying to get these tones since I was young, listening to my heroes; now they?re at my fingertips. I have seven guitars, all left handed super Strats with Seymour Duncans, except for one with EMG?s. This amp loves them all. It retains each one of their personality with smooth integrity. As with most tube amps the hum and buzz at idle can be a pain but I think this is pre-amp tubes,When I'm playing the amp I get no noise and totally controlled feedback..It's actually FUN to play!!!

This is where I have all the respect in the world for Trace. I originally got the amp back in late spring. I fired it up and it sounded good, but not great. Later that evening it popped a fuse, so I replaced it. It popped again. The next day I called Trace. He said sounds like a faulty output tube to him, so he sent me a new quad of EL 34?s, no charge.
It took about 2 weeks to get here. When they got here, I replaced the quad, played for about and hour, and POP!, there goes the fuse again. So I got back on the horn with Trace. He said if I could get the amp chassis to him, he would take care of the rest. He had it about three weeks, e-mailed me and told me it was on it?s way.
I got it back and btw, this is the third quad of EL 34?s I received for free. He said that they had got a batch of bad rectifiers from their supply house and needed to be replaced in my amp, and he was sorry. I put the tubes in my amp, fired it up, and Holy Shit!, this amp sounded great, incredible, awesome! It has killer articulation, and yes it does sound good at low volumes. But that?s not where I play it normally. You got to get the master up to at least six to unleash the Plexi-awesomeness. I?m going to get a THD Hotplate for it because this sucker is LOUD! Yet it has all the subtly in the world. The combination of Hex pre-amp, and Plexi transformer makes the ultimate future, retro amp.

In all fairness to Trace, I didn?t submit my review until now. I play it every day at least an hour or so. It seems to sound better the more I play it. So the fact, he fixed it for free, sent me a third set of EL 34?s, and although inconvenient, I would rate it a 15 if I could.

Unintentionally, I put Trace to the test and this man impressed me. He didn?t drag his feet or pass the buck. He grabbed the bull by the horns and dealt with my problem, quick and painless. I will buy another amp from Trace, and have told all my friends about him! This dude is the real deal! I'd give him a 15 in this catagory too!!

I've been playing about 18 years,I also have a Marshall JMP50 MKII from 1977 and although I love that amp,This amp is on a much higher plane...It's a fire breathing dragon on one hand and the most articulate sustain machine on the other.If it were lost or stolen I would definatly be bummed,But,I would probably save up more money and go for Trace's new Plexi head and see if he could hot-rod the pre-amp section a little...One thing I forgot to mention,I usually use a little delay in my tone but with this amp I put the delay away,It's that FAT and responsive....