Modding my 900! (All tube, with clips)

[iron broadsword]

Not a bad problem to have!

 

[HOT TUBES 70]

Iron BroadSword ..... nice work !!
That 900 sounds damn good after your handy work under the hood ....
The video is the clincher , you can really hear the upper end clarity , and the overall tightness of the chords improve after the mods .

 

[iron broadsword]

It's all tschrama, man. He NAILED it with these mods. It feels like a different amp, and definitely sounds that way. I didn't even have to take the board out, everything could be done quickly from the top of the board and only took about an hour total.. had all the parts on hand, and would've only cost a buck or two anyway.

I borrowed a condenser mic from a friend and am gonna try micing it from further away.. should be more accurate. The lower gain clip that I posted was the most accurate to my experience today thus far though, but it was recorded at VERY low volume and has no help from the speaker at all. At band volume or even less it is just so smooth and raunchy. This is the clip I mean - http://ghostsauce.net/random/900 test 3.m4a

 

[Adrian R]

Re: Modding my 900! (with clips)

I had a 1990 JCM900 4500DR head I used for 15 years. Was a fantastic amp but I always wished it have a better bottom end.

I'm telling man..and to anyone else whom has a 41/4500...simply put a BBE Sonic Maximizer in the loop and you'll not have to do any of these mods...

My dual reverbs sounded awesome and surprisingly very organic setup this way...gave the amp WAY more dynamics making it sound more like a Marshall..

 

[tubes]

You've gotta post some clips of that bugera, I'd love to hear what it can do!

Hey tubes, what kind of sound are you looking for exactly? Trying to figure out where you're at.

Good question - I don't really know the answer. I expect I'm trying to do everything.

We play in a lot of different genres and maybe I expect one amp to do well in any and all of them.

It's a preposterous expectation to have of any amp, but I'm actually mostly happy with my 4100 and some pedals.

Of course it's great to find the sweet spot with any amp, never mind the genre of music.

To quote you...

"It was amazing. It is SO clear and has so much character to it... every small detail of your pick attack and fretting is projected and heard clearly."

We can call that HOME.

I could have expressed it better, or carried on with extensive detail... but it's late.

 

[ibmorjamn]

Re: Modding my 900! (with before/after clips)

I like that 900DR grind ! I prefer the 4100 to the 2100 MKIII I had. The DR has this certain evil character on its gain channel PLUS a GREAT clean channel which takes OD pedals very well. All around just a more versatile amp which really shows its power and teeth when you start turning it up. No wonder I gots 2 of them ! Oh and now one is running EL34 , and the other stock config 6L6. But we al know these were originally built around EL34's when they first came out. All in all they are a very desirable Marshall to have. I had bought one 4100 Dual Rev 5881 brand new back in the 90's and am now happy to have 2 more.
The fun part of these....easy to mod if you want. My EL34 one has a couple little tricks to it but still retains its basic authentic JCM 900 character , with just a little bit 'mo!
But do try these 4100 DR's with at least a decent EQ in the loop.....just opens up a whole new dimension without using any soldering iron at all !

very well stated. So many say the 900 dual is bad , wrong.
It is usually miss used.

 

[iron broadsword]

1] C27, (4n7)snipe one leg off
This removes the weird, post-overdrive, pre-EQ, shaving off some of the fizz, restoring mids, and giving a subtle bass boost. It doesn't do anything for more gain or more articulation. It does help the tonestack to react more like a traditional marshall.

When this is all said and done and my honeymoon with this thing is over, I may consider putting this on a switch in the back, considering it still sounds okay with the other stuff we did. I liked the character of the amp beforehand and it is very different now.. so it might be nice. More testing required for sure.. One thing I've noticed is that going through the V30 cab here at home really doesn't sound as good as it did through my T75's yesterday. The Class5 sounds great through it though.. might be because the c5 is a darker amp and offsets the v30's.. I know the stock c5 speaker is real nice with it too and it is similar to a greenback, so this might explain it for me.

 

[Adrian R]

When this is all said and done and my honeymoon with this thing is over, I may consider putting this on a switch in the back, considering it still sounds okay with the other stuff we did. I liked the character of the amp beforehand and it is very different now.. so it might be nice. More testing required for sure.. One thing I've noticed is that going through the V30 cab here at home really doesn't sound as good as it did through my T75's yesterday. The Class5 sounds great through it though.. might be because the c5 is a darker amp and offsets the v30's.. I know the stock c5 speaker is real nice with it too and it is similar to a greenback, so this might explain it for me.

Dude, as I said..try a BBE in the FX loop man..and boost it up front with a CLEAN boost pedal..The amp sounds killer then! Also, be sure you have removed the 5881s and biased up properly (65-%70) 6L6GCs..(or EL-34s with network mod)


This is what I did for years until I got my DSLs...then there was no going back once I figured them out...imo WAY more organic, better sounding amp with a naked FX loop...

 

[iron broadsword]

I've gone through a few different 6l6gc type but I use sovtek 6l6wxt+ right now, and they are biased at the 70% mark as of a few months ago. I've not tried a BBE in the loop, but I have used a para eq many times with good results. The amp just feels totally different now though... Not better or worse, but different and better suited to what I am looking for.

As for boosts up front, that's how I've always used the amp. I prefer an OCD set clean for hard rock/metal, but a tubescreamer is real nice for taking a lead break. Since modding I haven't had tried much up front but I hit the tubescreamer for a few lead breaks on Sunday and it sung as good as it ever did.

This thread is really just a blog of this adventure so that other people can hear what they are or aren't missing out on. Trying to document it all because if it were me who was reading this and considering to mod my own, I'd want to hear all the details. IMHO, I still think the stock 4100 is a fantastic amp in it's own right without any help up front or in the loop. It has always held it's own in any setting I've had the pleasure of using it. But at the end of the day, I am a tweaker. Tweakers gonna tweak.

 

[solarburn]

I know this is obnoxious playing but I tried to git sumpt'n...clean channel gain dimed with just a smidge of pedal.

[ame]www.youtube.com/watch?v=QKmQWJaOiEc[/ame]

Lead channel straight in gain at 8 out of 22.lol

[ame]www.youtube.com/watch?v=w3RWF9ArvwA[/ame]

 

[iron broadsword]

That was great! The bugera? Sounds closer to my amp post-mod

 

[solarburn]

That was great! The bugera? Sounds closer to my amp post-mod

Yeah that's the 1990. Whoops forgot to label it. It's huge sounding the more volume. Fun amp based on a great circuit!

 

[iron broadsword]

Ok, so after the previous mods it sounded VERY similar to just about every 2203 clips I could dig up, and I'd never be able to tell the difference in a blind test.. but I noticed I wanted just a smidge more bottom out of it again so after talking to tscrhama I did "Liam"s R15 mod, where you swap r15 with a 220k and then piggyback a 4n7 and 100k onto it.. and now it's got the thump that it does when you've got the master up above 7, as part of the preamp so you can have it at any volume.

NICE.

Very nice mix of vintage and modern and exactly what I am looking for. The bottom is still clean and very tight even with the gain up, though I use roughly around acdc level of gain but wanted more bottom and this does it. I will do some more sound clips this week or next for comparison again.

For anybody trying this in the future, with the gain up past acdc and into modern land it did have great bass to it before this r15 mod, but that is not how I run it. I could also achieve this same effect with a para eq in the loop, but it's nice to have it all in the amp.

 

[solarburn]

Ok, so after the previous mods it sounded VERY similar to just about every 2203 clips I could dig up, and I'd never be able to tell the difference in a blind test.. but I noticed I wanted just a smidge more bottom out of it again so after talking to tscrhama I did "Liam"s R15 mod, where you swap r15 with a 220k and then piggyback a 4n7 and 100k onto it.. and now it's got the thump that it does when you've got the master up above 7, as part of the preamp so you can have it at any volume.

NICE.

Very nice mix of vintage and modern and exactly what I am looking for. The bottom is still clean and very tight even with the gain up, though I use roughly around acdc level of gain but wanted more bottom and this does it. I will do some more sound clips this week or next for comparison again.

For anybody trying this in the future, with the gain up past acdc and into modern land it did have great bass to it before this r15 mod, but that is not how I run it. I could also achieve this same effect with a para eq in the loop, but it's nice to have it all in the amp.

I like the characteristics of that mod. Having it thump at lower volumes too still clean tight and clear...good one. This amp circuit is very vintage at times if that is what one wants to play. Love the mid gain vein of this circuit. Oh and a great hard rock amp with the Lead channel.. I just don't go any heavier really but that lead channel gets it on nicely for me.

Look forward to more of your clips. I feel like I need more guitars now like an SG and LP to really take this amp where I want it. Usually I look at mods for the amp using what guitars I have but an LP with this thing set with some good Paf's...yeah man.

Another thing I've noted about this amp circuit is usually I want to apply some delay right away to fill out notes when I solo...just a little delay I never use much really...with this amp I haven't felt the need too yet. Which is good cause I'm using it with the 1960 trying to help it sound better at low volume...not thinned out.

 

[solarburn]

That was great! The bugera? Sounds closer to my amp post-mod

Hey IB I actually made this clip before the other 2 just straight into the Green channel gain dimed. No boosting. I forgot I did this one. I think it sounds great with the amount of gain on tap from the Green.

Forgive me for intruding on your thread but I do it cause I share the same feelings you do about the 900. Great damn amp!

[ame]www.youtube.com/watch?v=KJez_zGkA0c[/ame]

 

[tubes]

This thread is really just a blog of this adventure so that other people can hear what they are or aren't missing out on. Trying to document it all because if it were me who was reading this and considering to mod my own, I'd want to hear all the details. IMHO, I still think the stock 4100 is a fantastic amp in it's own right without any help up front or in the loop. It has always held it's own in any setting I've had the pleasure of using it. But at the end of the day, I am a tweaker. Tweakers gonna tweak.

And very much appreciated ironman.

I didn't do very well answering your question about what sound I was looking for here: it was late that night. And I'm not really as thick as I might appear to be in one post.

But that's irrelevant:
As you say: "if it were me who was reading this and considering to mod my own, I'd want to hear all the details."

True.

 

[iron broadsword]

s'all good.

Been a busy week at work but I've gotten a chance to play here and there. I've found that I can get some absolutely mind-bendingly thick and clear metal tones with my EMG81-equipped Torero now. I don't know if the dual rectifier I'll soon be purchasing will be able to do as good a job.. One of the last mods tschrama posted here removes fizz and it makes the high gain stuff SO FRIGGIN SMOOTH. I'll have to take a look at what that is doing to the circuit.. Very very similar to putting a 10nF cap across the volume lug of a dual-rectifier preamp I built, so much so that I am wondering if it is in fact doing the same thing.

But yeah anyway, metal tones.. you know the high gain modern metal sound that is ultra clear, wide, thumps, has soaring highs and yet somehow really smooth because it is crazy loud and the amp is working hard? Yeah, sounds like that. At any volume.

 

[Dogs of Doom]

I had a buddy, who IMO, had the sweetest sounding 2204, back in the '80s/'90s. At one point, he acquired a 50 watt 900 (not sure which model) & he hated it. He took it to his modder & the guy replaced the solid state stage w/ an added 12AX7.

He swears up & down that that was the best Marshall he's ever owned since...

I brought that up here, when I 1st joined & got scoffed at...

 

[iron broadsword]

Hahaha, figures. That's awesome though, I'd love to hear it. For what it's worth, this is the sweetest sounding marshall I've ever played (although there are many I haven't played at all...), but it is tailored to my needs so I should hope so! It's not mass-produced, but I've got a signiture amp now.

Been thinking about getting new face plate for it. Something not permanent in case I hate it down the road.

 

[Dogs of Doom]

here's a video - not the greatest mix, etc.

From 1991 Guitar straight into the amp:

www.youtube.com/watch?v=NRv4Uy7i3mg