Amp Mods/Builds

[WildBillJohnson]

Anyone here mod or build their own amplifiers.... I'm in between rigs right now and I've had my jca20h for a while... just ordered a couple caps, resistors, choke, and tubes for it. I'm hoping to reshape the high end on it and get a little further into high gain territory with it. Kinda unorthodox but I've heard a few clips of these little one channel amps slamming. What are you all doing?

 

[Mr Wright]

There was a similar thread somewhat recently.
I'm working on a from-scratch build of a hot rodded marshall for my high-gain tastes. I made a trainwreck rocket clone from most of a kit that I got from a guy over at ampgarage.com as my first build.

 

[WildBillJohnson]

Cool dude! How difficult would you say it was on a scale of 1-10? Im not familiar with Trainwrecks... I'll have to check them out. Besides being a guitar player I play bass in Devium in Ohio and both of my guitarists build amps/pedals. These guys are making some awesome stuff and I've always had the bug. One of them built a jcm900 on a turret board... we have dubbed it the "James"cm. Came out pretty narsty... especially with one of his boosts in the front end. Good luck with your build and sorry for the repetitive thread.

 

[WildBillJohnson]

Oh and I just youtubed the Trainwreck..... that's a big .... yes!

 

[Vostre Roy]

I take for granted that since you have friend who built amps and such, you're probably already aware of this, but I always bring it to any thread discussing amps build and mods:

Be aware that an amp have enough current, even when unplugged, to kill you. Respect electricity and don't rush anything, be prudent.

Now, my personnal experience. I went berserk and tried to build one of Weber kit, the 8CM100 (JCM800 clone). I say "berserk" because I pretty much went ahead of my skills ahaha

http://www.sevenstring.org/forum/lu...ions/217156-weber-8cm100-building-thread.html

Since then, I stepped back a bit and went into the pedal realm. I've built 2 BYOC pedals and I'll order some parts next week to build 3 differents bass preamp pedals from schematic/layout I've found here and there on the web.

About your mod, are you using any reference for that mod or you're planning to do this from scratch? Theres a couple of way to enhance the gain section of an amp and I wonder what you'll do to your amp

 

[WildBillJohnson]

Safety is always an issue.... I mean everyone wants to die right? I got the same advice from my guitar players... start with pedals and move up. Luckily I have both of those guys to refer to when I'm in trouble. Now the jca20h... this amp to me just needs the high end shaped a little and the low end beefed up a tad. So, I have a Hammond 156m choke, a couple caps, resistor and JJ tubes... literally just arrived. I went with high gain 12ax7 for v1 v2... heard mixed reviews on these but JJ's typically from what I've heard are a tad darker. And that's what I'm going for. The choke will tighten the low end and add a little clarity. The caps and resistor are just to change a couple values. That mod was referenced from another forum which claim to tame the "frazz" with a slight lpf. I may or may not do it depending on how it sounds with the tubes and choke. But I agree Vostre Roy safety first. I'm interested in your bass pre's how are they turning out?

 

[jordanky]

I've built a few of my own pedals and it's super fun! I also have repaired and modded a shit ton of pedals for myself and others as well. I would love to build a Bassman type amp but I'm too scared of electricity to commit fully. I am pretty sure I could do it, but the threat of frying myself to death looms and keeps me at bay for now.

 

[WildBillJohnson]

Oh and we all use boost right? Right now I'm using a classic ts clone which shoves the amp into that territory but in a couple weeks I'll have an 808 clone that gives the amp the right kind of presence. I'm really surprised this little 20watt one channel crunch machine is getting the tones that it does. I've looked at Friedman mods and hsg.... just not sure what the next plan of action is after these mods. I'll probably jump that hurdle when I get there. Do you have any suggestions?

 

[WildBillJohnson]

Jordanky the way I understand it is... take your time... drain the caps... use your right arm.... just be safe. It is dangerous but doable. One of my guitarists is the repair tech at Sound City Music where I teach at. He does quite a bit of work.

 

[Vostre Roy]

Safety is always an issue.... I mean everyone wants to die right?

Indeed, but I try to keep every amateur builder/modder alive long enough so I can learn from their mistake (kidding, be safe, I got shocked once and it ain't really pleasant)

I got the same advice from my guitar players... start with pedals and move up. Luckily I have both of those guys to refer to when I'm in trouble.

You're lucky to have such close references to talk to, use them as much as you can and you'll learn way faster than I'm doing

Now the jca20h... this amp to me just needs the high end shaped a little and the low end beefed up a tad. So, I have a Hammond 156m choke, a couple caps, resistor and JJ tubes... literally just arrived. I went with high gain 12ax7 for v1 v2... heard mixed reviews on these but JJ's typically from what I've heard are a tad darker. And that's what I'm going for. The choke will tighten the low end and add a little clarity. The caps and resistor are just to change a couple values. That mod was referenced from another forum which claim to tame the "frazz" with a slight lpf. I may or may not do it depending on how it sounds with the tubes and choke. But I agree Vostre Roy safety first.

Sounds like a good plan. Dunno about the choke stuff though, I haven't experienced much about those but maybe one day I,ll put one in my Dark Terror and look for the difference in the sound. As for the rest, it shouldn't harm your amp, just make sure that every caps (especially those big electrolytic ones) are drained and you'll be fine. Keep us informed about the result!

I'm interested in your bass pre's how are they turning out?

Well I haven,t started yet, I'm gathering information and hunting for parts to make it going. Basically, I'll build those three:

- Ampeg B15-N preamp clone, tube preamp stombox from a schematic someone posted on Weber Amps forum page. Dunno if I have the right to share it
- HBE Hematoma, wich is a two channel preamp/overdrive pedal, from here: Guitar FX Layouts: HBE Hematoma
- Sadowsky Preamp in a stompbox, dunno if I have the right to share it so I wont lol

I should order my parts next week

 

[WildBillJohnson]

Dark Terrors are pretty narsty man. We use one at the practice space matched with the "James"cm. The tones complement each other very nicely! It may already have a choke but I'm not sure I haven't inspected it.

 

[Vostre Roy]

Dark Terrors are pretty narsty man. We use one at the practice space matched with the "James"cm. The tones complement each other very nicely! It may already have a choke but I'm not sure I haven't inspected it.

They don't but Mercury Magnetics got a drop-in uprgrade for it, might get one at some point. I was in contact with them to see if their Holy Terror mod (for the Tiny Terror) could be applied to my Dark Terror but there's more difference than I expected between the two. Its still in my "will do one day" book, probably after I'm done with pedals and my Weber

And yeah, the Dark Terror is dope. The guitarist in my previous band played with a 3120, pretty Marshal-ish sound and they were going along surprisingly good.

 

[Mr Wright]

The trainwreck wasn't hard to build at all. Granted the chassis was pre-punched and I had half of the parts in a kit.

I only had trouble at the end because one of my solder joints was bad and that was just a simple error that I fixed.

Once I get a couple free evening's I will start my next build and post that on here somewhere

 

[WildBillJohnson]

They don't but Mercury Magnetics got a drop-in uprgrade for it, might get one at some point. I was in contact with them to see if their Holy Terror mod (for the Tiny Terror) could be applied to my Dark Terror but there's more difference than I expected between the two. Its still in my "will do one day" book, probably after I'm done with pedals and my Weber

And yeah, the Dark Terror is dope. The guitarist in my previous band played with a 3120, pretty Marshal-ish sound and they were going along surprisingly good.

What does the holy terror mod do for the tiny terror?

 

[Merge]

I became interested in amp building a few months ago. I bought a few books, and have done a lot of reading. I think I'll start with building a 9v battery powered amp, and go from there,

 

[WildBillJohnson]

What design are you using?

 

[Mr Wright]

My ground up build is going to be based off of a Ceriatone Yeti.

It wouldve been much cheaper for me to just buy a Yeti (and it would be better built most likely), but I wanted the experience of building it.

 

[Vostre Roy]

What does the holy terror mod do for the tiny terror?

AFAIK, it replace the stock trannys by Mercury Magnetics ones, adds a choke anfd change some values in the preamp section (maybe the poweramp too, can't recall right now). They sent me a cd with the schematics so I can compare it to the dark terror but I didn,t took the time to really get into that project.

It suppose to add dynamic and a bit of gain to the original circuit IIRC

 

[Mr Wright]

http://www.sevenstring.org/forum/lu...tomizations/249567-anyone-ever-built-amp.html

That was the other amp building related thread lately

 

[WildBillJohnson]

Cool dude I've just scratched the surface on that thread but I can tell theres some stuff in there I need to read. So.... I've got the tubes in my JCA20h.... sounds good but I think I'm going through with the mods I mentioned earlier. Here is a link to a video... Cam sound. The guitar I borrowed (and may trade for) from Identity Device. He is a member on here. And the guitar just went out of tune on its own. I really think the place I jam and practice at is haunted.... crazy shit like that happens all the time. Anyway take it easy on me and let me know what you think about the tooooone!