Beginner Amplifier modding

[Coolneans126280]

Hi all

Ive been actively modding guitars for over 2 years and have pretty much mastered the Iron so im quite interested in moving on to amplifier modifications and was hoping if I could get a few pointers as to where I can learn about them. I have a Marshal JCM 2000 I wanna hot rod with something pretty crazy and unique. Im thinking of possibly adding more tubes as gain stages but i have no idea where I can learn this stuff from.

Id really appreciate any help you can offer as I might even turn this into a buisness. (Im currently limited to guitars)

 

[GuitarStv]

Re: Beginner Amplifier modding

Modifying an amplifier is physically similar to modifying a guitar (you're just soldering bits into it). If you want to create your own mods and do serious design changes (like adding an extra tube gain stage) it is an awful lot more complicated though, and you need a thorough understanding of electrical circuit design.

So, I'd start with at least a years worth of circuit design study at a college.

 

[aiaosu]

Re: Beginner Amplifier modding

I would suggest finding existing mods that have been proven and slowly attempting those mods, starting simple first. With the amount of current running through amps, you can really cause damage and it can be dangerous. While you do the mods, try to understand the schematics and what is happening in the circuit. The simpler the circuit, the easier it will be to learn.

Randall Smith (Mesa Boogie) and others like him started by modding amps. As they learned the circuits and how they worked, they improved designs and came up with their own ideas. Mesa Boogie used a Bassman as the starting point.

I've started learning about amps by buying broken amps, finding out what went wrong, and trying to upgrade key components. It's not rocket science but there is a lot to learn. I don't have the time or money to do too much damage.

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[RockinProf]

Re: Beginner Amplifier modding

Hey,

Just from my perspective, as a JCM 2000 owner as well, this isn’t the amp I’d start with. The PC board is incredibly busy as are the circuits. It is doable, but there’s so much chance of frustration there. If I were to pick a start to mod amp I’d look at the new VHTs. Not trying to discourage, but steer you away from a very frustrating experience.

 

[Ewizard]

Re: Beginner Amplifier modding

Amplifier modding is not something that you just learn overnight. While you could probably very easily do the component swaps and whatnot, understanding what it is you're doing takes years to wrap your head around. I started by doing just what you are looking to do, simple mods to change this to that and that to this. While I could do it, it took about 15 years or more before I could almost build an amp in my head and not have to rely on a previous mod to come up with the idea naturally. I can look at a schematic and tell you what is doing what and what changes to X part will do. I am not even close to an amp guru though, I can just understand the signal flow and how the parts affect the circuit.

If you are going to get going in this I too suggest that you just start by following already known mods. Find the schematic to your amp of interest and with the mod instructions, execute slowly and with surety. If you really want to learn a lot really fast, build an amp or two from scratch from kits. I would also read through a couple websites I will link below. They will give you a lot of info and help you begin to understand what it is your changes are doing and why. My only advise is that if you don't already know how to read a schematic, be sure that is the first thing you learn. The rest of it is math and most all of that is worked out for you already, but if you can't read a schematic, you're dead in the water.

https://www.aikenamps.com/

http://geofex.com/tubeampfaq/TUBEFAQ.htm#sounddiff

https://robrobinette.com/Tube_Guitar_Amp_Overdrive.htm

http://www.valvewizard.co.uk/

 

[Mincer]

Re: Beginner Amplifier modding

Honestly, the best way to learn about this is to search out your local amp doctor and learn from him/her. Start by building simple Fender kits (BYOC has a few) and move up from there.

 

[LLL]

Re: Beginner Amplifier modding

Rule #1: Always discharge the caps first before poking around in there!

 

[aiaosu]

Re: Beginner Amplifier modding

Honestly, the best way to learn about this is to search out your local amp doctor and learn from him/her. Start by building simple Fender kits (BYOC has a few) and move up from there.

This would be great but some of these guys don't like having people around when they are working. Just been my experience.

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[aiaosu]

Re: Beginner Amplifier modding

And sometimes it's because they don't want to train potential competitors in a limited industry

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[LLL]

Re: Beginner Amplifier modding

For learning from others, your best bet is to join an online amp modding group/forum. They're out there.

Back when I started in early 2Ks, I cut my teeth on a JTM45 (Marshall) Yahoo group along with the Plexi Palace forum (now pretty much defunct).

 

[Coolneans126280]

Re: Beginner Amplifier modding

Thank you all for the responses you have all been really helpful. I understand that i should start by applying existing mods first which is pretty obvious. Do you have any good sites where i can find schematics? And just wanna say special thanks to Ewizard been very helpful.

 

[Ewizard]

Re: Beginner Amplifier modding

These days, just look for the schematic of the amp you're interested in and it will pop up in images on Google. There are a few schematic sites, but honestly, it is easier to just search for the one you're looking for. Most often times the site that hosts them will pop up anyway.

 

[aiaosu]

Re: Beginner Amplifier modding

https://www.thetubestore.com/guitar-amp-schematics

Tons of them on here sorted by manufacturer.

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