One-wire mod for 1987x - help please!

[Greg_L]

I have a 2001 Marshall 1987x 50w Plexi reissue. No FX loop. PPIMV. Otherwise stock.

I'd like to do the one-wire cascade mod and have it switchable somehow.
I want the "bright channel" to remain stock and have the "normal channel" be the cascade channel.

Is this possible?

Through searching various forums I've found tons of info on the one-wire mod, but nothing for a reissue with a PCB like mine. I can't read a schematic. I can't re-engineer an amp. But I can do the work with instructions. All of the info I see is for PTP boards. That does me no good. My amp looks like computer inside.

If anyone has any tips, ideas, or instructions on how to do this I'd be very grateful. Please help.

[danman]

I don't have any links that I can provide that will work for PCB amp's only. I will say that if you are not experienced in dealing with a PCB, it is very easy to lift or ruin a trace on the board. Desoldering and modding these boards takes experience and I would hate to see you mess up your amp. I'm sure a good tech could implement the mod with a switch for a reasonable fee. If you are intent on trying it, I have found the version that forum member "Michael RT" posted to be very good. You can find info on Youtube and over at the Marshall Forum on how he does his one wire mod. Just Google "michael rt one wire mod" and you should find it.

Here is another great layout that our member Neikeel came up with. It is based on a turret board though...https://drive.google.com/drive/folders/ ... zd3STVYd3c Check out the first layout that says 1959 or 2203. That gives you the ability to switch between the standard circuit or the cascaded circuit. It is based on the 100 watt models but the preamp is the same as the 50 watt ones.

[Greg_L]

I don't have any links that I can provide that will work for PCB amp's only. I will say that if you are not experienced in dealing with a PCB, it is very easy to lift or ruin a trace on the board. Desoldering and modding these boards takes experience and I would hate to see you mess up your amp. I'm sure a good tech could implement the mod with a switch for a reasonable fee. If you are intent on trying it, I have found the version that forum member "Michael RT" posted to be very good. You can find info on Youtube and over at the Marshall Forum on how he does his one wire mod. Just Google "michael rt one wire mod" and you should find it.

Here is another great layout that our member Neikeel came up with. It is based on a turret board though...https://drive.google.com/drive/folders/ ... zd3STVYd3c Check out the first layout that says 1959 or 2203. That gives you the ability to switch between the standard circuit or the cascaded circuit. It is based on the 100 watt models but the preamp is the same as the 50 watt ones.

Hey thank you for the reply.

Yes, I'm already very aware of those guys you've mentioned. And yes, they do great stuff! And yes...unfortunately for me...everything they do is turret board work. I know my circuit is essentially the same, but it's on a PCB. As you've mentioned, it's not great to go swapping stuff all the time on those things. I would if I could, but I think I really just need someone that has a tried and true method for these PCB reissue Plexis so I can just do it once and be done!

Not that I don't want to learn, I really do want to, but this amp may not be the best for it.