Lee Jackson Metaltronix Amplifiers

[Libernox]

I am curious to hear how this mod is supposed to be installed into a late era 800 amp. The video shows Lee installing it into a JMP or early 800 style as well as how a 2203X is. In other words, the pots and board are two separate items and the leads are flown in off the pots to the board.

In a late era 800 amp, the pots are attached to the PCB. The PCB is also not attached to the chassis by the standoffs like in other Marshalls.

I am intersted in installing this mod, but cannot really figure out how this would be best done in this type of Marshall..... I have gone as far as contemplating pulling the board and installing a PTP board, but this seems excessive just to install a little mod like Marshall Mod #1.

[LeeJackson]

Hello

I have done the mod both ways before,

If you leave the controls soldered to the board, you need to dremel or cut the circuit board traces away from the controls and wire directly to the controls with the shielded cable.

The other is to disconnect the controls and flip them around facing the bottom of the chassis, this is easier to get to.

if you just removed the preamp and master, the rest of the controls could hold the board.

If your going to take the tone controls out, then I would take all the controls out including the presence and mount the main PC board to the top of the chassis with standoff's like the older marshall's did.

It might be a lot more work, I have found it to sound better.

[Libernox]

Thanks Lee,

I was also the guy who emailed you with the same problem. I am awaiting the parts in the mail. I have decided that I will mount the PCB to the chassis via stand-offs, and then fly the leads to the board. Hell of a lot easier this way.

I think that this model of the 2203 PCB is retarded. I know that Marshall went this route to save costs, but it is a literal nightmare to tech. I also do not like the way that they went from 6 filter caps down to 3. I know that electrically the same thing is going on, but you cannot play with the filter cap values the same way that you can with 6 cans.(this amp is in fact a 800 1959 but I got lucky and scored a stock board from the same year 2203 and swapped them out).

Just curious on this mod. Just how much extra gain is there on tap? Also I noticed in the video that you did not twist the heater wires to the new tube. Would twisting the wires help noise or does it matter in this case?

Glad to see that you are back in action and back in Austin as well. You worked on one of my older 2204's years ago when you were with S. Austin Music.