trinityamps.com

Hey there folks!
I am attempting a few mods on the TC 15 and hope you can help.

I am using the Ef86 into the V3 stage and tonestack. I have the bottom (inverting side) of the PI grounded before C8

I am taking the Ef86 out from pin 6 into the input of C1. There is a lot more gain than is practical from the EF86.

I believe, and perhaps you could confirm that I need to add the 470k AC load resistor below the treble bleed cap C3

I am hoping to make the amp behave like my old Bad Cat Cub III
I will use the V2 stage for a dumbulator, and try Merlins Squish control next.

Big Thanks!

https://www.ampbooks.com/mobile/classic-circuits/matchless-pentode/
Here is a detailed look at the Ef86 circuit

I tried the load resistor and it helped greatly! The gain is a little hotter than I like, so I will go back to the stock values for r33 and r34 and try to tame it down a little.

Maybe this will save someone some nasty harsh tone…. Without the load resistor the amp sounded more like a Chinese ac15 than a matchless.

I did the squish/morph mod using the spare 1meg pot. It really helped tame the gain and harshness and adds a nice compression. Photo is from the discussion on the 18watt forum.

The load resistor really helped once I tested it! The gain is too high for my taste, so I'll reset r33 and r34 to their default settings and see if that helps.
mario games