glpg80
Well-known member
I’ve been spending this week tuning the presence circuit on my project after the resonance mod from last year. The presence circuit that was in it had a 25pF cap in for what I assume to be an easy gain mod, but it basically made the presence circuit open and not very reactive to knob turning especially after the resonance mod shifting frequency responses around to even the amplifier out a bit to be less top end heavy all the time.
I went up to a 0.02uF and liked what I was hearing, so I went one step further to 0.68uF ala old Marshall plexis and it was magical. Gave the amp some D chord bark and made it sound less flat overall. The top end of the notes on solos have a very distinct Marshall smear to them which I personally love. The amp seems to get tight down low and very smear like up top - I’d say it was a successful week
Here’s a quick video clip. I dialed in a darker tone to tune the presence circuit. Having it dialed in for a brighter tone made it more challenging to tell the difference between different values as I went up.
I should mention all cathode resistors are stock in this video - it’s mainly the SD-1 doing the work.
I went up to a 0.02uF and liked what I was hearing, so I went one step further to 0.68uF ala old Marshall plexis and it was magical. Gave the amp some D chord bark and made it sound less flat overall. The top end of the notes on solos have a very distinct Marshall smear to them which I personally love. The amp seems to get tight down low and very smear like up top - I’d say it was a successful week
Here’s a quick video clip. I dialed in a darker tone to tune the presence circuit. Having it dialed in for a brighter tone made it more challenging to tell the difference between different values as I went up.
I should mention all cathode resistors are stock in this video - it’s mainly the SD-1 doing the work.