Mesa Mark IIC++ JFET Replica

[complex-barb.0t]

OK, where is the order page?

Came out great.

 

[albatros_1994]

OK, where is the order page?

Came out great.

thank you, i really wish i could build and sell stuff like this more often, what a dream

 

[FloridaRolf]

very cool build, keep it up

 

[IGC]

New project, again and again. I want to share with the internet
a Mesa Mark IIC++ "Replica", the preamp is really interesting as it's different from other metal amps, how good it sound even with all those stages center-biased (1.5K on the cathode almost everywhere), it's aggressive and tight without sounding muddy/fuzzy.
I used BF245Bs at 25v, they served me well on the other jfet project. I started 2-3 days ago and built the basic preamp on a prototyping board, no EQ a the beginning and no EQ a the end because i don't have the right pots and enough cables, at the moment i have a standard gain pot setup, tuned to kinda simulate having the Bass knob at 0 on the original amp, again, kinda.
I tried to bias the stages as close as possible to the original, the cathode bias caps i'm using right now are not the same as the orignal amp, but i needed to adjust the size to make it sound as it should, the total gain seems fine but i will finetune the general voicing of the stages as soon as the preamp receives a EQ, but it already sounds fine to me.
I don't own a Mark IIC++, so i'm forced to use youtube videos as reference.

It's a total mess at the moment, but i wanted to work fast, i'll solder all on a point to point board as soon as i receive the components i need.
Here is a beta-grade schematic and really bad pictures
View attachment 140325View attachment 140324View attachment 140326

i also recorded some stuff running it through a 2xEL84 power amp, i take the signal from a load-box and that apply a slight EQ + Stereo IR (Mesa Cab + SM57 / The One + SM57), to get a realistic final-sound.

Mesa Mark IIC++ JFET Replica

Listen to Mesa Mark IIC++ JFET Replica by Generaleramon #np on #SoundCloud

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The next steps are: solder all this stuff on a real board, the two EQ, voice it "right" + finetuning, than design a faceplate.

Sweet! Just wondering what are the white things next to the FETS? An adjustable coil or resistor?

 

[technomancer]

Sweet! Just wondering what are the white things next to the FETS? An adjustable coil or resistor?

They look like Piher potentiometers, probably being used as an adjustable resistor.