Footswitch problem in Mesa Boogie Studio Caliber

[carlosjosetavares]

Hi
I have a Mesa Boogie Studio Caliber amplifier, which I really like.
I bought it without a footswitch.
Recently I found a MB Mini Rectifier footswitch. However, it does not change the channels (Rhythm/Lead), despite switching ON/OFF the LED.
Can anyone share a schematic for the footswitch of the Studio Caliber?
What I tried to do was add a 680ohm resistor to the positive terminal of the LED, according to the diagram below (For the MB Mk III), but does not switch between Rhythm and Lead, despite the LED switching ON and OFF.
Thanks in advance.
Carlos

[Jon Snell]

Depends whether 22 or 22plus.
If a 22plus replace the 680R with a 3k3.

[carlosjosetavares]

Dear Jon
This model is not a 22 nor 22+, but early DC-2 20W Studio Caliber. But anyway, I'll give it a try with the 3k3 ohm resistor.
So, the resistor value plays a role in activating the relays in the amp for channel switching? because the LEDs are activated by the footswitch.
Thank you for your kind help.
Regards
Carlos

[Pedro Vecino]

This is the schematic of the switching part on the Studio Caliber. Pedal schematic not shown. Perhaps from there it can be deduced.

[carlosjosetavares]

Hi Pedro.
Thank you. I will see if I can figure it out.
Best wishes
Carlos

[Jon Snell]

Ah, you only stated a studio caliber but here is the DC2 studio. It uses a TRS jack and twin switches.

[carlosjosetavares]

Hi Jon
Actually, that's the contour model. Mine is perhaps the 1st version without the contour (see a photo of amp on top). So, it's only a mono cable to select between Rhythm and Lead.
The faceplate and manual only read "Studio Caliber":
https://www.zikinf.com/manuels/mesa-...r-en-24826.pdf

[carlosjosetavares]

Based on Pedro Vecino´s schematic, can you advise on which resistor I should use?

[Pedro Vecino]

https://store.mesaboogie.com/product...ad-switch.html

As indicated on this page, the footswitch for the Studio Caliber is the most classic of all, for many amp models. It should be 3K3 + LED

[carlosjosetavares]

Thank you Pedro!