Mark V 25 signal path

[Marianitem]

This post is about the signal path in the Mark V 25.

When I was learning about the amp deciding if I should get it or not, I couldn't find info about the signal flow blocks (in what order are the different components and controls).
I just thought I could share some stuff I figured out myself that I couldn't find when I needed it.

I find this info useful to decide what, and where, to connect certain devices, and how to control levels.

This is based on me connecting the guitar and other devices in different points, and checking what happens.

I could be wrong, so feel free to correct me, or add missing details.

This is the signal path according to my tests:

Input >
> Channel/mode >
> Treble Bass Mid >
> Gain >
> Master <> GEQ (order unknown) >
> Fx Loop >
> Presence <> Reverb (order unknown) >
> Power Amp >
> Speaker out / CabClone / Headphones


Master and GEQ are in this order on a Mark V 90 schematic that I found, so it probably is in this order.

The Reverb is after the loop, not before as I read in a few places. Although in the V 90 schematic the reverb is before the channel's Master. But in the 25, if I monitor the signal from the FX Send there is no Reverb. And if I insert a signal (without going through the front of the amp) into the FX Return there is Reverb.

In the Mark V 90 schematic that I found the reverb send seems to be before the FX Loop, so I do not have a source to figure out the order of Presence and Reverb.

If only using the amp as a power amp by connecting an external preamp to the FX Return, it would be safe to say that the Poweramp has no input level control (it's at 100% all the time). The external preamp's master would be the way to control the volume. If using the amp this way, you also have Presence control and Reverb.

And that's all I got. Hope it helps somebody.

 

[bandit2013]

The Mark V:25 and Mark V:35 may have a few less tubes than the Mark V90. However, when you look at the tube task chart, they all share the same number of gain stages. The difference is the Mark I circuit was removed. The V:25 and V:35 made use of relays to insert the overdrive gain stage in front of the tone stack for crunch mode. Very similar to the Mark VII and Badlander. If they had permitted to run the V2B as well, that would be the Mark VII mode setup and the crush mode of the Badlander. The V model is one of the marks that place the GEQ in front of the FX loop. That circuitry is also used to create the send level for the loop much like the big bottle Mark V90.

Tube task chart can be represented graphically like this: