Mk IIb minor mods

[Dirt123]

My Mk IIb did not come with a Gain switching jack for some reason, so I added one earlier this week. It is very nice, being able to switch the gain on & off with a foot switch.

Last night I made one more change. Since my amp doesn’t have a reverb, it has an extra hole in the rear of the chassis. I wired the signal for the channel switching relay and the gain switch to a stereo jack and mounted that in the spare hole. I made a two-button switch box with a stereo cord. The box has a little toggle switch that jumps the channel footswitch to the gain footswitch, so that when I hit the channel switch, I can have the gain switch on automatically. This is cool for me because I like the rhythm tone with out the extra gain. I may quit using an over drive pedal now!

Now if I can just add a graphic EQ…

 

[Stu Gutz]

Cool! You will now have to change your signature to: Mark II B *with* frills.

 

[Dutchman]

If you want variable gain with your MKIIB place a Ernie Ball volume pedal in the effects loop. Not just off and on but infinitely adjustable gain.
Very cool.....I'm not sure but I think the MKIIB is the only Boogie model that will do this

 

[RR]

If you want variable gain with your MKIIB place a Ernie Ball volume pedal in the effects loop. Not just off and on but infinitely adjustable gain.
Very cool.....I'm not sure but I think the MKIIB is the only Boogie model that will do this

Yeah, there's a input jack (well mine has) underneath the chassis (as well [another but stereo jack] for the EQ / gain boost footswitch) that you just plug a guitar cable to the Ernie Ball volume pedal, right Dutchman? But I can't remember which jack of the Ernie Ball volume pedal if its the out or the in[?]. Yes, just one cable.

 

[Dutchman]

If in fact you have a MKIIB, on the back of the amp the will be a effects loop. Labeled ~ Effects with a 1/4" jacks stacked vertically labeled send and return. I Use the send to the input of the Ernie Ball volume pedal and the return fron the output of the Ernie ball volume pedal. This takes over the gain control of the amp. Back off the pedal for cleaner sounds lay on the pedal to let the dirt fly.

I do not use the 1/4" jack under the chassis for anything. Although it can be used with a dual footswitch, if you have an EQ and Reverb to turn them on and off. It has nothing to do with the effects loop.

Hope this helps, this is yet another way to do it.
William G. Sacks has written, "A cool and little-known option with the Mark IIB (or original Mark II): while the effects loop isn't worth much as such, you can run the output of a volume pedal (without your guitar being plugged into its input) into the 'return' jack, and get on-the-fly preamp gain control! This is a feature that very few tube amps have ever had, even inadvertently - it uses the pot in the volume pedal as a passive limiting device, such that when the pedal is 'wide open,' it allows the preamp tubes' full voltage to pass into the power section. As the pedal is backed off, it decreases the amount of preamp signal allowed through the 'loop,' cleaning up the sound. One of my best friends sets his clean channel's preamp to 9 and uses an Ernie Ball pedal to vary the overall tone. Oh, I wish we could convince Mesa to make this a regular option on their new models..."


Here's a link to the manual

http://www.mesaboogie.com/manuals/Mark%20IIb.pdf#search=%22mark%20IIB%20manual%22

 

[Dirt123]

I have done the volume pedal trick. It’s pretty cool. My footswitch is just to activate the gain boost , which is the same as pulling on the master knob on the MkIIb.

The Boogie manual describes plugging in the volume pedal to the pre-amp out / power-amp in under the chassis. This woks like a master volume. Plugging into the FX loop is the variable gain thing. Both cool options.