Effects loop for mk2a?

[Ozone7]

Hi all. First post here.

I have a '79 Mark 2 60/100 with graphic converted from US to UK voltage.
I'm going to convert it to head and cab to get it back into service without risking another back operation.
Also... I really want to add an fx loop.
The problem is that I'm hearing from amp techs that there just isn't room for a third party board and connectors as the chassis is already packed solid.

I have been told that if I have a pre out and power in, then I am golden.

I do (although I can only see one jack on the back panel and the other must be on the underside of the chassis).

Is this true? And will it work for decent gear like Strymon, in terms of level.

Thanks!

 

[Zlofengir]

Congrats on being a Mk II-A owner! Lots of cats ignore these in favor of the II-C+'s, but IMHO, these are hidden gems that have a sound unlike any other Boogie. I recently acquired a '78 1x15 60/100 combo, I know what you mean about the weight; I plan on some Mesa Trak Lock casters very soon!

There are two jacks underneath the chassis, one is for a multi function footswitch that (depending on the amp) controls reverb, gain boost, or EQ, the other is the junction jack which takes everything from the preamp before the power amp. You could use this along with the Preamp Out/Power Amp In jack as an effects loop of sorts, but all it does is add the effect after the preamp before it hits the power stage. I could see using a modulation or delay here, but not any type of overdrive/distortion.

But, there is something else that many Mk II A and B owners aren't aware of; it can be used with a volume pedal to be a overall master volume to tame the amp! Check this out! http://thegenerationofmusic.wordpress.com/2012/03/17/guitar-how-to-the-mesa-boogie-mark-iiaiib-ultimate-master-volume-pedal-trick/

It took me some experimenting, but I have found that some effects sound better in front of my amp than others; truthfully, I prefer my Mk II dry... It just sounds SO good with just the guitar plugged in!

Good tone hunting!

 

[b00g13mk2B]

The level of the line out is very hot. You may be able compensate with low input volume settings on your effects and keeping the master volume low. But may not be able to fully drive the power section. The effect would need a lot of gain. I have a Midiverb, have to play with the amp master volume and effects input. But can't get full volume with this setup.

 

[Rick Mark2A]

I have been using a Ceriatone C-Lator with my Mark IIa for a couple years. Solves any issues with using your loop. I couldn't be happier with it.

 

[Ozone7]

Thanks all.

The Ceriatone looks good, but it's a rack unit and I don't have the space.

In an effort to find the relevant jack sockets, I took the tubes out this morning and had a look.

Weirdly I seem to have (what are labelled as) reverb and EQ.
Which I would assume are on/off.

But nothing like a pre out or power amp in.

I also have a phono type socket which I think is for the reverb signal? it's plugged in.

There's a switch in there which I don't understand also. Any ideas? FET or something?

I will post a photo later.

So, is the jack on the back the pre out or the power amp in?

And is it possible that I only have half of the circuit?

Thanks

 

[Ozone7]

Here are links to photos of the chassis with connections and the rear panel

Hope this works. Not come across a forum which doesn't direct post.....

 

[Ozone7]

OK, so that didn't work. jeeez

OK. Trying again

 

[Ozone7]

Third time the charm?

https://dl.dropboxusercontent.com/u/86160214/Photo%2026-06-2014%2008%2030%2051%20am.jpg

https://dl.dropboxusercontent.com/u/86160214/Photo%2026-06-2014%2008%2031%2037%20am.jpg

 

[b00g13mk2B]

Just got a G Lab SA-1 Signal Adapter for my MK2A. First test in the basement is good, will get the rig out this weekend. I have a Midiverb but have not been able to drive the amp to more than a loud bedroom volume. Just straight amp at a gig, and often hard to balance between too soft and too loud (the big jump around 1 on the master).

I set the Boogie master volume to 2, bring the preamp signal from under the chassis to the SA-1 attenuate side. The attenuation is around -8, send to the Midiverb input and adjust as normal. The midiverb output goes to the boost input of the SA-1 and the boost is set to about +8 (about what you attenuate), back into the amp. The output knob on the Midiverb is now a master volume. Can get full volume down to a whisper.

Compared to a C-lator, the attenuate and boost controls require a small screw driver or trimpot tool - not easy to change on the fly. but does not seem necessary to have to tweak once you set it up for a venue. You need to have a separate 9Vdc/center negative power supply which is easy enough to find.

Wish I had found this (or a C-lator, Kleinulator) long ago. Not concerned about solid state versus tubes at this point. If you have a Boogie EQ, your signal goes through transistors!