Mark IV loop question...

[NinjaRaf]

Got a question on the Mark IV loops. So, this amp has 2 loops. One is switchable, and the other is not. My impression was that I could plug something into the non-switchable loop and it would be on all the time, and then I could use the switchable loop to put stuff like delay and reverb to have turned on with the clean channel and for lead stuff. However, when I try this, it doesn't work...so I've just been running my NS2 through the switchable loop to kill noise.

 

[TedEH]

On mine, there's a switch to select if you want the "normal" or "switchable" loops, but only one works at a time. Maybe there's a mod out there that can make both of them work, but I've not heard of it before. What you *can* do though, is run everything through the switchable one, then there's a bunch of little switches to force them always on for a particular channel. I like the idea of having R1+R2 be clean (unless I turn the loop on with the footswitch), but the loop is always/automatically on for the Lead channel.

 

[NinjaRaf]

Thats interesting. I will have to look at it more at home.

I have to have the loop on all the time for the NS2 when on the lead channel. It would be awesome to have a switchable one, too, that I could run a reverb/delay through for clean stuff and lead stuff. R2 is basically useless for anything I play haha. I just need the 2 sounds, really.

 

[psycle_1]

http://www.freeinfosociety.com/electronics/schematics/audio/pictures/mesaboogiemark43.jpg

It looks like you can do it if you take the input of the normal loop and move it from the Loop Select switch and put it on the junction where LDR19 and LDR18 meet (the return of the switched loop). Cut the trace between the junction of LDR19/LDR18 and From Reverb Circuit. Move the return of the normal loop from LDR19/LDR18 to the junction at From Reverb Circuit.

 

[psycle_1]

I don't have a Mark IVA to look at, so I'm going purely by the schematics. In theory it should work.

 

[NinjaRaf]

haha yeah, I'm not touching that with a 10 ft pole. The only amp mods I've done are bias mods and some other rando mods on a 5150.

However, if I can find someone to do it for me (maybe Mesa will do it...), than I may consider having it done.

Either way, I appreciate the info!

 

[psycle_1]

I'm an amp and guitar tech on the side. PM me if you want me to have a go at it.

 

[NinjaRaf]

Thanks! I will keep that in mind!