Mark IV combo effects loop.

Hello,

I picked up this combo mark 4 and after having the tubes replaced it sounds great but I'm having trouble using effects through the effects loop.
I use an Ibanez tube screamer which works great when I put it between my guitar and the main AMP-input but off course I would like to be able to have this effect permanently on, only on channel 2and3, not on clean channel 1. For this there should be the effects loop ... but I'm unable to make this happen.

If I'm correct I need to use the normal loop. (normal/switchable rocker -> set to normal)
Pedal input connected to SEND, pedal output connected to RETURN.
RHY1/RHY2 rocker set to middle position ?
RHY2/LEAD rocker set in the middle ?

I have tried all possible rocker settings but it seems that the pedal is always engaged and, moreover, the sound is terrible on all channels.

Could there be some kind of malfunction in the effects loop ?

thanks for your thoughts in this
cheers
Hans

If you plug into the normal loop, the effect is always on. You may want switchable. As far as the sound, the first thing I would check is the pre-amp tubes. I believe the V2 pre-amp slot is the FX return.

FWIW, Those type of pedels don't do well in the lead channel or in the FX loop in a Mark IV.

swbo101 said:

FWIW, Those type of pedels don't do well in the lead channel or in the FX loop in a Mark IV.

Click to expand...

+1. Boost/Overdrive pedals should be in front of the amp; modulation/delay should be in the loop.

Hi swbo,

I found out how to switch my chorus on, in the clean channel only so the switchable loop works as it should and it sounds as it should with a chorus. (problem 1 solved ..)

You're probably right that those kind of overdrive pedals should be in front & not in the loop I've read that elsewhere on the internet too.

My AMP tech also writes me that many pedals cannot cope with the high output of an effects loop. (it overdrives the first stage of the pedal) and that this could remedied by lowering the output volume of the effects loop.
Only there is no such knob on the Mark 4 (maybe not even on all mesa's I dont know that)

SO, if i want to exclude my tubescreamer from my clean channel, I will have to look for a solution in front of the AMP.

thanks for your reply !

Hans

The channel volumes control the signal level going into the effects loop- that's your send level.

Get a loop switcher like the Carl Martin Octaswitch (http://carlmartin.com/octa_switch_mk2/), Moen GEC9 (http://www.moenfx.com/gec9.html), the Rocktron Loop 8 (http://www.rocktron.com/controllers.html - there's a rack and floor version) GCX audio switcher or (http://www.voodoolab.com/gcx.htm) or similar.

Any of them allow pedals in bypassable loops in front of amps and in effects loops and offer some switching functionality as well - I have the Moen GEC-9 and it works really well.

Aside - I occasionally use to use am MXR distortion + in the effects loop of my studio preamp (volume high, distortion low) and got a really unique lead tone that was so don't give up on that idea, just watch your volume levels!

I know this is an older post but my question seems to fit best here. Plus it expands a bit upon the further question and I was not able to fine another post by searching.
I recently picked up a Mark IVa (7/91) combo and an having an issue understanding the Normal and Switchable effects loops.

As I understand it from reading the manual, the Normal Loop is always on. The switchable loop allows you to place an effect that can then be turned on/off via the footswitch (or MIDI switched or programmed via the rockers) as desired.

I am running a Boss GE-7 through the normal loop as I always want this on. I then have my Boss DD-3 in the switchable loop as I want to be able to turn this on/off as desired via footswitch. I have the switchable rockers set in the middle as to not have it programmed. I have tried placing the main effects loop switch in both the normal and switchable setting and am not getting the desired result. It is either one or the other.

Do the loops not work this way and I am misunderstanding the manual or is there something I am missing. I have tired what I feel to be every combination of changing the rocker switches with no luck.

Thanks in advance and the Mark IV is an incredible and inspiring amp!

Side Note: Now that I think about it more, I can just run both pedals together in the normal loop and switch the delay on/off as needed using the pedal rather than the loop footswitch button. However, it would still be nice to know if one effect can run through the normal loop all the time and use the Boogie footswitch to turn the delay on/off (this keeps the pedals close to the amp with short cords rather than running them up front with the rest of the pedals.)