Hi guys,
I couldn't find much guidance anywhere on how to do this exact setup that I had in mind, and initially I didnt think it was possible. In the end, I figured it out so I thought I would share my set up on here to help anyone who might want to achieve the same, or similar. Here's what I have going on:
Guitar > HX Effects > PRS MT-15. Wired in the four cable method (4cm) as per the manual
Bass > HX Effects > Amplifi 150
Here is what I wanted to achieve
Guitar using the HX Effects via 4cm, so I can have pre and post amp effects
Bass going to separate amplifier
The only reason I want to incorporate the bass with the HX Effects at all, is to be able to use the Looper for guitar and bass
Initially I tried to get this going using the A and B effects pathways and having the bass plugged in to Input R and Output R. However, no matter what I did in HX Effects' signal flow at the "Y Split", I would always end up with the bass coming back into the guitar amp's power amp - I couldnt strip the bass (on Input R) out of Path A basically. To my research and experimentation there is no way with HX Effects to assign and configure the L/R channels as individual mono inputs to achieve this.
What eventually cracked it for me, was figuring out that it is possible to use Path B as a discrete input channel with the HX Effects with some clever thinking and use of volume and return blocks. The logic here is to use Return 2 as the input for the bass (or other second instrument) because you have control over where to place this in the signal flow using the Return effects block. I placed Return 2 on path B. You then need to place a volume block on path B before Return 2, and set it to 0 - that way you are muting any of the signal coming from the main input (guitar in my case) along path B.
On Path A I have the regular FX Loop 1 as needed to run the guitar in 4cm and that works fine. I have a distortion in front of the loop, and delay and reverb after. I could use effects for the Bass on Path B after the Return 2 block if I wanted, but for now I do not.
At the point were Path A and B meet, in my case I use the Mixer block as is default. The mixer has Level and Pan controls. My initial logic would be to set Path A pan to 100% Left and Path B pan to 100% Right. For reasons I do not understand, all I need to is set B Pan to 100% Right and leaving A Pan in the center is OK. I then put the 6 channel looper pedal after the mixer.
This setup works perfectly for me - guitar and bass through the HX effects, processed separately for effects, and go through the same looper block, then out to separate amplifiers.
Hope that can help someone!
p.s. I had to build a very simple circuit using a relay to control the channel switching of the PRS MT-15 using the HX Effects external amp switch as when I connected them directly I had an awfully loud buzzing!
