Is a rack something like this too much modulation with ER 301 as the only sound source? I am looking to modulate modulation. I have most of these modules. Still waiting on the ER 101 and trying to decide on the Quadra. I am a newer ER 301 use and I cant get over how much clean sound you can get out of it. So I am wondering if I should ditch having other sound sources all together?

what do you think?

Seems fine to me...the only flaw I see is that you're missing an ADSR-type envelope source or two for one-shot modulation of mod signals, especially via linear VCAs. My inclination would be to lose the A-160 and the buffers, then drop in some Ladik IADSR, DADSR, or AHDSR 4 hp modules to make that happen and to also give you some function 'tweaks' beyond a simple ADSR EG.

This is actually one of the first plans where I haven’t included my BL ADSR. I was thinking I’d be able to have a little more flexibility over all with the Quadra AD.