I know how to slave the two stacks together using the effect send of the primary and into the return of the slave head. How do I properly access and use my effects loop in this situation?
I'm thinking that what you want to do is 'daisy chain' using the inputs rather than using the FX loops. Very old technique used by Hendrix and Clapton, amongst others. This way you can keep all the FX loop jacks free for their proper use. The concern here is to make sure the speakers can handle the load.
The other method would be to use an A/B switch and split the guitar signal to both heads. I use a Big Shot ABY Switcher, by Radial Engineering, that allows for the signal to go to amp A or amp B or both. Again, this manipulates the signal on the front side of the amp, leaving the FX loops open, and eliminates the master/slave configuration. Also this helps in case you have one unit that fails.
Not sure if I have addressed your question so hope this helps.
Cheers!
