Switching Questions/ Ideas

[space_ryerson]

Hi all,

I've had a couple of switching ideas kicking around in my head lately, and I want to run them past you to see if they would work properly.

The first idea is a switch box which would allow you to switch between an external preamp and the internal preamp(s) with a guitar amp that has an effects loop like this:

I have been wanting a 'third channel' of sorts in my amps for flavor, and I figured that this may work:

One concern is that the preamp, amp, and guitar share a common ground point. Is this bad? I imagine that this would be good, but I'm not the most experienced when it comes to these things.

My second idea was along the ideas of Craig Anderton's 'FX order switcher'. I'm going to be playing shows sometime soon, and I don't like carrying my entire fx arsenal with me. There are times when I like having my modulations going either before the amp, or in the fx loop. Now, rather than carry two flangers, two choruses, etc., I figured I could set up a switch box with a 4pdt switch like so:


I have some concerns for this as well. I will be again sharing ground points, but is is bad to have my guitar signal near the signal going through the fx loop from a noise perspective?

Also, I have noticed that my fx are much louder compared to the bypassed signal going through my fx loop. I have heard that fx loops are +6 db, but I haven't ever seen that in writing.
On some of my pedals, like a phaser for instance, there isn't a volume control, and it is inherently louder than the bypassed signal, due to the nature of a phaser itself. My idea is to put a passive volume control in an external bypass box which reduces the volume of the output of the pedal, but not the bypassed signal. I figure I would use something like a 10k pot.

Is there a better way to reduce level when I do this? I could add a cap to keep the high frequencies going through, I'm guessing. Would a buffer be in order?

I'm interested in hearing your thoughts about all of this. I know these are really basic ideas, but I haven't seen anything quite like them browsing around the board for a while. I am also looking at adding LED's at a later date. The first box could easily do that with a 3p2t, but the second box gets a little messy-er.

Thanks for looking!