My plans for Dual AMZ MOSFET Booster (FX Loop box)

[ryanscissorhands]

I ordered the Dual AMZ Mosfet boost from GGG (done by the prophecysound people), and have almost finished the board. I decided that since I built the beginner project boost, three boosters were unneccessary. So I thought why not make one half of the AMZ a buffered loop?

Then my mind wandered to the endless possibilities for a two-loop loop box and the various switching schemes I could use. I think I have decided on the following:


The idea is that each 'channel (A and B) is bypassable, and with the use of a toggle switch, is either just a boost, or a buffered send/return channel. I decided to go with a DPDT switch because I shouldn't need an LED to know the status-- the position of the toggle switch is a pretty good indicator. I figure I won't have to change from a loop to a boost in-song much, so no stomps needed there.

Once I get it finished and whatnot, I'll post pics and a report of it. Oh, and I've decided to run a bi-color LED for it--one half will be red, the other blue, so that when channel A is on, then it's red; B is blue, both will combine to be purple.

If anyone sees any reason why this plan should not be built as is shown in said diagram, speak now, or forever hold your peace.

Edit: oh, and the red things are just the connections for bypass.

[ryanscissorhands]

Okay, can anybody confirm that the following, in theory, is a sound wiring diagram?

[Khas Evets]

Don't you want two outputs coming from A and B, one buffer and one boost, feeding the toggle? As it stands, you are either sending the output to the effect or sending it to the next stage. I think you could achieve the boost/buffer switch with just a SPDT before the send. The return doesn't need to be switched.

A couple other considerations...

Is there ever a time when you would want no buffer or boost. I'm thinking of a Fuzz Face for example. Of course you could always put that before this box. Also, when both channels are bypassed, there is no buffer active. Not sure if that matters to you.

[ryanscissorhands]

First off, thanks for the reply.

I am aware that with both bypassed, there' no boost. I decided that's okay because if I need a boost, I have my beginner project. But the thought occurred to me that if I can't get the boosters to be at around unity, then when I bypass both, I get a major drop in my signal. So I added a 100K Volume knob to each boost so that I can set the overall gain to around unity, even if I crank the boost a bit. I like the way it starts to break up, so the vol pots were key.

I still don't quite follow how I could do the toggle with a SPDT. If I want the effects loop on, I need to toggle it to send it to the loop (one pole) and when it's off, I don't want any connection to the FX loop incase it picks up noise or whatnot. I figured with a DPDT It would be total cut-off bypass. What am I missing here?

I was going to try to fit everything into a 1590N, but it was just a little sketchy. Plus I wanted the battery in there. So I picked up a 1590BB just now. I'll have plenty of room then, and won't have to struggle with my layout. If I had more experience, I would go for it, but it's my second full build, so I'm playing it safe and spacious.

[Khas Evets]

There's a version of the AMZ Mosfet Boost that has two outputs, buffer and boost. I thought you were using that. If you're achieving unity with a pot, that's different. That's what my comment about the SPDT was regarding.

[ryanscissorhands]

Oh, sorry, there was a similar confusion in another thread this week. I kno wthe "improved" dual output booster you're thinking of, but no, it's the regular one, only two of them on one circuit board (see GGG). It's pretty cool, actually. At first I thought, "I wish I had two so I could build both a buffered looper and a dual-boost pedal. Then I decided I would do both in one.