Hmm, true bypass looper + switchable volume as pseudo clean channel

Started by ghostsauce, May 28, 2015, 03:12:30 PM

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ghostsauce

Some outside the box thinking for anybody in my situation - I wanted to use a single channel on my amp for cleans and crunch, but riding the guitar volume isn't working for me as I lose too much highs and volume.. plus I like compression and often delays & such on the clean. SO.. I set my les paul style guitar so the neck pickup is clean, then I built a true bypass loop box that goes inside my fx loop for a one-stomp clean boost (SHO, to compensate for volume loss) + compressor + chorus/delay/whatever. Works great, but I just realized.. if I installed 2 more jacks and used a 5PDT instead I could use the other 2 poles to switch a volume pot in/out from the guitar signal before it hits the amp's preamp. BOOM, 1 hit clean channel with appropriate fx.

And.. sadly they don't make 5PDT's and I don't wanna lose my LED cause I am crazy like that. Then I found this: http://s1128.photobucket.com/user/guitarpoet1/media/2014-04-29_13-47-13_zps1c81aa70.jpg.html

That seems to be my answer.. But the pot is no longer completely bypassed this way, so I'm wondering how the pot hack will affect the signal. Never tried hooking a pot up via an SPDT before.

MrStab

as far as i can tell, in the diagram you linked to, the pot IS completely removed from the signal path when the switch is open. it's only permanently connected to ground, with nothing going into it until the switch is pressed.

i'm a bit unclear on what exactly you need, i'm a simple sort, but i can recommend a coupla things from the rough gist that i do get. firstly: relays, relays, relays, relays. no more switching limitations.
alternatively: you could use RG's Milennium Bypass system if a 4PDT will be enough for the signal side of things, but you still wanna keep the LED.

...also, it has to be said: if this is already in your FX loop, there's less point to true bypass as the signal from the amp's FX Send will be low-impedance anyway (afaik).
Recovered guitar player.
Electronics manufacturer.

PRR

> they don't make 5PDT

I believe a 6PDT is a standard *rotary* switch.

Obviously a foot-switch is what you want.

Time to study relays. A relay is a switch controlled by electricity instead of finger/foot. One SPST stomp-switch can turn-on multiple relays. Each relay is readily available DPDT and 4PDT. So you need two relays, and relay-power, but it isn't a major project. (Since the stomp-switch can turn-on both LED and relay, you may only need one 4P2T relay.)

> I found this:

That works by "shorting-out" the signal more or less. It is very critical about what drives it. It may change bass/treble balance. (Tho for lead/rhythm guitar, maybe in a "good" way; mellow when cut-down.) It may not be able to smoothly cut-down the output of active systems such as active pickups or many pedals. I think your plan to allocate extra poles to this function is wise.
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ghostsauce

Hmm, thanks for the info. Before I look at millenium bypass, I might try the volume on a single pole of the switch and try a cap across the outer volume lugs to compensate for treble loss. I use passive pickups with this rig anyways so it's worth a shot.

@mr stab - I want to use one switch to turn down the volume going to my amp's preamp, to get a clean sound, and also switching a volume boost and other fx into the fx loop. Just for the 'set it and forget it' kinda setup.

ghostsauce

Alright, I hooked a pot up to two jacks to test the volume pot and it did suck treble pretty bad when turned down, so I added a 150k in parallel with a 1nF cap and now it bleeds enough treble that it still sounds right when the volume is down. Gonna wire a switch to it when I get a chance and see if it affects the 'bypass' signal as well.. if it still sounds good in bypass I'm gonna go with a 4PDT and be done.

Hm, idk if I'm crazy but it seems I retain more treble without the res/cap. Gonna have to mess with it. Anyway, I can put a para EQ in the loop to fix it.

MrStab

Quote from: ghostsauce on May 29, 2015, 01:42:11 PMI added a 150k in parallel with a 1nF cap

Quote from: ghostsauce on May 29, 2015, 01:42:11 PM
Hm, idk if I'm crazy but it seems I retain more treble without the res/cap.

You're not crazy. imagine the outer lugs of the pot are a fixed resistor - you've just put 150k in parallel with it. if you used a 500k pot, you now have around 115k between the signal path and ground (=more treble bleed). You've also altered the taper, as in the pot rotation is no longer logarithmic, but as it's meant to be set-and-forget, that probably doesn't matter.

Use a bigger pot, or a different solution.
Recovered guitar player.
Electronics manufacturer.