DIY True Bypass/Feedback Loop (aka KROK)

[expanoncolin]

Hallo together,

i build this pedal: http://www.beavisaudio.com/techpages/PedalHacker/LooperWithFeedbackLoop.gif

i dont get any feedback.

and now i ask me wich pedal i have to use to get a feedback. my distortion pedal seems not to be enough to make a feedback. which pedals work best? or is no pedal needed and my circuit is broken?

Pretty much any distortion pedal should give you feedback, but you should try a variety of pedals.  Does the sound change at all when feedback is engaged?  If not, it is probably not wired correctly.

-Colin

[bergar]

hallo expanoncolin,

thanks for your reply.
When i dont use any pedal the Sound doesnt change. When i use my distortion Pedal i hear Distortion or no distortion, but no Feedback. Do i understand this right, a passive Feedback Loop can only work if there is a pedal in the circle with any form of amplification build in? When such a pedal or amplifier isnt in the circle the feedback loop has the same potential like the main circuit so the signals dont go into the circle and dont backfill it self. here is a picture how i build it up. any significant mistake?

[expanoncolin]

If there's no difference in sound with a distortion pedal (or many others) when the feedback switch is on vs. off, then it's probably been wired incorrectly - check your work!

-Colin

[mikebike]

often weed and electronics dont mix.

[ouija]

How would I go about adding a photocell to trigger feedback oscillation in this feedback looper 

thanks for assistance

[expanoncolin]

Replace the potentiometer with the photocell.

-Colin

[RPS-ten]

Hello,

Finally got my bypass/feedbacker to work 

But wondering about the feedback knob - as others have mentioned only works in the last 1/4 turn. So I'm thinking maybe change the 500K pot to say 250K or something to get more of  range a sweep and maybe even more interesting noises??


IMAG0357 by rps-10, on Flickr


IMAG0358 by rps-10, on Flickr

[Atom666]

Hey there. Just got my feedbacker running. I skipped the BP and just ran feedback on/off with a cool green LED. Going to rewire a few bits mostly because i have some longer than needed wires and a couple of joints could be neater but now that I know it's running and sounds great it'll be a labour of love. I put mine in an old Dane electro pedal casing (that died many moons ago). Just wanted to say thanks Colin and everyone else. It has been a great read and a real fun project that actually sounds amazing!
Good luck with your pedals people
Thanks

[frances-rhodes]

hi everybody

i'd like to build a feedback looper, and got redirected to this thread from the other one (much shorter) and i can't seem to find the answer i'm looking for. (i didn't read all 33 of the pages in this thread, i apologize if this question was answered before!)
about the plastic chassis mount jacks, should all 4 jacks be plastic or only the send and return ones?
and in case of "all-4-plastic jacks", wouldn't it be a problem if the in/out jacks are isolated from the metal enclosure (used as a shield)?

i'm french, so sorry if my words aren't exact, i'm still not 100% sure of the vocabulary!

thanks

[expanoncolin]

If you use all plastic mount jacks (no metal ones), you should connect one of the jack's ground to the metal chassis via a wire.  If any of your jacks are metal you don't need to do this.

-Colin

[frances-rhodes]

If you use all plastic mount jacks (no metal ones), you should connect one of the jack's ground to the metal chassis via a wire.  If any of your jacks are metal you don't need to do this.

-Colin

ok, so if i build this as it's shown on the schematics, with the feedback pot, and 4 metal jacks, there shouldn't be any problem. i think i read in one of the 2 threads that the schematics didn't work and some people had issues buildind one, i'm not sure i understood why exactly!

but thanks for the answer colin!

[expanoncolin]

There are a million reasons this can not work quite right, but the issue is almost always wiring.

-Colin

[mick_ccc]

Hi everyone!

And first of all thanks for this great thread about feedback looper, I built one as my first diy project few years ago and it was one of the best discovery I made!

I've looked for information about adding an expression pedal input to the feedback looper pedal, but could not find it.
But I'm sure that you peaple already thought about it. So is there a way to do this, in order to obviously control the feedback about by foot?

Thanks!
Mick

[expanoncolin]

Hi everyone!

And first of all thanks for this great thread about feedback looper, I built one as my first diy project few years ago and it was one of the best discovery I made!

I've looked for information about adding an expression pedal input to the feedback looper pedal, but could not find it.
But I'm sure that you peaple already thought about it. So is there a way to do this, in order to obviously control the feedback about by foot?

Thanks!
Mick

Hi Mick, an expression pedal jack just connects an external pot through a cable in place of the internal pot.  More information here:

http://experimentalistsanonymous.com/board/index.php?topic=148.0

-Colin

[mick_ccc]

Thank you Colin, I'll have a look at this!

By the way, if you're interested, I've made some videos to demonstrate the feedback looper on my website, here they are:

With a whammy:
http://www.youtube.com/watch?v=HenZnmSIkhM

With a Zvex Mastotron;
http://www.youtube.com/watch?v=D6RNalMJMGk

With a MXR Blue BOX:
http://www.youtube.com/watch?v=TzTT4RWfV5E

Bye!
Mick