Stereo pedal re-processing

[Mark Hammer]

One of the most underexploited features of many commercial stereo pedals is the ability to reprocess.  By "reprocess", I mean that the pedal ostensibly has two channels of throughput, and the output of one of those channels gets turned into the input of the other.  Whatever yu did to the signal the first time gets done once more by the other channel.  As you might expect, this gets most interesting with time-based effects.

A buddy loaned me his TC Alter Ego this week.  It sounds great on its own (nice pedal), but the modulated delays sound otherworldly when reprocessed; like ethereal reverbs, rather than delays.  It can work on lots of pedals.  I've done it to my L6 Echo Park and Liqui-Flange, both of which are stereo.  I've also done it with my L6 M5 and my Muza FD900 delay/reverb.  I won't suggest that it will work with any and every "stereo" pedal, but it will work with many of them, to very interesting effect.  As I've noted here in past, reversing a reverse delay gets you forward delay, though because of the manner in which some stereo pedals are able to take a mono input and provide both outputs from that one input, your final output, upon second processing, will be a mixture of forward (rereversed) and reverse delay.

In some instances, you may have to use some sort of padding between first and second processing, in order to avoid screeching feedback.  BUt I've found many instances where it isn't needed, as long as levels are kept sensible.

Definitely worth playing around with, although I suspect some sort of adaptor box would be useful, such that the user coud hit a stompswitch and go back to "the once-through" instead of "the twice-through".  I'd be interested to hear some of your experiences with this, and maybe compile a list of pedals it does and doesn't work with.  The key thing is that the pedal needs to have two ins and two outs.

[Aph]

Sounds like you need to design a reprocessing switcher type thingy pedal that you can hook up stereo pedals to... perhaps buffered with a "reprocessing volume" control. 

[TejfolvonDanone]

TC Electronic did a video a while back with their own stereo pedals doing this except the reverb:
https://www.youtube.com/watch?v=kgsrk85t1ho

[mth5044]

Sounds like you need to design a reprocessing switcher type thingy pedal that you can hook up stereo pedals to... perhaps buffered with a "reprocessing volume" control. 

Correct me if I'm wrong, but the simplest form is just a bypass box, as the second in/out on the stereo side is basically another pedal. Add the simplest of volume controls and you're good to go.

[Mark Hammer]

TC Electronic did a video a while back with their own stereo pedals doing this except the reverb:
https://www.youtube.com/watch?v=kgsrk85t1ho

Thanks for that!    And here I thought I was on to something new.  Turns out I was 2-1/2 years late to the party.
What the guy in the video doesn't discuss is just how darn close the Alter Ego comes to being a reverb, when used in this way.  It really stoips being obvious echoes, and becomes more of a "wash".

[cnspedalbuilder]

Even if you were two years late, I wouldn't have thought of this till seeing your post. Can't wait to try it out with my TC Nova Stereo Delay!

[cnspedalbuilder]

Tried this with my TC Nova Delay and it's amazing. With my copper guitar pick, playing that produces some crazy noises reminiscent of "Bela Lugosi's Dead". The straight delay will give you a gorgeous ring with the decay, and the reverse setting is too beautiful for words. Now I have to make room on my board for one regular delay and one set for "reprocessing".

[Mark Hammer]

See what I mean?  I don't know why manufacturers don't include that sort of stuff in either their ad copy or user guides.

I'm trying to get the guys from That Pedal Show to devote an episode to re-processing.  Lord knows they have enough stereo pedals hanging around to do that with, and the switching systems to compare once-through and twice-through.

[nocentelli]

...Definitely worth playing around with, although I suspect some sort of adaptor box would be useful, such that the user coud hit a stompswitch and go back to "the once-through" instead of "the twice-through".  I'd be interested to hear some of your experiences with this, and maybe compile a list of pedals it does and doesn't work with.  The key thing is that the pedal needs to have two ins and two outs.

Not sure why i have never tried this before, works well with BOSS DD7, DD20 and RV5: DD-7 was least unpredictable with more degradation in analog mode and a pretty, tinkling, reversed-reverse delay; DD-20 has slightly more quirk factor with the modulation mode proving interesting and the "smooth" mode generating some alarming reverb'd crescendos; The RV-5 is maybe the most fun, although carelessly switching between modes can be hairy since each mode oscillates at a different setting of level/EQ/time, with Hall mode particularly prone to howling above noon on the level.

Here's a switch that should work to toggle a single pedal between standard mono operation (with grounded channel B to kill oscillation) and "stereo reprocessing mode":

[Mark Hammer]

Thanks for that.  Much appreciated; especially the sheer number of pedals you tried it out on.

A nice vacation from the predictable, isn't it? 

[potul]

When I first got my TC Electronics Alter Ego one year ago, I tried to do this same thing in an attempt to get a "U2 like" delay, usually done by putting 2 different delays in parallel or series.

I did not achieve what I wanted but I could get interesting sounds out of it.

[Mark Hammer]

Of course the limitation is that such pedals generally have only one set of controls that apply equally to both channels.  That's certainly convenient, and makes for a smaller footprint, but yes it prevents the sorts of things you were hoping to achieve.

I etched and stuffed a couple of boards with Dean Hazelwanter's HT8955-based SHECO delay, machined a rack panel, and installed a wad of toggles and pots for a dual delay with independent controls for each side and crossfeeds in the feedback path.  It sits among other to-be-wired-up projects I'm slowly working my way through.  The SHECO only gets 800msec, and the HT8955 is only 10-bit resolution, but I'm looking forward to what is attainable when the feedback of one delay gets fed to a different delay....once I get to it.