Ideas for an extra delay jack?

[Mark Hammer]

Here's the scenario.  Two months back, I happened to be in Halifax, and popped by Diamond Pedals, where I spent a delightful afternoon chatting with the director of operations.  I asked if I could score a couple of boxes from him, and he graciously gave me a couple of pre-drilled powder-coated D-sized chassis that were from discontinued or never-marketed products.  With a set of pre-existing holes, I mused about what I could build in there that would dovetail nicely with the number and spacing of holes, and decided to installed a Tonepad Rebote 3 delay and a Valve Wizard Equinox reverb.  Remarkable what you can do with a fistful of PT2399 chips.    The Rebote has 3 cascaded PT2399 chips, and while it is not officialy set up for tapping points between them, such tapping could be easily accommodated. 

Anyhow, the chassis has holes for two output jacks (I have no idea what was originally supposed to go there), so I'm trying to figure out what I want to do with the additional output jack.  There are several possibilities I've thought of, but likely many more I haven't.  Some of you may have added an extra jack and tried something so I thought I'd canvas you for ideas.

Here's some of what might be possible:
1) A simple dry and wet output that would have the Rebote's clean signal fed to the Equinox for one output (w/defeatable reverb) and Rebote wet coming out the other jack.
2) Tapped delay with additional jack taking a tap from Rebote chip 1, or 2, or maybe a mix of both.
3) TRS jack for inserting additional processing in the Repeat loop of the Rebote.
4) Rebote-only tap for the additional jack, and Rebote+Equinox for the main jack.
5) Alternate modulation of the Rebote (i.e., something other than the onboard LFO)

Pretty much most of these options would entail an additional perfed buffer stage from a tap to feed the extra jack.  I should note that tap-tempo has never really held much utility for me personally, so don't bother suggesting it.

Ideas?

[GGBB]

All good ideas. The first thing that popped into my head was a modulated out. Might be fun for some stereo mixes. But I kind of like your TRS loop better - could stick a chorus in there in fact.

[notnews32]

I'm a big fan of expression pedals and triggers/LFOs bridging one pedal to another..

I would try to use the jack as an LFO-in, wired to the delay time... and try to modulate the delay time with a sample/hold+noise circuit or something. You can either use a standard modulation LFO circuit, or go wacky and use a random-ish S&H circuit to get pitchy weirdness. Or just use a standard expression pedal to control delay time and be able to smoothly ramp up/down the pitch like that. Or wire feedback to the exp-jack and do awesome swells that way??

It all sounds good.. I'm looking forward to seeing/hearing your creation! Lots of possibilities.

[Mark Hammer]

I'm a big fan of expression pedals and triggers/LFOs bridging one pedal to another..

I would try to use the jack as an LFO-in, wired to the delay time... and try to modulate the delay time with a sample/hold+noise circuit or something. You can either use a standard modulation LFO circuit, or go wacky and use a random-ish S&H circuit to get pitchy weirdness. Or just use a standard expression pedal to control delay time and be able to smoothly ramp up/down the pitch like that. Or wire feedback to the exp-jack and do awesome swells that way??

It all sounds good.. I'm looking forward to seeing/hearing your creation! Lots of possibilities.

The "alternate modulation input" idea is appealing.  If the Rebote 3 had an even number of delay chips, I might lean more towards tapping the delay at the "halfway point" for the second jack, since that could yield relatively rhythmic Ping-Pong outs.  But since the unit uses three cascaded chips to yield a little over a second of delay time, there wouldn't be anything particularly rhythmic about tapping after chip 1 or chip 2.

Consequently, there may be more utility in using that jack as an input than an output.  The master control of delay time is dictated by a fixed-time pot and a modulation-amount pot being mixed at a single common node.  Provided the voltage range is appropriate, there is no reason why the on-board LFO couldn't be replaced with another source.  As some folks may recall, well before we had the Digitech Whammy or EHX Pitch Fork, foot control of delay time in Memory Man type analog delays was used to get wide pitch bends.  Indeed, that was the primary purpose of the old EHX Hot Foot pedal.

Making all of that voltage controllable, however, opens up more possibilities.  So now you have me thinking about a companion box/footpedal to plug into that jack.

[Quackzed]

jack for a momentary 'endless repeat' footswitch.... you press it and it switches from the decay knob setting to a fixed resistance that is set to 'endless' or as close as you can get...

[Ben Lyman]

I like a plain ole dry signal output so my single note and double stop leads can stand out clearly.  Kinda boring use of the extra jack but probably the most practical for me (with 2 amps, that is)

A volume pedal or mosfet booster after the dry out jack is useful. Two volume pedals might be interesting, one at the dry out and the other at the wet out.

If the box has room, a built in mosfet boost with volume knob and footswitch going only to the dry out jack. Guitar solos jump out of the mix, then back into the void when finished.

[Mark Hammer]

Thanks Gil and Ben.

Endless repeat has its uses, although I have fewer such uses, and truth be told, it's one of those things where you really want decent fidelity after the first few repeats, and PT2399s are not really the first choice for that.

The chassis itself has plenty of space for a boost, and an additional footswitch for same, but I have enough other ways of achieving boost that it doesn't need to be in this box.
If it was the case that it was a modest max delay (e.g., 350-400msec) and the output did not involve a reverb tacked on the end of things, separate dry and wet outs would make as much sense here as it does on plenty of other pedals.  I have a DM-3 clone I made with splittable outs and it can be useful.  I also made a Rebote 2.5 for my modular system with a dry-kill toggle that lets it be a wet-only processor to feed to a mixer module (so that dry and wet can be processed independently).  Here, I wanted something I don't already have.

I have an Echo Park that will do Ping-Pong and picked up a Muza FD-900 earlier this year (great little box) that comes with echo and reverb in the same unit, with fixed modulation available for each.  So, I'm leaning even more in the direction of notnews's idea of external modulation input as the option of choice. It's something that I don't have in any other device (including rackmount stuff).  And now that you made me think of it, it could even conceivably be operated with a Source Audio Hot Hand (that outputs 0-3V3 control voltages).

[samhay]

Drill another hole and add a send-return for wet signal only?

[garcho]

TAPLFO sync input, play with your favorite techie drummer

[nocentelli]

jack for a momentary 'endless repeat' footswitch.... you press it and it switches from the decay knob setting to a fixed resistance that is set to 'endless' or as close as you can get...

This is an awesome mod: I have a Red Witch Violetta, a tiny "analog sound" digital delay with an expression pedal jack that overrides the repeats pot when plugged in. It seemed ridiculous to use an expression pedal that is literally eight times bigger than the actual delay pedal, it's also somewhat tricky to set the repeats just right "by foot" on the fly. I made a matching 1590A "repeats control" box that I can plug in to the exp jack, which houses an alternative repeats pot (to set the normal level of repeats), a momentary SPST jack and a second "repeats boost" pot: The switch momentarily connects the second pot between lug 2 and 3 of the repeats pot, thus increasing the number of repeats by a preset amount. By setting the two pots appropriately, I can add a few more repeats for the end of a phrase, go from several repeats to a big wash at the end of a song, or trigger it to go into self-oscillation then drop back down to a couple of repeats. The setting of the "repeats boost" pot also allows me to control how long it takes to build up to oscillation.

[Mark Hammer]

Drill another hole and add a send-return for wet signal only?

No pressing need, if mixers can use TRS jacks for effect send/return, so can I.  As it happens, I have a bunch of TRS switching jacks in my parts drawer.

But at this point, it's not about me anymore.  These are all thoughtful ideas for other folks planning out their own DIY delay.

[samhay]

^good point on the TRS jack option.

[thermionix]

[Mark Hammer]

Turns out I have not one, but two spare holes for jacks.
Reading a review of the Earthquaker Avalanche Run on the busride in to work this morning, it occurred to me that I could use those three jacks in the following way:

- order is delay -> reverb
- can provide a delay out and a delay+reverb out
- delay+reverb out can be fed back to a feedback-in jack, such that repeats are processed with reverb and whatever else I wish to stick in there on the way to the feedback-input jack
- final output comes from the delay output jack

Note that this would also permit simple processing of the delay feedback, prior to being reverbed.  Geez, I gotta finish this sucker so I can demo it!

[notnews32]

so with two spare holes for jacks, you have a total of 4 non-pedal-face jacks.. right? You're going to use
#1 for (stereo?) signal input,
#2 toggles between dry+delay or dry+delay+reverb out,
#3 for a stereo/trs- type feedback loop you're patching in before the reverb,
#4 for a fully wet delay-only out patched from before the reverb

Did I read that correctly?

Is your amp setup configured in stereo or mono? I'm guessing you're broadcasting in stereo if you're considering such a wide variety of outputs patched from various points in the circuit. This pedal seems very capable!.. aside from a tap-tempo, this will be able to output pretty much any delay-based sounds that any non-crazy delay can. If you have another delay unit, or if you're just not into delay pedals, that can create those wacky/glitchy/pitch-bendy sounds, then this pedal is perfect.. though the feedback loop could get you into that ballpark if you throw the right wrench in the works.

I'm eager to hear what you come up with.. be sure to post right away!!!

[Mark Hammer]

To clarify, there are two output and two input jacks.  One input is the main one.  The other breaks the input to the Feedback/repeat pot, so that an external signal can be fed into the feedback loop.

One of the outputs is the delay, and the other is the reverb.  The connection between the delay output and reverb input is never broken so that the reverb can be fed to the 2nd input jack, and what appears at the delay out is what you feed to the amp. The first repeat is clean delay, but additional repeats have reverb on them.  Alternatively, I can take the delay output, process it in some way, and feed it to the Feedback pot.

I did a few mods, shown below in red.  The 27k feedback resistor is split into 15k and 10k, and a cap to ground can be switched in from their junction to roll off mids and highs...gradually on successive repeats.  I also used a toggle to switch between full bandwidth in the master delay path and a bass-cut version, with a smaller-value cap.

Still trying to finish wiring it up, so I'll post pics and sounds when I'm done.

[alparent]

And your building this as my Christmas present 

How nice of you Mark ...... your the best!