Short, simple delay for ADT ?

[Xavier]

I will shortly start building a DIY multiFX, all fitted with mono effects.

Since I normally use 2 amps, and I will fit a splitter at the end of the chain (so i can feed the 2 amps), I was wondering about the following.

Is there any simple circuit out there, that allows me to delay one of the outputs between 10 to 30 miliseconds against the other one ? This would provide a "pseudo-stereo" ADT kind of thing.

The only issue is that I need the delayed signal in full quality, so I am not sure I can use any of the available PT2399 projects..........I wouldn't even need any control, a switch with a fixed 15 ms delay would be enough for this.

Any idea ?

[artifus]

not quite the amount of delay you're looking for but how about a simple phase splitter? the revised amz mosfet booster demonstrates this.

[cloudscapes]

any of the pt2399 projects with the feedback path cut?

[Derringer]

from the gallery

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/ADT+schem.gif.html?g2_imageViewsIndex=1

I have not built it but it's on my to-do list

[Perrow]

from the gallery

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/ADT+schem.gif.html?g2_imageViewsIndex=1

I have not built it but it's on my to-do list

That looks like fun. It's on my todo now too.

[Xavier]

Thanks for the schematic suggestion !!! I will have to breadboard it since I assume this one has both the original AND delayed signals ? In any case, a good starting point !!

[chi_boy]

from the gallery

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/ADT+schem.gif.html?g2_imageViewsIndex=1

I have not built it but it's on my to-do list

This does look interesting.  Is there a further write up anywhere?  I did find this, so it looks like it was built:

http://www.aronnelson.com/gallery/main.php/v/Schematics-etc/ADT+47K.wmv.html


Just spitballing here, but do you think this would this work using a DMM, namely a madbean DirtBag Deluxe as a foundation?  MN3008's are still easy to get.  It uses 2, but perhaps the first one could be jumpered out of the circuit.

http://www.madbeanpedals.com/projects/Dirtbag/DirtBagDeluxe.pdf


The feedback loop could easily be eliminated and save a few parts.  The question is, could you leave off the blend pot and route the the dry signal and the delayed signal to different output jacks to achieve the stereo out effect?  (both of those signals converge at the blend pot)

There are pros and cons; I'm sure there are more, but it's late here.

Con:
Much more complex ($)
Spaces for 2 chips, need only 1
Delay is filtered (not desired by OP)
Delay would be much greater than desired by the OP, but adjustable.

Pro:
Verified PCB
Adds modulation to the delay
Delay is filtered (Doesn't the MN3008 need that to sound good at he output?)

It seems the ADT pedal is somewhat of a fantacy device, but this could be fun, just the same.

[Fender3D]

In my experience, I noticed the best "stereo image" on stage depends on how far you place your amps.
You'll notice kinda filter matrix effect if you keep your amps near each other (might be interesting though...), while sound won't be "filterd" if you place amps on both side of your drummer (he will hate you   )

One of my older setup involved Ibanez HD1000 (modded so I could jump from PS to Echo with the push of a footswitch), dry signal on one Marshall, HD1000's wet signal on the other Marshall.
I prefer a small modulation involved...

Then I discovered ART Multiverb LT image settings, they were 3 or more small delays without feedback and really enlarged my sound...

[maartendh]

Hello,

I entered this ADT-schematic some time ago for the contest (design an effect with 15 parts maximum) and I did not write any further comment on it at the time.

Basic idea is that a dual tracking or automatic double tracking is a relatively short delay of about 10 milliseconds or  a little more, which used to be made with a bucket brigade delay chip (BBD) consisting of 512 or 1024 stages. The clocksignal that would give you this short delaytime was low enough to be heard, so it had to be filtered out, thus making for complex circuitry.
What I did was using a BBD with a higher number of stages (the MN3008 has 2048) and run this at a higher clock speed, which eliminates the need for filtering out the clockticks from the audiosignal.

Probably this had not been done before as prices of BBD's were proportional (or maybe even more than that) to the number of stages in the past when these pedals were designed; a shorter delay chip + filtering probably was less expensive than using a longer delay time chip without filtering.  In the more recent past I found MN3008's at the same prices as the MN 3007 or MN3004 (with less stages than the 3008) (maybe because of the introduction of the PT2399 and the V3005 and the like?).

So I did away with all of the filtering, found that it worked and that it was appreciated in the contest. The design probably could be improved, as I really needed those 15 parts for the basic design. First of all I added a 100 n capacitor, connecting the output to ground in my own build. I have not looked into any further improvements, but I suspect that you could use the first stage of the TL072 to get rid of some noise as well.  You could add a pot for mixing clean and delayed signal. Maybe you can extend the concept even to chorus and other types of delay, I did not try yet.

Anyway, have fun,
Maarten

[Xavier]

Thanks for all the insight !!!

Someone mentioned adding modulation..........well, that's what essentially a chorus effect is, where you have the dry signal on out A, and the modulated , effected signal on out B. Some chorus pedals even have a delay knob.

I guess the main idea is to have a circuit that is as simple as possible. Otherwise you just stick a stereo delay at the end of the fx chain.

[Scruffie]

EHX did the Full double tracking (I put up a schematic for that converted to the v3205 somewhere) & the slap back delay (which used a SAD1024, i modified it to a 3207 but didn't find it worth cutting hairs with the previously mentioned circuit).

Both pretty simple, the slap back definitley came in a stereo version, not sure about the FDT... easily altered though.