Envelope controlled delay to emulate tape

[disorder]

I'm listening to the album "nebraska" by bruce springsteen and admiring the slapback delay thats all over it on guitar and vocals. I'm pretty sure it was done with an old Echoplex but what I like is that the wet/dry ratio seems to change with how hard he hits the front of the Echoplex. For example check out this song, it has a somewhat buried slapback on the vocals through out the song but when he lets out those loud "hoo" and "woo" sounds the echo becomes much louder in relation to the dry signal. I'm sure back then this was actually an artifact due to the front end of the echoplex clipping or the tape saturating. But I'd like to building something similar, could I essentially envelope control the mix pot? That simple?

https://www.youtube.com/watch?v=nU5MyNuBdhg

[midwayfair]

The echo on that track is pretty consistently within a couple decibels of the dry, but the easiest thing would probably just be a simple envelope detector/LED driver from the dry signal, and an LDR in series with either the input or output of the delay. Put a resistor across it to limit it somewhat and away you go.

[thehallofshields]

Has anyone ever tried an Envelope controlled Delay?
Are there any commercial builds that implement it, digital or analog?

I think the idea warrants some experimentation.

Personally, I'd like to try a 'ducking' effect where the feedback is increased as the input signal is decreased.

[StephenGiles]

Yes, tried it in mid 1980s using variant of Craig Anderton's Pluck Follower. It worked after a fashion but "it's do-able"!!

[duck_arse]

I put an enveloped ldr across the delay pot in a bredboreded pt2399 thing, and it sounded like .... erm, a wah? did some vowell sounds.

[Kipper4]

I put an enveloped ldr across the delay pot in a bredboreded pt2399 thing, and it sounded like .... erm, a wah? did some vowell sounds.

Next project D.A.?

[StephenGiles]

Next project - why not a rippleless auto filter?

[thehallofshields]

I put an enveloped ldr across the delay pot in a bredboreded pt2399 thing, and it sounded like .... erm, a wah? did some vowell sounds.

Did you tie it to the Mix, Time or Feedback?

I can see Time doing a Flange effect that might sound Auto-Wah like.

[duck_arse]

tied across the delay pot and its stop resistor. same problem as ever with enveloping a pot, as the resistance decreases, so too the sweep. would only need a switch to move it from time pot to f/back//mix tho.

I've been meaning to take this up with you, kipper. too much else on plates, like the sponge tractor. oooohh, a good pedal name .....

[Kipper4]

Shhhush
If PPR smells a tractor !!!!!!!!

[balkanizeyou]

I've had this envelope-delay idea in my head for quite a while, so after reading this thread I finally got to breadboard a 2399 circuit almost straight out of the datasheet with the LDR across the Time pot with a Dr Q.-like envelope follower and I have to admit it sounds suprisingly cool.
After some tweaking (had to cut a lot of unpleasant bass from the delay side) it makes nice "tape slowing down at the beginning of the chord and speeding up after the sustain" kinda effects (or the opposite way around), with depth set low it can even sound kinda chorusy and for all you noise-makers - with the wrong pot settings it can get really ugly lol. Overall, that sounds better than I expected.

[Kipper4]

Schematic please or it didnt happen
I'm curious to know how its speeding up and down!!!!!!

[balkanizeyou]

I don't really have a schematic yet as I just put it together on the breadboard, but I'll try to draw one tomorrow. Here's an idea of how it sounds (disclaimer - I'm not a guitar player so I just played a few random chords, also sorry for the sound quality):
https://www.youtube.com/watch?v=T4yOpRBAAfI

There's no mystery in the slowing up and down - when you pick hard the resistance of the LDR, transistor, fet or whatever you put there increases/decreases (depending on the setting), which changes the delay time and speeds up or slows down the repeats. When the note fades out the opposite happens.

[Kipper4]

Thanks
Well it definitly speeds up. I'm not sure it slows down.
Messing with the envelope decay pot should alter the response time.
You could also try a stop resistor between one of the ldr legs and the thing. So it varies the min R. or try different LDRs

[balkanizeyou]

thanks for the ideas, I'll surely try them when I'm back from the vacation that starts tomorrow (yippie-yay!). I think the slowing down effect was inaudible because the attack pot was turned down, so the envelope hits it peak miliseconds-fast and already starts decaying, which is heard as the speeding up. I'll mess with the resistor & capacitor settings in the follower to make the attack more audible.

In general this effect may not be too musical, but I like those weird kinds of things, so I'll try to work some on this stuff (when I'm not on the vacation of course )

[thehallofshields]

Here's an idea of how it sounds (disclaimer - I'm not a guitar player so I just played a few random chords, also sorry for the sound quality):
https://www.youtube.com/watch?v=T4yOpRBAAfI

Nice! That was my idea exactly and it sounds way better than I imagined it.

I hope to have some free time after a few weeks and I'm going to get this breadboarded.

[rutabaga bob]

Cool!   

[duck_arse]

if you wanted an unpredictable-ish tape-spill-ish noise effect sound, make the envelope cap too small, so it ripples the led driver. I had this on bb tonight, many sounds similar to balkanizeyou's.

(but worse playing.)

[turdadactyl]

I don't really have a schematic yet as I just put it together on the breadboard, but I'll try to draw one tomorrow. Here's an idea of how it sounds (disclaimer - I'm not a guitar player so I just played a few random chords, also sorry for the sound quality):
https://www.youtube.com/watch?v=T4yOpRBAAfI

There's no mystery in the slowing up and down - when you pick hard the resistance of the LDR, transistor, fet or whatever you put there increases/decreases (depending on the setting), which changes the delay time and speeds up or slows down the repeats. When the note fades out the opposite happens.

That's an awesome effect!  It reminds me a lot (sonically) of some of the sounds you get out of the Ibanez ES2, although with the ES2 you still have to manually change the delay time.

Def would be interested to see a schematic on this after your vacation.

[rutabaga bob]

Schematics - yes!...layouts - yes!
Y'know...vacations are over-rated...