Building a analog delay for stereo setup

[jhnlfgrn]

Hi!
I have a stereo guitar setup. I use a aby pedal and two amps. I use a i ibanez ad-9 and have it 100% wet after the aby to one amp with 20-40 ms delay with no repeats to get a stereo spread.

I would rather use my ad-9 as a "real" delay and build a "simple" analog delay only to get 100% wet delay, with just one knob to control the delay from around 0-50 ms.
(I have build some pedals on veroboard but never designed one myself.)
Does anybody know a schematic for a delay that does this?

/Johan

[vigilante397]

Welcome to the forum Johan

The simplest solution would be finding a design you like the sound of then removing the extra controls and substituting them with fixed resistors. For example, if your "Feedback" knob is a 25k pot and you just want it maxed all the time, pull out the pot and put a jumper between pins 2 and 3 and a 25k resistor between that and pin 1.

This can be done with any design, but if you're looking at analog delay then you'll probably want to work backwards from what BBD chips you can get. I made a terrible mistake in designing a pedal around the MN3005 then ordering a bunch of V3205, which are similar but absolutely not direct replacements. So find a chip you can get, find a circuit that uses that chip that you like the sound of, and go from there.

If you're a beginner I would highly recommend buying a fabricated PCB, as analog delays can get a bit messy. Madbean's Aquaboy, based on the Boss DM-2, may be a good place to start.

I hope this helps, and good luck!

[Scruffie]

EHX Full Double Tracker, it's fairly simple to replace the delay time switch with a pot, just a cap between pin 1 & 3 and a pot between pins 2 & 3 of the 4047 with a series resistor.

[jhnlfgrn]

Welcome to the forum Johan

The simplest solution would be finding a design you like the sound of then removing the extra controls and substituting them with fixed resistors. For example, if your "Feedback" knob is a 25k pot and you just want it maxed all the time, pull out the pot and put a jumper between pins 2 and 3 and a 25k resistor between that and pin 1.

This can be done with any design, but if you're looking at analog delay then you'll probably want to work backwards from what BBD chips you can get. I made a terrible mistake in designing a pedal around the MN3005 then ordering a bunch of V3205, which are similar but absolutely not direct replacements. So find a chip you can get, find a circuit that uses that chip that you like the sound of, and go from there.

If you're a beginner I would highly recommend buying a fabricated PCB, as analog delays can get a bit messy. Madbean's Aquaboy, based on the Boss DM-2, may be a good place to start.

I hope this helps, and good luck!

Thank you!
I can get hold of the mn3005 chip so aquaboy is possible to build. I googled it and it doesnt do 100% though. Do you know how to kill the dry signal in the aquaboy?
http://www.madbeanpedals.com/projects/_folders/Delay/pdf/Aquaboy.pdf
I dont know much about schematics and how a mixer works in a pedal but is ic1_a where the signal splits and in ic1_b where the delayed signal blends in with the dry? I you remove the R8 does it kill the dry signal? I am just guessing now so dont laugh:)

/Johan

[vigilante397]

I you remove the R8 does it kill the dry signal?

I'm not laughing, you understood that absolutely right. Well done

[jhnlfgrn]

I you remove the R8 does it kill the dry signal?

I'm not laughing, you understood that absolutely right. Well done

Ok! Great!
Thank you for the help!

/Johan

[jhnlfgrn]

EHX Full Double Tracker, it's fairly simple to replace the delay time switch with a pot, just a cap between pin 1 & 3 and a pot between pins 2 & 3 of the 4047 with a series resistor.

Thank you for the tips!
The 4047 seems to be hard to get though.

/Johan

[duck_arse]

https://www.taydaelectronics.com/catalogsearch/result/?q=4047
http://diy-tubes.com/index.php?route=product/search&filter_name=4047
https://www.mouser.com/ProductDetail/Texas-Instruments/CD4047BE?qs=sGAEpiMZZMuyBeSSR239IZQlTgCI5L2Rn0wctDkLnYk%3d
https://www.mouser.com/ProductDetail/Texas-Instruments/CD4047BE?qs=sGAEpiMZZMuyBeSSR239IZQlTgCI5L2Rn0wctDkLnYk%3d

..... and that's just four .....

[vigilante397]

https://www.taydaelectronics.com/catalogsearch/result/?q=4047
http://diy-tubes.com/index.php?route=product/search&filter_name=4047
https://www.mouser.com/ProductDetail/Texas-Instruments/CD4047BE?qs=sGAEpiMZZMuyBeSSR239IZQlTgCI5L2Rn0wctDkLnYk%3d
https://www.mouser.com/ProductDetail/Texas-Instruments/CD4047BE?qs=sGAEpiMZZMuyBeSSR239IZQlTgCI5L2Rn0wctDkLnYk%3d

..... and that's just four .....

+1 I've never had any trouble finding them. Where are you located Johan?

[Mark Hammer]

For what you want it to do, my best recommendation would be to make the Madbean Cavedweller delay, and simply lift the resistor that mixes dry in, break the feedback path, and max the wet level.  Yes, it uses a PT2399 digital chip.  But for a short delay time for stereo spread, it is more than acceptable; especially since you're not interested in blending wet and dry in the same build or using repeats.  If I understood Roger Mayer's comments in the Dave Hunter effect book, he feels (or at least felt, 10 years ago) that the difference between analog and digital really takes place as longer delays decay.  And since that's not what you're going to do, digital should be good enough; especially since your sampling rate will be quite high with a 20-40msec delay time.

[anotherjim]

The basic audio delay was the intended "serious" application for the PT2399. It was designed for multi-speaker time alignment jobs in PA systems.
This is worth a look...
http://sound.whsites.net/project26a.htm
Note that the input impedances provided in the circuits are low to be suitable for line level connections found between mixers & power amps. A suitable high impedance buffer stage should be added to input for use between guitars and guitar amplifiers.

[Mark Hammer]

Even better.  Thanks, Jim.

[jhnlfgrn]

Thanks for all the help and suggestions!
I think I will use the Cave Dweller vero-layout on tagboardeffects (http://tagboardeffects.blogspot.com/2016/09/madbean-cave-dweller-2015.html) and simplify it by using the schematic Jim linked to.

I think I need to buy a breadboard to experiment on


/Johan