Digital Delay Pedal

Building guitar pedals is a time-consuming, often frustrating, and expensive process. If you think you will save time and money by making your own digital delay pedal, I highly advise you to read R.G. Keen's page on the economics of pedal building. However, if like me, you are obsessive, enjoy messing around with electronics and want to make something that looks and sounds uniquely your own, continue reading ahead... just don't say that I didn't warn you!

Follows are detailed instructions on how I made my own digital delay pedal. I must admit that I used a laser cutter as an integral part of the process, but I feel most of the tasks that I am using it for can be performed with many more modest tools. My focus of the Instructable is not so much in the assembly of the circuit, but the assembly of the case, as this is where the real crux of the problem lies. Cramming a lot of things into a little enclosure is not particularly easy. Yet, it's my hope that these instructions will help in some way to simplify the process.



Short Delay:





Long Delay without Feedback:





Long Delay with Feedback:

Step 1: Go get stuff

You will need:

(x1) "BB"- sized Steel Enclosure
(x1) PT2399 Echo Processor
(x1) TL072 low noise op amp
(x1) LM7805
(x3) 100K potentiometers
(x1) 50K potentiometer
(x1) 5K potentiometer
(x1) PCB
(x1) DPDT stomp switch
(x1) SPST toggle switch (SPDT okay)
(x1) Power jack (with cut-off)
(x2) 1/4" mono jacks
(x5) Knobs
(x1) sheet 1/16" santoprene rubber (McMaster-Carr 86215K22)
(x1) sheet 1/8" cork

capacitors:
(x1) 100uF
(x3) 47uF
(x1) 4.7 uF
(x6) 1 uF
(x3) 0.1 uF
(x2) 0.082 uF
(x3) 0.0027 uF
(x2) 0.01 uF
(x1) 100 pF
(x1) 5 pF

resistors:
(x2) 1K
(x11) 10K
(x2) 15K
(x1) 100K
(x1) 510K
(x2) 1M

Comments

[Basementjacks]

what is the capacitor value after the 1k resistor coming out of pin 14?

[Basementjacks]

what programme do you use to open the files?

[randofo]

I used Corel.

[Basementjacks]

having trouble finding a power jack with cut off. help please :) thank you!

[randofo]

This one looks like what I used:
http://www.futurlec.com/DCPower-ChassisMale.shtml

I don't remember exactly. You should be able to maybe find something at Radioshack.

[Basementjacks]

where abouts did you order the parts from? i cant find the casing, the rubber sheets or the cork

[randofo]

The case I got from Small Bear, the cork I got from a local craft store, and the rubber came from McMaster.

[Basementjacks]

Hi im delighted to find this project as i needed something for my end of year project for college, just a few questions if you wouldn't mind answering: what type of capacitors are these? e.g panasonic, aluminium? and do i definitely not need an arduino board? also, would you recommend using the full casper schematic or did you make your own for personal reasons or because it was a better layout as such than the original schematic? Thank you!

[randofo]

some are ceramic and others electrolytic. Usually, the dividing point is 1uF.

You can use theirs. I changed a few parts to my liking, but nothing too significant.

[AljonSalvatore]

I really need your help. Your work is awesome and it'll be very much helpful to me. I'm sorry but can you put up some of your conclusions in doing this product since you're the one who've made it. I just really need it for my research. Please be kind to me. Hehe. I'll appreciate your feedback. Thank you. =)

[randofo]

What sort of conclusion?

[crrollyson]

What kind of lazer cutter do you have/recommend?

[randofo]

I have been using an Epilog. I don't have much experience with others, so cannot recommend them.

[RedBinary]

You have the whitest foot that I have ever seen.

[randofo]

It's almost as if I am wearing a white sock.

[RedBinary]

Inconceivable!

[danricramz]

only my comment for this project is only the capacitor uf. has indicated. but the voltage does not. so it can be over voltage the IC and it won"t work properly.. please reply me as soon as possible thanks.....

[charlez95]

can you send to me the full schematic ??
thanks in advance

[randofo]

See the links above for more information about the circuit.

Resistors are 1/4 watt. Capacitor voltage does not matter much... try 16v+

[charlez95]

how many volt does cap have ??
what watt is the resistor.

[Gizah]

What's the cap symbol with no indicated value after the 510k resistor? And where do you use that SPST you mention in the parts list?

[randofo]

5 - 10pF. You can probably even leave it out.

The SPST switch I was using as a power switch. You can probably use stereo jacks instead of mono such that when you plug in a mono guitar cable have the extra stereo connector complete the circuit by making the ground connection.

[nikolozj]

oh! I thought "better diagram" meant the one you drew but with better quality. I just wanted to have a better picture of your own diagram, even tho you said that it's almost entirely based on casper one, I still wanted to look into it with its all details. I can't recognize some parts of your version of diagram because of low quality of file, even if I save it on disk and then zoom it, then the quality gets worse and I can't see clearly for example cap marks or any other detail... I'm a beginner amateur electrician so I need to study diagram carefully to get it. please let me have your version of diagram with better quality and sorry for causing so much trouble!

[randofo]

Let me know if you still have questions.

http://www.instructables.com/files/orig/FCJ/EBN8/GA1BGINA/FCJEBN8GA1BGINA.jpg

[nikolozj]

could you please update "better diagram" link? thanks!

[randofo]

link updated. for redundancy:

http://cdn.makezine.com/make/blogs/blog.makezine.com/upload/2009/10/build_an_experimental_echo_pedal/Echobenderrev02.jpg

[nikolozj]

hi! good job. but I noticed in video that it has some "switch noise" when you switch it. is that avoidable?

[randofo]

If I was running the line out from the pedal into a recording unit, you wouldn't hear it.

I suppose you could try to find a quieter switch or crank up the volume of the amp.

[oweng4000]

Dear Mr. randofo,
Why is the bread boarded circuit so much more complicated than the normal circuit?

I don't see an arduino in the soldered version of this circuit, but for some reason it is connected to the breadboard. What is the arduino doing?

Thanks,
Owen

[randofo]

It is being powered by the 5v regulator for something else. You can ignore all of that.

[nitzbitz1]

Just wanted to point out that the parts list you supply says you need 2 .0082uF caps but you actually need 3. 1 off pin 6 of the TL072, and 2 for pins 9-12 of the PT2399. Just a quick edit if you have time to fix it.

[nitzbitz1]

whats the point of the second switch on the back that isnt wired to anything? (at least not in any pictures including the final ones...) and which pins on the dpdt switch hook up to where? i have never used one and it's the only part of the circuit diagram that i dont know how the pins relate to the physical switch. In the diagrams there are always 4 pins on one side and two on the other and i dont know how those relate to the 3 and 3 setup on the actual swtich. Any help or links are appreciated.

[randofo]

The extra switch was supposed to do something 'extra' but I decided not to include the feature and so it is just there for show and to fill the hole I had prematurely drilled.

Two of the adjacent outer pins of the stomp switch should be tied together for true bypass. The two middle adjacent pins are where you connect the audio wires from the jack. One should be input and one should be output. The other two adjacent pins should connect to the effect. The one in line with the input jack should be connected to the fx input and the one connected to the output jack should go to the fx output.


  STOMP SWITCH

          #--#
    in---#  #---out
fx in---#  #---fx out

[nitzbitz1]

Thanks a lot that's very helpful, and all around great instructions. lets hope i can get it to work once all my parts arrive!

[zer0_da_hero]

This may not be right on topic but... Can one use the TL072 low noise op amp as a stand alone signal booster?

[randofo]

Yes. Check out op amp based preamps.

http://www.google.com/search?q=tl072+preamp+schematic&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a

[zer0_da_hero]

brilliant, i know just what to do

[oweng4000]

I was looking at the parts list and thinking, "oh I can do this, this looks easy." then I got to the breadboard it page.....

[S POE]

Whould'nt happen to have a photo of the otherside of this board would you?

[2muchfreetime8]

do u hav a schematic like teh one here in that it shows the layout of the ICs (TL072 op amp), but much cleaner like the one in your link? thank you