Saturday, 25 February 2012

Crap-Fi Delay

I thought the delay freaks may like this interesting alternative to the pristine digital delays that you see all the time.  This was put together by allesz at freestompboxes, and below is his description of the circuit:

"It is the results of my experiments with the ultra famous pt2399 chip.

It is a simple circuit and it works good but: the mix and repeats pot are a little interactive in quite a strange way (anyway they work different from a standard echo: to turn off the delay you don'use the mix pot, but you turn to zero the feedback pot) and the on off is a little bit noisy (the clip is recorded at low volume and you will hear kids (always noisy) and clicks so, mostly, the clicks are from the mechanical sound of the switch, but a little noise makes it to the amp too) in order to minimize the clicks the input is grounded on bypass.

The major differences between my schem and the others pt2399 projects I know are that I didn't use the opamp between pins 14 and 13 and I didn't put a cap between pin 2 and three (repeats sounded cleaner to me this way).

I put a small switch to select between long and short delay; the long delays are quite dirty

Anyway this is a dirty cheap crappy fi delay, so if you mind noise and fidelity look elsewhere; I know it can be perfected but for me it is good as it is."

Allesz clip can be heard here.  To wire the switch so the input is grounded during bypass, use the method shown in my offboard wiring post.


Geiri's demo of his build:

85 comments:

  1. You can call this one verified, if it wasn't already.

    It's really noisy and absolutely so lo-fi that i would say this one is a must have toy.

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    Replies
    1. Excellent, thanks for that mirosol!

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  2. Thanks a lot for this layout, it is really a wonderful delay! I'm very glad i've builded this one.

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  3. Hello, can you please tell me what do i connect the repeat 2 lug to? thanks.

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    1. You should see 'Mix 1 & Repeat 2' at the bottom right of the board, so just take it to Mix 1, or take it to the next hole to the left on the bottom row of the vero if you prefer not to have 2 wires going to the same pot lug.

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  4. I have a very strange problem with this pedal. It only works in a chain with other pedal and if I use a daisy chain power supply. The effect doesn't work on his own. I've already tried different adaptors, but that really doesn't seem to be the problem... Any ideas on this?

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    1. You could check the regulator first. 78L05 is rated at 100mA, and there's nothing to protect that from higher amps. I've seen pretty strange behaviour from burned regulators.

      Does it work with a battery?
      +m

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    2. ...considering that PT2399 would somehow drag more that 100mA.

      Short is easy way to burn regulators.. I guess that it's even easier than burning them with higher voltages.
      +m

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    3. Yes a very strange problem. Measure the voltages at the IC and regulator pins with the daisy chain and then on it's own, to see what differences there are.

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    4. Very very strange... When the pedal is daisy chained, the output of the 78l05 gives me 4,98V; which is perfect. But when the pedal isn't daisy chained, the output of the 78l05 gives me 8,10V! I don't understand how a 5v regulater can emit 8,10V...

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    5. How have you got your offboard wiring? I'm just wondering whether you have a ground point isolated from the rest which is only being satisfied through another pedal via the daisy chain. Just check for continuity between every point of ground and reflow if any of the connections look suspect.

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    6. Yes thanks that was the problem. I had the neg power lug connected to a wrong lug on a jack.. Problem solved and another pedal working perfectly!

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    7. I was having the same crazy problem with the daisy chain working and the straight 9v adapter not working. I resoldered (is that a word?) all of my ground connections and now its working great. It sounds dirty, spacey, and awesome. With the feedback set to full it can make some very cool experimentalish drone/noise/doom sounds.You the man IvIark (and allesz!).

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    8. Was wondering how critical the 470K-pot is... Kan I substitute it for a 500K?

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    9. It is crucial. I used 500K for mine, and the last 30K just drains all of the delay, so it's really a no-go. I had to swap it for 470K. Some firm in UK sells them for relatively cheap prices.. http://www.ecomponentsuk.co.uk/proddetail.php?prod=53-0010

      If you have 250K pot, then you could use that and add 220K resistor in series with either lug 2 or 3. That will severely impair your control, but it's still better than losing the effect altogether after last 10% of the sweep.
      +m

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    10. OK, tnx! I've immediately ordered a 470K-pot...
      Cheers!

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  5. http://a6.sphotos.ak.fbcdn.net/hphotos-ak-snc7/s320x320/301778_324139410999111_100002091650466_719618_820566351_n.jpg

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  6. I notised that when you turn the repeat knob almost fully open, that when you play a sound it will keep repeating it. When you turn the pot to far, it will just become a dirty noise, but at one point it keeps repeating fairly clear the sound you played. Now I want to measure the value of the pot at that point, and swith it with a fixed resistor to get some kind of repeater pedal. Now my question: I want a pushbutton that turns the effect on, and a pushbutton that bypasses the effect when you push it so that you can play something else besides the repeating sound. Would it be possible to do something like that and how should i wire it all up?

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  7. I don't get it... I've built 2 and they both don't work. I don't hear any delay, just my guitarsignal with a lot of hum. And the brand new 470K-pots sound scratchy. Obviously I've done something wrong twice, but I've checked and double checked the board. Could it be that the batch of cheap Chinese PT2399's are doing me in?

    I'm a solder-by-numbers type of guy, so my knowledge is limited. But I've built quite a lot of stuff before that works well.

    Any help would be nice, tnx.

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    Replies
    1. Well we know the layout works so that only leaves either build error or faulty components. Do you have any other delay pedal build that you could test the PT2399s in? There has been lots of people who have had problems with that IC so that is where I'd put my money. But also check you're getting 5V on pin 1, the regulator is another component known to cause issues.

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    2. 5V at pin 1 is fine. So that leaves the PT2399 or me doing the same thing wrong twice in te build. I haven't built another delaypedal yes, but was planning on making the DBD. Now I have more then one reason for doing so... :-)
      Will keep you posted; tnx for your help!

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  8. Hello, thanks again for all your great posts and vero projects. After troubleshooting my build of this for a long time i finally realized my pot wiring was completely wrong. I had the spdt switch wired to the repeat knob. Made the changes and now it works great, and sounds great too. I think if possible a diagram of the off-board wiring may help people in the future that are having trouble with this build.

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  9. hey all, i'm getting some crazy pt2399 problems
    sometimes the effect works (and works great!) but most of the time im getting crazy pitch bending delays. if i jiggle and push and prod the IC sometimes the effect will start to work but most of the time the effects get crazier.. or sometimes no voltage will appear at pin 1.
    could this be a regulator problem, IC holder problem, dodgy pt2399's or something different?
    also the IC does some crazy sounds when powered on and off

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  10. So, going on what mirisol said, would using just a 250k rather than the 470k just give me less delay time, but no wonkiness on the control?

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  11. Sorry, less repeats, like, would I lose self oscillation?

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    Replies
    1. You'd probably get less repeats and shorter control, but less wonkiness..
      +m

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  12. I'll mess with it and report back lol. Thanks mirosol :)

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  13. the 250 is producing REALLY distorted single repeats, I've check the board and everything looks fine there

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  14. I'm getting 5v at pin 1 so I'm assuming it's the knob

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  15. And even with a different pot, a 1m that i ran a resistor in series with to get 420k sounds the same. What in the world is going on?

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    Replies
    1. I ended up scrapping mine some time ago, as i didn't find this circuit reliable enough. If you have more of the chips, you could try swapping it. And i had same experiences with Verben too...

      Personally i'm going for deep blue delay as the next delay experiment.
      +m

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  16. just finished this build and am having some strange issues. the dry signal (effect off) is fine. turned on and with a signal applied i get a the dry signal and then all of the delayed repeats are really distorted. i've doubled checked all connections and i've tried it with 2 different 2399s. does this sound like a familiar problem? wondering if i did something obvious i'm overlooking since it looks like others got there's working

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  17. Wow, this thing does sound like crap. Haha, it's a pretty neat noise maker though. Although, no oscillation :(

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  18. Just finished up my build. Sounds pretty awesome.

    https://soundcloud.com/#ejendres/lofi-delay

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    Replies
    1. Excellent thanks for the clip Eli. You need to take the # out of the address for anyone wanting to listen.

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  19. ahhhhh jesus man...I can not make it work!
    help me....already rode two boards and it did not work.

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    Replies
    1. This puppy is *very* sensitive. I've built one, but scrapped it later as it just felt unstable in the long run. If you have subbed some component values, that could explain your behaviour. Other chance is that your particular PT2399 just won't work right. This is pretty common with designs that take the chip's performance to (and over) the limit. Have you tried swapping the chip? Do you get any signal through it? Voltages on IC pins? Is your regulator ok? Those 78L05s tend to burn very easily if there's even a slightest short after the regulator. Does probing the signal path reveal anything?

      For the parts you have, i would recommend Deep Blue or Rebote. Those are within safe limits of PT2399 capabilities, thus making every single chip work correctly. Plus reading the comments carefully, you could mod the Deep Blue to have very long delay times.
      +m

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  20. single modification was the POT 470k for 500k ...tried two PT2399 an 2 78L05.....
    the 78L05 may be a small? or giant regulator?

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    Replies
    1. What voltages are you getting at all the IC pins?

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  21. Hi,

    Is there a reason why some of the 100n's are red and the others not?

    Thanks!

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    Replies
    1. Yes the red ones match the Panasonic poly caps I use, but they can't be neatly used with a 2.5mm pitch so I used a ceramic symbol there as I would probably use a multilayer ceramic there. In all these layouts, the value is more important that the colours which are purely representative of what I expect I would use when building it. Any cap will work.

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    2. Thank you so much Ivlark! Can't wait to test this out!

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  22. Hi guys, I've had a few problems.

    I've tried 2x 78L05 and 4x PT2399 - I am getting sound but no delay.

    When I turned the mix knob, it acts like a volume, and the repeat knob is almost working like a tone.

    All pins on IC are getting power.

    Any Ideas guys?

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    Replies
    1. If you post all the IC and regulator voltages that may give us a clue as to the problem area

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    2. I = 0v?
      G = 8v
      0 = 7v

      IC is getting about 7-8v on each. This is my first build with an IC.

      Any help would be appreciated

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    3. You've got something physically wrong with your build somewhere. I is the supply and should be around 9V (depending on whether you're using a power supply or battery), G is ground and should be zero volts. O is the output which should be 5V. You're going to have to check through what you've done but it looks like you've swapped the 9V and ground wires to the board.

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    4. Ive checked the 9V and ground, both are correct (i even tried swapping and lost signal and had only hum)

      I've checked everything else except the sPDT switch, if this was faulty, could this cause the power issue?

      Thanks

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    5. If the regulator voltages you posted are correct, then they must be reversed. Are you sure you haven't plugged a centre positive power supply in? If you're getting 8V on the G pin then that rail is supposed to be ground and so zero volts. You're definitely not going to get any (correct) sound out of it unless you're getting close to 9V on I, zero volts on G, and 5V on O.

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    6. When I swapped the 9V and ground the regulator got hot.

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    7. What did you measure the voltages against? The pin and what?

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  23. The pin and from 9v in, is that correct?

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    Replies
    1. Aah, you need to measure between the pin and ground

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    2. DOH! Sorry, I have measured from the ground and I am now getting
      I - 9
      G - 0
      O - 1.5



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  24. Hi there.Is ok if for 100uF caps I use this type? http://www.dongfangic.com/UploadFiles/22/b666ea450cbf71aa702bc2268a0611d2.jpg

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  25. If anyone is having trouble getting the 470k pot, just take a 500k and put a 6.8M resistor on lugs 1 and 3. This will give you roughly 465-66k.

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  26. Pessoal não consigo entender onde coloco o Potenciômetro ; TIME !? alguém pode ajudar /?

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  27. Time 1 and 2 connects to lug 2 of the toggle switch
    Time 3 connects to ground

    Look at the schematic here:
    http://freestompboxes.org/viewtopic.php?f=88&t=15274&p=173244#p173244

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  28. Is the SPDT switch MTS-102 (ON - ON) or the MTS103 (ON - OFF - ON) ?

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    Replies
    1. Thank you very much. I bought all the components, now I will try to build it!
      How could I make the "cuts" in the board ? With a Knife, for example??

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    2. Use a large drill it and twist it in the hole till the copper track is completely separated. Check the build section below to help guide you on your build. I assume this is your first, and it would be a good idea to read this first before trying to build anything.

      http://tagboardeffects.blogspot.com/2012/04/vero-build-guide.html

      Delete
  29. This comment has been removed by the author.

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    Replies
    1. The output pin of the regulator and pin 1 of the IC are on the same row so you can't be getting 1.68V on one and 4.48V on the other. You need to double check those voltages to see which is right.

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  30. Sorry, I wrote wrong here in the computer.

    The correct order is:

    1 = 4.98 V
    2 = 3.66 V
    3 = 0.07 V
    4 = 0.09 V
    5 = 0.57 V
    6 = 0.53 V
    7 = 3.20 V
    8 = 1.68 V
    9 = 3.69 V
    10 = 3.22 V
    11 = 1.05 V
    12 = 2.39 V
    13 = 2.75 V
    14 = 2.67 V
    15 = 3.46 V
    16 = 3.47 V

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    1. You're getting 0.07V and 0.09V on pins 3 and 4 which should both be connected to ground via solid links, and so should both be measuring 0V. Check the soldering for the 3 ground links (2 under the IC, 1 to the left of the IC). If the placement is correct and soldering is good you should be getting 0V on those 2 pins.

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    2. I tried to turn on the pedal onde more time until change the solid links, then I could notice that the potentiometer of 470K begin to burn !!! A great flame was created inside it. Now I don't have more hope to build it ... I could change it but I don´t know if all the circuit are good.

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    3. Well ... I changed the potentiometer 470K for one with 500K, because I did not have other equal to the 470K. So, I measured the IC voltages and they are equal to the last post that I made.

      I would like to know if my wiring is correct. First, I am using the scheme from Beavis Audio's to include a battery.

      Some pictures from the pedal:

      http://migre.me/lTcbn - Here it was pluged the Time 1 & 2 to Sw2 and Time 3 to Ground (Is that ok ?)

      http://migre.me/lTcp7

      http://migre.me/lTcs7 - The soldering

      http://migre.me/lTcvr - upper view of the circuit

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    4. it's all wrong. you mirrored everything when you shouldn't
      read this first and you'll understand your mistake
      http://tagboardeffects.blogspot.gr/2012/04/vero-build-guide.html
      don't try anything one that board to avoid burning more things...!!!
      hope i helped!

      ξεναγος νεκρόπολης

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    5. I remake all the circuit using another board. So here we go:

      Some pictures:

      http://migre.me/lTDRn

      http://migre.me/lTDTT - About this picture, I would like to know if the sequence of the wire are: Black in the pot 3 to the ground of the board; Pot 1 (green) and Pot 2 (purple) to the Sw2 ?

      http://migre.me/lTEt4 -

      I pluged all the components. but it still does not work ! I used the wiring from this site.

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    6. hello e.gonn!
      your board now seems really good. your switch wiring is ok but you could just take one wire from pot's lugs 1 or 2 and with a jumper like the ones you made the links on veroboard connect those lugs together on the pot. less wire more space!

      now for the working part.
      we must know all your voltages from all ic's pins and the regulator's too.
      there is a pretty big chance that you have burned out both regulator and pt2399 at you previous attempt. we must also know if you tried your second board with new components(ic and regulator). it will be much easier for people to help if the know that components are not faulty as far as you can know.
      so...post your voltages to see if something's wrong there.
      and finally. we could use some photos from the back side too.

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    7. This comment has been removed by the author.

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    8. I have new data to show you:

      the IC voltages:

      1 = 4.99V
      2 = 2.40 V
      3 = 0
      4 = 0
      5 = 4.97 V
      6 = 4.81 V
      7 = 0.70 V
      8 = 0.52 V

      9 = 2.50 V
      10 = 2.49 V
      11 = 2.49 V
      12 = 2.45 V
      13 = 2.36 V
      14 = 3.43 V
      15 = 2.50 V
      16 = 0.04 V


      I changed the pt2399 and the 78l05 for a new.

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    9. I have new data to show you:

      the IC voltages:

      1 = 4.99V
      2 = 2.40 V
      3 = 0
      4 = 0
      5 = 4.97 V
      6 = 4.81 V
      7 = 0.70 V
      8 = 0.52 V

      9 = 2.50 V
      10 = 2.49 V
      11 = 2.49 V
      12 = 2.45 V
      13 = 2.36 V
      14 = 3.43 V
      15 = 2.50 V
      16 = 0.04 V


      I changed the pt2399 and the 78l05 for a new.

      Delete
  31. everything seems ok again, except pin 16 is too low.it should be also around 2,5v. so look for bringes around there, cause it's next to ground row...

    ξεναγος νεκροπολης

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  32. I gave up! I will try to build another delay with the parts of the Crap-Fi . Any suggestion?

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    Replies
    1. check out the mad professor deep blue delay. it's a more reliable circuit, and i think a lot of the parts should transfer over.

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    2. ahh...sorry i couldn't help you anyway...what happened with that one?
      yes.i agree too that deep blue delay is really cool and reliable. and it was my first pt 2399 build.
      you could also try Madbean Cave Dweller, which is really good small delay. i build it too, and it worked at once.

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    3. Thank you very much for helping me with the construction of this circuit.
      So in this case I don't know more what to do, and I think I will losethe board strip and some components if I continue to work it.

      So, about the other delay circuit, I saw the Rebot 2.5v in the Tonepad website and I think I will try this one, or the deep blue from the Tagboard.


      Delete
  33. I used LM7805 instead of the 78L05.

    The difference between the two components regulator voltagem is: LM7805 has Iout = 5mA to 1 A while 78L05 has Io = 1 mA to 40 mA.

    Is there any problem to this circuit ?

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  34. Hy my problem is too muddy and too quiett sound. Repeat is 500k pot. Please help. thx :)

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  35. Hey guys. I've just built this, loving the sound. Only thing, though, all the pots are indicated in reverse. I had to switch all lug 3's to lug 1, and vice versa, to get this to perform properly. Otherwise, awesome job! Thanks!

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  36. Hey guys, got this bad boy working and it sounds great.

    But, theres is an evil switch popping and in corporation with a delay its sounds awful.
    I tried every kind of pull down resisting, 1M between Input and Ground onboard, 1M between input and ground on the switch. It still pops very loud.

    Any ideas anyone?

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  37. I Have a strange problem with this one...

    Works perfect and sounds great, however it keeps killing my PT2399s.
    If i pluck too hard it starts squealing and self oscillating, if i then disconnect the power to stop it, it kills the PT2399. If i chuck in a new PT2399 it works perfect until the problem occurs again.

    Anyone have any ideas how i can stop this?

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