Saturday, 30 December 2017

Earthquaker Disaster Transport Jr

Had a sleepless night, so I decided to knockout some new layouts before the end of the new year. This one kicked my ass a bit, but I got it as small as I could. a nice sounding delay, that's similar in architecture to the Deep Blue Delay. It's a nice sounding warm, natural delay.

From the source:

The Disaster Transport JR is an analog voiced digital delay with 625ms delay time with an all analog dry signal path and true bypass switching. It was designed as an anti-modern delay for those who appreciate a nice vintage tape echo with all it’s peculiarities. Its unique tone control doubles as a noise filter on longer delay settings and really helps the delay shine with a dirty signal. The mix control allows you to boost the effected signal to nearly 4x the original signal level and the repeats control goes from one signal repeat to near infinite repeats all the way through to self oscillation.

Controls
Mix: Sets the output level of the effected signal. This should be treated as a gain control/master volume for the delay line. Unity is around noon and everything above noon will boost the delayed signal louder than the original. This is a gain control so, like any pedal with a lot of gain, a hint of noise and distortion at max setting is completely normal.

Tone: Most delay pedals are heavily filtered at the output to remove the clock noise and other unwanted hash that is common from extending the range of the delay time beyond the limit of the circuitry. This usually leaves the delay sounding dark, muddy and disappear when hitting it with dirt. The Disaster Transport has done away with a lot of the heavy filtering and replaced it with a tone control which allows the user to choose their desired sound and results in more natural tape-like repeats. The tone control is at it’s darkest fully counter clockwise and brightens as you turn it clockwise. A good rule of thumb is to leave the tone control between off (fully counter clockwise) and noon at longer delay times. This will remove all the common noise from hyper-extending the circuit.

Time: From about 30ms fully counter clockwise to about 625ms fully clockwise.
Repeats: Sets the regeneration of the delay line. From one single repeat fully counter clockwise, subtle repeats around 9 O’clock, strong naturally decaying repeats at noon, near infinite repeats around 2 O’clock and full on self oscillation fully clock- wise.


Original:




Tails:

A version of this pedal was requested with tails, so I took a look at the Deep Blue Delay, which this is based off of, and made the same modifications.  To have tails, you don't use a 3PDT switch and the usual stomp switch wiring, you're going to use a DPDT switch  with the input and output wires going directly to the sockets.  With tails the stomp here will cut new signal going into the PT2399 and so when bypassed the output of the PT2399 will continue repeating with the last input it received and the repeats continue, and IC1 will then act as a buffered bypass.  You may want to to swap the 47K resistor at pin 7 of IC1 for a 50K trimmer so you can adjust the buffered bypass level so you can have to perfect unity with your bypassed signal.  Another alternative is that you can add a second stomp to true bypass the whole thing  which will give you the option to mechanically bypass the effect as usual, or simply bypass with tails when you want.



73 comments:

  1. Thank God for your sleepless nights! ;)

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    1. haha. yea, it's a blessing and a curse when it happens. i get a lot done, but then pass out for like 3-4 hours the next day as soon as i hit being up for 24 hours. i'm pretty confident it's good to go, but like i said it kicked my ass and took like 2hrs to get it where i was happy enough with it to post it.

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  2. Thanks for the layout. This is going to be great!

    As soon as my PT2399's come in, I'll get started on it. I ordered them a couple of weeks ago so they should be in, in maybe 2 weeks or so.

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  3. Just completed this build and it's only passing clean signal. Was hoping to have more time to troubleshoot and get it verified tonight, but it got too late. Looks like there is an issue at the Repeats 2 connection. It should be connected to the diodes and a 22k resistor, but there is a 100nF connection there. Hopefully I will have time to figure it out tomorrow. There is also only 29 cuts and it says 30, not sure if it's just a miscount or one is missing. Thanks for all the hard work Zach, it's a nice, compact layout.

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  4. which schematic did you use?

    i built it, dont think i made any errors. mine is also only passing clean signal. thanks for the layout!

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  5. Finished troubleshooting on paper, didn't have time to make the changes to my build tonight, but I think I got it with shifting a few parts around. The main things are that R12(47K at IC2 pin 15) on the PedalPCB schematic is missing and the 10uF above IC2 should go from pin 5 of IC1 to ground (right now its connected to ground on both ends).

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  6. I had the same result as Servant07. I am making the changes he suggested.

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  7. Got it working tonight. Unfortunately I had to add an extra column for the missing resistor at column 17. Here is a link to the new 23 column wide layout: https://www.dropbox.com/s/lgvctnhdtqyfmpw/DTJ.png?dl=0

    If you already have the 22 column board built, here is how to get it working, it isn't pretty, but it works: https://www.dropbox.com/s/wfjt75c1iiz6v6k/DTJ-Fix.png?dl=0

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    1. Cheers man. I'll update the layout and see if I can correct it without making it larger. If not I'll just add the column like you did.

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  8. Nice work man! How does it sound?

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  9. couldn't keep it 22 rows, so i added a column, kept the same placement as the modded layout from servant, but i added a link cause i hate standing resistors if it's not 100% necessary. should be good to go now.

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    1. The 47k resistor that was added is going to pin 16, it needs to be down a row to pin 15. Move the cut under the 10k at M13 over to the right 2 columns, then you can swap the 10k at the top of column 14 with 47k at column 17, then you can bring it down a row. It's like solving one of those puzzles where you slide the squares around lol.

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  10. Replies
    1. no the original didn't have tails. i'll look over what was done with the Deep Blue Delay, since the disaster transport is based off it, and see if i can do the same thing to this.

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  11. could some please link me to a schematic?? thanks heaps!

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  12. Hello,
    I'd really like to build this pedal with a Tap-Tempo mod. (i don't need the tails mod)
    Is it possible ?
    What's the simplest way to add it ?
    Many thanks in advance.

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    1. Read the deep blue delay thread!

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    2. do you mean this post ? http://tagboardeffects.blogspot.com/2012/03/pt2399-tap-tempo-daughterboard.html

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    3. Yes, that’s correct. Scroll down to where Mark suggest a kit which is supposedly great!



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  13. Maybe this is a very noob question, but what does polarity in C/21 (1uF) change?
    I was troubleshooting my build and apparently it didn't make any difference. Turns out I had input and output swapped.. -__-
    It's working following the layout, positive to C/21 but I would appreciate your opinion while I can still work the circuit.
    Thank you for the layout and all your comments and suggestions.

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    1. ps: Is it possible to add a Time led to blink with tempo? If so, how? Tried connecting Time pin 3 and later pin 1 to ground (through 5.1k rsistor and led) and it didn't work. :/

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    2. Never mind the time/tempo led. You need another circuit board to get it working, not fitting my 1590b enclosure.
      Any info on the C/21 (1uF) capacitor polarity?

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  14. Top job! Thanks very much Zach (and Servant07 for helping troubleshoot it)! Just boxed mine up and I think it's my new favourite PT2399 based delay. The tone control makes all the difference.

    Just to ask, is there any way to include a send and return (to add further effects to the repeats) or maybe even a kill dry switch? I've seen similarly modded builds of the Deep Blue delay and wondered whether anyone knew how to implement them to this layout.

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  15. Hello!
    Mine works (repeats: ok, time: ok, tone control: ok). The problem is that even if I apparently get correct voltages, the volume of the repeats is HORRIBLY low. Triple-checked the layout, re-did all the solder points. Maybe trying to switch to another value on components can help? Thanks

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  16. Got it working with the new layout! Only had 20 wide Vero left, so had to do some frankenstein stitching two pieces together. Really cool delay, definetly boxing it up soon/

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  17. Hi, I'm interested in making this pedal, but I'm unsure exactly which pins of the switch I need to connect to which parts of the board/LED for the tails addon? Can anyone help here? Maybe a diagram of the switch and say what pins are to be connected to what? Many thanks in advance

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    1. P.S. where did you get the schematic for this? Is it available anywhere? Would like to make a PCB and would rather not have to reverse engineer this veroboard!

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  18. Hi all. Any chance of a Diagram of the DPDT tails/trails wiring... Brain not functioning! Much appreciated!

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    1. Storyboardist has a PCB layout here:
      http://effectslayouts.blogspot.com.au/2018/01/earthquaker-devices-disaster-transport.html

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    2. Sorry. Reply meant for one two above.

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  19. Ugh built and not working, not passing any signal. Thought it may be the battery so I used an 22v power supply (only one I have) figure that's what the regulator is for anyway? But the transistor released smoke. Datasheet says max 30v so I figured that would safe with 22v



    any ideas?

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  20. Built this (the first layout) and it seems to work fine. However, I have questions for those who have built this before:

    It just does not seem to have some of the extremes noted in the blurb or in the video. For example, when you turn the tone knob all the way treble, it doesn't have any sort of hiss like in the video. I do hear it as more trebly than the bass side, but it's not a particularly big change. No hiss is good, but maybe it's a sign?

    The repeats knob all the way up does not start oscillation. It gives reasonable repeat amount (maybe 10-12 seconds), but it is not infinite like you can do with the PT2399. (The BYOC has a trimmer that allows you to set the range of the repeats knob and you can set that to oscillate.)

    Also, the mix knob, while it works fine, doesn't really ever seem to make the repeats appreciably louder than the dry. Maybe a little, but it's so little I can't be sure it's not just my imagination.

    Now, the fact is, I like it fine how it is, but does this sound like how it's supposed to be? (I never hear any indication that those shunting diodes are doing anything) Do others have the same result, or should I start hunting down a flaw somewhere in the PT2399 part of the circuit?

    Thanks

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    1. Hi there Andre,

      The repeats knob should start oscillation between 2 to 4 o'clock. At least mine does, but it depends on the other knobs values.

      Having the mix and the tone knob maxed should give some sort of distortion on the repeats. I don't get any hiss with the tone all way up, but I can hear some fainth distortion on repeats.

      Your build doesn't seem to work like it's supposed to. I'm no expert so I cannot give much help.

      In my next build of this circuit I'll try to invert C/21 (1uF) polarity to negative and replace K17 (100uF) with a 200uF capacitor.

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    2. Thanks, Phobick. I ended up swapping out the 22K just to the right of the diodes, for a 50K trimmer. I found that lowering it a bit from the required 22K (a guess would be maybe 2-5K at most) put the pedal able to reach oscillation. I set it so that at maximum is has the never ending repeats. It otherwise works as it should at less than maximum.

      I noticed when setting it that if I went a little lower than that, the oscillations became a bit more intense. It is my understanding looking at the schematic I drew out that these diodes then serve to keep the oscillations for getting louder and louder. They sort of keep things contained, and by their nature, add some distortion. I backed off from that full setting, and have it where I want it now, but I know it's there and might put it back that way to mess with it a bit.

      Anyway, I think this thing is probably working fine. It sounds just like my other PT2399 delay. I was just wondering about the oscillations, which a trim pot fixes.

      I suspect (as ALL PT2399 circuits seem suspect) that there is enough variation in these chips so that stock values don't work the same for all chips. Maybe even cap variance is enough. At any rate, a trim pot does the trick.

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  21. Hi, I was wondering if anyone could help me with the stomp wiring for the tails mod. When it says in the diagram stomp 1 and stomp 2, what do these pins refer to? Is it numbered like this ( http://www.learningaboutelectronics.com/images/DPDT-toggle-switch-diagram.png ) or like this ( http://www.diystompboxes.com/pedals/DPDT.gif )?

    It would be really really useful to have some kind of diagram with the tails mod and true bypass. I know the deep blue delay mod has a diagram but it has a whole extra board with a FET on it, do we need this for this EQD pedal too? Thanks in advnace

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  22. Which resistor controls the volume level of the repeats heading into the mix knob? I have little to no more than 1:1 mix when maxed, which is actually fine, but I would like to be able to raise it a bit on the wet side.

    I tried putting a trimmer on that 20K in the lower right, but it didn't seem to have an effect, surprisingly. I also tried changing the 220K from mix 3 to ground, also no effect. Maybe the increase in volume is absorbed elsewhere or something. Any ideas?

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    1. OK, to answer my own question and for those that follow, it seems that the resistor off pin 14 of the PT2399 has affect on delay volume. Which makes sense. It is the 22K that you'll find coming off that pin just right of the chip.

      Put a trimmer in that place, as well as in place of the 22K closest to the diodes. This resistor controls feedback range.

      You will find these two resistors to be somewhat interactive. You can raise the volume of the delay a bit, but then you have to back off the feedback a bit. With some adjustment, you can get it to barely start feeding back just past 3 o'clock on the repeats pot, then go into full oscillation all the way up.

      getting this adjustment right also made my tone knob more as expected.

      I suspect, based on other experiences with this chip (PT2399) that there is a certain amount of variance between each one and that you will not necessarily get what you expect making this circuit stock. You may need to tweak it, as I did, to get it like expected. The two named resistors seem to be most key.

      FYI

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    2. So to clarify a little better (I realized I left out details):

      Pins 14 and 15 are two op amp outputs from the 2399. Just like any opamp, there are feedback resistors controlling gain. In this case they are the 22Kjust to the right of the chip, and the 47K four spaces right of that that extends way up to the top row. If you increase these resistors, you get less negative feedback into the 2399 and the gain goes up. If you decrease them, the gain goes down (coming out of 14 & 15). Use these resistors to control the overall gain of the delay that you mix back into the dry. If you want it to be 1:1 with the mix pot at 12:00, then set up these resistors accordingly. I used some trim pots.

      The wrinkle here is that there is something that is interactive: The feedback for repeats. The repeats pot has a hand in this, but what you really need to adjust is the 22k coming off lug 2 of that pot. This controls the repeats feedback. lower that resistor and you will get oscillation earlier in the repeats pot. My preference is to have it start its oscillation somewhere around 4:00 on the repeats pot.

      So to get it right, you need to balance the gain of the two internal opamps coming out at pins 14 & 15 of the PT2399 so that you get the gain you want to see on the mix knob, then you need to adjust the repeats feedback to have the oscillation start where you want it.

      I suppose, if you give too much gain to the PT2399, you could see some distortion, so keep an ear for that.

      In my case, I mostly had to raise the gain of 14 & 15 to get it all correct.

      Hope this explains this chip a bit for someone who follows.

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  23. Hi Zach!!

    Build it and love it... thank you so much for a great layout.

    Any chance you'll have another sleepless night in the near future to maybe check out how the "Disaster Transport"'s modulation works and fits into this? :-)
    (not talking about the Sr.)

    Keep up the amazing work.

    FZ

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  24. Hi!
    Tried this One, It works really fine exept that the repetitions sound super distorded. The only things i've changed are the 1M resistor with a 1,2M and the 1n5817 with a 1n5819(because i've fnished the right ones). What i've done wrong?

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    1. See my post just above about the two resistors off pins 14 & 15. You probably need to lower the value values a bit, which will decrease the gain the the 2399. After that you may need to increase the feedback a bit to compensate.

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  25. So I've built this one and everything works just except that I only get one repeat and the repeat knob doesn't seem to work. Any suggestions?

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    1. Sounds like the issue is in the feedback loop. Look at everything in the path between pins 14-16. If you ground out the feedback signal, but not the output of the delay, you'd get that result. I'd start there.

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    2. I had a similar issue with another PT2399 delay pedal today. Check the repeat knob resistance with a meter. Check resistance on leg 1 - 2 and leg 2 - 3 and leg 1 - 3. The resistance should vary between 1 - 2 and 2 - 3, depending on the position of the knob and you should get maximum resistance between 1 - 3.

      On my problem circuit a capacitor was defective and had shorted at 1 ohm. It kept my repeats at 1.

      In this circuit leg 1 should be grounded but legs 2 and 3 should be several kohm above ground.

      Give that a try.

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  26. the layout has been updated. it's been brought to my attention that the output cap was backwards. if you've been having some issues see if flipping it to may the layout as it is now fixes it.

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    1. Thanks for the layout Zach. I'm wondering what the circle on the layout with "IGO" label left of D1 stand for?
      Thank you!

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    2. its the voltage regulator

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    3. I see, that makes sense. Thank you!

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  30. That's the 78L05 voltage regulator, input, ground output from top to bottom. Feeds the PT2399 the required 5v.

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  31. Hi all,

    Has anyone built this with the March updated layout? I’ve just put one together and I’m getting no delay signal, but clean guitar tone through from I’m assuming the op amp. PT2399 voltages look a bit weird too, the pins at the end that should all be 2.5v are around 4.8.

    I’ve checked the layout through and it seems fine, if someone can verify the newest layout then I’ll go back to the drawing board!

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    1. All of the signal runs through that output cap, so if you are only getting one side, the problem is not that cap, it's elsewhere. I find that these kinds of missing wet signal problems are almost always inadvertently grounding the wet signal. Look for solder bridges. YMMV.

      On the subject of the reversed cap, most of us that have built this have the cap the old "wrong way". It doesn't seem to really matter. Pedal still works. Is this a problem waiting to happen, or not an issue?

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    2. Thanks for the input!

      Yeah, after spending some time with the schematic the dry signal section seems fine. I've audio probed it outand the wet side leaves the TL072 and makes it to the input of the PT2399 (pin 15?) or at least it makes it to the socket of the chip. If I then socket the chip again I can't pick the signal up from the leg of the chip which is weird.

      If I can't sort it out then I'll build another board, sometimes that helps, but it's quite frustrating. I've reflowed all my solder and knifed my tracks three times over now and triple checked the layout, so while something is going on I don't know enough to properly fix it.

      Again, thanks for the help!

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    3. start measuring points to ground. This is a known good layout, so there are very few possible reasons when it doesn't work. For me, shorts to ground are the usual culprit.

      Did you find an actual schematic for this? I had to make a half-assed one from the layout, a real one would be nice.

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    4. I did yes, over on the free stompboxes forum, though I had to sign up for it. I'm not sure if the schematic is based off of a layout or a trace, but theres also a picture of the production board in the post so I'm hoping its from a trace.

      I'll keep working on it later and if I find the problem I'll update the post, it might help someone in the future :)

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    5. OK so I built a new board and it fired up and worked first time, no issues at all. Didn't have to knife tracks, reflow anything, rewire anything. Not sure whats wrong with the first one still. Possibly a dead component but I just don't have the understanding in electronics to troubleshoot it properly.

      I can follow a layout and have built loads of stuff but still find it tricky to learn whats going on under the hood. One day maybe!

      Again, thanks. For anyone else wondering, the updated March layout above is definitely verified.

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    6. Ahhh, thanks, Colin. I missed that.

      Well based on the schematic for the DTJr/Catalyst, (and referring to my earlier post) R14 can be swapped for a trimmer to set the point of oscillation, lower R = sooner oscillation. Set to taste.

      R12 & R18 set the gain of the PT2399's op-amps. Higher R = higher gain = a higher amount of delay volume available with the Mix pot. Set to taste.

      I have these as trimmers in my working pedal, but one could as easily use a trimmer(s) to find correct values and replace with solid resistors.

      I'm not sure why mine did not work as intended with the stock values, maybe there is a mistake somewhere causing me to have to compensate, but it works fine having done so.

      Glad your second one works well.

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    7. One question - if R12 and R18 both set the gain of the PT2399's op-amps, do they need need to be set to the same value if using trimmers or new resistors?

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  32. Just built this as per the latest layout without tails. Worked perfectly first time. The tone control works well. I don't really use much delay, if at all. Still, great sounding and easy to use. Nice layout Zach, thanks heaps.

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  33. stupid question, but Can I sub the 1N4148 With a 1N4001? I keep forgetting to add items to my cart here and there and don't want to pay for shipping for the 5th time this month haha.

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  34. Can I use a a 78m05 instead of the classical 78l05?

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  35. great delay! Thanks Zach! Built this one and it seems to function properly but the volume is very low. Any idea what could cause this? I've swapped out the ICs, checked/rechecked values, re-flowed solder joints, etc. I'm stumped. Any one else have this problem?

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  36. Meh... trashed it and built a Deep Blue Delay. Worked first try. Sounds awesome. Good thing these parts are cheap :).

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  37. Hello.
    May I use 1n4001 (1n4007) isntead of 1n5817 ?

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