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.




28 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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    2. This comment has been removed by the author.

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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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    Replies
    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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  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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  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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