dd-3 "analog"mod

[delbowski]

hi, i'm pretty new here and found some info through the search function that led me to some mods on dd-3s that would cut out some highs on each successive repeat for a more "analog" feel.  i've read one post that said to put a .047 cap across the outside lugs of the feedback pot and a .057 across the level pot.  another post mentioned something about putting a .47 across the feedback.  another post said that i need to wire in the cap in the feedback section of the circuit instead of at the pots.  i've tried putting the .047 and .057 across the two pots, but the difference hasn't been too noticeable to me at all.  it cuts the amount of repeats as it logically should, but i'm not hearing much of a difference in the sound.  is there any advice on this?  my cap is labelled 473, which would be 47,000pf, which would be .047mf right (just to make sure i'm not messing that up)?  any help would be greatly appreciated.  thanks.

[tommy.genes]

I ended up using a 0.1 uF across the feedback pot only. I tried 0.22 uF as well and liked the sound, but there were just too few repeats. 1 uF barely even got one repeat.

Another cool mod is a feedback loop. Locate the wire that goes from the wiper of the feedback pot back to the main board. Send it through a normally-closed TRS jack that you put in place of the dry out jack. With nothing plugged into the feedback loop, the pedal works as normal. But when you plug a stereo "Y" cable in, you can add effects in the feedback loop so that each repeat gets more effect. Cool for dub-style.

I mention this because you could go ahead and install a beefy cap across the feedback pot, and then put something like a booster or overdrive in the feedback loop to "goose" the signal and still get a lot of repeats.

-- T. G. --

[delbowski]

thanks...

i'm sorry for the "noobness", but is a normally closed trs jack a stereo jack?  is it the kind of stereo jack i'd get from small bear for my input jack or is it something else all together?  also, what lug of the jack would the wiper lead go to and what lug would the boards lead go to?  this would be an awesome thing to have in this pedal, i really appreciate the help!

[Peter Snowberg]

TRS = Tip, Ring, Sleeve, a.k.a. a stereo jack. 

This is the same style you would use for an input jack, but you want to make sure it's one that has switch contacts in addition to being stereo. They're a little less common, in fact Small Bear doesn't seem to have a suitable part in stock list. Luckily, the "marshall" type Aron sells is perfect. Four for $2.40.

  <-- Click on the image to open up a store window

These jacks have six terminals. Three are the normal tip, ring, and sleeve connections. The remaining three are switched contacts that are connected to the other pins when a jack is not inserted.

Jumper from the wiper to the tip connection to make the send, because it doesn't get shorted to ground if you plug a mono plug in. The tip connection should also have a jumper to the switched ring connection. The normal ring connection then goes to the wire that was originally connected to the wiper. This is your return. The sleeve gets connected to ground.

You can have all kinds of fun with an insert in the feedback path. You may even want to skip adding the cap internally and instead add it to a TRS plug. You could also build a boost into a plug with the cap.

Try using a graphic EQ in the feedback path if you want serious shaping. 

[delbowski]

thanks a lot!  makes sense to me... can't wait to try it out!  i appreciate the help very much

[tommy.genes]

I see Peter gave you a very thorough reply before I got back to read your question.

The jack I used only had a normally closed connection on the tip, so I had to use the ring as send and the tip as return, with a jumper between the ring and the N/C tip connection. As long as I don't mistakenly plug in a mono cable, this arrangement works fine.

I mainly mention this in case you happen to find a jack like mine locally. Otherwise, I whole-heartedly endorse doing business with Aron.

-- T. G. --

[delbowski]

help!!

i did what i thought was the mod but things went bad quick!  QUESTION: i swapped out the direct out jack for an nc trs.  i followed the directions above, or at least i think i did.  the black wire from the switch was connected to the ground of the direct out jack, so i put that to the sleeve lug of the trs.  what do i do with the leads that were connected to the direct jack's other lugs and go to the board?  leave them disconnected?  the led isn't lighting up and i'm getting no change when i switch it on and off.  no signal is getting through at all.  all that happens is a LOUD buzz.  ANY HELP would be greatly appreciated.  i know i'm a noob, so please forgive a beginner... thanks!

[delbowski]

ok... i fixed the buzz problem, it was a ground issue elsewhere.  i can't seem to get the "effects loop" mod working though.  when i engage an effect in the loop it freaks out and makes noise and only repeats once; it doesn't do what it should.  also i can't get the delay pedal to turn on of off with the switch (which is good if you like delay ).  any help please?  thanks in advance...

del

[delbowski]

i guess the good Lord decided to have mercy on me cause everything is working great now.  i should be grounded for my grounding problems!   the effect and mod work wonderfully... if you haven't tried this mod i highly recommend it.  thanks to all who helped out!  i really appreciate it...

del

[Jurbo]

Hi!

My first post here... I just happened to stumble upon Analogman's mod site, and ended up here for the DIY variety of the same thing.

I did the hi-cut mod to my Japanese DD-3 (the one with the huge chip, version 1 or something). I soldered a switchable 0,47 uF cap between node 12 and GND, so the cap connects to Level and Feedback (and ground, ofcourse) simultaneously. I tried different caps between 0,1 uF (which didn't really do much) and 0,68 uF (which was cutting a bit too much for my taste). 0,33 and 0,47 seemed both very usable. I also tried trimmer pots to soften the impact of the cap, but couldn't really find anything worthwhile with them (started with a 1M trimmer, went down to a 1K eventually).

Anyways, I strongly recommend this mod, as now my DD-3 has two different, usable sounds (would have made that three but I didn't have the On-Off-On switch)! 

[Dooter]

Today my on-off-on switches arrived so I tried the mod.

I used .15uF on both the effect level and feedback pots. This worked nicely because one side of the switch applies the cap over the effect level which gets the subtle once only degradation, then the middle position is no caps then third position applies the cap over the feedback pot to give cascading degradation. The final effect feels like two different levels of darkness.

Works fine. Only issue I had was drilling the hole too close to the LED mount, so I had to grind a semicircular channel all down one side of my switch so It married with the screw post of the LED assembly. I also had to grind the LED assembly board to fit too. Also as I used chunky foil caps I had to hide one using extension wires on the other side of the LED assembly. All good fun.

[minimongo]

Im very new to forums and DIYing effects.
Could someone please, in the simplest way possible, walk me through what is needed to get this right?
Ive done what I thought was correct and the pedal wont even turn on...

[Hatredman]

Did it all went well in the end, minimongo?