RDH Electronics - Dub delay box

[ponce]

Does anyone have the schematic of this cool delay? Do you think it's PT2399 based?

https://m.youtube.com/watch?v=HYkW7c4pnXA

https://www.google.hr/search?client=ms-unknown&biw=360&bih=310&tbm=isch&sa=1&ei=H03fW-nsFIiYkwWPm6GABw&ins=false&q=rdh+dub+delay+kit&oq=rdh+dub+delay+kit&gs_l=mobile-gws-wiz-img.3...10808.11866..12297...0.0..0.129.461.0j4......0....1.........30i10.VjqGP72tegU#imgrc=C5P3KESBjjw3BM:

[ElectricDruid]

No, I don't have the schematics, and I think it's a 50/50 chance of it being PT2399-based. The other 50% is FV-1 with a variable clock rate.

TBH, that's probably still 75/25, even with the two options. Yes, probably PT2399.

[Mark Hammer]

The demo for their delay kit shows a 14 or 16pin DIP.  The basic delay video was posted mid-Sept, 2013, and the "Dub" delay was posted mid December.  I take it the latter is essentially the basic delay with a mod or two.  Both videos use a reggae track to demo.

My money is on a PT2399.  While FV-1 chips were certainly around then, they hadn't been as incorporated into kits as the PT2399 was at that time.

[ponce]

What mods you think could be done to Deep Blue Delay or Rebote to get close to this one?

[Mark Hammer]

I've done mods in past that effectively did what the "dub" unit does.  Basically, what you do is shave off the bass, progressively over repeats.

For instance, the Deep Blue delay has a 22nf cap in the Feedback path.  If you drop its value to, say, 4n7 or 3n3, it would shave off a little more bass and lower mids with each repeat, until it gets shrill.

[FUZZZZzzzz]

Read the title, but cannot hear the video (work). I thought about this one, maybe its somewhere in the right ballpark?

http://tagboardeffects.blogspot.com/2016/09/king-dubby-delay.html

[ponce]

This seems to be a simpler circuit according to the picture of the guts.



Here's the video again:

[ponce]

I've done mods in past that effectively did what the "dub" unit does.  Basically, what you do is shave off the bass, progressively over repeats.

For instance, the Deep Blue delay has a 22nf cap in the Feedback path.  If you drop its value to, say, 4n7 or 3n3, it would shave off a little more bass and lower mids with each repeat, until it gets shrill.

Good to know. What's with those switches, where do they go?

I've modded my DBD build with the momentary switch on the repeat pot for the max repeats and self oscillation allready , but this one seems to do more dubby stuff.

[Mark Hammer]

The "dub" aspect is pretty much entirely a progressive change in the bandwidth of the repeats.  If one was making a PT2399-based delay of any kind, a similar switch function would involve selecting between full bandwidth in the repeat path, or restricted bandwidth.  Because the bass rolloff is simple and shallow, it still leaves some bass and lower mids with each repeat, that can be further trimmed away on the next repeat.  That's how it gets progressively shriller.

All that entails is installing a feedback cap 1/5 to 1/10 or so smaller/lower than what is normally installed, and using a toggle to add another cap in parallel with it, to restore normal repeats.  It's a smart thing to add, but not a complicated one.  I also like to add a toggle in the feedback loop for rolling off more high end with each repeat, to get a more natural-sounding echo.

[ElectricDruid]

One point to note is that the "dub delay" version they've got on the site uses the feedback switch to remove the feedback, rather than set it to maximum. This being dub, it's up near maximum most of the time anyway, but you need a button you can press to cut it out if it threatens to run totally out of control and ruin the vibe.
So it's the other way around to the usual set-up.

+1 Mark's comments about filtering the repeats.

[Mark Hammer]

I have to note that my "dub collection" consists of one 45rpm single of "King Tubby Meets the Rockers Uptown" by Augustus Pablo.  Pretty representative, from what I understand, though.

[ponce]

Indeed, that's a very good dub record. 

[thermionix]

What is dub?

[Mark Hammer]

Dub is a reason to have very large woofers, and an echo box of some type.

Descended from reggae, it was often a sort of Caribbean electronica before there was electronica.  A nice write-up here:  https://en.wikipedia.org/wiki/Dub_music

[thermionix]

Music in this genre consists predominantly of instrumental remixes of existing recordings

As far as I got.

[nocentelli]

Music in this genre consists predominantly of instrumental remixes of existing recordings

As far as I got.

That's a shame, your single quote undersells the genre considerably. Pioneering and innovative use of effects, often DIY-ed equipment (due to limited availability/prohibitive cost and desire to be unique), and closely tied to the soundsystem culture of JA in the early '70s onwards. Many supposed "remixes" are actually original recordings that were manipulated to such an extent by the dub producer that an entirely new piece of music was created.

[duck_arse]

put coarsely - get a clash record, take most of the sound away, add repeats and bass, sometimes.

I do like dub.

[thermionix]

dubya