Tuesday, 8 July 2014

Rub-a-Dub Reverb Deluxe

Request.  This is a 1776 Effects project with more info available here.  Check out their other projects and PCBs available at their store:

The Rub-a-Dub Deluxe utilizes the new Accutronics BTDR-3H. The
BTDR-3H allows the reverb decay to be adjustable. In addition, the
Rub-a-Dub Deluxe also adds a tone control (based on Culturejam’s
Box of Hall) and a trim pot to allow for a volume boost or cut.






53 comments:

  1. Would there be any advantages to splitting up the decay pot into two separate controls?

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    1. A dual pot (or two resistors) is a requirement of the BTDR-3H as per the Accutronics datasheet. I'm not sure exactly what internal function they perform to require two, but it is required.

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    2. Mat,

      I don't see any reason why trying out 2 pots rather than 1 dual gang would *hurt* anything. The worst you risk is just having to clip those 2 pots loose and go with the dual gang if it turns out odd.

      It would seem to me (and I'm stupid) that the dual gang pot would either A) have each gang controlling a separate but related feature (I see that the BDR-3 is capable of pseudo-stereo), or B) the resistance is the parallel combination of each gangs value, kept true by having the wipers attached to the same pole. I don't see why that wold ever be used instead of the proper single gang value, but then I'm stupid. :)

      So in case A) it might be that those related functions/values only sound good when kept at the same setting, or else it's a feature that the circuit designer felt was pointless (ie. the pseudo-stereo).

      In case B), who knows..

      Might be fun to test it out, though.

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    3. Oh, and also what IvIark said. But as long as you are connecting 2 pots it should satisfy the need for 2 resistors though it might sound pants if they are not set at the same value. I might have to test that out when I get mine just to see what it does.

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  2. Obviously Joshua (1776effects.com) time traveled to the near future and nabbed a box of these Belton bricks (along with some dude from Germany). Otherwise these are Unobtani-... nah, been used to much.. these are nowhere else to be found. :(

    I went ahead and ordered a board and brick from Joshua. Chaps the buttocks a bit since the layout is so small and simple, but it didn't cost too much more than the brick itself would likely cost, so not bad.

    From the images I've seen it's not any smaller than the BDR-2. I had hoped they'd figure out how to make it even smaller (considering the size difference between the bdr-1 and the bdr-2) but it's certainly small enough to still be extremely happy with, all things considered.

    I would love to see the average cost of the BDR-2 decrease to around $10 after the BDR-3 becomes more available. I doubt that will happen, but it would be nice :D

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    1. Yeah, that's the "Dude from Germany" I mentioned.. couldn't recall the page and was a little tied up when I initially posted. I'd probably pay more ordering it from there than I I would ordering the brick and board from 1776. Folks in the Old World :D would likely come out even or better ordering from the Doctor.

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    2. Don't mind me... I'm just stuck at work and INCREDIBLY BORED at the moment :p

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    3. You need internet TV. Judge Judy's on :o)

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  3. Hi Mark:
    This is the DELUXE version and utilizes the new Accutronics BTDR-3H, but the standard version utilizes the BTDR-2H (very easy...)
    You can make the standard version?
    Thanks!

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  4. This is awesome. I wonder if the new brick gets rid of the modulation. These reverb circuits all sound pretty good, but the "always on" modulation is a bit of a drag.

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  5. I see the mix control is in fact simple volume control to decide how much reverb is blended in with the dry signal and looking at the schematic I'm wondering, would removing the 22k Make it 100% wet?

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  6. So will this work with BDTR2 or is that a different layout? Read the comments but still a bit confused sorry. Have a brick laying around.

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    1. No the Deluxe is BDTR3 only, I'll add the standard layout tomorrow which doesn't have quite so much control, but does use the BDTR2

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  7. And thanks for the layout! :)

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  8. I have the standard rub a dub with the version 2 (long decay) brick. It sounds beautiful but I think I would prefer the short brick. It's obviously a one trick pony, and the long decay sounds great at home but is way too long for me at band levels.

    The deluxe seems interesting because it has control over the decay. If it can do a springy short decay sound as well as the long brick sound that would be cool. Major plus if the version 3 brick ditches or tames the modulation

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  9. This comment has been removed by the author.

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    1. Yeah I moved the position of the regulator and so had to move the track and must have forgotten to move it on the bare board layout too. Mix 3 connects to the position on the board and Tone 1 so that is correct.

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    2. Thanks IvIark.

      I have reverb now and the decay pot is doing it's job, problem is the output as a whole is incredibly quiet. Trimmer make very little difference.

      I'm gonna go over my build again in the morning... too damn hot right now

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    3. The wet and dry are split off and run in parallel in this circuit, so if both the wet and dry are too low then it suggests a problem with the splitting or mixing side of the opamp. The problem could literally be anywhere along the signal path though and so from the start to the output wire, any problem along there could cause both wet and dry to be low, but as a bonus, at least that means everything around the brick is probably ok.

      If you can't find anything amiss I'd strongly suggest building an audio probe and seeing where the signal is dropping in this order:

      Input wire
      22n
      100K
      IC pin 2
      IC pin 1
      22K
      IC pin 6
      IC pin 7
      1u
      1K
      Output wire

      Somewhere along that line you'll here the volume drop out and that will give a clear indication where the issue is. It's probably something as simple as a bad joint somewhere along that line.

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    4. Thanks for taking the time to put together such a detailed reply, much appreciated. However all the tips in the world can't prevent the builder from being a dick! :P

      Real embarrassing simple mistake on my part!

      Anyway, it's a worker, nice BIG reverb on max, better than I was expecting (having previously built the Tenebrion) tag it! :) Good job too as I spent way too long on the box - http://i1199.photobucket.com/albums/aa465/sminki/Rub-A-Dub-Reverb-Deluxe.jpg

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    5. Excellent, thanks for verifying and for the pic, looks great.

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  10. built this but noticed some errors

    cut on top track is in different position on populated and unpopulated layouts
    mix 3 goes to bottom track, but also says in blurb that mix 3 goes to tone 1

    i'm only getting a dry signal, so wondering if anything else is amiss

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  11. Thanks for the layout!
    Mix 1 to ground?

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    1. Sorry if I asked something stupid.
      I have built this pedal according to the schematic but the mix pot did not work properly. It changed the signal but it did not take off the wet signal totally, so it was not possible to set the signal dry at 0 position. It seemed also strange to me that lug 1 of the Mix pot was not connected anywhere. I checked the schematic at http://1776effects.com/wp-content/uploads/2012/08/Rub-a-Dub-Reverb-BOM.pdf and it says that the 50k MIX pot has to be connected to ground through its no 1 leg. I connected it and now the pedal works perfect. Maybe I made two mistakes? I do not understand your replies.

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    2. No I was laughing at Smink's post and you're absolutely correct Peter, Mix 1 should be grounded I missed it off the notes.

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  12. Anyone know if the new brick got rid of the modulation?

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    1. You can't, it's an issue with the brick. I'm not sure if this has been fixed in the latest version though, it may be worth checking with Accu Bell

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  13. Is this layout missing R10 (33ohm)?

    http://1776effects.com/wp-content/uploads/2014/05/Rub-a-Dub-Deluxe-BOM.pdf

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    1. Yes. I have a bit of paranoia about low value current limiting resistors in series with the supply and so usually don't go down lower than 100R. I do usually swap lower values for a 100R though but here I've just omitted it, which may be because we were already up to 21 columns. If you do feel the need you can always put it inline with the 9V wire offboard.

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  14. could you wire up the trimmer to a pontimeter. If so how would you wire it up. Thanks

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  15. I have a spare drilled enclosure laying around with 5 holes for pots, so I think I'm going to build this one but split the dual gang pot into two single gangs as well as switch the trimmer for an external volume control. If the dual gang functions like a stereo volume where two signal paths need to be set equal, then setting the two single gangs at equal values might be a pain, but it could actually have the potential to be more precise, as you could get around the tolerances of a dual gang that can't really be adjusted if each gang is a bit different. It might turn out odd, but hey, that's what experiments are for! I'll report back with results once the parts come in. Oh, if anyone could suggest this, since there's also a switch hole on the enclosure I wouldn't mind filling, is there any capacitor I can change to have some sort of tonal change switch on this reverb?

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    1. To fill one of the holes, you could add a DRY signal kill switch. Its pretty fun. I did this on my build. Allows for some really spacey sounds.

      Just put R4 (22k) on a toggle. Removing it kills the dry signal.

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    2. I'll definitely do that then. Thanks for the suggestion! Just gotta order everything and I'll get cracking on the build.

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  16. Finally tracked down a brick to build this, had to use a 500k dual pot as there was an error in a parts order. It gives a dub-style feedback when cranked! I notice the original schematic is 100k dual - I take it the pot value is the issue here? Sounds great on low settings though!

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  17. I got a strange result with this build... I did separate the dual gang decay pot into two separate ones, but that's ironically not what gives me the weird result! I'll begin by describing the decay though... The two pots work almost the same independent when one is all the way down and the other is played with. The first decay pot connected to BTDR 7 and 8 makes a BIT more of a delay-like slap back and decays a bit shorter when all the way up. The second connected to 9 and 10 has more of the super vibey resonance to it and takes a little longer to fade out when all the way up. It's also worth noting that the decay is pretty short when one knob is down compared to both knobs being even barely used.
    Now, on to the weird stuff... I switched the trimmer out for a B10K, and as I turn the volume down, it only turns down the dry volume. After a certain point it gets really farty, and after that I can make it let only the resonance through (not quite the same as 100% wet sounding though). Also, the TONE knob starts to get some noticeable delay in the mix after about 11 o'clock, so I have to keep it down there for solely reverb. If I wanted to get rid of that, I'd probably just go with a 2K, but the tone difference isn't really that big from 0 to max, so it might not even be worth it to do that. I'll just stick with what I've got and maybe find some use in it. Finally, I put the 22K on a switch for a 100% wet option, but when I switch it to that, I get a crazy high gain sound... It almost sounds like a cross between a fuzz face and a Boss DS-1 cranked all the way. I have no idea how that happened... But I've found this thing to be more than spacey with max decay, so I don't think I'll need the 100% wet mod. Maybe I'll find some use for that bizarre accidental fuzz!

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  18. UPDATE: The accidental fuzz sounds bad and is pretty much useless. Also, I put the reverb with higher gain on my amp, and it sounds absolutely awful. It sounds like a $20 slapback delay (can't get rid of the delay effect) with an uncontrollably long decay even at minimum settings. Any ideas as to what's wrong? I need a reverb and I'm half tempted to trash this and just build something else.

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    1. I've built the pcb version and my signal is sometimes clean, sometimes no signal (unless I hit strings really hard -> some distored noise), or some fuzzy feedback/oscillation. I was afraid that my brick was broken. Now I've read your post I hope I can find what is wrong wit my build.

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  19. Try using a lower value pot, 100k dual or lower. The manufacturer specs a 10k pot for decay times

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  20. Just finished my build works like a charm. Thank you for the layout! Using the Dual 250k Lin I find that most of the action is happening in the lower 20% section of the turn radius. So, like Jon suggested, i'm gonna try a 10k lin there, also as suggested in the BTDR 3 documentation.

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  21. i like this one.i built a brick 2 m and l neither had much control.this is a much more useful build and the reverb can be set to just a hint.if your not wanting an over the top reverb this has great adjustments from just a tad to over the top

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  22. Mine rub a dub is not working right. Boost, Tone, mix, decay knobs alter the sound. But the sound is not reverb but more like fuzzy noise (probably delay feedback of the belton brick?). I think the problem is: my battery is 7.6V. When I plug the battery in the effect (I don't turn on the effect yet) the difference between V and ground is 4-5 V. But the reg out is then only 2.5 V instead of 5. Can this be the cause the fuzzy feedback noise? Which component can be the cause? I already changed the regulator. Or is it just because my battery is not 9V?

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    1. yeap.change your battery.
      if you use a regulator in any effect, and you need xV from its output, you must give in the input at least xV+3V so that the reg works properly

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    2. indeed :) it was just the battery.. thanks savvas.

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  23. What’s the smallest enclosure size this would fit in?

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    1. I did fit it in something like a 1590B, without a Battery, low profile jacks, that should work :)

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    2. I did fit it in something like a 1590B, without a Battery, low profile jacks, that should work :)

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  24. I have this build working except for the tone knob. I've been doing a probe and I have a good signal at the first and third lugs. Does this sound like a faulty pot? I would replace it but I don't have any extra 5k pots.

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  25. Just built this and i have a couple issues/questions:

    I tried turning the trimmer into an offboard pot but the volume increase is so drastic when turning the effect on. Ive tried rewiring the pot but it doesnt seem to be doing anything.

    The decay is almost like a slapback with high repeats, is this normal?

    The mix knob, even when cranked doesnt give a particularily "wet" signal. You can definitely hear it working as you turn it but when cranked you still have to hit a short note to hear the decay.

    When you crank the decay knob after 30-40 seconds it starts to what sounds like self oscillate, a noise builds and builds and then starts "screeching"

    Any ideas?

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    1. I'm having the exact same issue. Also used the trimmer as an offboard pot....

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