Thursday, 24 October 2013

General Guitar Gadgets D-Verb

A nice simple reverb project that a few people have asked for, with this layout based around the BTDR-2H brick.  The short description from the GGG website:

This is a great sounding digital reverb project.  Based on the Belton Digital Reverb Brick.
This really is an excellent reverb and is also the base of some of the reverb units being built by Hermida Engineering, used by many big name guitarists.




I've left the original layout up, but this is one row smaller so thought it worth adding for anyone who wants to keep the size down:



29 comments:

  1. Are the other Belton Bricks easily dropped in to get a longer decay?

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    1. There are 3 versions of the BTDR-2H, you have to specify short, medium or long decay

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    2. Will the BTDR-1H works the same?

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    3. Not as a drop-in replacement. It has a different pinout, so check the datasheet and swap the wires that need to be swapped. Those older bricks are also noticeable bigger.
      +m

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  3. Hi Mark!
    Have you seen this?
    http://freestompboxes.org/viewtopic.php?f=28&t=22417&hilit=all+star
    It's an improved variation of the D-Verb

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  4. Oh, wet mod, that would be fun!

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  5. Just finished building this and have 2 issues. First, the LED won't light up. It is getting the proper voltages though. Second, although the reverb works, I lose some signal strength. Built the BOH reverb a couple of weeks ago and it sounds great with not signal loss. Any suggestions?

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    1. I built the smaller vero version and it works fine. I think it's not necessarily a signal loss but more of a tone suck. I think this circuit takes out a chunk of mids and some bass. Maybe upping the cap values might help.

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  6. I swapped 22n for 100n and it seemed to take care of the tone sucking problem. At least in my rig, it sounds identical to my dry signal plus the reverb. Socket it and try different values to your taste.

    I A/B'd this circuit with the real tube driven spring reverb on my Mesa Boogie. Although it was not as lush, it sound pretty nice. Box of Hall with Dwell mod was nice as well but I just wanted simple one knob control and I'm finally content. This will get boxed and finally my fender champ now has a reverb :)

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    1. Excellent, thanks for verifying and the improvements guys :o)

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    2. Solved the LED issue. I forgot to connect the ground wire from the switch to the output jack. I will try swapping the 22n for a 100n to see if this solves the volume drop/tone suck problem. Thanks

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    3. Tried the 100n cap in place of the 22n and this did not make any difference. The GGG version uses 2 TL072 (8 pin) op amps while this version uses 1 TL074 (14 pin). My voltages are in line with the GGG version but I am wondering if the problem might be with the TL074. Has anyone done a layout using the 2 TL072s instead?

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    4. I can't see that being an issue. The TL074 has four independent channels with a single supply and ground connection, two TL072s have four independent channels with two supply and ground connections. That's it. In terms of spec they're identical and as the channels all act independently there is no reliance on any internal interaction between them. What voltages are you getting at the IC pins?

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    5. That is what I thought. Here are the voltages: 9V supply - 8.9V. Pin 1 - 4.1V, 2- 4.1V, 3 - 3.6V, 4 - 8.2V, 5 - 4.1V, 6 - 4.1V, 7 - 4.1V, 8 and 9 - 7.7V, 10 and 11 - 0V, 12, 13, and 14 - 4.1V.

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    6. The voltages look ok to me, maybe a cold joint somewhere?

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    7. I noticed that the voltage dropped from 8.9V to 8.2 volts on the other side of the BAT 46 diode. Is this normal? Wondering if this reduced voltage going into the op amp could be the cause of the low volume. I'm thinking either a solder bridge or cold joint as you suggested. Will re-inspect the board.

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    8. 0.7V drop through a Schottky diode did seem a lot to me, but it is a similar drop you'd expect to see from a more common silicon diode which are often used for the same task and so it isn't anything out of the ordinary. 8.2V should be fine anyway, but you could always test it by taking the 9V supply to the hole next to the regulator I pin and so bypassing the diode.

      Also what voltage are you getting from the output of the regulator?

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    9. I am getting 5 V (4.97) on the regulator output. Checked the underside with a magnifying lamp and did not find any solder bridges or cold joints. I will bypass the diode when I get a chance to see if that does anything.

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    10. Bypassed the diode and although the voltages went up on the IC (Pins 1, 2, 5, 6, 7, 12, 13, and 14 - 4.4V; pin 3 - 3.9V, pin 4 - 8.9V, pins 8 and 9 - 8.3V), there is still a noticeable volume drop. I checked the voltage drop across the diode when it was removed and it only goes down by 0.5+/-V.

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    11. For some reason I do not get a noticeable volume drop when playing through my '59 Bassman clone (2 6L6s) or my Tweed Deluxe clone (2 6V6s). Playing through my EL84 based amps (Matchless Lightning clone and Marshall 18 watt clone) I experience a very noticeable volume loss. I am not getting this with by Box Of Hall reverb unit on any of my amps. What gives?

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  7. I'm guessing this ain't going In a 1290B with that brick as well? Not worried either way just wanted to drill te correct size ahead of time.

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  8. made this and it sounds great. used a 100n instead of 22n. no volume drop.
    is there a quick way to add a dwell or feedback knob to this? like the byoc version?
    thanks! tom

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    1. nevermind, i used johns daughterboard from his box of hall dwell mod. heres an adapted layout of what i did.
      http://img.photobucket.com/albums/v355/tomkogut/GGG-D-Verb-DwellMod_zps4f937bf6.jpg
      i used a 1k for the daughterboard resistor. at max it gives me a nice long fadeaway.

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  9. the best way to not lose sound is power the reverb with 18 volts... i'd try all , it's the only way to have a good sound

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  10. Built this today with major hair pulling. The layout works fine, mine sounds great. I had an old tl074 from a byoc that ended up being dead after all these years. Made a dual tl072 daughter board on vero. It was a major pain, I really don't like wiring but 28 solder joints later it was worth it. Invest in a desolder pump!

    I used a 100n cap in place of the 22n, I have no signal loss or tone lameness of any sort. I added the dwell daughter board on vero too. Also put the belton on a daughter board. Didn't use the diode, just jumpered.

    So main board, 2xtl072 board, dwell board, and belton board. Pretty silly but I managed to get it running super. Ugh!

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  11. Hey, how would I overdrive the amp that sends the signal into the belton brick? I'm thinking like the altitude control on the death by audio reverberation machine.

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