Results 1 to 18 of 18

Thread: Digital reverb add-on kit for typical DIY amp builds?

  1. #1
    Supporting Member Steve A.'s Avatar
    Join Date
    May 2006
    Posts
    4,503
    Thumbs Up/Down
    Received: 117/0
    Given: 77/0

    Digital reverb add-on kit for typical DIY amp builds?

    With the various digital reverb chips available a small company should come out with a good kit that we can add to our amp builds. Here are a few suggestions for different kits.

    • A Fender/Vox kit with the reverb input signal taken after the first stage, tone stack and volume control. That way the input signal would be fairly clean unless the amp input was overdriven. The reverb signal would be mixed back into the audio signal chain through an op-amp directly ahead of the phase inverter, after the FX loop and an optional cascading overdrive channel. There would be a reverb drive control, a reverb return level control and an input signal treble cut tone control. (These controls could be panel mounted pots or trim pots, the amp builders' choice.)

    • A Marshall style kit similar to the Fender/Vox kit for amps with a tone stack ahead of the phase inverter. For this kit the reverb input signal would be taken after the initial gain stage but would include 2 or 3 tone controls to further shape the reverb input signal.

    • Both designs could be incorporated in the same add-on kit, with headers on the circuit board to be connected to pots and switches.

    • The kit would include a separate power supply module which would provide a regulated voltage from one of the B+ nodes, perhaps the one powering the first stage.

    I would expect the initial kits to retail for around $150-200 but that the price might come down considerably after production was ramped up. What would be included would be 2 or 3 printed circuit boards with th3 switches, pots, jacks and other auxiliary parts provided by the amp builder.



    Any suggestions or comments? I believe that there would definitely be a demand for something like this in the DIY amp building community if someone could put such a design together, perhaps financed by a kickstarter campaign.

    Steve A.

    P.S. There could be a stripped down version of this adding just a buffered solid state FX loop ahead of the phase inverter, perhaps with a series/parallel option.

    P.P.S. These kits would be based on the assumption that an op-amp mixing stage ahead of the phase inverter should be fairly neutral in sound and response.

    0 Not allowed! Not allowed!

  2. #2
    Lifetime Member
    Join Date
    May 2006
    Posts
    4,294
    Thumbs Up/Down
    Received: 157/0
    Given: 0/0
    Good idea - and very close to one I've been working on in a desultory way for quite a while.

    My cut on it was to make a mini-tank shaped device with RCA phono jacks in and out that could be plugged in to replace a spring tank. There are a limited number of input impedances and levels for spring tanks, and even fewer output impedances and levels. The Belton BTDR-2 digital reverb gets good reviews for sounding much like a spring reverb. I've done some minor design, adjusting input level and output levels so the interface to the amp would be the same at the ends of the reverb cables.

    The only addition needed would be a source of 5V at up to 200ma. This is a modest PITA in a typical tube amp. Messing with making this from the heater supplies is possible, but frankly the simplest thing would be to wire in one of the 5V output wall warts inside the amp.

    Sadly, my ability to design things is far larger and faster than my time to get prototypes built. The boards are laid out and ready to print, pending only some mechanical mounting issues. I have an amp-tech friend that has squirreled away a couple of dead small-size tanks for me to use in making a proto, but he's out of town, the sun is in my eyes, I have blisters on my fingers....

    On top of that, I have just received my first run of repro Thomas Vox knobs. Chrome, knurled, very, very close to the real thing. Sigh. So many designs to do, so little time.

    0 Not allowed! Not allowed!
    Amazing!! Who would ever have guessed that someone who villified the evil rich people would begin happily accepting their millions in speaking fees!

    Oh, wait! That sounds familiar, somehow.

  3. #3
    Supporting Member Steve A.'s Avatar
    Join Date
    May 2006
    Posts
    4,503
    Thumbs Up/Down
    Received: 117/0
    Given: 77/0
    R.G. Speaking of spring reverb tanks I sure wish that a boutique company would "spring" up to sell Fender tanks like the old ones, either by rebuilding current production tanks or designing something from scratch.

    As for supplying power for add-on boards and modules inside guitar amps can the "voltage pump" idea in many modern FX pedals be used in creating a regulated DC voltage from the 6.3VAC filament windings?

    Thanks!

    Steve A.

    0 Not allowed! Not allowed!

  4. #4
    Old Timer olddawg's Avatar
    Join Date
    Dec 2007
    Location
    Carlsbad, CA and Kona, HI
    Posts
    2,689
    Thumbs Up/Down
    Received: 66/0
    Given: 1/0

    0 Not allowed! Not allowed!

  5. #5
    Senior Member nosaj's Avatar
    Join Date
    Sep 2011
    Location
    Pace, FL
    Posts
    1,938
    Thumbs Up/Down
    Received: 303/33
    Given: 33/21
    Quote Originally Posted by olddawg View Post
    Or these? They're for Organs but I'd think a tube amp would be just as accomadating to one of these.
    Fisher Spacexpander and ElectroTone OrganMate (as well as the current Trek II reverb add-on
    nosaj

    0 Not allowed! Not allowed!

  6. #6
    Old Timer olddawg's Avatar
    Join Date
    Dec 2007
    Location
    Carlsbad, CA and Kona, HI
    Posts
    2,689
    Thumbs Up/Down
    Received: 66/0
    Given: 1/0
    http://diy.smallbearelec.com/Library...ton_BTDR-3.pdf

    Spec sheet. All it seems to need is a 5vdc supply and and external dual pot.

    0 Not allowed! Not allowed!

  7. #7
    Senior Member
    Join Date
    Jun 2011
    Location
    South West Arkansas
    Posts
    158
    Thumbs Up/Down
    Received: 17/0
    Given: 0/0
    there are so many good reverb pedals out there that I just don't bother adding reverb to a build these days. Only if I build an exact clone on request for someone.

    0 Not allowed! Not allowed!

  8. #8
    Old Timer olddawg's Avatar
    Join Date
    Dec 2007
    Location
    Carlsbad, CA and Kona, HI
    Posts
    2,689
    Thumbs Up/Down
    Received: 66/0
    Given: 1/0
    Quote Originally Posted by mac dillard View Post
    there are so many good reverb pedals out there that I just don't bother adding reverb to a build these days. Only if I build an exact clone on request for someone.
    Well yes and no. If you are using overdriving the preamp it can get ugly. A pedal in the effects loop works better.

    0 Not allowed! Not allowed!

  9. #9
    Supporting Member Steve A.'s Avatar
    Join Date
    May 2006
    Posts
    4,503
    Thumbs Up/Down
    Received: 117/0
    Given: 77/0
    Quote Originally Posted by olddawg View Post
    Well yes and no. If you are using overdriving the preamp it can get ugly. A pedal in the effects loop works better.
    It is pretty much blues guitarists who really want or need reverb built in to an amp. A long time ago I figured that I needed reverb or sustain from overdrive, but not necessarily both.

    In rewiring my already-butchered 1965 Pro Reverb with a D.... clean channel and an OD channel based on a 2204 Marshall I gave up trying to get a decent OD sound running through the 3M3/12pf reverb splitter so I ran it like the stock Normal channel directly to the PI... much better.
    (The Dumble clean channel through the Fender reverb circuit sounded like angels on high.)

    Hence my specification that the reverb signal be taken early in the circuit and mixed in right at the phase inverter. Blending in a clean reverb signal with an overdriven signal can be cool.

    Steve A.

    P.S. Attached below is the Son of Promaniac schematic from 1999 which without mention included my D mods for the Normal Channel as a Halloween bonus. Shhhh... don't tell anybody!


    .sopm_1.pdf

    0 Not allowed! Not allowed!
    Last edited by Steve A.; 06-05-2018 at 05:18 AM.

  10. #10
    Old Timer
    Join Date
    Dec 2007
    Location
    Poland
    Posts
    1,578
    Thumbs Up/Down
    Received: 12/0
    Given: 3/0
    Steve,

    There are several circuits available based on Belton Reverb modules. Why can't you use one of them?
    Also, FV-1 chip is often used. And they are available as a small module. I designed a programmable effect using this chip: GalleryGaleria - Eagle AudioEagle Audio . It mimics The Shadows band sound but it is too complicated compared to what you need.
    I suggest looking at the Belton modules.

    Mark

    0 Not allowed! Not allowed!

  11. #11
    Lifetime Member
    Join Date
    May 2006
    Posts
    4,294
    Thumbs Up/Down
    Received: 157/0
    Given: 0/0
    Quote Originally Posted by Steve A. View Post
    R.G. Speaking of spring reverb tanks I sure wish that a boutique company would "spring" up to sell Fender tanks like the old ones, either by rebuilding current production tanks or designing something from scratch.
    That may be tough. I wound up getting some of the last Accutronics tanks before they were bought out when I did the protos for the Workhorse amps. They didn't sound right, and in talking to some tech people at Accutronics, they let slip that they could no longer get the same damping material that the driver/pickups ran in. The replacements didn't sound right. I don't know how that got solved, but it was a long time ago and maybe Belton has figured it out. It's funny that the exact material in a plug of stuff made them sound way different.

    As for supplying power for add-on boards and modules inside guitar amps can the "voltage pump" idea in many modern FX pedals be used in creating a regulated DC voltage from the 6.3VAC filament windings?
    Sure. You can make 7-8V that way, and run it through a 7805 regulator to make the necessary power. But it's a PITA, like all the ad-hoc schemes to make low voltage DC from heaters. A single lightweight lump that takes in 120Vac and puts out 5V DC without a lot of muss and fuss seems both conceptually and practically simpler. Maybe I'm just getting lazy.

    0 Not allowed! Not allowed!
    Amazing!! Who would ever have guessed that someone who villified the evil rich people would begin happily accepting their millions in speaking fees!

    Oh, wait! That sounds familiar, somehow.

  12. #12
    Member
    Join Date
    May 2018
    Location
    San Diego, CA
    Posts
    59
    Thumbs Up/Down
    Received: 33/6
    Given: 16/3
    Last I looked at the Acutronics reverb tanks.... the reason for the poor sound was the spring material ... The old original springs made in the 60's and 70's had a significant % nickel content...
    Reverb springs made today are much lighter and no nickel content.... totally different cheaper metal..
    The mechanical resonance of the springs are just too bright and nasty sounding.... all the damping wont do much except band-aide a crappy spring..
    As for selling to Fender...that would never happen ... They would get the first spring unit, copy it and never pay you..then a few months later send you a "cease and desist" claiming they own the spring IP...
    I designed a stereo Digital Reverb with a Sharc processor a few years back for major pedal company...they still have never paid me and they are selling this pedal in high volume....

    0 Not allowed! Not allowed!

  13. #13
    Old Timer Leo_Gnardo's Avatar
    Join Date
    Sep 2012
    Location
    Dogpatch-on-Hudson
    Posts
    5,402
    Thumbs Up/Down
    Received: 500/12
    Given: 527/0
    Quote Originally Posted by cerrem View Post
    Last I looked at the Acutronics reverb tanks.... the reason for the poor sound was the spring material
    Whilst we're properly slagging the last-of-the-run US Accutronics tanks, let's not forget the last 5 or so years of production when they treated us to rapidly failing transducer coils. One customer went through half a dozen Accu tanks over the course of 2 or 3 years. He hasn't been back to see me for anything since, that was about 14 years ago.

    Has anyone tried the "new" Belton made Accutronics tanks? Or are they the s.o.s., just up priced because they have the revered brand name on them?

    0 Not allowed! Not allowed!

  14. #14
    Supporting Member
    Join Date
    Mar 2017
    Location
    Massachusetts, USA
    Posts
    1,134
    Thumbs Up/Down
    Received: 59/0
    Given: 1,132/0
    Quote Originally Posted by Leo_Gnardo View Post
    Whilst we're properly slagging the last-of-the-run US Accutronics tanks, let's not forget the last 5 or so years of production when they treated us to rapidly failing transducer coils. One customer went through half a dozen Accu tanks over the course of 2 or 3 years. He hasn't been back to see me for anything since, that was about 14 years ago.

    Has anyone tried the "new" Belton made Accutronics tanks? Or are they the s.o.s., just up priced because they have the revered brand name on them?
    I got a tank from Antique Electronic Supply recently, think its stamped "Accutronics". Sounds pretty stinky.

    0 Not allowed! Not allowed!

  15. #15
    Supporting Member The Dude's Avatar
    Join Date
    May 2010
    Location
    Sioux Falls, SD
    Posts
    5,399
    Thumbs Up/Down
    Received: 370/1
    Given: 312/0
    Reverb sound is a matter of taste, but I've used the Mod tanks with good results. You may or may not like them.

    0 Not allowed! Not allowed!
    “Yeah, well, you know, that’s just, like, your opinion, man.”

  16. #16
    Old Timer Leo_Gnardo's Avatar
    Join Date
    Sep 2012
    Location
    Dogpatch-on-Hudson
    Posts
    5,402
    Thumbs Up/Down
    Received: 500/12
    Given: 527/0
    Quote Originally Posted by The Dude View Post
    Reverb sound is a matter of taste, but I've used the Mod tanks with good results. You may or may not like them.
    Same here, I've been getting along with the Mods just fine. Before that, Ruby brand from Magic Parts, they look identical.

    In some applications a short tank sounds better than a long one. I try what's in stock until satisfied. It's also a plus that Mod tanks, at least the direct Fender replacement ones, are sold in short, medium and long decay choices. Short is long enough for me and my customers. I don't see what's the point of a never ending echo echo echooooooooooooo..................

    0 Not allowed! Not allowed!

  17. #17
    Senior Member
    Join Date
    Aug 2015
    Location
    Edmonton, AB
    Posts
    116
    Thumbs Up/Down
    Received: 96/0
    Given: 59/0
    Quote Originally Posted by Leo_Gnardo View Post
    Same here, I've been getting along with the Mods just fine. Before that, Ruby brand from Magic Parts, they look identical.

    In some applications a short tank sounds better than a long one. I try what's in stock until satisfied. It's also a plus that Mod tanks, at least the direct Fender replacement ones, are sold in short, medium and long decay choices. Short is long enough for me and my customers. I don't see what's the point of a never ending echo echo echooooooooooooo..................

    Me too... getting along with the Mod tanks, that is.

    Once I tried a long decay Mod tank cuz I "thought" I wanted a *very* lush reverb...
    Turned out to be waaaaay too much.
    Even the medium was too much, short works fine.

    0 Not allowed! Not allowed!

  18. #18
    Supporting Member Steve A.'s Avatar
    Join Date
    May 2006
    Posts
    4,503
    Thumbs Up/Down
    Received: 117/0
    Given: 77/0
    Are the shorter delay MOD tanks better than what Fender has been using in their amps recently?

    The worst tanks I've heard are the cheap Asian ones in a plastic frame mounted inside a SS amp chassis, like in a cheap Frontman amp. I like what were used in the MIM Fender SS amps in the 90s (Princeton 112, etc.)

    Steve A.

    0 Not allowed! Not allowed!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. DIY digital noise blocker
    By Guitarist in forum Guitar Effects
    Replies: 5
    Last Post: 05-05-2017, 11:36 PM
  2. Replies: 8
    Last Post: 01-10-2011, 12:33 PM
  3. DIY Digital pot for tube amps
    By GainFreak in forum Theory & Design
    Replies: 4
    Last Post: 11-01-2010, 04:24 PM
  4. DIY Kit
    By a1terrier in forum Mods & Tweaks
    Replies: 3
    Last Post: 12-07-2009, 09:00 PM
  5. Multi Function Digital Counter Kit
    By spud1950 in forum Tools and Coil Winding Gear
    Replies: 1
    Last Post: 05-18-2008, 01:00 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •