possible springless reverb...

[choklitlove]

i'm not positive, but i came across this circuit on the electronic peasant's site.  there's not much explaining it since it's only a small part of a huge percussion synth project, but maybe it could help us get that diy springless reverb project we've all wanted.

http://www.electronicpeasant.com/projects/ssdrums/mixer.gif

and the project is on this page: http://www.electronicpeasant.com/projects/ssdrums/ssdrums.html


sorry if this is wrong and stupid of me.  what do you think?

[blanik]

or someone could open up and reverse engineer an Electro Harmonix "Holy Grail" Rev..., sounds great,
i never opened up but i figure it's probably not a complex circuit...

R.

[varialbender]

Cool, I've always wanted to see a BBD reverb and this is my first. I'll try to figure it out later, but good to know where I can find the schem.
PS pretty sure the Holy Grail is digital, so that'd be pretty different, but cool nonetheless.

[choklitlove]

or someone could open up and reverse engineer an Electro Harmonix "Holy Grail" Rev..., sounds great,
i never opened up but i figure it's probably not a complex circuit...

R.

yeah it's very digital.  here's where the holy grail magic happens:

(that huge chip in the middle)

Cool, I've always wanted to see a BBD reverb and this is my first. I'll try to figure it out later, but good to know where I can find the schem.
PS pretty sure the Holy Grail is digital, so that'd be pretty different, but cool nonetheless.

i was wondering about that.  what does BBD stand for/mean?

[varialbender]

BBD = Bucket Brigade Device. Imagine old-school firemen all lined up passing buckets of water forward. I think the way BBD chips work compared to that little analogy is that each stage in a BBD is like one of the people in the line, and each stage holds the part of the wave for a tiny bit of time then passes it on to the next stage until it finally reaches the output.
Anyway, that's the main ingredient in analog delays, choruses, flangers, etc...

[christian]

Thats pretty much just a delay effect with feedback. MN3208 has 2 times the stages that the classic MN3007 has, so you get 2 x longer delay. Good luck in finding one of these! You can also sub a MN3008, but its not fully circuit-compatible.

So dont expect too much on this circuit

ch.

[trevize]

it's not the state of art of portability but if you want to experiment with springless reverb at home or for home recording studio use
try to build a plate reverb.

[Ashurbanipal]

Here's an old project for a BBD reverb using mn3011 that I think SmallBear sells:
http://experimentalistsanonymous.com/diy/Schematics/Reverb/MN3011%20reverb.pdf

The mn3011 I think is a six tap delay so I guess would be more suited for reverb. Haven't had the balls to try to build this.

[Mark Hammer]

The circuit referred to at the electronic peasant site is not an electronic reverb.  IT is an echo unit, and not much different than things like the Memory Man and AD-3208, except that it aims for short delays and, correspondingly, has fewer stages.

Reverberation in the real world consists of multiple reflections from multiple distances, arriving at the ears at multiple intervals, often with multiple frequency responses.  When BBDs like the MN3208 are used to produce delay, all repetitions are at a single arrival time, and multiples thereof.  At long delays you won't hear it, but at short delays, turning up the regeneration produces a boxier sound as a result of repeats at the same delay time.

The MN3011 (and its little brother, the MN3214) was a chip produced to try and electronically mimic reverberation by having multiple taps at intervals that were not multiples of each other.  The assorted circuits I've seen using the 3011 are nice tries, I suppose, but tend to lack a number of things crucial to having a decent reverb sound.  First, there is usually no means for introducing regeneration or extending the decay time.  Second, all repeats have the exact same bandwidth (where in real life, later repeats have less treble).

I haven't looked closely enough, but I gather that digital implementations, such as the Crystal semiconductor chip used in the Holy Grail, use algorithms that not only introduce multiple reflections/copies but also vary the bandwidth of earlier vs later reflections.  There is certainly nothing that precludes having a chip like the 3011 do something like that, it's just that no one has done it, and digital approaches seem to make it easier to deliver a decent product and reverb sound at modest priceproints.

[markm]

Here's an old project for a BBD reverb using mn3011 that I think SmallBear sells:
http://experimentalistsanonymous.com/diy/Schematics/Reverb/MN3011%20reverb.pdf

The mn3011 I think is a six tap delay so I guess would be more suited for reverb. Haven't had the balls to try to build this.

Interesting circuit none-the-less.
I wonder the age of the article though....early 80's maybe late 70's?

[Mark Hammer]

1981 or thereabouts.

[blanik]

i got fooled by the Electro-Harmonix "low tech" look... that Holy Grail might not be an easy clone project after all!... lol

R.