[sdiy] Weird hobby of the week: BBDs

[Scott Stites]

> have to admit, i'm mostly with Harry on the BBDs. for chorus and flanging
i
> think they are OK, for echos, delay, and especially reverb, i think they
> suck, like really suck. (excepting the EH memory man, it's EH!)

Harry obviously has a good point - BBD's are noisy.  You just can't throw
one in a circuit and expect good results.  Effective low pass filtering is
an absolute must.  Pre-emphasis and de-emphasis help, and in 99% of all
cases, if there is no compansion or (shudder) gating, you're still going to
have a fairly noisy device.  The exception would probably be very high clock
rate, high bandwidth flanging where a compandor would kill the 'grit', if
that's yer thing.

For the past several months I've been working on a modified clone of the
Boss Dimension C, little brother to the D.  It uses two BBD's running with
clocks controlled in anti-phase, and I can say no project up to now has been
so satisfying.  It's very quiet and it does what it does extremely well.
It's got pre-emphasis, very effective antialiasing filters, and two NE570
compandors in it.  There's a lot more trickery in there as far as
controlling the tone of the thing (interesting crossmixing, eq, etc.).

I'm actually building two of them, and last night at 1:00 AM I finally fired
up the first set of boards to check the audio.  It sounded horrible - very
noisy and unpleasantly distorted.  I turned around and there was this tall,
bearded man wearing a beret laughing and saying "I told you so...".  I
rubbed my eyes, and he disappeared.  Weird =-D.

Come to find out the timing cap of the right channel compressor was not
connected to ground.  I made that connection, and the thing just sang......

> I cringe when i imagine BBD reverb, ouch. much prefer a cheap digital
reverb
> compared with BBD. but, to each their own...

The Rockman reverbs to my ears always sounded pretty decent, though the
gating to prevent fast transients can be a drag.

The MN3011 appeals to me more as a device for chorus/flanging than as
reverb.

> one useful project i did with BBD was a  Resonator module i built ala Ron
> Berry the analog acoustic modeler (see Sound on Sound magazine on-line).
> this works quite well and because it has a VCF on it, and because i use a
> short delay time i can hide some of the crappyness of BBD).

Sounds interesting, thanks!

> for all you pro BBD folks i still recommend that you search out used
chorus
> pedals which are very often quite cheap (especially the less popular
> brands). i pick them up for $20 or $30US at most... then hack mangle them
> into something. this saves a lot of work on the filters, clock, etc. i
think
> that my Resonator module was made out of a DOD analog delay...

I had a DOD analog delay in my guitar years.  One noisy SOB, but I loved it
=-D

I've never purchased a BBD with more than 1024 stages (other those already
in devices, that is).  For longer delays, I rely on the Princeton digital
chips, but even they can sound like crap without proper filtering and even
compansion (IMO).  The only BBD's I have that are more than 1024 stages are
the two MN3011's, and those were *given* to me by a very, very nice person.

Cheers,
Scott