[sdiy] BBDs

[Scott Stites]

Anthony wrote:

>Any flanger circuit that uses a 4046 for the clock (lot of others too) can
be >easilly modded for VC use.
>Just mix a a jack for the CV and the original LFO. 100K resistors work
fine.

Yes, indeed.  A/DA used a 4007 for voltage control of a 4047 with buffers
for their outstanding flanger as well as the STD-1.  Works very well, too.

>Here's a really cool circuit:

>http://home.debitel.net/user/jhaible/jh_storm_tide_flanger.html
>It's a pretty big circuit though.

Heckuva flanger.  Don't forget JH's Dimension D project, too!  The Dimension
D is what the Dimension C was based off of - same general concept, a bit
different implementation, used MN3007's originally (JH used four TDA 512
stage devices, which I imagine were more accessible in Germany at the time).
The Rolls Royce of chorus devices, IMO.

>I'm working on one using 2 R5106's. (Probably more suitable than 3207's)
>For the MN3207's if you need really fast clocking speeds (which you really
do) >- up to 1.5 MHz can be done - you need a buffer. Three inverters for
each >clock phase (using a 4049).

MN3207's can be overclocked to get really short delay times suitable for
flanging.  I agree the SAD devices were probably the best suited for
flanging (though the shorter staged MN devices were pretty good - too).
Later incarnations of the A/DA flanger used the MN3010, which is pretty much
set up like the SAD1024 (two individual 512 stage sections), without the
really high clock rate specs (100 kHz max for the MN3010).  Didn't stop
A/DA, though - they clocked them at the same rate anyway and it worked fine.
I used to have one of those A/DA's - outstanding flanger.  The MN3011 has
the same max clock rate, and they clocked that one up to 150 kHz on the
STD-1.

>Here's a link for that:

>http://www.hollis.co.uk/john/ultraflanger3.jpg
>It's for MN3007 but I think it's not too rough to adapt. Just tweaking the
bias >and power supply.

>There are schematics for flangers with MN3207's, but all of the reviews of
these >models are fairly poor. I'm guessing that too slow clock speeds were
used so >what they really were were more like tubular chorus.


The MN3207 is actually spec'ed to twice the clock rate that the MN3007 is.
In fact, the Morley Sapphire flanger used the same clock set-up as A/DA, but
it wasn't near the flanger (and didn't hit the clock rates) that the A/DA
did.  Quite easy to tweak up, though.  I clocked an MN3207 around 1 MHz by
playing with the values.  But, there's more to a good flanger than just a
high clock rate, and A/DA didn't miss a lick.


>MN3207's work great for chorus though. The Dimension C used 2 and it's
>superb. Really to get blown away by chorus it should be stereo and the Dim
C is >true stereo. And even though it's pretty subtle it blows people away.

I couldn't agree more.  It so blew me away, Jeff Pontius and I teamed up and
built a couple of them in rack mount version.  I handled the circuits and
Jeff handled the hardware and final assembly.  It's one of the sweetest
things I own.  I ran Modezero's dry samples through it, and compared it with
Modezero's effected examples of the Dim C - pegged it pretty much dead on.

http://mypeoplepc.com/members/scottnoanh/birthofasynth/id9.html

There are more pages about it (links at the top).

>Here's another good starting point:

http://ampage.org/cgi-bin/hammer/index.cgi?cmd=lt&xid=&fid=&ex=&pg=1

A very good starting point indeed.

>I need to find the link to the flanger uses a 4007/4047 for the clock.
>If I can't find it I'll mail a scan of my handdrawn version.

Check out the Morley site - the Sapphire Flanger is there.  Mike Irwin did a
clone of the A/DA using the SAD1024.  A breeze through Aron's Stompbox
List's search function should bring up a link to a drawing of it by Stephen
Giles.  Use the values Mike put in there, but adjust the supply voltage
accordingly - MN32XX are lower voltage parts.

>All of these links have good chorus examples.
>I hope that gets you started. (Hope I didn't over-answer)

Better than under-answer.  =0)

Cheers,
Scott