ADT-Automatic Double Tracker Simulator

[Mark Hammer]

Small Bear carries an 8-pin version of the MN3208 - http://www.smallbearelec.com/Categories.bok?category=ICs+Delays+and+Echo

I *think*, but am not absolutely 100% certain, that the BL3208 has the same pin out as the MN3207, just twice as many stages.  Assuming they do have the same pinout, if one had a 3207-based chorus pedal (and there are loads of those at decent prices), subbing the on-board MN3207 with one of those 8-pin BL3208s would double your delay time, without having to change anything else like the filtering.  A chorus whose delay range went from 5-20msec would now go from 10-30msec.  One would likely need to adjust the depth control a bit though, because the same amount of clock modulation at longer delays will require Gravol for all users and listeners.  A simple fix is to simply stick a fixed resistor in series with the input lug of the depth pot.

So, two questions:  1) Who knows what bargain-basement chorus pedals are currently sold that use through-hole (no surface mount) MN3207 BBDs?  and 2) Is the BL3208 identical in pinout to an MN3207?

EDIT/UPDATE:  Did some digging and the BL3208 can successfully be plugged into the socket where an MN3207 used to be.  Pin for pin compatible.  I think we may have a winner here.

[Quackzed]

i got my rocktek(3205) ch01 pretty rockin by tweaking the d-time cap and adding a chorus/vibrato switch plus i added a fast /slow switch AND a trem switch (also makes the led go on and off ) PLUS i found a spot for a switch that changes the waveform of the chorus... kinda ramps up then starts over, ramps up again... sounds just like sci/fi startreck or Robalard... remember him? the alien who loved all kinds of candy bars? then tried some "earth fruit" and discovered it was yummy and not bad...

[rockgardenlove]

I like Mark's question.  I need a chorus to base my project on

[rockgardenlove]

So there are no DIY chorus's!?  I'm suprised!

[Mark Hammer]

There are several over at Tonepad, but after clones of the CE-2 and Small Clone became available (not to forget the completely DIY Zombie from John Hollis), I suspect people ran out of interest in making others the way there is no end to the fascination for new fuzzes.  Unfortunately all 3 of those chorus units employ an MN3007 for which the 3207 (and 8-pin 3208) can not just plug in and work without modification.

What we need is a project for an MN3207-based chorus so that a BL3208 can be plugged in for ADT experiments.

[Dave_B]

If you can wait until August, this book promises to explain it all.  The authors were interviewed for the current TapeOp mag and they mention a big section of the book being dedicated to ADT.

This book has been promised for such a long time, I forgot about it. 

[rockgardenlove]

http://generalguitargadgets.com/diagrams/IbanezCS9.gif
Ibanez CS9 chorus.  Does that look right?  I think that has the right chip.

[rockgardenlove]

Just a little bump so it won't pass over to the second page

Will that CS-9 work?  Anyone know where I can get a PCB layout?

[rockgardenlove]

Bump?

[Mark Hammer]

Yes, that will work.  never seen one myself, or a layout.

[rockgardenlove]

Hmm alright...

That would be horrible to perf...I think a layout is the only option.  I'd like to eliminate as much as possible though first.  I won't be needing stereo for the chorus, how might I take that out?  I also don't want any buffers, etc. 

I think I have a basic idea of what to do, I just want to verify.


Thanks!

[rockgardenlove]

Bump 

[rockgardenlove]

I'm back!

I've been experimenting with LFO circuits to find which ones I want.  Simple op-amp ones are turning out the best...nothing too special going on with them.

I'm using a pretty fast LFO to change the speed on a slower one...sounds pretty cool indeed.  They're hooked up to a simple trem setup just now...haven't used them on a delay yet.

I think I'll base it off the PT80 delay. 

I'll be posting schematics and maybe some clips up here, if you're interested. 

More ideas/comments/facts/anything is welcome!  Post everything you know, it helps!

[dr]

......somewhere in my magazine collection here, I read that effect was done by wrapping white cloth adhesive bandage tape around either the pinch roller or the capstan-if I remember correctly......I am looking for it today..............dr

experience is what you get when you didn't get what you wanted