2 SAD512s = 1 SAD1024?

[jdub]

Hello all-

Searched the forum & couldn't find any specific info on this: Does anyone know how to wire up 2 SAD512s (the 16-pin versions) to perform the function of 1 SAD1024? I've heard of this being done, but haven't been able to find guidelines.  I'm not really all that hip on BBDs, but I have a general idea of how they work (clocking, etc.)...

Since the 16-pin SAD512s are pretty much 1024s with a non-functioning B-side, would this process entail splitting the pinout of the 1024 between the two 512s (i.e., match B-side pinout of 1024 to the corresponding pns on the 512)? Since the two sides of a 1024 share Vdd, gnd and (I think) Vbb, I assume that these pins on the 512s would have to be individually connected- that is, each 512 would have to connect to Vdd, gnd & Vbb, correct?  I would like to use these in (what else?) a 9v Electric Mistress, if it can be done, since I have 'em laying around.  Any pointers would be much appreciated. Thanks!

[StephenGiles]

Sledgehammer to crack a nut. Buy the SAD 1024 from Smallbear and save yourself a lot of hassle.

[dthurstan]

I don't know alot about BBD Tech, but what you want to do is called cascading. I asked about cascading any bbds and oldschoolanalog replied with some great links.

http://www.diystompboxes.com/smfforum/index.php?topic=73962.msg600553#msg600553

Check out the generalguitargadgets.com link. It shows how to connect to MN32XX type chips. I guess if you see how thoses 2 chips are connected you can figure
out how the two SADs connect!

Hope this helps.

Dave

[jdub]

Stephen, buying a 1024 from Small Bear (or anyplace for that matter) would definitely be my first choice, but Steve apparently doesn't have them for sale anymore- I couldn't find them in his stock list, anyway-and I haven't been able to locate them anywhere else except through parts locators with (at least) $300 minimum purchases. Plus, I'm kind of interested in seeing if I can get it to work, just for fun (and since I have the parts).  I appreciate the suggestion, though!

Thanks much for the link(s), dthurstan- it would have helped if I'd used the poper search term, I guess!  I'll dig through this stuff and see if I can suss it out.  My gratitude for the help, guys.

[R.G.]

Since the 16-pin SAD512s are pretty much 1024s with a non-functioning B-side, would this process entail splitting the pinout of the 1024 between the two 512s (i.e., match B-side pinout of 1024 to the corresponding pns on the 512)? Since the two sides of a 1024 share Vdd, gnd and (I think) Vbb, I assume that these pins on the 512s would have to be individually connected- that is, each 512 would have to connect to Vdd, gnd & Vbb, correct?  I would like to use these in (what else?) a 9v Electric Mistress, if it can be done, since I have 'em laying around.  Any pointers would be much appreciated. Thanks!

Yeah, it probably works. At least in the cascaded modes. The results in the interleaved modes might depend on side-to-side matching to get minimum distortion. That may need different tweaking per side, or may not ever sound as good.

[StephenGiles]

Stephen, buying a 1024 from Small Bear (or anyplace for that matter) would definitely be my first choice, but Steve apparently doesn't have them for sale anymore- I couldn't find them in his stock list, anyway-and I haven't been able to locate them anywhere else except through parts locators with (at least) $300 minimum purchases. Plus, I'm kind of interested in seeing if I can get it to work, just for fun (and since I have the parts).  I appreciate the suggestion, though!

Thanks much for the link(s), dthurstan- it would have helped if I'd used the poper search term, I guess!  I'll dig through this stuff and see if I can suss it out.  My gratitude for the help, guys.

If it's for fun - I'm with you!

[jdub]

R.G., I find myself unworthy of your sage advice, but if you feel so inclined, can you please clarify to this BBD semi-neophyte the difference between cascaded mode and interleaved mode? Am I correct in assuming that they are what they sound like- the former being a one-after-the-other affair, and the latter being a back-and-forth connection?  Are both modes additive in terms of delay time?  Which mode is normally present in flanging applications?  I humbly await your reply... 

[oldschoolanalog]

http://www.synthdiy.com/show/?id=881
The datasheet is your friend .
Your answers await there...

[jdub]

Dig it.  I already have this datasheet (that synthdiy site is a great source), but I think the terminology threw me off.  If I understand correctly, cascading corresponds to serial config, and interleaving corresponds to parallel & differental config... um, right?   

[oldschoolanalog]

Correct!

[jdub]

Excellent. Thanks, Dave!