What's the best use for my SAD1024?

[Guatis]

Is the DEMistress worthy or is there a better use for this chip? (delay? chorus? )

Please help me...

[nelson]

There is an SAD1024 version of the EH clone theory which is a chorus/vibrato pedal. I have the schematic for it.

[Mark Hammer]

While the MN3007/3207 and the SAD1024 can both be used for either flangers or chorus pedals, it is generally easier to successfully clock the SAD1024 at the high rate needed to produce the short delays for best flanging.  You CAN do it with an MN3007 but most posted schems do not incorporatethe circuitry needed to make an MN3007 do those tricks.

For that reason, my own recommendation would be to reserve any SAD1024 you have in your possession for flanging purposes, rather than "waste" it on a chorus.  You can make an MN3007 (or the more available MN3207) do chorus tricks quite easily.  Someone still makes 3207's, but no one is making SAD1024's anymore.

As for whether the DEM is "the one" to use it for, that is a matter of personal taste, but certainly the many thousands of folks who possess one are extremely happy with it, and there is a decent layout for one available at generalguitargadgets (GGG).  If you already HAVE an SAD1024, then I would describe the circuit as not requiring exotic parts (you have the most exotic one already).

A schematic for an SAD1024-friendly version of the old A/DA Flanger has been posted and while it is a fabulous flanger, I do not believe a louyout has been posted for it.  Everyone I know who has built one has used stripboard or something similar.  Consequently, the DEM is pretty much a "safer" build.

There are some mods for the DEM in an article in DEVICE posted at my site (hammer.ampage.org)

[nelson]

ok, I guess my suggestion was off.....

[Mark Hammer]

ok, I guess my suggestion was off.....

Not at all.  Some people have absolutely no use for flangers and love choruses, in which case MY suggestion would be way off.  I'm just saying that if it makes no difference to Guatis whether s/he makes a chorus or flanger, the SAD1024 makes a better flanger than an MN3007 does, but the two chips are pretty much equals when it comes to choruses.  I'm the kind of guy who likes to use things in contexts where they may have "special" characteristics, that's all.

[nelson]

I am working on a clone of the EH clone theory the MN3007 version, I have a  beta version of the PCB artwork drawn up. Its my first try at designing a PCB from a schematic, its turned out too big, and I have used too many jumpers.

Do you have any advice on PCB design mark?

I am using MS paint and MS visio.

[DiyFreaque]

I've toyed with the thought of using a SAD1024 as a stereo flanger by clocking the individual 512 stage sections separately and using the separate outputs.  I'm thinking of using an adaptation of Thomas Henry's quadrature function generator to generate an lfo with an additional 90 degree phase output for the stereo effect - (I'd like to make it parabolic - a very excellent TH sineshaper that I've been using for a while will get me down the road on that).  The 512 stages would nice for ultra-short delays, but would suffer a bit in the longer delay range of the flange sweep.  I guess the breadboard will tell me if it's worth it to use a SAD1024, or just go with two MN3207's.

Kinda reminds me of the Seinfeld episode where Elaine would evaluate having relations with suitors based on if they were 'sponge-worthy' or not...

Take care,
Scott

[Mark Hammer]

Do you have any advice on PCB design mark?

Yes, some excellent advice - ask someone smarter about these things!  :lol:

Seriously, there are many many others with considerably more field experience in such matters than I have.

Scott,

The SAD1024 is quite "flange-worthy" :lol:  :lol: .

You may have missed this thread from way back, so I'll bore the others by repeating it....

If you've ever heard a sample of the Ibanez Flying Pan (combined auto-panner and phaser), you will undoubtedly note that between the inter-output volume panning and the sweep of the phaser, the effect is interesting for a moment or two and gets pretty disruptive thereafter.  So, nice for a riff-long post-production effect, but a PITA as far as being a leave-it-on effect.

What I have suggested to many is a "wet panner".  This pans the wet signal back and forth between a left and right mixing stage.  The question is, "Why bother?".  Well, the cognitive requirement to track the progress of one sweep cycle (the phase effect), with the interruptions produced by another (the amplitude sweep cycle) makes it more cognitively demanding and listener fatigue sets in rapidly.  It's like trying to listen to a radio broadcast when the sound keeps cutting out.

As well, from another angle, the standard sum-and-difference arrangement just doesn't cut it when listening in stereo.  If you have headphones on, fine, but otherwise the sum and difference cancel each other out in mid-air.

Wet panning, on the other hand, shifts where the effect is occurring without the jarring volume changes of panning the mixed signal, without requiring sum and difference issues, without requiring dual processing via BBD or whatnot.

Of course what sort of modulation you wish to employ, and the systematic relationship between modulation sources is quite another matter.  For instance, I could see where use of a quadrature oscillator that moved the effect across channels in a manner *sort of* synced to the sweep of the effect itself, could be interesting.  Unyoked LFOs could be interesting in other ways too.  Incidentally, where panning of the ENTIRE signal using a square wave LFO would be irritating, panning of the wet signal only (keeping the dry rock steady) could provide interesting animation without the irritation.  From another angle, use of slow ramp waves to modulate a wet signal's sweep in mono might be uninteresting.  Move that slow ramp sweep around with a triangle, though, and it might get a little more interesting.

[DiyFreaque]

Panning the wet signal between channels - brilliant!  Hadn't thought of that approach, thanks Mark.  That would eliminate the pitfalls of two different clocks running, and eliminate a BBD (in a two BBD approach) or allow the full use of 1024 stages in the SAD1024 approach.

The + and - mixing per channel separation technique does suffer from a degree of cancellation, and it would be nice to have it as an option rather than the main mode of stereo propagation.

Well, with the Dim C project winding down, I've got some breadboard real-estate and a crop of BBD's to play with.  I can try a number of approaches and see what tickles my BBD-bone.  

Thanks,
Scott

[puretube]

[Guatis]

Hey Mark thank you very much for your advice. Actually i started building the DEM when i started this topic, so what you tell me is what I "wanted" to be told.

Saludos desde CHILE!!

[analogmike]

HI,

Being practical, best is to save the sad1024 for vintage repairs. If you make something new, use a chip that is more commonly available like any of the MN series. If you make something with the SAD1024, what do you do if the chip dies? Hope that helps!

[mudmen]

What about brand new EH Deluxe Mistress Flangers ?
Are they still based on SAD1024 ?

[Mark Hammer]

If you can order enough of them, you can have pretty much ANY chip made for you specially.  Getting an order of 10,000 for your own company, though, does not mean these chips will be available to component distributors.  So, it is possible for ONLY Electro-Harmonix to have ongoing access to SAD1024's or CA3094's, because they have ordered some enormous quantity  That does not mean that individuals will necessarily be able to purchase these chips anywhere, even while E-H has bins of them.

I don't know what E-H uses for the DEM, but the fact is that they sell enough pedals to have the buying power to use the chips they WANT and not just the chips that are available.  Cripes, for all I know, they have a secret stash of 8-pin SAD512's!! :lol:

[nelson]

I wonder who EH gets to make their chips....

[StephenGiles]

............Bush Electronics Inc!!!!!!!

[analogmike]

I wonder who EH gets to make their chips....

Mike Matthews talked about that in our book. They do not have ANY chips made for them, they are not big enough. They bought all the MN3005 chips they could but ran out of them last year, for the dlx mem man. They had a lot of MN3008 too so now they are using those instead.

They have NO sad1024 chips at all.

The reverb chip in the Holy Grail was dicontinued but they bought enough for several years.

[StephenGiles]

HI,

Being practical, best is to save the sad1024 for vintage repairs. If you make something new, use a chip that is more commonly available like any of the MN series. If you make something with the SAD1024, what do you do if the chip dies? Hope that helps!

I've only ever had one SAD 1024 die on me in 28 years - so long as you are careful I would use one every time. Even if you only have one, take precautions (something for the weekend sir?) and switch from board to board  if necessary.
Stephen