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 Forum index » DIY Hardware and Software
Simmons SDS 3 - DIY?
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Dave Kendall



Joined: May 26, 2007
Posts: 421
Location: England
Audio files: 3

PostPosted: Mon Jun 18, 2007 2:56 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi all.

Would it be worth considering using LM13700s instead of 3080s?
(that is *if* the circuit would work with them.....)
13700s are still being made, and the scarcer 3080s can get saved for stuff that absolutely needs them. Of course pcb layout would be different.....

What do you guys think?

cheers,

Dave
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Randaleem



Joined: May 17, 2007
Posts: 456
Location: Northern CA, USA

PostPosted: Mon Jun 18, 2007 6:54 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Dave,

That might make sense at some point.

Right now CA3080's are plentiful and cheap. I could order a thousand if needed, and have them in a few days.

I'd prefer to stick with the core circuit in the first pass and then after we have some experience with the results (and if 3080's become hard to get) the 13700 might prolong the agony Laughing

Randal
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Randaleem



Joined: May 17, 2007
Posts: 456
Location: Northern CA, USA

PostPosted: Mon Jun 18, 2007 8:11 pm    Post subject: Experts in the corner.
Subject description: This is gonna be one FAT clone!
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Hi again,

Can't contain myself. It's pretty cool what can happen when you find an expert in a subject, Show some appreciation and then shut up, and sit back to learn.

I've just had another long day with some excellent work and results towards our SDS3 project.

Can't spill too much right now; but let's just say that the shortcomings of this beastie are about to be handled by its strength. Yes, cryptic. Think of it as a high resonance statement. More feedback later. I gotta go digest some brain food that was dished up for our mutual benefit.

You ever get an idea that just makes SO much sense that you wonder why it wasn't obvious earlier? Ya can't even sit still to think; cuz your body's saying, "Move it man. Don't lose this one."

"In Xanadu did Kubla Khan, a stately palace dome decree, Where Alph, the sacred river ran, Through caverns measureless to man...

"Mr. Coleridge, sir? Mr. Coleridge? Someone at the door for you..."

Randal

Still dealing with the triangles. Which is fun and exciting too; But My mind is bent toward the SDS3 right now. Oh, AND a little pattern tool kinda thing you guys just might appreciate Laughing It's a good week already! Much yet to do.

BTW, As I've just typed an idea has come for how to gain the benefit of the new idea without losing ANY of the original SDS3! Wow! this is cool.
Thank you Mono. If you hadn't asked about Bubble I wouldn't have gotten to do this. And thank you Bubble for giving me this opportunity!

Remember I kept saying I thought the kit should come as pairs?
Mighta been a case of knowing before knowing...
The triangles can wait no longer! They DEMAND my attention. Very Happy
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mono-poly



Joined: Jul 07, 2004
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Location: Rotterdam, Netherlands
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PostPosted: Tue Jun 19, 2007 7:16 am    Post subject: Reply with quote  Mark this post and the followings unread

Oow i am so excited how this is going forward to a pcb Smile
I prefer to stick to ca3080's to stay as close as possible to the origional design.
People then even can choose to stick a metalcan version into the ic socket.
Mods like the vcf being controllable by cv is nice.
And perhaps as i asked before maybe the pitch of the oscilator with cv would be nice to.

Laughing
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Randaleem



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Posts: 456
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PostPosted: Tue Jun 19, 2007 9:43 am    Post subject: Reply with quote  Mark this post and the followings unread

mono-poly wrote:
Oow i am so excited how this is going forward to a pcb Smile
I prefer to stick to ca3080's to stay as close as possible to the origional design.
People then even can choose to stick a metalcan version into the ic socket.
Mods like the vcf being controllable by cv is nice.
And perhaps as i asked before maybe the pitch of the oscilator with cv would be nice to.
Laughing


Mono,

I'm excited too. So if I hear you correctly: You want it to be exactly the same as it WAS; but with all kinds of NEW added stuff! Laughing

Alright, I get it. I'm with ya. As far as I can tell; the biggest part of the reason TO do this is to get THE Simmons sound, warts and all. If we do all this and we don't have that; then the project's a failure IMO.

But as long as we can add things which don't prevent us from getting to THAT sound whenever we want it, all is cool.

First question, since you've asked for access to the oscillator via CV. Where's the VCO in this circuit?

It's a very economical circuit. I don't mean money; though that is surely part of why it's the way it is. This synth does a lot with very little. I think we can add just a little and get a LOT in return. Without losing any of the classic qualities. Let's look at how?

Right in the middle we've a nice fat Moog ladder filter. There's an arpeggiator (they call it a "run gen"), ONE garden variety LFO, a noise source, a mixer that doesn't mix, and some microphone pass through which must've made sense to somebody at some time?

Then we have the MIDI looking pad input (Makes me wonder how many of these ended up on a trash heap because someone younger bought it and plugged the MIDI cable in, turned it on and it didn't work! Razz )

There's a simple AR EG with a specialised attack mode to simulate click which can be set to go pos or neg. on attack. Way out right we've got a lone 3080 performing VCA duty, and. that's. about. it. So where's the VCO?

Well you guys are all Synthaholics so you probably knew from the start; it's the filter. THAT's our single VCO. But if it's our VCO, then where's our filter? Hmmm... Well the ONE filter is doing BOTH jobs. Economical; like I said.
But there's a problem with this two-timing,(Isn't there always!) and it's that we have to choose to emphasize EITHER tone or filter, and as we move towards one end of the frequency scale or the other we can only get what' left at that end as the filter has done away with the rest!

So our filter plays VCO and goes into oscillation to give us tone, and the AR EG sends the filters center/cutoff frequency up or down on attack to take care of both head stretch and stick impact. As long as we're in Toms, or Bass we're okay. Try to get a snare sound? As you increase toward noise with the filter, now we don't have any tone and cannot sharpen the filter response enough to get any click!

We also have only the ONE lfo, and it feeds all voices through a switch per voice and an attenuator per voice. So if we have it set to give us the clangorous sounds of cymbals and hats, we lose the ability to get our other voices where we want them.

But hey; all of this is what gives us that classic SIMMONS sound! Very Happy

So as I'm standing there looking at the schematic to see where to add the things Mono and others have mentioned, I'm thinking what we really need is more LFO's (one per voice minimum, better mixing, and an independent VCO per voice).

I'm listening to my expert explain all this and I'm running all these VCO circuits through my mind, trying to find the one that will give us the most bang for our bucks. Ray Wilson, Thomas Henry, Bernie Hutchins, Rene Schmitz<SP>, etc. all take their place in my mind and I'm calculating the cost and the PCB real estate required, and the time and the trouble and...
then. it. hits. me. as. I'm staring at the schematic and that big fat filter in the middle.
You know the one that isn't a VCO, but "plays one" in this synth? yeah ; just duplicate the filter and we now have our VCO AND a filter! Ta dah!

So I'm thinking of the new added filter board lying atop the main board. And then. it. hits. me. again. (I'm slow sometimes Shocked ) There's a filter EXACTLY like the one we want right next door! How cool is that!? So we/I only need to add some interface circuitry between two voices! Anybody here ever combined filters before in a patch Wink

So here's the plan, open for comments:

1) Recreate the units as they were, but with an LFO and noise per voice. (both are provided on each card, you can populate 'em or not when you have multiple cards)
2) Lose the midi that isn't connector;
2a) keep the mic 1/4" jack and level controls for triggering from pads and other stuff(My expert tells me that "Most of my pads work very good on the mic inputs, even V-Drum pads with mesh heads!!!").
2b)We'll trade the level slider for a rotary pot that actually sets the "borrowed" filter at a tone, along with some VC of each filter.
3)We can handle the mixing with an out board tie-together-module like the 5th channel in the original. An optional board as it were.
4)Perhaps VC of the LFO as well.
5)And add the panel switch for classic or enhanced mode which effects the module couplers.

That's eight pots, 4 to 8 jacks and 4 or 5 switches per voice. A nice panel layout is partially complete, and the schematic is being bread-boarded to find attachment points for the new "couplers". We'll probably patch out the LFO and maybe the AR from the voices to gain flexibility; still working that all out. (Need to check signal levels and what it will take. Got to know when enough is enough Confused

I'm really excited and proud of the possibilities this gives us. With the coupler(s) off, you have a classic SDS3 without any audio line or CV line changes other than better mixing. And more LFO capability. Switch the couplers on though... And you've got one VERY fat drumsynth!!!

I'm aiming mine for a 5U MOTM / dotcom format. How many are planning to put this into Frac or Euro? Or Serge/Buchla?

There are a few ways to skin this cat; and this is a first pass. So I can see for example that some might want to skip the add-ons. Which is one of the really cool things about this approach.

If you want a basic no-frills clone; the only thing you're gonna be 'forced" to have is empty spots on the board where the LFO and couplers live. Conversely someone might rather have the dual filter voice available without cutting the available total voices in half. That person can simply buy a few extra boards and populate the filter portion, and piggyback it like the one my mind's eye originally saw.

Knowing the format you guys are planning to fit these into will help in PCB layout sensibility. so please chime in, speak up, let me know? If there's a lot of 3U response; I'll lay it out a bit different than if 4 or 5U is predominant.

I think it's fair to say that getting this right might add a week or maybe two onto the previously mentioned timeframe. But this should be VERY cool.

Thank you, more later,

Randal

Last edited by Randaleem on Tue Jun 19, 2007 6:20 pm; edited 2 times in total
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para



Joined: Oct 16, 2006
Posts: 276

PostPosted: Tue Jun 19, 2007 11:01 am    Post subject: Reply with quote  Mark this post and the followings unread

- frac

yes : to all 5 on the list and your idea of adding a second filter/voice is a great one. but i'm not 100% clear on if you are going to have them both on a single board or if your talking about using a second one as a daughter board in order to achieve the other filter?

as for the "couplers" /vactrols you are talking about using. i'm worried about parts cost raising up past reasonable, is there any chance of using a 13700 for the new additions instead as they can be had much cheaper. when you add up 3 or more units it could quickly get out of reach.

also there is an arpeggiator, noise source and mixer on the original? is the mixer just a single volume control per voice? if so yes cut it out, and is the arp simple /small enough to keep around? that could be nice


exciting,

steven
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deknow



Joined: Sep 15, 2004
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PostPosted: Tue Jun 19, 2007 12:17 pm    Post subject: how does the sds1000 compare? Reply with quote  Mark this post and the followings unread

i've got an sds1000 brain box (my recolection is the filter on the kick doesn't work). how does this compare?

deknow
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Dave Kendall



Joined: May 26, 2007
Posts: 421
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PostPosted: Tue Jun 19, 2007 12:38 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Randal.

Nice work you're doing here - I probably won't be able to resist a few boards...... Smile

Quote:
Right now CA3080's are plentiful and cheap. I could order a thousand if needed, and have them in a few days


I don't know if I'm the only one having trouble getting hold of 3080s East of the Big Pond. Last time I tried, it was either loads of $$$, a kind-hearted diy'er with spare stock to sell, or a Hong Kong eBay vendor (Hmmmmm.....).
I did get a few, but they're just for existing projects, not for new ones, with only 1 or 2 spares.

Anyone know a good EU or UK source?

Dunno, maybe it's only me in 3080 drought country .....

cheers,

Dave
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mono-poly



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PostPosted: Tue Jun 19, 2007 12:41 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hey Randeem

I don't know that much about designing so i am really fine with your suggestions.
But i would love to see single channel cards and with cv on the modulation bus of the card.
Then everyone can put an lfo he likes on that input or perhaps another cv source like a sample n hold.
But man you're really more exciter about this then i am.
Did you ever play with a sds-3 or 4 ?
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goodrevdoc



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PostPosted: Tue Jun 19, 2007 12:52 pm    Post subject: Reply with quote  Mark this post and the followings unread

I vote for Frac/Euro. Also, I really like the ideas about the dual filter/VCO and LFO per channel. Is there noise source per channel? If not that would be cool. Thanks for taking this up again, btw.
-justin
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Randaleem



Joined: May 17, 2007
Posts: 456
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PostPosted: Tue Jun 19, 2007 6:22 pm    Post subject: Reply with quote  Mark this post and the followings unread

goodrevdoc wrote:
I vote for Frac/Euro. Also, I really like the ideas about the dual filter/VCO and LFO per channel. Is there noise source per channel? If not that would be cool. Thanks for taking this up again, btw.
-justin


hi,

I just edited the other message to add:

1) Recreate the units as they were, but with an LFO and noise per voice. (both are provided on each card, you can populate 'em or not when you have multiple cards)

Last edited by Randaleem on Tue Jun 19, 2007 8:23 pm; edited 1 time in total
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Randaleem



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PostPosted: Tue Jun 19, 2007 6:28 pm    Post subject: Re: how does the sds1000 compare? Reply with quote  Mark this post and the followings unread

deknow wrote:
i've got an sds1000 brain box (my recolection is the filter on the kick doesn't work). how does this compare?
deknow


Here's what my knowledgable friend as to say on that point:

"The SDS3 filter is THE BEST ever used in a drumsynthesizer. Not the SDS5's SSM 2044! Not the CEM-toys in SDS7,8,9 a.s.o."

I don't have extensive personal experience with drum synths, but circuit-wise, what he's saying here makes sense.

Randal
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Randaleem



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PostPosted: Tue Jun 19, 2007 7:32 pm    Post subject: Reply with quote  Mark this post and the followings unread

para wrote:
- frac

yes : to all 5 on the list and your idea of adding a second filter/voice is a great one. but i'm not 100% clear on if you are going to have them both on a single board or if your talking about using a second one as a daughter board in order to achieve the other filter?


The 2nd filter is either "borrowed" from one of your existing channels by activating the coupler to put it into your "active" channel. Or you could build a 2nd board with filter components only and set it physically as a daughterboard.

The coupler is basically a set of switches that disconnects the filter and related desirables from its board and patches this into another "active" board. You double your filter PER voice by cutting your TOTAL voices in half. (Unless you add filter/VCO daughterboards to each channel. )

Quote:

as for the "couplers" /vactrols you are talking about using. i'm worried about parts cost raising up past reasonable, is there any chance of using a 13700 for the new additions instead as they can be had much cheaper. when you add up 3 or more units it could quickly get out of reach.


That's a potentially valid concern. The cost if you are willing to have fewer channels when using the enhanced mode is ONLY the cost of the coupler, which is negligable. Maybe 2 bucks.

But you've brought up something I didn't really want to get into yet; which is the fact that once you can separate the filter from the unit, you can insert another filter instead! Laughing And if you have internal patch points for adding a VCO, you can do the same thing with another VCO!

But right now I want to get the basic functionality out there. We can add these other things later as anyone might want. If I set up a good framework on the first PCB, then anyone could add to it.

So a 13700 filter or a Thomas Henry XR or 566 VCO makes sense too. The use of the the EXISTING filter and circuitry makes things easy and fast to get out the door with next to nothing for added cost.

People who only want the Simmons sound won't have to wait. They won't be paying extra to get things they don't want or need.
(The extra LFO that most ANYONE will want is already there. If you have your own favorite LFO, just use it through a patch point and leave the on-board LFO unpopulated.

You raise an Excellent point, BTW. The problem is trying to please everybody with only one circuit. Can't be done, in my experience.

So the method I've outlined allows to satisfy 80% quickly and inexpensively, and allows add-ons to take care of the other 20% with extra circuitry/cost.

It's also worth noting that doing it this way means the least amount of change to the original circuit. I'm basically going in and "patching out" the individual components of the circuit, and inserting in/out switch points. These changes will be needed for ANY similar addition to the circuit anyways.

So it's a win-win IMO.

The beauty and curse of modularity is at work here in spades. We can do things so many ways that it can end up being hard to choose a "clean signal" path...

For example, how about this alternative? Just make a semi-wide-range VC-LFO and let it be the added portion. Put one on every board, and then if you're using the on-board one in the voice as VCO, use an outboard one for modulation.
(Or borrow from your "neighbor's LFO" using a coupler scheme similar to what i've mentioned for the filter.)

Or? Keep the single voice as it exists now, and make an improved 5th special effects channel, which has all the extras.
(FWIW,This was the way I was originally headed. The cool thing is; we can STILL do it this way. The only thing I'm actually adding at this point are patch points and a means to switch in/out circuit blocks.

Quote:

also there is an arpeggiator, noise source and mixer on the original? is the mixer just a single volume control per voice? if so yes cut it out, and is the arp simple /small enough to keep around? that could be nice


Yes, but the mixer is poorly implemented. adding LFO modulation changes the pitch of your voice (in a not good way).

Here again everything that is wrong and everything that is right about modular voice design is at work. The original SDS3 has ONE noise, ONE LFO, ONE arpeggiator, and NO VCO's... four voice cards complete it.

These shared "special effects reduce cost. BUT they also limit the voices which can be made, as well as variation within the voices in a four voice unit.

The way I see it, folks are either gonna have a few of these or a bunch. If only a few, then let's load up every one with ALL the extra's; including anchovies! Very Happy

But if someone is contemplating an 8 or more voice unit, he'd probably prefer to share some resources to keep cost in check.

Trying to satisfy these mutually opposed requirements is where I come in. How can I give the guy whose gonna buy eight boards what he wants AND let the guy who's buying one or two ALSO be satisfied? Not to mention that the guy who has eight wants variation or he wouldn't be choosing eight.

With cost always in the picture somewhere...

The middle ground is to have a 2 card minimum; one voice and one extra's PCB. Add voices as you wish. When you have too many voices for one special effects card, add another. This is the typical way this kind of thing gets done.

Quote:

exciting,
steven


Yes, it is.

Randal
[/quote]
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para



Joined: Oct 16, 2006
Posts: 276

PostPosted: Wed Jun 20, 2007 2:54 am    Post subject: Reply with quote  Mark this post and the followings unread

sorry when you said "coupler" i thought you meant "opto coupler" as in vactrol which start in the $4 range and move up from there. also it looked like you were talking about 3 or more of them per board from what i understood. i thought this is how you were adding CV to each new control, and why i suggested the 13700 to take its place (not adding an extra 13700 filter). i had completely misunderstood your use of them. and i'm going to keep my mouth shut.

steven
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mono-poly



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PostPosted: Wed Jun 20, 2007 3:39 am    Post subject: Reply with quote  Mark this post and the followings unread

My ideal circuit would be as close to the orgional one.
But with the patchpoint as you did mention.
And the modulation card seperated like the origional one.
Maybe we can do the voice and modulation card on one board.
Everyone one wants to have different lfo's for each voice.
But with patching options so i can use a different modulatuon source from external gear.
I don't k know how manny patchpoints van be made with the origional design.
But i wanna stay as close as possible to the origional sound.
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Randaleem



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PostPosted: Thu Jun 21, 2007 2:56 am    Post subject: Reply with quote  Mark this post and the followings unread

Steven,

I'm glad you spoke up. It shows that I was not clear in what I was saying.
Hope to hear from you whenever there is something you want to say!

No worries,

Randal

para wrote:
sorry when you said "coupler" i thought you meant "opto coupler" as in vactrol which start in the $4 range and move up from there. <snip>
i had completely misunderstood your use of them. and i'm going to keep my mouth shut.
steven
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Randaleem



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PostPosted: Thu Jun 21, 2007 4:55 am    Post subject: Reply with quote  Mark this post and the followings unread

mono-poly wrote:
My ideal circuit would be as close to the orgional one.
But i wanna stay as close as possible to the original sound.


Mono,

Your first and last lines here say it all. The original sound needs to be there. period.

Fortunately I think we're in good shape on that front. I've looked into parts today and every key sound-influencing component is still available in enough supply to make this a go.

But as Bubble referred to in an offhand way a few pages ago; in a circuit like this small things can matter. Single side vs. double side layout. Wide vs. narrow traces, distance between parts, trace length, etc. That's why so many Moog filter replica's fall short of Moog-ness..

I asked earlier if you who are interested in getting these boards would tell me what size system you plan to put them into. A few responded; most who did seemed to favor the 3U height panels. Going into a frac or Euro style synth.

Now if you look at the SDS3 pic at the beginning of this thread; you'll see that the unit is more than 5-1/4" "tall". What you don't immediately see is that the PCB is the same size as the front panel. All those pots are mounted sitting on the PCB surface. This is a big board!

I could add a pic, but I'm new here and don't yet know all the ins and outs; Can we add a picture to a thread or post? How? Are there any guidelines to follow for the forum's sake?

Back to the PCB; It is broken into individual circuits along the lines of the 5 channels shown on the SDS3 front panel. What I'm getting at is there's no way this board done in the original format will fit into a Frac or Euro case unless that case is as deep as MOTM is tall! Now it's certainly possible to make the board smaller; not every part is going to affect the sound. We hope Confused

So what I'm asking again is how you guys plan to use these boards? Do you plan to set up a drum synth or are you only wanting to add a drum voice or two to your existing modular?

This single board voice module has 10-12 pots, 5 DP switches, and 3 leds. That's before any CV jacks are added.

It's pretty easy to fill a 5U x 19" rack width with a drum synth. For example, I was looking today at the SDS5 that a few have mentioned.

No, we don't want its sound; a very quick look at the circuits of the 3 vs. 5 shows that the 3 is indeed a superior analog drum voice. But it is also true that the SDS5 is much better packaged for use in a modular synth setup. So I was looking at how the two might be reconciled in what we're doing here. The SDS5 has up to 7 voices in a full rack width.
Anyway...

I've reached the fork in the road that needs to know if a long skinny board like the original is going to work for you who have expressed interest? Or does it need to be a smaller rectangular board?

How deep are your Frac and Euro cabinets? Looked at another way, can you give up enough horizontal width to let the board(s) stay in its original form by devoting at least 9 horizontal inches of width to drum stuff?

Am I truly cloning this or offering a MMvoyager-esque updated re-release?

I'll make it work either way but you guys are my guides. I'd really like to hear from you all about whether you can use a large board or whether it needs to be small? If there's enough interest perhaps I can make both. But I need to have an idea of where you all stand? Please help me out here? Thank you.

Randal

mono-poly wrote:

But with the patchpoint as you did mention.
And the modulation card seperated like the origional one.
Maybe we can do the voice and modulation card on one board.
Everyone one wants to have different lfo's for each voice.
But with patching options so i can use a different modulatuon source from external gear.
I don't k know how manny patchpoints van be made with the original design.


Some of these other questions have their answer reliant upon the choice of board size and format. So perhaps we can re-visit them after you've had a chance to chime in about your setup and needs for it?

I'd like to share One last thing that was kind of funny that happened last night:
This SDS3 has the Moog ladder filter as most of you know at this point. So I've pulled out my various sheets of Moog ladder filter info because that filter more than most is VERY dependant upon layout and component selection to get ITS sound.

(Which is why the thing above about the boards is so important to us; the "Simmons SD3 sound" IS the "Moog filter sound".)

Getting back to the story: What many of you also know is that ARP cloned the Moog ladder filter in its early 4035 VCF. (And hid that fact in a block of epoxy!)

So I've got those ARP 4035 sheets out too. (Because it IS a smaller layout. see how this all fits together? Very Happy And guess what? While the Simmons filter is "kind of" like the Moog schematics... It is almost EXACTLY like the ARP drawings! I mean you can easily see that one begat the other full grown! Made me smile. Very Happy

As Mosc said in another thread recently, "There really is nothing new under the sun." Perhaps all is vanity? Wink

Let me know what you all think.
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Dave Kendall



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PostPosted: Thu Jun 21, 2007 6:12 am    Post subject: Reply with quote  Mark this post and the followings unread

Hi Randal.

Regarding formats, my vote would be for a small size single-voice PCB for euro/frac, with on-board VC-LFO, CV control of parameters wherever possible, and patch points/inter board coupling links.

If that could be done keeping the original sound, people could customise, and add modules as and when needed.
I wouldn't be fussed about the mixer - I'd probably take each voice out individually to a mixing board anyway.

Just my 2 pence worth.....

cheers,

Dave
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para



Joined: Oct 16, 2006
Posts: 276

PostPosted: Thu Jun 21, 2007 11:23 am    Post subject: Reply with quote  Mark this post and the followings unread

Quote:
are you only wanting to add a drum voice or two to your existing modular?


yep

once you remove the space used for all the surface mount interface components the board size will drop, if you just keep the trace width close to the original and don’t run any important traces too long there we should be fine. i would imagine that component choice is far more important to the sound then having a trace 1/2" longer or shorter, i can't really believe it matters that much.

also i never mount the PCBs parallel to the panel, i prefer 16mm panel mount pots at a 90 degree angle so we can just drill some holes and slide it in. so the PCB can be 7" by 4" if you want, but the smaller and cheaper the better.

i'm pretty sure that frac is 7" deep but i use a custom case

10 - 12 pots per voice? what am i missing? even still this will all fit on a dual frac panel if your careful.
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Randaleem



Joined: May 17, 2007
Posts: 456
Location: Northern CA, USA

PostPosted: Thu Jun 21, 2007 5:27 pm    Post subject:
Subject description: Panel needs list Pots, Switches, Jacks and LED's
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Edit: I completely forgot and left out the foot pedal jacks. They're in there now...

Para,

Thank you for the reply. Couple of answers for you:


Quote:

then having a trace 1/2" longer or shorter, i can't really believe it matters that much.


Most times it doesn't; with a ladder filter it can. But the layout for the ladder filter in this case is not an issue; having looked more closely at it last evening. So we'll see how it goes.

Quote:

10 - 12 pots per voice? what am i missing? even still this will all fit on a dual frac panel if your careful.


Pots:

1) LFO rate
2) Mic. level (input sensitivity)
3) Click level
4) Pitch
5) Decay
6) Bend
7) Noise /Tone mix
Cool Bend level
9) Run time (Arp. length-TIME)
10) Effects level (modulation input atten. for LFO and Arp.)
11) Channel level

To this we might reasonably add,

12) Separate Tone/ Noise level (adds one pot. Increases variation. Gives up quick mix via one pot)
13) Filter resonance/ Q
14) Arp..length-NUMBER
15) Aux filter input (level attenuator)

X) Master pitch (in multi voice setups)
Channel level could be left off in single voice setups, multi too; depends...


Switches:

1) LFO select (wave type)
2) LFO on/off
3) Run/Arp. on/off
4) Bend up/down
5) Mic. on (channel in/out)
6) Effects on/off
6a) Separate effect on/off (for Aux input to filter)

LEDs:

1) LFO rate
2) Run/Arp. visual indicator
3) Bend indicator
4) Trigger indicator

Jacks:

1) Input
2) output
3) CV-LFO
4) AUX LFO In
5) LFO out

You've got a Moog ladder filter! Pretty useful by itself. So,

5) Aux. Filter in
6) Filter out
7) CV-Freq
Cool CV-Q

Then,

N) Addtl. CV-ins? Which ones?

1/4" Jacks:

1) Pitch pedal
2) Decay kill pedal
3) In/out pedal
4) Mic on/off Pedal

N) Pedals for other CV inputs?


Yeah, it adds up Smile

I'm going to add an SDS5 mod to mine; which may end up as a board available separately. A button push switch to easily move between 4 "voices" (within a channel) 3 presets, and the panel knobs. It's only pots, trimpots and analog switches.

Nice addition IMO. But I won't make it invasive or let it hold things up. Just wanted to mention the possibility. Conversation starter, perhaps?

Actually; I've just decided to make this board available separately for sure; I can think of lots of places where a button choice between 3 presets and the panel knobs might be useful!
This will be a cool little utility module that could be applied to any number of synth modules!

Randal

Last edited by Randaleem on Thu Jul 05, 2007 6:00 am; edited 1 time in total
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mono-poly



Joined: Jul 07, 2004
Posts: 937
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PostPosted: Fri Jun 22, 2007 1:52 am    Post subject: Reply with quote  Mark this post and the followings unread

Hey Randal

I think the stuff you mention is pretty cool to me.
Dunno if more mods would affect the sound.
But i am quite happy like this.
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mono-poly



Joined: Jul 07, 2004
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PostPosted: Thu Jun 28, 2007 2:52 pm    Post subject: Reply with quote  Mark this post and the followings unread

Hi Randal

Are there any updates so far?
I am still excited about this Smile

Cheers,

Dennis
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Randaleem



Joined: May 17, 2007
Posts: 456
Location: Northern CA, USA

PostPosted: Sun Jul 01, 2007 3:27 am    Post subject:
Subject description: some interesting things about the 3080 and 13x00 chips, from their designer
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Dave,

I saw a site today that made me think of your post here. It was by the designer of the 13600 and 13700 chips. He said that the 13600 and 13700 were identical to the 3080 with a couple added features due to the then-newly available 16pin dip packaging. They dropped the 3080 circuit directly into the chip twice. (The entire thing was done in less than five minutes as a training exercise for a new mask artist!) Then they had 2 sets of 3 pins left so they added the darlington buffers, which left 1 pin per 3080. That became the connection to the linearizing diodes.

Only after the training was complete was it given thought to sell them. Build it and they will come. The designer said he'd recently returned from a visit to several? organ mfrs to discuss their needs.

Thomas Henry mentioned recently that the 13700 could replace the 3080. This little article showed that they are even closer than I understood them to be!

Even though 3080's are still around by the thousands; it's nice to have 2 in a single chip. 3280's are harder to come by. But still available too!

Randal

Dave Kendall wrote:
Hi all.

Would it be worth considering using LM13700s instead of 3080s?
(that is *if* the circuit would work with them.....)
13700s are still being made, and the scarcer 3080s can get saved for stuff that absolutely needs them. Of course pcb layout would be different.....

What do you guys think?

cheers,

Dave
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Clack



Joined: Aug 08, 2005
Posts: 438
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PostPosted: Sun Jul 01, 2007 4:02 am    Post subject: Reply with quote  Mark this post and the followings unread

yes, you say that they are plentiful but they really arn't in the UK or maybe even Europe! maybe it would be easy to modify ? I am very interested in this project but wont be able to build it with some overpriced imported part!
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filterstein



Joined: Mar 17, 2007
Posts: 42
Location: The Netherlands

PostPosted: Sun Jul 01, 2007 4:37 am    Post subject: Reply with quote  Mark this post and the followings unread

No need to worry about those parts.
Even if you can not get them locally, you can order them here:
http://www.futurlec.com
They got the whole lot; 3080, 3082, 13600, 13700
No minimum order and only 4 dollar tho ship to the UK.
Plus that you'll be blessed by a good exchange rate.
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