Moog Modular Patching Question...

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EricK
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Moog Modular Patching Question...

Post by EricK » Fri Sep 07, 2012 2:31 pm

In a very basic patch on a modular, where does the cp mixer fall in the signal chain?



I have read here that the mixer is a very important part in the "Moog sound" overdriving it a little, but I am not sure if this comes before or after the VCA.

I know how the signal chain works in the Voyager, but why I'm asking is because I'm going to buy the STG Soundlabs five channel mixer, which is supposed to be a clone of the RA Moog CP3 topology, and I'm trying to figure out where to mount it in the cabinet.

Thoughts?

Eric
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chromium
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Re: Moog Modular Patching Question...

Post by chromium » Fri Sep 07, 2012 6:29 pm

Well, you could use that STG mixer in a number of ways, summing CVs/modulators or mixing audio signals. I have my mixers placed sort-of centrally in the cabinets because of that, but it's all pretty subjective - no wrong way to do it!

FWIW, the STG stuff is among my favorites. I have the Wavefolder, Diode Ladder filter, and Signal amps, and those seem to make it in many a patch. I bought parts to build a couple CP mixer clones (power regulators and all) before he started building these. Still haven't gotten around to that... Ah well, one of these days!
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Re: Moog Modular Patching Question...

Post by CZ Rider » Sat Sep 08, 2012 3:03 am

EricK wrote:I'm trying to figure out where to mount it in the cabinet.

Thoughts?

Eric


Well, the nice part about the Dotcom is, and unlike the Moog modular, there is no backplane. So you can move almost any module anywhere at any time. My original plan of module locations was to put the oscillators on the bottom.
1st module layout:
Image
While it looked nice, when patched up, the oscillators were difficult to adjust with all the patch cords in the way. So it was easy to decide on a more practical module layout, after I used it for a time. I ended up putting all the most adjusted modules on the top row.
Image
As far as where in the chain the mixer goes, that is a big part of the modular fun. The Dotcom system above has both a STG mixer and the Q112 4ch. mixer. The patch pictured has the three saw waves into the Q112 and three pulse waves into the STG, each ones output into the two Q150 VCF audio inputs. I just spent the past 1/2 hour trying to figure out how to get the STG mixer to do the Moog modular feedback loop distortion trick. Need a better module description for the STG, but ended up taking the leftmost output of the STG into an unused Q108 VCA, and feeding the negative output back into the STG mixer. So with that patch a VCA is in the middle of the mixer, with the envelope controlling the sharpness of the feedback distortion effect. Fun stuff, and it sounded nice!

The Moog is a really different animal. Even though they look alike with the MU format, there is a patching philosophy that does not carry over from the original Moog system with the CP3 mixers and 901 oscillators. For instance the mixers aided in boosting the 1.2 volt P-P 901 oscillator outputs for modulation sources, by doubling on each mixer input. No real need to double a Dotcom or any other modern 10 volt P-P oscillator for a CV source. And the Moog 901's have seven 1 volt/oct adding CV inputs, so the CP3's did not need to be a precision tuned mixer for pitch adding. Another Moog patching technique was any low voltage could be doubled or tripled by simply splitting via a multiple and patching into a CP3 or any of the seven CV ins on the 901. The CP3 also could act as a reverse attenuator, source for simultaneous opposite wave forms for CV or audio, or just a modulation CV mixer. A real modular approach.
Here is a patch I am using now on the Moog.
Image
The left CP3 has two oscillators patched with both saw and pulse. Saws at about 7 and pulses at about 6. Any higher settings result in massive distortions. The positive output of that CP3 feeds into the right CP3 input set at about 6. A third oscillator pulse added at about 6, with another input from the 905 reverb set at 7. The negative CP3 output feeds the 905 reverb for a feedback loop. The large knob on the 905 acts as a "Badass Knob". Turned counter clockwise increases the Badass effect, it goes from Mellow to past Eleven. The left CP3 positive output feeds the 907 FFB, with the 907 feeding the 904a Low Pass filter. You could put a 902 VCA in between the 907 and 904a for an even hotter signal if you wanted. The 904a feeds into a final 902 VCA. Simple Minimoog type patch where the CP3 plays a big part of creating that sound. The fun part is figuring out other ways to use those same modules for completely different sounds. It's endless!
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Re: Moog Modular Patching Question...

Post by EMwhite » Sat Sep 08, 2012 11:47 am

I'm new at this as you are, Eric but there is a thread on Muffs in the STG section about how to go about getting 'that' sound. Suit trims/calibrated the module before shipping the mixer but your mileage will vary based on signal levels going in and the type of signal, etc.

JLR to the rescue, he put together a quick video of various waves through an STG mixer with a view at an Oscope. You don't have his problem yet (trying to get that sound and not able to) since you haven't yet taken receipt, but you should have a read of the thread, it's interesting stuff.

One thing you will want to do (as I have) is to 'exits' the Voyager via effects loop insert on the tip, never to return (ha ha). In other words, have the audio exit the Moog mixer; go into the STG mixer for that crunch/wave distortion, then into a filter and VCA of your choice while leveraging envs from your Voyager panel via VX-351.

I'm using a MOTM-440 filter and a home made VCA based on the 13700 design and it sounds incredible.

But nothing stopping you from using the sleeve return of a typical Insert cable back into Voyager using STG mixer just to add color.

My other bit of advice is hurry up and be prepared to wait. Meaning: HURRY and get your STG order in, because you never know when Suit is going to run out of boards or panels; then be prepared to wait 4 weeks or 8 weeks. He runs around alot and is involved in so many things including collaborating with D3 on the Archangel which is busy in build right now! But well worth he wait.
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Re: Moog Modular Patching Question...

Post by Goom » Wed Sep 12, 2012 10:13 pm

EMwhite wrote:I'm new at this as you are, Eric but there is a thread on Muffs in the STG section about how to go about getting 'that' sound. Suit trims/calibrated the module before shipping the mixer but your mileage will vary based on signal levels going in and the type of signal, etc.

JLR to the rescue, he put together a quick video of various waves through an STG mixer with a view at an Oscope. You don't have his problem yet (trying to get that sound and not able to) since you haven't yet taken receipt, but you should have a read of the thread, it's interesting stuff. (snip)


Would you happen to have a link to the threads? I couldn't find it. Thanks!

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Re: Moog Modular Patching Question...

Post by EMwhite » Thu Sep 13, 2012 12:20 am

Goom wrote:
Would you happen to have a link to the threads? I couldn't find it. Thanks!


Here: http://www.muffwiggler.com/forum/viewto ... &start=all

Be sure to scroll down to the video posting by John L Rice from June 17th for the demo.
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Re: Moog Modular Patching Question...

Post by EricK » Thu Sep 13, 2012 12:56 pm

Thanks for all the replies (and links/photos), guys.

CZ,
Can you send a link to the stuff that you did when you acquired that s&h unit? That to me was the epitome of the Moog sound, and was the first example that came to mind when Just Me mentioned the STG mixer I'd like to emulate that Moog thump, which I am assuming is both the envelope and the mixer?


To anyone else,
So, can someone explain why the mixer makes so much of a difference? If it just squares the wave up, generating a new waveshape, then couldn't you do that with a special oscillator or is there something else that is going on (such as AC coupling in the Taurus) that is more than just a unique waveshape?

The reason why i asked about the signal chain is because I didn't necessarily think it would be pertinent to generate a unique waveshape and then filter it out, which is why I thought it would be VCO>VCF>Mixer>Vca positioning.

I emailed STG minus the specifics of this post, and he recommended the same arrangement as the Voyager.

Thanks again,
Eric
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Re: Moog Modular Patching Question...

Post by Just Me » Thu Sep 13, 2012 10:31 pm

What happens to the sound is as subjective as the various distortions guitarists obsess about. It is the topology of the amp that creates the sound. Why does the tube brand make a difference in your amp? Same sort of thing.
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Re: Moog Modular Patching Question...

Post by CZ Rider » Fri Sep 14, 2012 12:53 am

EricK wrote:CZ,
Can you send a link to the stuff that you did when you acquired that s&h unit? That to me was the epitome of the Moog sound, and was the first example that came to mind when Just Me mentioned the STG mixer I'd like to emulate that Moog thump, which I am assuming is both the envelope and the mixer?

Not sure, but there is this one demo of the 1125, also had a polyphonic Voyager playing over top.
Moog Modular triggered by 1125 Sample Hold MP3 4.7MEG download

That classic Moog modular sharp pluck sound is one that kind of eluded me. I would hear this almost bass guitar type pick sound along with the bass note decay in old Moog recordings. Could never get that sound on my Mini. Just recently I upgraded my Moog to have the same envelope arangement the large Synthesizer III C/P systems had, by adding the 911A delay and third 911 envelope generator. And there it was! By firing two envelopes, one a short/sharp pluck along with a slower decay for the bass string into the VCF, I was able to duplicate that picked bass guitar sound. Also a bit of distortion from those CP3 mixers with the loopback. Same patch as in that photo in the earlier post.
Moog Modular Distortion Bass Pluck MP3 3.2MEG download
Here is the upgraded envelope arangement.
Image
I would imagine you could get a similar pluck sound with a Dotcom by adding an extra envelope to modulate the filter.

That whole mixer distortion/saturation thing, is just one of those classic sounding elements missing on some systems. The distortion "dirtys" up the tone a little, and by using descrete components, you get a different type saturation then you would using op-amps. So using a mixer in that way just gives you more choices in tone coloring. Since my Moog had two mixers, I have put one mixer after the VCF but before the VCA, to add in sine waves from the oscillators, the way they did it on the CS-80.
But I am having a ton of fun now that you got me thinking where the mixer goes EricK. That VCA in the middle of the mixer for feedback sounds great. On the Moog I put a 902 VCA in between the 907 FFB output and the 904A VCF input. An envelope/VCA controlled boost. The signal was always a little weaker after passing through miles of wire in those coils of the 907 filter bank. That 902 in the middle is a nice way to control the gain, and the gain can be shaped with an envelope, nice!

Did read that Muffwiggler thread about the STG mixer. The STG mixer was designed to work with 10 volt P-P oscillators, like the Dotcom ones. Won't distort with lower amplitude oscillators like the sine out from the 2.5 volt RS95E or the Moog Voyager oscillators. Have to boost them or multi them to get up to those levels.

So I was curious, just how much I distorted the waves from my 901's, after going through two CP3's with some feedback added. (Good question EricK!) So I pulled out the scope and had a look. I generally mix these by ear, and have an idea where the magic tones are for me. To my surprise, I was not really distorting them much, and almost all the flat clipping was on the bottom side. The CP3's are not symetric and on the -6 rail, clip before the upper +12 rail. It's a subtle area between when just the bottom is clipping and where the top clips, but that is where I usually find that magic tone. When the top begins to clip just a bit louder, the sound looses something. Never knew it was the top clipping I always back off from, I do it by ear? Interesting that the CP3's are lopsided. The STG is a tiny bit like that too, but I had a difficult time getting just the bottom half clipping. Might be a way to offset with those voltage inputs, so I must experiment more with the STG mixer.

I guess we all have a different idea what that classic Moog Modular sound is. To me it's a filtered sound, and most of the demos I hear from MOS-LAB don't seem to have that high end filtered sound you would hear on so many old Berlin School recordings. My 904a has a limited range on setting 1, I do not really hear that on those demos where I can see their 904A clone is set on 1. Perhaps they thought it was a defect and fixed it? The Dotcom filter clone does not have this either, but there is not a range selector on it.
From the Moog docs for the 904A:
" Frequency range switch sets the band over which the FVC knob operated in two-octave steps:
1} 1Hz to 5kHz
2} 4Hz to 20kHz
3} 16Hz to 80kHz"
So the 904A at the range setting 1 has a wall at 5kHz, and no matter how much voltage you send to the inputs it stops there.
Here is an MP3 example of the 904A wall:
Moog 904a demo of the 5kHz wall MP3 2.1MEG download
Starts out as a standard Moog sounding sequence. At the 25 second mark, I turn the filter knob all the way up. That's as much as the filter will let through at setting 1. At 35 seconds I turn the filter to setting 2. Now you can hear the the high frequencies that were being filtered. At 42 seconds I turn the filter knob down so you can hear the envelops shaping the filter again. Doesn't sound bad on either setting, but I can hear that wall on many old recordings like TD's Pheadra sequenced Moog and others.
Guess you would need another fixed filter after a Dotcom Q150 to simulate the 904A wall?

The classic Moog sound to me are the ones where you hear them, you know right away it was created by a large Moog. There is a lot of overlap where even a Mini will sound similar, or even an equally equiped large modern modular. For me it almost always involved the Fixed Filter Bank, another really filtered tone, but seems the toughest to replicate with other gear.
The classic Moog Fixed Filter Tone:
The Moog FFB tone MP3 2MEG download
Oh, and can't forget just how much bass comes out of these old Moogs too!
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Kevin Lightner
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Re: Moog Modular Patching Question...

Post by Kevin Lightner » Fri Sep 14, 2012 2:23 am

For me anyway, I find the Minimoog's tone more enjoyable than the modulars.
It's just frustrating being so limited in what you can do with it.
I also like the Minimoog glide better than the modular's.

As to what the "Moog sound" is, (again- for me), it's the filter, oscillator jitter (901s anyway), asymetric distortion (as CZ pointed out, which incidentally, the CP3As don't have) and some of the envs.
I also personally feel that many people couldn't tell a Moog from, say, a Polyfusion if they didn't know.
(not everyone... "many people")

I worked on Chris Franke's big Tangerine Dream modular that was a combination of Moog, PPG and Projekt Elektronik modules.
What struck me funny is when Chris asked me to lunchbox some of the PE filters.
When I opened them up they had.... ARP filters in them. (!)
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Re: Moog Modular Patching Question...

Post by Goom » Fri Sep 14, 2012 9:44 pm

EMwhite wrote:
Goom wrote:
Would you happen to have a link to the threads? I couldn't find it. Thanks!


Here: http://www.muffwiggler.com/forum/viewto ... &start=all

Be sure to scroll down to the video posting by John L Rice from June 17th for the demo.


Thanks! Nice info there....

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Re: Moog Modular Patching Question...

Post by EricK » Sat Sep 15, 2012 11:30 am

CZ Rider wrote:The Moog is a really different animal. Even though they look alike with the MU format, there is a patching philosophy that does not carry over from the original Moog system with the CP3 mixers and 901 oscillators. For instance the mixers aided in boosting the 1.2 volt P-P 901 oscillator outputs for modulation sources, by doubling on each mixer input. No real need to double a Dotcom or any other modern 10 volt P-P oscillator for a CV source. And the Moog 901's have seven 1 volt/oct adding CV inputs, so the CP3's did not need to be a precision tuned mixer for pitch adding. Another Moog patching technique was any low voltage could be doubled or tripled by simply splitting via a multiple and patching into a CP3 or any of the seven CV ins on the 901. The CP3 also could act as a reverse attenuator, source for simultaneous opposite wave forms for CV or audio, or just a modulation CV mixer. A real modular approach.

Image

You may remember at one point I was looking to have a NOS version of this built and only got so far as the 921a. Before I got my Voyager and before I considered .com I spent a lot of time looking at this picture thinking about how it would be patched in a third-eye attempt to learn how to use it. What you just described above is an aspect of these instruments that I would have never anticipated. Very interesting. Id like to encourage you to make some more videos.

Thanks,
Eric
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Re: Moog Modular Patching Question...

Post by Kevin Lightner » Sat Sep 15, 2012 1:44 pm

Moog 15s have CP3As and 921s.
921s have hotter outputs than 901s.
CP3As are powered by +/- 15v instead of the -6/+12 CP3s use.
They have more headroom and gain.
3As also use opamps instead of discrete transistors.

The 921 (not 921B) has the most gain of any vintage Moog oscillator.
One can obtain much deeper modulation or trigger things more easily using a 921.
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Re: Moog Modular Patching Question...

Post by CZ Rider » Sun Sep 16, 2012 4:23 am

Unless there was a revision change I'm unaware of, I always thought the Moog 15 had a discrete transistor mixer. The mixer I have here, matches the schematics for the 15, very similar to the CP3, without the click filter and has an added trimmer for DC balance. The model 15 did have the 909 power supply, almost like the old 910 PS, without the extra 10 volt output. So no +/- 15 Volt like the larger 930 supply had on the 35, 55 models. Here is a mixer board from an early model 15. Very similar to the CP3 with matched transistor pairs, but note the added trimmer as there are two.
Image
So I would imagine the 15 sounded different from the 35 and 55 models, as it had the asymmetrical clipping the older Moogs with CP3 had. I thought that was one of the better features of those single cabinet Moogs. Even with the newer 921's they still had the older style of mixer.

While the 921's specs are listed as a little hotter,( 0.5 vs. 0.6 ) it's not by much. The big 921 has the aux outputs that are almost the same in form and function as the 901-C output stage that boost the output for modulation purposes. The 901-C and 901-D both amplified and rectified the 901 outputs, much like the aux. section on the large 921. Probably nowhere near as hot as the the 7 volt output from the 921 aux. section, but there is an easy way to get that kind of output from the 901's. The 901-C did amplify the 901 waveforms and clipped the pulse wave. Not sure how much it amplified? But this is one very simple circuit I would like to breadboard and clone to try out.
Moog 901-C schematic
The schematic shows a circuit very much like the CP3 that both amplifies and outputs a +/- waveform selected by a 6 position rotary. With a dual ganged output attenuator, and a very interesting positive and negative clipper for the pulse wave.
A small pic of the 901-C,(looks almost identical to the 921 aux. section.):
Image
And then there was the bigger 901-D that both amplified and offered variable clipping per waveform. Had a mixer section below that looks surprisingly like the CP3 with 4 inputs and a master gain to mix together the modulation waveform. Probably could make some very interesting modulation waveforms with this. Might sound interesting too!
Image

So what happened to the 901-C and 901-D? They all but disappeared by the time the 1968 system I, II, and III were introduced. My guess is they were not as necessary as they were in the older '65 -'67 systems. In those early systems there was no CP3 mixer yet, just a single CP mixer. That was usually tied up mixing the oscillator audio outputs. So something was needed to both boost and mix complex modulation waveforms. With the later system I, II, III, there were more mixers and more CV inputs to the oscillators with the new lighted switching CV bus system. The new systems now had a dedicated mixer under every large 901, kind of like a modulation mixer, that could both double and invert a waveform for modulation purposes.

So how do you get a 901 to output a 5 or 6 volt P-P swing like the 921 can? That's easy, all you need is a multi and a few patch cords. The large 901 is like the LFO oscillator and has a seperate attenuator for each waveform. Just take the variable waveform output you need and patch that into a multiple. Then patch the three multi outputs into the three inputs on either a CP3 mixer or the three inputs on the 901A driver. Use the variable knob above the 901 waveform as a modulation ammount. Using a multi as a multiplier is one of those basic patching schemes on an old Moog many overlook, and it applies to any voltage from oscillator outputs to 911 EG outputs. If you decide to use the CP3 by adding two or more of the same waveform, you can multiply the voltage many times and add others, along with both a positive and negative output. For even more fun you can run the output through a 902 VCA for voltage controlled modulation via an envelope or ribbon controller or whatever. This is the modular way of thinking, where you have these basic building blocks that you decide how to use them and in which way. Even though a small Moog system like the one I have might seem old fasioned and limited, it really isn't. The only limiting factor is your imagination. I'm happy to say I still see my old Moog as this unlimited source of sounds, I never get tired of finding new ways to use it. This is the true joy of using a modular synthesizer as it never gets old.
I just recently discovered a patching scheme to set the scale of the 901's right from the front panel. Very handy in a live situation, I can tune and scale the 901's is a few seconds now. Always something new and unexplored!
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Re: Moog Modular Patching Question...

Post by Kevin Lightner » Sun Sep 16, 2012 6:18 am

Fwiw, I didn't say the Moog 15 had a CP3 or CP3A.
I simply stated that the 3A used opamps running on hotter voltages than the 3.

The +/- outputs of the large 921 are indeed much hotter than the separate outputs or the outputs of 901s or 921Bs.
Take a scope and you should see this. :)
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