Behringer System 55

[SkyWriter]

There is one trimmer for triangle symmetry, and two for sine.
Triangle adjustment is first. It lines up the ends of the positive peak. You only have to set this once in the calibration.

The Sine, done 2nd, one trimmer adjusts the bottom symmetry, the other the top symmetry of the sine wave.

[emuarc]

Picture of the AMSynths 984 Quad Mixer - sounds fantastic - limited run goes into production next month

[SkyWriter]

That's a beauty Rob!

How many HP ?

[SkyWriter]

I'm going to sprinkle this around. AndyHornBlower on GS came up with a great way to add a low frequency dampening to Behringers potentiometers - stops the extra little drift you get when you let go the knob, and have to nudge it, or tap it, or breath on it to go back where you left it :0)

https://www.gearslutz.com/board/showpos ... tcount=488

[emuarc]

That's a beauty Rob!

How many HP ?

38HP, high grade pots and knobs, with production units at £250, the panel is black adonised rather than the Behringer printed ali.

[SkyWriter]

That's a beauty Rob!

How many HP ?

38HP, high grade pots and knobs, with production units at £250, the panel is black adonised rather than the Behringer printed ali.

I'm sold! 4X4's are wonderful tools. And I love the look.

Btw, webstore says 48HP.

[KSS]

Photo proportions confirm 38HP. <--Because either here or there could've been the typo.

[SkyWriter]

Photo proportions confirm 38HP. <--Because either here or there could've been the typo.

Ah! I can put my little rulers away then :0) thanks KSS!

This mixer is really a welcome addition to us 55 nutz with complement B** fixations. I've got 6 CP3A-M's in my config already, mostly for CV controls and audio sub-mixes. I like to patch in stereo, and a 4x4 is a gawdsend* for multipath audio patching :0) I used to have a couple of peavy 6x6 monitor mixes in my old system - noisy but ..... wow what you could do with them! I'm thinking, I'll have to signup twice for rob's builds to be happy.

Rob came through with my xmas wish!

*-I want to say "nondenomoinational-mythical-figurhead-send". But it's distracting in the mainline statement.

**-you're gonna shot your eye out kid!
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Rob, gotta ask what're the screw sizes you show there? One is a rail screw the other looks like subassembly. Just looking to match up hardware. Yeah, I am OCD about some stuff. I can have an inch of dust, but if the screws don't match, I'll never be truly happy. :0)
=======
Decided to put mute buttons on the CP3A-M's instead of the toggles. Just much quicker to mute stuff with a button, and not a lot of space to swing a toggle. Just need to find the right subminiature push-on, OFF-ON. "Red" button :0) no LEDs, I hate LEDs.

[SkyWriter]

Had a minor expansion over xmas. :0) The two emptys are for a backordered 960 on top, and AMsynth's AM984!! <- I keep getting the number wrong. Heh!

The Atom and Smog are placeholders for 4th back ordered 921, and a A-101-1V Vactrol Steiner Filter to complete the cabinet. Also have to finish the B914 cap mod (Top B914). I wish initially bummed about the 12-16 degree angle between rows on the Go cabinet after stacking three. But the angle isn't excessive. I know lots of folks like the slammed 45 degrees.

I love Ebotronix's jungle gym setup :0) you can almost climb that thing to get the top knobs :-)

What're other builds doing?

In this image it's just sitting on top. I have a couple of 0.5" x 0.5" posts to tie them together, and some dowels to pin them together. I'll finish the sanding and stain it once the rest of the parts arrive. I can't believe I can just reach those top knobs :-)

In the meantime, toggles, buttons, switches and fun to add!

Still can't believe I have the equivalent of like 2 times a System 55 plus a Complement B - although it's like a transistor radio version of Pop's big tube console.
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Interestingly, the case lips above and below the rows look like they might be separate pieces glued on. Certainly you can't mold it that way. It they could be popped off there would be lots of room for mults, trunk panels, maybe even those weird short 1U modules. I might put a little cable management hooks there.

[Hyberus]

That's a lovely system. Personally I'm sticking with a 914 and a 904b for the moment, but maybe one day I will build my Chris Franke Moog . . .

[SkyWriter]

That's a lovely system. Personally I'm sticking with a 914 and a 904b for the moment, but maybe one day I will build my Chris Franke Moog . . .

I literally love it! Thank you!

Looking forward to seeing a Chris Franke recreation. :0)

So much cool synth stuff this past year. So much work left to be done too. :-)

[Hyberus]

Four 960s for a start . . .

[SkyWriter]

Hmmm.... experiments with knobs.

"The middle knob was just right"

Until I have a precision BPM Clock to work my delay-line polyrhythms - this is going to work OK.

[NiteEagle]

Daniel Fisher having fun with stereo 914 FFBs.

[SkyWriter]

Neat video! I have to put my other B914 back together. :0) been busybusy.

[Xtheunknown]

What are the Behringer System 55 module voltage ranges for:

- VCO output (is it +/- 5 volts)
- VCF input (will they accept +/- 5 volt output from my other Eurorack VCOs)
- ADSR output (0-8V or something else)
- ADSR switch trigger

Any help is greatly appreciated.

[SkyWriter]

What are the Behringer System 55 module voltage ranges for:

- VCO output (is it +/- 5 volts)
- VCF input (will they accept +/- 5 volt output from my other Eurorack VCOs)
- ADSR output (0-8V or something else)
- ADSR switch trigger

Any help is greatly appreciated.

These are measured on factory calibrated modules:
921 and 921B audio outputs are Bipolar +/- 1 VDC, 2VPTP.
921 AUX bipolar output is +/- 4 VDC, 8VPTP. Unipolar 0-4 VDC.
911 output 0-6 VDC
Triggers are about 0-4 VDC
960 data output can get up to 8 VDC at 4X


You need some attenuation and boosting to get everywhere. For me, it's not a big deal.

[Xtheunknown]

What are the Behringer System 55 module voltage ranges for:

- VCO output (is it +/- 5 volts)
- VCF input (will they accept +/- 5 volt output from my other Eurorack VCOs)
- ADSR output (0-8V or something else)
- ADSR switch trigger

Any help is greatly appreciated.

These are measured on factory calibrated modules:
921 and 921B audio outputs are Bipolar +/- 1 VDC, 2VPTP.
921 AUX bipolar output is +/- 4 VDC, 8VPTP. Unipolar 0-4 VDC.
911 output 0-6 VDC
Triggers are about 0-4 VDC
960 data output can get up to 8 VDC at 4X


You need some attenuation and boosting to get everywhere. For me, it's not a big deal.

Thanks so much! Do you know if the 904A will work well with Eurorack VCO voltages (typically +/- 5V or 10V P-P).

[SkyWriter]

Yes, I just have to attenuate audio going from Mutable to B55 a bit, or it distorts a bit. Some might like that aspect. A fixed attenuator can be built into a cable too.

[Cyber-N Powers]

A strange 960 behaviour: If step one is set to skip, and oscillator turned on, it behaves like step one is set to stop. And if step one is set to skip after a sequence starts running, and another step is set to skip at the exact moment the step is active the sequence jumps to step one which behaves like it is set to stop. Is this a bug or a feature?

[Zaphod B]

I've investigated today on the Boog 914 filterbank to find the individual outs for each band. There are solder points labeled TP1 to TP16 on the back of the module, so it was an easy task with an oscilloscope and a sawtooth oscillator at the input.

Here are the results:

N Frequency Label
0 LP TP7
1 125 TP3
2 175 TP8
3 250 TP14
4 350 TP2
5 500 TP9
6 700 TP15
7 1000 TP4
8 1400 TP5
9 2000 TP16
10 2800 TP1
11 4000 TP12
12 5600 TP13
13 HP TP6

TP10, TP11: ???

So, with 2 Boog 914 and 14 VCA (let's say 2 new and cheap Doepfer A-130-8 8 VCA/ mixer), you've got a 14 bands vocoder for 370 euros.

Now, I have to think about how to put jack sockets on the module (there is room for them up and down the panel).
Any suggestions?

I found your suggestion of making a vocoder using existing components intriguing and followed up on it. I had previously made one in software using a Daisy Seed and was really curious how an analog version would turn out. So I created an analog vocoder using 2 B914s, one 14 envelope follower board by my own design, 2 doepfer B130-8 vca arrays, a mixer and I threw in a patch panel as well (connections are normalized but using patch cables other mappings are possible). Here is a short video showing the device. I'm using a drum loop here as a modulator and a synth pad as a carrier signal. For your (and my) enjoyment I added some delay, reverb and panning. This acoustic recording was made using a Zoom h4n pro: Vocode-O-Matic A(12+2)

[SkyWriter]

Very cool (Ow! My Brains!) Zaphod B! I've been most interested in the band-patchbay. I got Wraps yesterday, which allows remapping the format effects too. I like it a lot!

It has some of the features I was looking for in a hardware vocoder; shiftable patch format, variable envelope follower response.

[galanter2]

I've investigated today on the Boog 914 filterbank to find the individual outs for each band. There are solder points labeled TP1 to TP16 on the back of the module, so it was an easy task with an oscilloscope and a sawtooth oscillator at the input.

Here are the results:

N Frequency Label
0 LP TP7
1 125 TP3
2 175 TP8
3 250 TP14
4 350 TP2
5 500 TP9
6 700 TP15
7 1000 TP4
8 1400 TP5
9 2000 TP16
10 2800 TP1
11 4000 TP12
12 5600 TP13
13 HP TP6

TP10, TP11: ???

So, with 2 Boog 914 and 14 VCA (let's say 2 new and cheap Doepfer A-130-8 8 VCA/ mixer), you've got a 14 bands vocoder for 370 euros.

Now, I have to think about how to put jack sockets on the module (there is room for them up and down the panel).
Any suggestions?

I found your suggestion of making a vocoder using existing components intriguing and followed up on it. I had previously made one in software using a Daisy Seed and was really curious how an analog version would turn out. So I created an analog vocoder using 2 B914s, one 14 envelope follower board by my own design, 2 doepfer B130-8 vca arrays, a mixer and I threw in a patch panel as well (connections are normalized but using patch cables other mappings are possible). Here is a short video showing the device. I'm using a drum loop here as a modulator and a synth pad as a carrier signal. For your (and my) enjoyment I added some delay, reverb and panning. This acoustic recording was made using a Zoom h4n pro: Vocode-O-Matic A(12+2)

Is it really as easy as soldering a wire to each solder point? They all get tied to a single summing node for the regular output right? Wouldn’t this result in cross talk of some kind on the individual outs? And wouldn’t each of the individual out wires need some kind of buffer amp on the way out to other modules?

(I ask just knowing enough electronics to mess things up...)

[Zaphod B]

Is it really as easy as soldering a wire to each solder point?

Yes and no. The envelope follower is a rectifier circuit that should be sensitive enough to give an output also for low level signals. I added an op-amp for each of the 14 filters. I did not mention that in my initial post because the op-amp could have been part of the envelope follower, which at present it is not. The current version of the vocoder is a prototype which I may redesign.

They all get tied to a single summing node for the regular output right?

Yep, I used 2 VCA blocks and add their outputs using a regular mixer.

Wouldn’t this result in cross talk of some kind on the individual outs?

For 12 of the 14 filters I would say No: in principle their signals stem from different frequency bands so they occupy a different part of the audio spectrum.
For the remaining LOW pass and HIGH pass filter the signals may influence some of the band pass signals in the summing stage. But I wouldn't worry about this. This would happen in the B914 itself as well.

And wouldn’t each of the individual out wires need some kind of buffer amp on the way out to other modules?
(I ask just knowing enough electronics to mess things up...)

There are no individual out wires in my design that lead to jack socket if that is what you are asking about. The B914 filter bands are fed using the test points listed in the initial each to their own VCA and each one is controlled by the output of one of the 14 envelope followers. I've used flat cables to make the necessary connections.

[galanter2]

Right, so if one wants more general purpose individual band outputs on the front panel, they would each need an op amp then.

(What I meant by crosstalk was this. I solder a wire to the 1000 hz solder point. What keeps the signal from the, say, 1400 hz band finding its way out there too?)