Multiples - Buffered Or Unbuffered

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TrueFallacy
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Multiples - Buffered Or Unbuffered

Post by TrueFallacy » Sat Mar 12, 2011 12:40 pm

Can someone explain to me the difference between the buffered and unbuffered mutlis. I am looking at the Intellijel mixers and also liked the idea of the unity mixer. If I am starting with a 6U system, how many do you suggest?

My ideas- One buff. and one unbuff, but then that unity mixer sounded like a nice add on as well. It's like an anti multi, right?
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polyroy
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Post by polyroy » Sat Mar 12, 2011 1:14 pm

Buffered multiples are powered so that each multiplied signal doesn't lose any power. Unbuffered means the signal is weaker after each output. I use passive ones but depends on what your using them for and how complexly your using the multiples in regards to stacking them up. I plan to get some buffered ones though when I get more oscillators.

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sduck
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Post by sduck » Sat Mar 12, 2011 2:41 pm

Buffered mults are handy if you're driving a bunch of VCO's from one voltage source, especially if it's an underpowered one like my mfos sequencer. Otherwise they're kind of overkill - you probably only need one buffered mult in your system. I use passive ones mostly.

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Klopfgeist
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Post by Klopfgeist » Sat Mar 12, 2011 11:52 pm

Unbuffered mults don't necessarily mean you will lose signal at each output. It's mainly impedance issues. Buffered mults are active.

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Post by sunsinger » Sun Mar 13, 2011 3:06 pm

I've got an Active (buffered) Mult from Suit & Tie Guy.
Some applications I use it for:

An "Active Mult", allows me to send a quantizer's output voltage to multiple oscillators without dropping the original pitch's voltage, keeping all oscillator splits off the mult in tune.
The passive mult will drop the pitch voltage each time the original voltage is split off the mult. Two splits is enough to drop the pitch voltages out of tune by a good bit.

At times, I will run a STG Time divider, or MOTM pulse divider. When sending a clock output to a passive mult, I notice clock dropouts or errors if I split clock signal out to 2 or 3 devices.
This no longer happens using the Active Mult. Active mults are very nice to have

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Re: Multiples - Buffered Or Unbuffered

Post by Del » Tue Oct 12, 2021 4:51 am

Just throwing in a question here rather than start a new thread for a minor issue...

Can anyone suggest a reason why an audio signal going from a filter to Intellijel’s buff mult and then a mixer is distorting when the same signal is not when going straight to the mix module? Other signals direct from an oscillator are being multiplied normally, without distortion.

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Re: Multiples - Buffered Or Unbuffered

Post by Kattefjaes » Tue Oct 12, 2021 5:03 am

Del wrote:
Tue Oct 12, 2021 4:51 am
Just throwing in a question here rather than start a new thread for a minor issue...

Can anyone suggest a reason why an audio signal going from a filter to Intellijel’s buff mult and then a mixer is distorting when the same signal is not when going straight to the mix module? Other signals direct from an oscillator are being multiplied normally, without distortion.
Feels like a leading question pointing to the possibility of the mult... clipping? That seems odd. Do you have a scope so you can put some sines through at different levels and see if that's happening?

Otherwise I'd wave my hands and mutter "something something impedance" in an unhelpful manner.

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Re: Multiples - Buffered Or Unbuffered

Post by Del » Tue Oct 12, 2021 6:34 am

Thanks. I don’t have a scope. That’s why I just did a sound test with a basic oscillator. The signal from the filter was looped back into it, but I can’t see that that should have any effect since the un-multed output was fine.

I swear, every time I spend some time with my synths or modular, there’s always one thing acting unaccountably, and I end up on forums or writing emails to customer support rather than making music.

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Re: Multiples - Buffered Or Unbuffered

Post by James_S » Tue Oct 12, 2021 6:47 am

If I'm splitting audio, passive, if I'm splitting CV, active.

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Re: Multiples - Buffered Or Unbuffered

Post by Del » Tue Oct 12, 2021 7:04 am

James_S wrote:
Tue Oct 12, 2021 6:47 am
If I'm splitting audio, passive, if I'm splitting CV, active.
How about stackable cables for audio? I thought I’d heard you weren’t supposed to use mult cables for audio. Probably another misunderstanding of mine.

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Re: Multiples - Buffered Or Unbuffered

Post by jsleeio » Tue Oct 12, 2021 7:24 am

Del wrote:
Tue Oct 12, 2021 7:04 am
How about stackable cables for audio? I thought I’d heard you weren’t supposed to use mult cables for audio. Probably another misunderstanding of mine.
was the person you 'heard' that from also advertising mult modules for sale?

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Re: Multiples - Buffered Or Unbuffered

Post by jsleeio » Tue Oct 12, 2021 7:25 am

Del wrote:
Tue Oct 12, 2021 6:34 am
Thanks. I don’t have a scope. That’s why I just did a sound test with a basic oscillator. The signal from the filter was looped back into it, but I can’t see that that should have any effect since the un-multed output was fine.
if it's not too much trouble, could you draw up a quick & dirty patch diagram for this? your "looped back" term here made me wonder ...
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Re: Multiples - Buffered Or Unbuffered

Post by Del » Tue Oct 12, 2021 7:33 am

jsleeio wrote:
Tue Oct 12, 2021 7:25 am
Del wrote:
Tue Oct 12, 2021 6:34 am
Thanks. I don’t have a scope. That’s why I just did a sound test with a basic oscillator. The signal from the filter was looped back into it, but I can’t see that that should have any effect since the un-multed output was fine.
if it's not too much trouble, could you draw up a quick & dirty patch diagram for this? your "looped back" term here made me wonder ...
Sorry. How about if I’m just clearer? I was feeding back one output of Filter 8 into the second input, and then sending another of the low pass outputs to a mixer.

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Re: Multiples - Buffered Or Unbuffered

Post by James_S » Tue Oct 12, 2021 7:38 am

Del wrote:
Tue Oct 12, 2021 7:04 am
James_S wrote:
Tue Oct 12, 2021 6:47 am
If I'm splitting audio, passive, if I'm splitting CV, active.
How about stackable cables for audio? I thought I’d heard you weren’t supposed to use mult cables for audio. Probably another misunderstanding of mine.
Well, I said in my post I use buffered (active) for CV and passive for audio, so stackable would be find for audio. I also have a 2hp passive module and a few Befaco mults which are the plastic ones that aren't racked. Anything CV input through my WMD Buffered Mult although I've also got a Lapsus Os on the radar.

For me, the bigger my rack gets, the more buffered mults I need. One is certainly nowhere near enough for me.

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Re: Multiples - Buffered Or Unbuffered

Post by jsleeio » Tue Oct 12, 2021 7:38 am

I mean the whole patch, not just the part you think is relevant
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Re: Multiples - Buffered Or Unbuffered

Post by Del » Tue Oct 12, 2021 5:41 pm

jsleeio wrote:
Tue Oct 12, 2021 7:38 am
I mean the whole patch, not just the part you think is relevant
In the interest of getting to the bottom of the issue, I would like to do what you ask. But it’s a bit of a cord salad right now. Maybe I’ll see if I can simplify things and isolate it.

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Re: Multiples - Buffered Or Unbuffered

Post by EATyourGUITAR » Thu Oct 14, 2021 8:54 am

jsleeio wrote:
Tue Oct 12, 2021 7:24 am
Del wrote:
Tue Oct 12, 2021 7:04 am
How about stackable cables for audio? I thought I’d heard you weren’t supposed to use mult cables for audio. Probably another misunderstanding of mine.
was the person you 'heard' that from also advertising mult modules for sale?

experiments aren't going to damage anything. try it and use your ears
I agree this sounds like some BS. The cable doesn't treat audio differently from CV. It either works or it doesn't. Maybe if someone had some actual data showing that stackables have higher capacitance compared to a mult module I would see why this argument is being made. I always hated stackables since before I was selling mults. I hated 3.5mm jacks when I was using a 5U modular with 1/4 jacks and euro was still using a lot of bad jacks. Now that the cliff and qing-pu jacks are newer improved models I have sold my 5U and I only have a euro system. Only the vintage eurorack modules have some bad jacks on some of them. Stackables have had some revisions in the design and manufacturing. Some of them are as you would expect and some of them are prone to failure. But even the best stackables will put added stress on the jacks in your euro modules that will lead to premature failure IF your euro modules are mounted vertically. If your eurorack is flat on a table then it is up to the user to be careful with sideways pressure when inserting a patch cable.
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jsleeio
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Re: Multiples - Buffered Or Unbuffered

Post by jsleeio » Thu Oct 14, 2021 5:01 pm

Del wrote:
Tue Oct 12, 2021 5:41 pm
In the interest of getting to the bottom of the issue, I would like to do what you ask. But it’s a bit of a cord salad right now. Maybe I’ll see if I can simplify things and isolate it.
please do, if you can

I ask because you mentioned oscillator => mult => mixer

... but then also mentioned a filter, and it kinda sounded like you had patched a feedback loop: filter output => filter second input. If you weren't quite careful with the level of that second input (does it have an attenuator?) you could easily send the filter input into clipping.

Also when you do that, and when you turn filter resonance up, you are creating a resonant peak. This is essentially what the resonance (or "emphasis" or "regeneration" in some filters — just different labels for the same thing AFAIK) control is doing... feeding the filter output back to the filter input with some degree of attenuation.
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Re: Multiples - Buffered Or Unbuffered

Post by Dave Peck » Thu Oct 14, 2021 7:42 pm

I use a passive mult system to send 1V/OCT pitch CV to eight oscs simultaneously and they all track very reliably and accurately over a seven octave range. It all depends on how the 1V/OCT source circuit is designed and how the pitch mod inputs of the destination oscs are designed.

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