Track Output to Octatrack Input

Elektron Gear Analog Rytm
#1

Hello everyone,

I have a small problem with the separate outputs of my Analog Rytm Mk2.

Connections:

  • AR BD – > Octatrack A
  • AR SD – > Octatrack B
  • Octatrack Main --> AR Ext In --> Analog Heat In

I would like to process the BD and SD outputs in my octatrack and have a problem with the incoming signal.

To do this I relied on the documentation of the two machines and on this page of support.

What seems strange to me is that the separate outputs are not balanced but, according to the document above, the signals they transmit is stereo.

So using a TRS cable my octatrack (which itself has balanced outputs) must invert the phase and this causes a big drop in volume as well as an alteration of the signal.

And trying with a TS cable, I theoretically only have part of the signal and therefore a significant drop in volume too.

I tried to recover the signal via Thru machine with these settings:

src-page

  • Input A/B – A
  • Vol – +63
    (same for B input on another thru machine)

Where

src-page

  • Input A/B – A+B
  • Vol-- +63

(No gain on mixer page and amp page)

On my Analog Rytm, all off my track volume are set to 100 and all amp page too (and machines volume are up to max) for this two tracks.

Of course I tried all these configurations with both types of cables.

And so it was after long hours of reflection, reading the documentation and all the subjects that could relate to the subject that I came to ask for a little help to understand what I did not understand. .

I find myself distraught in front of something that seems so simple to me.

Any help or ideas would be greatly appreciated.

Thank you for taking the time to read this.
Have a great day.

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#2

Welcome to Elektronauts …

The linked reference seems incorrect to me, with regards the AR Mk2 individual outputs I have always understood they were mono (as with the Mk1), and the only difference is that the Mk2 has 8 TRS outs (as opposed to 4 on Mk1) - so its 8 TRS outputs are in fact impedance balanced, not Stereo, even though they are on a TRS socket

So the stipulation in that linked document is factually incorrect imho

I’ll ping @eangman who curates the device documentation as i believe the information to be correct there, but incorrect on that linked page - this can be directed to the appropriate person to correct accordingly

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#3

Oh ok… The documentation may be wrong but I still don’t understand why this simple connection doesn’t work. I hope someone will have an idea about this.

Thanks for passing the info on to the right people.

And thank you for the welcome.

#4

Disclaimer!
I’m pretty sure this theory is correct, but I’ve paid no mind to getting the actual pinout correct in this explanation because I think it’s unnecessary for the concept to be understood. If you want to know specifics you can get into that yourself.

TRS / “stereo” cables & jacks are just wires; the signal going through them might not / doesn’t have to necessarily be “stereo”, as in a L&R pair of signals. It can be “mono”, meaning 1 signal or channel.

When the signal is stereo and going through a three wire cable ( TRS ) it’s essentially two TS cables sharing a ground like this
Wire #1 = Left channel + / T
Wire #2 = Right Channel + / T
Wire #3 = Left AND Right Channel - / S

When the signal is Balanced ( going through the same 3-wire cable, but “mono” it looks like this:
Wire #1 = +
Wire #2 = -
Wire #3 = ground

What this means is that a balanced cable / TRS or XLR can carry twice as much current as a two conductor/ TS cable

In practice, this means that using a TS cable in a TRS jack will result in a signal loss of around 10db, because the extra wire isn’t present and being shorted to ground.

This is why the signal is quieter with the TS cable… you are getting less of the information, but not for the reason you posted. It has nothing to do with “stereo” per se, because the 3-wire, balanced cable can also carry a mono signal - it just delivers more of the mono signal.

Hopefully this helps.
SCG

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#5

But none of the Elektrons have this kind (Normal/Full/Differential) of Balanced connection

So in reality the Ring (2) is not sending an inverted signal, you specifically don’t get a stronger signal whether you use a TS to TS cable or a TRS to TRS cable between an Elektron and a compatible device. You may get noise rejection in very long cable runs, so it’s advantageous to adopt impedance balanced as an option into your product, especially as it affords added compatibility to Balanced devices, but it’s not Balanced … it’s so-called ‘impedance balanced’ as i mention above, it’s a sort of Balanced-Lite i guess

More here …

https://www.soundonsound.com/sound-advice/q-how-impedance-balancing-audio-different-normal-balancing

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#6

Thank you very much for your explanations.

When the signal is stereo and going through a three wire cable ( TRS ) it’s essentially two TS cables sharing a ground like this
Wire #1 = Left channel + / T
Wire #2 = Right Channel + / T
Wire #3 = Left AND Right Channel - / S

When the signal is Balanced ( going through the same 3-wire cable, but “mono” it looks like this:
Wire #1 = +
Wire #2 = -
Wire #3 = ground

If you send a stereo signal to a mono balanced input , the input take the right channel , invert it, and sum it to the left channel right and this result of a drop of volume and destroy the signal .
It’s Right ?

In this case there is no difference in volume regardless of the cable used.
The volume is just low.

I can’t get the correct volume between the main output of my Analog Rytm Mk2 and the two voices that I process and re-inject into the ext in.
(the volume of a sample coming directly from the octatrack is good)

Whether through direct input or through a machine the result is the same and it does not matter which cable to use.

Yet the input level in the octatrack seems good (led input)
If I put the gain (in mixer menu) they start to be red and the sound is distorted.

So why is the volume so low? Impedance mismatch?

Do I need something in between to get the expected result? (DI, Gain, etc etc)

Is there a simple enough way to do this loop?

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#7

Good to know.

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