Input and output specs

[danishfurniture]

I received my Octo a few days ago from Amazon. I'm using it to record audio from a Eurorack modular synth, typically 10 volts p-p. I think those voltage levels may be too high for the Octo's inputs. I've started building simple resistor voltage dividers to bring the voltages down, but I don't know what would be optimal for the Octo's inputs. What are the min and max specs for the Octo's inputs and outputs? (My apologies if these are detailed somewhere else. I looked but didn't find them.)

Congrats on making a great HAT!

[flatmax]

Hi there,
Thanks for your enthusiasm for our product. We love it !

The Octo has 3v p-p levels for the RCA lines.
For the differential break outs, they have 12 V p-p, and would handle your synth rather nicely
The differential breakout is composed of a preamp, input differential board and output differential board. They are powered by one 15V DC supply.

Audio Injector Octo balanced breakout card, preamp and IO boards.

octo.balanced.front.jpg (235.21 KiB) Viewed 2796 times

thanks
Matt

[danishfurniture]

Hi Matt,

Thanks, very helpful.

Perhaps for my intended use, I should have bought the Octo with the differential breakout board, instead of the RCA interface board. (I haven't seen the differential breakout board for sale anywhere, but maybe I'm not looking in the right places.) Don't take that as a criticism in any way. I think the Octo is great!

The picture looks like the differential breakout board interface is for 1/4" plugs. Is that correct?

One site I saw (sorry, I don't remember where) indicated that making one's own interface board was a possibility. Is there a schematic somewhere online for the input and output connectors (where the ribbon cables connect to the Octo)?

So many questions ... Thanks for your time!

[flatmax]

hi there,

You can purchase the differential version from ebay. It does take a 1/4" stereo jack which gives the balanced output.

If you want to make your own connectors, I recommend using the kicad designes from github.

The differential design is now at the latest manufacture version.
https://github.com/flatmax/AudioInjector.Octo.balanced
https://github.com/flatmax/AudioInjector.Octo.RCA

thanks
Matt