Hello!
I want to apply my Eurorack effects to a normal instrument.
That's why I need to convert an audio signal (guitar, synth, etc) to Eurorack.

I was looking around, and the basic circuit is a "Non-Inverting Op-Amp Amplifier", using a TL072 op-amp and two resistors.

But I need some schematics, because I'm a newbie and I don't want to fry my equipment. I need a visual guide.

My idea is: A mono instrument jack, connected to a potentiometer to adjust the gain of the signal, and output to a minijack mono. All of this fed by the +/- 12v provided by the Eurorack power supply.

Any help, consideration, or advice is welcome.

Thanks!

 

Since I have no idea as to what the characteristics of "a Eurorack signal" are. Possibly others also lack that information.
SO I suggest that the TS provide us with a list of the specifications of that Eurorack signal. That will include voltage and line impedance, and source impedance and if it has any digital characteristics.
Seriously, I have not been aware of such.

 

Me neither. A standard audio signal is 0dBm, 775mV rms. Never heard of Eurorack.
Whatever it is, there's no such thing as a "normal instrument" either. The output from a guitar is very different from the output of a microphone which is different again from the output of a synthesizer.

 

That's why I need to convert an audio signal (guitar, synth, etc) to Eurorack.

After looking at " Eurorack" in audio catalogs, it looks like what I call "19 inch" rack.
My uneducated guess is, most likely "line level". About 1V or "0dBm, 775mV rms ". Ian0

convert an audio signal (guitar, synth, etc)

An audio mixer might be what you need it you need anything at all.
I have a collection of these from 2 inputs to 20 mic inputs.
Look at the picture. $85.98. Can input up to 6 mics at a time.
Can input up to 6 line level inputs. Has good ability to input almost any level. Has tone control for each channel. There are simpler versions. As you drop below $100, saving $5 to get 1/2 the functions may not be worth it.

 

And still not one word about what " convert an audio signal (guitar, synth, etc) to Eurorack. " actually means as far as an audio signal. Quite a few folks know how to convert analog to digital, balanced to unbalanced, and other formats.
BUT until the TS is willing to provide a definition, the task is not likely to be accomplished.
Possibly the TS can provide a pointer toward some of that " Eurorack." equipment.

 

Hello, I finally found a guy who has developed the idea that I was asking for here.
Here is the link to the project: https://kg.kg/levels-a-simple-line-instrument-to-eurorack-level-converter-finished/

"This 4hp Eurorack module does the unexciting but sometimes necessary job of converting Line level (1v-ish p2p) or Instrument (100mv p2p) signals to Eurorack level (10v p2p) and vice versa."

 

OK. So we know what it is now, and it needs 5V peak signals. So you need a buffer amplifier with a gain of 4.5
Op-amp and two resistors. 5.6k and 1.6k if it's a non-inverting amplifier. Done.

Why it uses 5V peak signals is anyone's guess. Maximising signal to noise is the reason given, but massive audio mixing desks work perfectly well with 0dBm signal without suffering from crosstalk and noise. I can only surmise that whoever designs these things either isn't very good or wanted to create an artificial market in over-priced level-changing modules.

 

I wonder about the actual benefit of accepting another "standard" that seems primarily intended to be incompatible with almost al existing equipment. AND that seems to be the intention of the creators of "eurorack". As I see it, strictly an effort to create a market for a product that is not really needed..

We already have a fully mature standard that has served well for a whole lot of years: It is the "IRIG (Inter-Range Instrument Group) analog data and documentation" set of standards. Created back in the later 1950's era, and used for a very long time.
At least the analog signal segment of the standard could still be useful, even in the music industry. IF some standard is actually needed.

 

Hi @Ian0 and @MisterBill2 eurorack is a kind of musical instrument present in the market for decades now.
In a lot of modules like LFOs you can find +-10v...
Now, regarding the comment
"suffering from crosstalk and noise"
What way do you recommend to deal with these issues? (I assume the noise emerges because of the amplification of the signal).
By the way, here is another module to achieve the same goal: https://rides-in-the-storm.de/modules/con

 

Noise is usually from inadequate cable conditions or lighting systems with solid state controls. Mostly, lighting system noise can be eliminated by using a power isolation transformer, or disconnecting the mains plug ground pin . CERTAINLY Iwillget a lot of hits for that comment!!!