Awwww, c'mon dude. That's like asking how long a piece of string should be.
Ask 2 experts and you get 3 different opinions.
Anyway, It all depends on the gear your YGGY will plug in to.
1. Does it have a volume control.?
2. If yes to 1, does the volume control sit right behind the input sockets and before the preamp circuitry.?
3. If yes to 1, what is is the resistance/impedance of the volume control, or does it sit further inside the circuitry?
4. If no to 1, what is the input impedance of your preamp.?
5. If the volume control is further inside the preamp circuitry, what is the input impedance of the preamp.?
What type of cables are you using to connect between the YGGY and your amp.? If RCA, are they just normal or 75 Ohm impedance.?
Under most normal circumstances just connect them up and enjoy.
If you're anal retentive enough, the output impedance of the YGGY is 75 Ohms.
So, do your homework and find out what your input impedance of your preamp is, then get a cable made that matches these specs.
OR Do your homework amd make something up yourself. Zimple....!
As you can see, if the inquirer is unsure of their system, this could tie up the customer service for a considerable time trying to sort out what the customer wants.
There is a software programmer saying which covers this situation:-