sl-30 + sl-40 w/o audio panel

[rvermeland]

Has anyone wired up an sl-30 and an sl-40 without using an audio panel? Do you connect both radio high outputs to the headset jacks? On older systems, one radion would be wired to the main radio via a low aux input. The sl's don't have this option. Suggestions?

Thanks,

-rob

 

[vlittle]

Has anyone wired up an sl-30 and an sl-40 without using an audio panel? Do you connect both radio high outputs to the headset jacks? On older systems, one radion would be wired to the main radio via a low aux input. The sl's don't have this option. Suggestions?

Thanks,

-rob

The SL30 and SL40's outputs are low impedance and cannot be directly connected together.

The fix for this is to use a small value resistor in series with each of the radio outputs (150 ohms work, but I've used up to 500 ohms with success). I would recommend wiring in an auxiliary headphone jack directly to the primary comm as a fail-safe, but that's up to you.

The transmit side (microphones and PTT) need to be switched so that you cannot transmit on more than one comm at the same time.

If you want a more elegant way of connecting them together, plus other audio sources in your cockpit, look at the AMX-2A on the vx-aviation web site. Even if you don't need to use this audio mixer/amplifier, the application note may be helpful in showing how to combine and switch the audio with two comms.

Thanks, Vern