Sigtronics SPA-400 levels

Gents

I have a SPA-400 with an ICOM A-200.

The radio levels are good but the Pilot to co-pilot levels seem a little low. I did place resistor in the headphone audio circuit from the Icom - but the 30 % increase does not seem enough.

Question - will adjusting the "Mod adj" on the SPA-400 increase the Intercom Levels?

Any Ideas?

Of course - I may be going deaf !

Regards Duncan RV9A finals bits

Hi Duncan.

I'm not familiar with the ICOM radio, but I'm using an SPA-400 with a Garmin SL40.

A couple of obvious things to check:

Is the Intercom audio turned up? Do the headsets have volume controls, and are they turned up?

Another problem that you will have is that if the series resistor to the ICOM is not large enough (I use 510 ohms), then all of the audio levels, except for the ICOM levels will be low. A quick check is to turn off the comm and see if the intercom levels improve. If it works better, then the resistor is the issue.

Along with the SL40, I have a GPSMap 296, Dynon D10A, RMI Micromonitor and an external audio source connected to my SPA-400, and the audio levels are fine. I'm using the Vx-Aviation AMX-1A audio mixer bus for this (my own design). You can find it at www.vx-aviation.com. In the data sheet, you'll see a schematic that may help you with your installation.

Vern Little
RV-9A