The International Cessna^® 170 Association

Does anyone know of a source for an economical audio panel (new or used)? I would like one that fits in an instrument hole, but I may have to use another style. I don't need a marker beacon or an intercom. Just a basic unit that wil allow me to use two com radios. Suggestions gladly accepted.

You could probably wire one up yourself without too much trouble. I had a home grown one in 82A which I still have the schematic for if you want. You could probably do it with four switches:

Sw1: Transmit Com1/Com2
Sw2: Audio Com1 On/Off
Sw3: Audio Com2 On/Off
Sw4: Audio Headphone/Speaker

I had a fifth switch that would serve as an isolation switch and shut. Keep in mind that all of this was for two comms - no Nav.

If that doesn't do it for you, PS Engineering makes one (PMA4000) that fits an instrument hole:

http://www.aircraftspruce.com/menus/av/audiopanel.html

Scroll down to find the PMA4000. It handles two comms and two navs.

You really need some sort of electronic mixer, as would be provided with an audio panel. It's not generally a good idea to directly parallel audio outputs from two or more sources, as would be the case if you had both Audio Com1 and Audio Com2 both switched ON at the same time in the switches-only setup described above. It's not likely you'd damage anything, but you would likely loose a lot of audio quality, something that's in fairly short supply in aircraft radios already.

Miles

I have the PMA 4000 audio panel / intercom in my airplane. The local FSDO insisted that it it be field approved which they did. It has been flawless in its operation. It even has provisions for unswitched audio inputs if you have a need for them. It also has an entertainment input that the com audio will mute for a cd player or mp3 player. It's been in for a couple of years now and I think you could get one new for under $800.00

Hey ol pokey!
I don't know if I should list here (seems I should list on the parts for sale sight) but I have an old ARC audio pannel with wiring setting on the shelf, PM me and I'll let you Know what I need for it.
brad

Frank, a very simple audio panel which is frequently found at junk prices is the Narco CP 25 series. (They have more advanced audio panels as well, CP 125/ 135/ 136, etc. etc. ) It is a push-button switching panel that will handle a couple of coms/navs/adf/etc and will also accept an intercom input, and is still supported by Narco, and has free wiring diagrams online.
As these (and certain other brands as well) have no audio amplifier built into them, they are very simple and troublefree.... but beware of any audio panel you acquire... if your radio will not drive a speaker already, you will require an audio panel with a built in audio amplifier. The Narco does not have that, because their radios already have output amplifiers. Many Bendix/Kink and other units do not. Check your PM inbox.