The Model 438 Audio Control Amplifier is a remotely controlled, electronic unit which operates upon command from switches and potentiometers in the cockpit. The amplifier is capable of switching and separately controlling the volume for up to 12 receiver inputs. It also switches five sidetone inputs and an interphone line.
Version 483-003 provides interphone operating levels for 8-station interphone system (37ohm interphone line) with more interphone audio to the speaker and headphone than the base model. Also increases the receiver levels to compensate for increased load on the receivers by multistation Model 438's.
- Two unswitched and unmuted inputs for aural warning input and an auxiliary input
- Headphone and selected speaker outputs are isolated
- Cockpit voice recorder output from headphone and interphone microphone audio
- Microphone audio can be recorded on the cockpit voice recorder at all times
- Pilot select COMM output produces a summation of COMM1 through COMM 4, DME 1 and 2, and the MKR 1 and 2 receiver inputs
- Compatible with the model 240, 250, or 251 PSC audio input channel (or equivalent)
- Speaker channel is powered through an internal fuse separate from the headphone channel
- Receiver and operating modes are electronically switched
- Electronic attenuator in each of the 12 receiver input channels
- 30 dB attenuator range control cockpit volume potentiometer
- Selective voice or code filtering on four receiver audio inputs
- Voice activated switch in series with microphone input
Product Codes | |
|---|---|
| Mfr Part No: | 438-003 |
| PMA: | PQ2204NM |
| PROAPP: | TSO: PT2204NM / PMA: PQ2204NM |
| TSO: | C50c |
Operating mode pin numbers:P40-18 Speaker switchP40-6 INPH hot switchP40-14 INPH to speaker switchP40-16 PTT switchP40-11 Voice switchP50-6,7,9,10,11,12,13,23,24,27,28,29 Receiver switchesP50-22 PA key Test.
- Stock: Out of Stock - On Backorder
- Manufacturer Part #: 438-003
Aircraft Fitment Finder
Returns & refund summary
- 30-day return window — with prior return authorization, unopened in original packaging.
- Restocking fee: 20% on unopened items, 30% on open-box items.
- Refund processing fee: 5.51% applies to all refunds (returns, cancellations, core-fee refunds) regardless of reason.
- Return shipping: paid by buyer.
- Non-returnable categories: installed/used parts, special-order or rebuilt items, programmed items (incl. ELTs), batteries, AOG-priority orders, international orders.
Full terms: Return Policy.
Authenticity & authorization
All parts sold by American Aviation Parts are genuine factory products sourced through authorized distribution channels. Our authorization status varies by brand — for some brands we are a direct authorized dealer; for others we are an independent reseller through authorized distribution. Either way, the part you receive is the same factory product, with standard documentation available on request.
See our full Manufacturer Authorizations page for the current per-brand status.
Need traceability paperwork?
If your installation requires FAA Form 8130-3, manufacturer Certificate of Conformance, or other traceability documentation, please call 1-877-722-8727 or email [email protected] before placing the order so we can confirm what is available for this part.
Shipping
Standard ground, expedited, and AOG shipping options are available at checkout. Full shipping-cost tiers and timelines are published on our Delivery Information page.
