8-Channel AES3 Distribution Amplifier

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1. 01

   Prepare the metal enclosure

   Use a metal rack enclosure with three shielded RJ45 panel cut-outs marked INPUT, OUTPUT A, and OUTPUT B, plus one locking 5 V DC input cut-out. Bond each RJ45 metal shell directly to the enclosure with a short, wide connection; this gives cable noise a safe path to the chassis.

   • Tip: Mark every RJ45 port “AES3 ONLY — NOT ETHERNET — NO PoE” before fitting it.

   • ⚠ Do not connect these ports to an Ethernet switch or PoE injector; that can damage the distribution amplifier and connected audio equipment.
2. 02

   Fit the input side parts

   Fit the four input transformers beside the INPUT connector. Keep each transformer close to its matching RJ45 pair: pins 1–2 for link 1, pins 3–6 for link 2, pins 4–5 for link 3, and pins 7–8 for link 4. Fit each 110 Ω 1% resistor directly across that transformer’s receiver-side pair.

   • Tip: Keep the two copper tracks of each pair the same length and route them next to one another.

   • ⚠ Do not substitute Ethernet magnetics for the AES3 transformers; the wrong transformer can distort the digital-audio signal.
3. 03

   Fit the receiver and copying stage

   Fit the four receiver ICs and the 74AHCT244 copying buffer near the input transformers. Add a 100 nF ceramic capacitor from 5 V to ground at every IC supply pin pair, placed as close to the chip as possible.

   • Tip: The buffer makes one separate electrical copy for Output A and another for Output B; it does not decode or alter the audio.

   • ⚠ Keep the input transformer secondary tracks short; long tracks can pick up noise and cause dropouts.
4. 04

   Fit the Output A path

   Fit Output A’s four driver ICs and four output transformers between the copying buffer and the OUTPUT A connector. Route the transformer secondaries to pins 1–2, 3–6, 4–5, and 7–8 in that order.

   • Tip: Keep every outgoing pair as a 110 Ω differential pair and avoid branches or unused trace stubs.

   • ⚠ Swapping the plus and minus wires of one pair reverses that AES3 link and may prevent the receiving equipment from locking.
5. 05

   Fit the Output B path

   Fit Output B’s four driver ICs and four output transformers in the same way. Route the output transformer secondaries to pins 1–2, 3–6, 4–5, and 7–8 on OUTPUT B.

   • Tip: Output A and Output B must remain separate after the copying buffer so a fault or unplugged cable on one output does not load the other.

   • ⚠ Never join an Output A pair directly to the same Output B pair; the two outputs must be separately driven and transformer-isolated.
6. 06

   Wire and protect the 5 V input

   Bring the certified regulated 5 V supply into the locking DC connector, then route it through reverse-polarity and over-current protection before the 5 V plane. Connect its return to the circuit ground plane; do not use the RJ45 signal pairs as power or ground wires.

   • Tip: Use a supply rated for at least 1 A even though the circuit draws less; it will run cooler and has margin.

   • ⚠ Check the connector polarity with a meter before plugging in the board—reversed 5 V power can damage every interface chip.
7. 07

   Inspect and test one link first

   Before connecting studio equipment, check for shorts between 5 V and ground. Then connect a known AES3 source to INPUT and a known AES3 receiver to Output A using the correct shielded 110 Ω cable. Verify channels 1–2 first, then repeat for the other three pairs and Output B.

   • Tip: If one pair fails, first check the pin pair order: 1–2, 3–6, 4–5, then 7–8.

   • ⚠ Power down before changing soldered connections; accidental shorts can damage the drivers or connected audio hardware.

// Hardware-only AES3 distribution amplifier.
// The AES3 signal path is entirely discrete: no ESP32 GPIO is used.
void setup() {}
void loop() {}

“Deploy to device” opens this project in Schematik, where you can flash it to your board over USB.