Aphex Systems 204 Aural Exciter Rack Unit
The Aphex Aural Exciter has been a fixture in professional studios, live rigs, and broadcast facilities since its introduction in 1975. The 204 is the dual-channel version, pairing the classic Aural Exciter with the Optical Big Bottom in a single 1U rack unit. The Exciter works in a side chain — adding even-order harmonics above a tunable high-pass point — rather than boosting signal directly, which means you get increased presence and air without raising noise or peak output. The Big Bottom does the same on the low end, optically compressing and extending bass frequencies for more resonance and definition without overloading the signal path. It's a subtle processor when used right, and a well-regarded one — studio, live, broadcast, instrument rigs, DJ setups, all valid applications.
This unit is in very good condition and fully functional. Both channels operate normally across all controls. Minor cosmetic wear consistent with normal rack use. Photos show the condition accurately.
- Make: Aphex Systems
- Model: 204
- Type: 2-channel psychoacoustic audio enhancer, 1U rackmount
- Channels: 2 independent channels (stereo or dual-mono operation)
- Aural Exciter controls: Tune, Harmonics, Mix (per channel)
- Big Bottom controls: Drive, Tune, Mix (per channel)
- Operating level: switchable -10dBV / +4dBu
- Frequency response: 10Hz - 38kHz (+/- 0.5dB)
- Dynamic range: 120dB
- Noise (unweighted 22Hz-22kHz): -93dBu
- Crosstalk (10Hz-22kHz): -79dB
- THD (at max output): 0.0003%
- Power: internal supply, 90-250VAC 50-60Hz, 12W
- Dimensions: 19" W x 1.75" H x 8.2" D
- Weight: approximately 2.75 kg
- Modifications: none
- Includes: none
Ships carefully packed and insured for full value.
International buyers are welcome — please contact us for a shipping quote before purchasing.
About Mill River Music
Mill River Music is an independent, human-powered music shop located in downtown Northampton, MA, run by a team of players, enthusiasts, and certified repair technicians. Every piece of used gear we sell is personally inspected, tested, and set up before it ships — we don't list it until we'd be happy to play it ourselves.
As Martin and Taylor certified techs, we hold our guitar work to a high standard, and we're committed to full transparency about the condition of everything we sell. No surprises.
When you buy from Mill River, you're supporting an independent local business that genuinely cares — about gear, about players, and about doing things right. We're here every step of the way. Reach out anytime.
