dbx Model 224
For $275, dbx promised your home reels could get uncomfortably close to digital. The Model 224 is the hardware behind that claim (HiFi-Stereo, May 1980, p.55).
Overview
The Model 224 is the center of dbx's Recording Technology Series: a simultaneous encode/decode Type II tape noise reduction system. The company advertised it with the line "For $275, dbx technology brings your home recording so close to digital, it's absurd." That pitch ran repeatedly in the hi-fi press. It was aimed at the home recordist with a stack of open-reel tape and a cassette deck, wondering whether the noise floor was worth fighting. dbx's answer was compression and expansion rather than filtering.
The headline number is the one dbx led with. The Model 224 gives the user the capability to record an unprecedented 85 dB of dynamic range on open reel and 80 dB on cassette (HiFi-Stereo, May 1980, p.55). Set that against the competition. As dbx's own advertising put it, the Dolby system a recordist had been "putting up with" reduced tape noise by 10 dB at the most, and only in the high-frequency region. The Model 224 was not a treble-only noise reducer. Type II is a full-bandwidth companding scheme, and the simultaneous encode/decode architecture means the unit can be used inline while monitoring, not just as a record-side processor. In dbx's advertising in the hi-fi press of the period (Audio, December 1980, p.21), the Model 224 was offered for $299.
Pricing drifted over the model's advertising life. Early notices carried the unit at $275, while later placements listed it at $299. The difference reflects catalog timing more than any documented revision.
Key Features
Simultaneous Encode/Decode Type II Operation
The panel is built around dbx's Type II tape noise reduction system, and the "simultaneous encode/decode" designation is the functional core of the thing. A recordist can encode to tape and decode on playback in one pass. That makes the Model 224 useful in a working home studio rather than as a one-way, record-only accessory.
Historical Context
dbx positioned the Recording Technology Series squarely against Dolby, and the advertising copy was blunt about it. The Model 224 was sold as the alternative to a system that "only reduces tape noise by 10 dB at the most, and only in the high-frequency region." The marketing framed the whole category as a two-horse race between high-frequency-only noise reduction and full-bandwidth companding. The Model 224 was dbx's bid to win that argument at the consumer and project-studio price point.
Exact production years are not documented in the available sources. The advertising record places the unit in catalogs at least through early 1981. The $275-to-$299 price movement across that span is the clearest evidence of how long it stayed in the line.
Collectibility & Value
Surviving Model 224 units turn up, but the market is thin and the documentation is thinner. The available sources give no reliable price data for the secondhand market and no documented failure pattern specific to this model. Treat any listing as a project until proven otherwise. Two-chassis companding units of this vintage generally need attention, and the Model 224 is no exception just because it is uncommon.
The original $275 - $299 asking price does not appear to translate into anything today. The Model 224 is a niche piece even within dbx's own catalog, and it lacks the studio-standard reputation that drives prices on the company's professional compressors.
Similar items on eBay
No exact dbx MODEL-224 listings are live right now — these searches show current dbx and similar vintage audio gear on eBay:
As an eBay Partner, we earn from qualifying purchases. This helps support our independent vintage technology research.