DBX NX-40 Noise Reduction System
This vintage NX-40 is fully functional and in very good condition.
For all audible intents and purposes, the DBX system found in the NX40 eliminates tape hiss.
But it also increases the overall dynamic range capacity of a cassette deck, letting you record both louder and softer sounds than you are used to.
The combined result is that the NX40 will let you make cassettes with nothing added, ones as quiet as (and virtually indistinguishable from) the original.
The DBX noise reduction system can't do anything to improve noisy sources (records, broadcasts, other tapes) - it won't make them quieter - but it doesn't let anything be added.
With a really quiet source, the cassette copy will be crystal clear and just as wide in dynamic range.
If you haven't used DBX before, you'll be startled at how close to identical the copy sounds.Specifications
Input sensitivity: 100mV (1.6V max)
Output level: 1.6V (max)
Noise reduction system: dbx II
S/N improvement: 30dB (dbx II)
Dynamic range: 88dB
Frequency response: 50Hz to 15kHz
Total harmonic distortion: 0.5%
Dimensions: 9-1/8 x 1-7/8 x 6-7/8 inches