Lexicon Range
If you are looking into pickup an old rackmounted Reverb or FX units by Lexicon there is a confusing array of models under the MPX and MX name.
The lines are blurred, but in general, the MPX Range focuses more on high-quality reverb and effects with a bit more flexibility and control, suitable for studio use, where as the MX Range Offers more connectivity options and is versatile for both live and studio applications, often at a lower price point.
I favour units with built in power supply so I have added that to the table alongside links to the original sound on sound reviews where available, to assist your purchasing decisions.

Table of Lexicon MPX and MX models
Model | Series | Type | Key Features | Built-in PSU | Total FX | Sound On Sound Review | Target Users |
---|---|---|---|---|---|---|---|
MPX1 | MPX | Reverb/Effects | Versatile reverb and effects, MIDI control, 24-bit processing | Yes | 240 | MPX1 Preview | Project studios, semi-professional |
MPX100 | MPX | Reverb/Effects | Dual-channel, 16 effects, simple interface, 20-bit processing | No | 16 | MPX100 Review | Home studios, live sound |
MPX110 | MPX | Reverb/Effects | Enhanced version of MPX100, more effects, 24-bit processing | No | 16 | Home studios, live sound | |
MPX200 | MPX | Reverb/Effects | Dual-channel, 24-bit processing, S/PDIF digital output, MIDI control | Yes | 24 | MPX200 Review | Home studios, live sound |
MPX500 | MPX | Reverb/Effects | 24-bit converters, balanced analog I/O, MIDI control, more user memories | Yes | 24 | MPX500 Review | Project studios, semi-professional |
MPX550 | MPX | Reverb/Effects | Upgrade from MPX500, more preset effects, user memories, 24-bit processing | Yes | 24 | MPX550 Review | Project studios, semi-professional |
MX200 | MX | Reverb/Effects | Dual-processor, USB connectivity for plug-in operation, 24-bit processing | No | 32 | MX200 Review | Home studios, live sound |
MX300 | MX | Reverb/Effects | More effects and routing options, USB connectivity, 24-bit processing | No | 32 | MX300 Data | Home studios, live sound |
MX400 | MX | Reverb/Effects | Four processors, extensive routing options, USB connectivity, 24-bit processing | No | 32 | MX400 Review | Complex setups, professional studios |
MX400XL | MX | Reverb/Effects | Enhanced version of MX400, additional features and connectivity options | No | 32 | MX400XL Review | Complex setups, professional studios |

Summary
Hopefully this table assists you when looking into acquiring old Lexicon multi fx units