Known Issues
- Extended low-impedance use can accelerate wear in output and supply sections.
- Aging electrolytics and prior modifications can affect stability under load.
Product Archive
MPS-2500
High-current Mobile Professional Series model documented for low-impedance operation targets in period FAQ data.
Category
Amplifier
Series
MS Series
Era
1992-1995 (archived FAQ source)
Specifications
- Output Power (4 ohm @ 12.5/14.4V)
- 50/80 WRMS x2
- Output Power (2 ohm @ 14.4V)
- 125 WRMS x2
- Output Power (2 ohm bridged @ 14.4V)
- 510 WRMS x1
- Frequency Response
- +/-1dB from 20Hz to 20kHz
- Signal to Noise Ratio
- >100dB
- Input Sensitivity
- 200mV to 2V
- Input Impedance
- >30k ohms
- Input Voltage Range
- 10.5V to 15.0V
- Typical Idle Current
- 3A
- Minimum Impedance (MPS)
- 1 ohm bridged / 0.5 ohm stereo
- Dimensions
- 17.0"L x 11.4"W x 2.4"H
Visual Identification Notes
- Archived FAQ image shows MPS2500 as the longer MPS chassis variant.
- Document connector labels and internal board markings before restoration work.
- Capture heatsink and terminal condition for provenance tracking.
Recommended Service Actions
- Validate baseline current draw and rail behavior before stress testing.
- Inspect thermal path and output stage closely before low-impedance operation.
- Record post-service load test results with supply voltage notes.
Parts List
Main power reservoir capacitor (4700uF / 50V class)
Original: 4700uF 50V radial electrolytic (legacy OEM variant)
Replacement: 105C low-ESR radial capacitor, matched lead spacing
Verification: Community Verified
Dual op-amp for preamp / crossover stage
Original: Legacy dual DIP-8 op-amp (marking varies by production run)
Replacement: Low-noise audio op-amp DIP-8
Verification: Proposed
DigiKey Recommendations
4700uF 50V low-ESR radial capacitor
DigiKey: P12345-ND
Placeholder DigiKey reference. Confirm ripple current, lead spacing, and can diameter against board footprint before finalizing.
Open DigiKey referenceAudio-grade dual op-amp replacement
DigiKey: P23456-ND
Placeholder DigiKey reference. Verify stability and compensation in original circuit before bulk install.
Open DigiKey reference
Related Repair Guides
- Signal-path noise diagnosis (generic workflow)
Template process for hum, hiss, and channel imbalance root-cause analysis before replacing semiconductors.
Related Forum Threads
- Catalog scans and ad archive (contributor thread)
Crowdsourced scan quality standards and indexing conventions for source documentation.
Gallery
MPS-2500 amplifier photo
Archived MPS2500 reference photo from Phoenix Gold FAQ MS/MPS page.
Historical Notes
MPS Series Low-Impedance Positioning
Archived MS/MPS FAQ material positions Mobile Professional Series (MPS) models for lower-impedance loading than standard MS models, with corresponding minimum-load guidance and model tables.
MS-Series Manual Archive Baseline
The Phoenix Phorum manual archive includes original MS-series documentation for MS250, MS275, MS2125, and MS2250, while the archived Phoenix FAQ indicates a 1992-1995 MS/MPS production window.
Source-Backed Verification
MPS-series archived FAQ values
Imported - Needs Primary Verification- MPS2240 is listed at 24/36 WRMS x2 (4 ohm), 65 WRMS x2 (2 ohm), and 288 WRMS x1 bridged (1 ohm).
- MPS2500 is listed at 50/80 WRMS x2 (4 ohm), 125 WRMS x2 (2 ohm), and 510 WRMS x1 bridged (2 ohm).
- The same page states MPS minimum impedance as 1 ohm bridged / 0.5 ohm stereo and positions MPS as low-impedance-focused.
Source: Archived Phoenix Gold FAQ - MS/MPS Amplifiers
Open source page
Sources / Notes
Archived Phoenix Gold FAQ - MS/MPS Amplifiers
Primary source for MPS2500 output table values and MPS load-focus context.
Open sourceMS-Series Manual Index
MPS manuals are not currently listed in this archive index; add primary docs when available.
Open source
Model Disclaimer Block
Repair information is provided at user's own risk. Verify all measurements and polarity before power-up.