Product Archive

MS-2125

Widely referenced MS-series platform with archived owner manual and known relationship to several special and limited Phoenix Gold products.

Specifications

Output Power (4 ohm @ 12.5/14.4V): 125/160 WRMS x2
Output Power (2 ohm @ 14.4V): 255 WRMS x2
Output Power (4 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
Power Supply Efficiency: >80%
Damping Factor: >300 @ 60Hz (manual reference)
Maximum Battery Voltage: 15.5V DC
Minimum Impedance: 2 ohm bridged / 1 ohm stereo
Dimensions: 17.0"L x 11.4"W x 2.4"H

Visual Identification Notes

Manual gallery provides baseline visual references for faceplate and control area.
Record serial and board revision markings during model intake.
Capture terminal and internal photos for future cross-model comparisons.

Known Issues

Aging capacitors and connector wear after long service life.
Thermal stress can affect solder reliability in output/power sections.

Recommended Service Actions

Establish pre-service baseline measurements and thermal behavior.
Validate PSU components and output stage integrity before calibration.
Document replacement BOM and post-service verification data.

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 reference
Audio-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

MS-2125 amplifier photo
Archived MS2125 product photo from Phoenix Gold FAQ MS/MPS page.

MS-2125 manual cover
Owner-manual cover extracted from archived PDF for visual identification and layout reference.

MS-2125 manual page 2
Manual interior page used as technical and historical reference material.

MS-2125 manual page 3
Additional manual page for control labels, tables, and period styling details.

Historical Notes

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

MS-Series archived FAQ specs and timeline
Cross-checked
- The FAQ provides per-model output tables for MS250, MS275, MS2125, and MS2250.
- The page states MS/MPS production years as 1992-1995.
- The FAQ distinguishes MS as high-impedance-optimized and MPS as low-impedance-optimized designs.
Source: Archived Phoenix Gold FAQ - MS/MPS Amplifiers
Open source page
MS-Series models with archived owner manuals
Cross-checked
- Manual index lists MS250, MS275, MS2125, and MS2250 owner manuals.
- The same directory also includes MS TA documentation and MAC-200 reference material.
- Archive PDFs provide direct model-specific material for visual ID and technical page expansion.
Source: Phoenix Phorum Manual Archive - MS/MAC Amps
Open source page
MS-2250 special series context
Imported - Needs Primary Verification
- MS-2250 is described as based on the MS-2125 with increased output capability.
- The source mentions fan shrouds as part of the original package and notes many are missing today.
- Source data suggests around 1000 units while explicitly noting official production numbers were not published.
Source: Phoenix Gold Registry - MS-2250
Open source page
Special-platform values verified against MS/MPS baseline tables
Cross-checked
- MS2125 values shown in FAS2300/FAS2400 sections match MS/MPS baseline values: 125/160 x2 (4 ohm), 255 x2 (2 ohm), 510 x1 (bridged 4 ohm).
- MQ430 values listed in FAS2300 match MQ430 values in MS/MPS page: 30/50 x4 (4 ohm), 90 x4 (2 ohm), 100 x2 (bridged 4 ohm).
- These overlapping numbers are tagged as verified from multiple archived sources in this site.
Source: Archived Phoenix Gold FAQ - MS/MPS Amplifiers
Open source page

Sources / Notes

Archived Phoenix Gold FAQ - MS/MPS Amplifiers
Primary source used for MS2125 spec table values and product photo.
Open source
MS2125 Owner Manual
Primary manual source used for efficiency, damping, and voltage-limit verification.
Open source
MS-Series Manual Index
Directory listing confirms archived MS-series documentation.
Open source

Model Disclaimer Block

Repair information is provided at user's own risk. Verify all measurements and polarity before power-up.