Known Issues
- Aging electrolytics and oxidized connection points.
- Variation in condition due mixed service history across surviving units.
Product Archive
MS-250
Foundational MS-series amplifier with archived owner manual and strong historical relevance in early Phoenix Gold product history.
Category
Amplifier
Series
MS Series
Era
1992-1995 (archived FAQ/manual sources)
Specifications
- Output Power (4 ohm @ 12.5/14.4V)
- 50/50 WRMS x2
- Output Power (2 ohm @ 14.4V)
- 90 WRMS x2
- Output Power (4 ohm bridged @ 14.4V)
- 180 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
- 2A (manual reference)
- Power Supply Efficiency
- >80%
- Damping Factor
- 1000:1 (20Hz to 10kHz, manual ref)
- Bass EQ
- 0 to +12dB @ 45Hz
- Minimum Impedance
- Stable into 2 ohm stereo loads
- Dimensions
- 8.5"L x 11.4"W x 2.4"H
Visual Identification Notes
- Manual gallery provides model-specific cover and interior visual references.
- Include high-resolution terminal and panel images during archive intake.
- Confirm any revision markings before publishing final specs.
Recommended Service Actions
- Start with controlled power-up and current monitoring.
- Validate supply rails and channel symmetry before deeper work.
- Log replaced components with sourcing and measurement 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
MS-250 amplifier photo
Archived MS250 product photo from Phoenix Gold FAQ MS/MPS page.
MS-250 manual cover
Owner-manual cover extracted from archived PDF for visual identification and layout reference.
MS-250 manual page 2
Manual interior page used as technical and historical reference material.
MS-250 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.
Early Phoenix Gold and M-Series Emergence
Archived Phoenix FAQ material lists M-series output tables and identifies a 1992-1995 production window, while secondary history notes describe the broader late-1980s to early-1990s brand ramp.
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 pageMS-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
Sources / Notes
Archived Phoenix Gold FAQ - MS/MPS Amplifiers
Primary source used for MS250 spec table values and product photo.
Open sourceMS250 Owner Manual
Primary manual source used for load-stability and electrical details.
Open sourceMS-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.