Product Archive

M50

Core M-series two-channel amplifier platform with well-documented owner manual and strong enthusiast restoration interest.

Specifications

Output Power (4 ohm @ 12.5/14.4V): 50/85 WRMS x2
Output Power (2 ohm @ 14.4V): 120 WRMS x2
Output Power (4 ohm bridged @ 14.4V): 245 WRMS x1
Frequency Response: +/-1dB from 20Hz to 20kHz
Signal to Noise Ratio: >100dB
Input Sensitivity: 200mV to 2V
Input Impedance: >10k ohms
Input Voltage Range: 10.5V to 15.0V
Typical Idle Current: 1.5A
Damping Factor: 250:1 (50Hz @ 4 ohm)
Bass EQ: 0 to +12dB @ 45Hz
Minimum Impedance: 2 ohm bridged / 1 ohm stereo
Dimensions: 11.25"L x 10.6"W x 2.0"H

Visual Identification Notes

Classic M-series white-and-blue front-panel graphics with gold sink variants in period hardware.
Manual page gallery includes controls/functions reference pages.
Board revisions should be logged when documenting serviced units.

Known Issues

Bias drift in aging units with worn adjustment hardware.
Thermal interface material degradation over decades.
Occasional offset instability from aged small-signal components.

Recommended Service Actions

Validate output stage before calibration adjustments.
Replace unstable trimmers and re-check after thermal soak.
Document final bias/offset values with ambient temperature.

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
Bias / offset adjustment trimmer
Original: Single-turn open trimmer, value depends on board revision
Replacement: Sealed multi-turn cermet trimmer
Verification: Needs Revision Check
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
Sealed multi-turn trimmer
DigiKey: P34567-ND
Placeholder DigiKey reference. Confirm orientation and adjustment direction against original layout.
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

M-series bias and DC offset baseline
Step-by-step process to stabilize idle current and validate DC offset behavior on M-series boards.
Signal-path noise diagnosis (generic workflow)
Template process for hum, hiss, and channel imbalance root-cause analysis before replacing semiconductors.

Related Forum Threads

M50 bias and DC offset troubleshooting
Bench-side measurement workflow for unstable idle current and thermal drift.
Catalog scans and ad archive (contributor thread)
Crowdsourced scan quality standards and indexing conventions for source documentation.

Gallery

M50 amplifier photo
Archived M50 product photo from Phoenix Gold FAQ M Amplifiers page.

M50 manual cover
Owner-manual cover extracted from archived PDF for visual identification and layout reference.

M50 manual page 2
Manual interior page used as technical and historical reference material.

M50 manual page 3
Additional manual page for control labels, tables, and period styling details.

Historical Notes

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

M-Series archived FAQ specs and timeline
Cross-checked
- The FAQ lists M25, M50, M100, and M44 model-level output tables at 12.5/14.4V and 14.4V load conditions.
- The same page states M-series production years as 1992-1995.
- The archived FAQ includes period product photos that are now used as top gallery images in this archive.
Source: Archived Phoenix Gold FAQ - M Amplifiers
Open source page
M-Series models with archived owner manuals
Cross-checked
- Manual index lists M25, M44, M50, and M100 model manuals.
- Each listed manual is available as downloadable PDF from the same archive.
- These documents are used as primary references for gallery cover pages and model-page source notes.
Source: Phoenix Phorum Manual Archive - M Amps
Open source page
Phoenix Gold early brand and amplifier timeline
Imported - Needs Primary Verification
- Phoenix Gold is described as starting around 1988 as an accessories-focused brand.
- The source states first mobile amplifiers appeared around 1990 (including MS-250 and MS-2125).
- The source describes early boards as 24K gold plated and notes M-series launch progression shortly after.
Source: Phoenix Gold Registry - History
Open source page
Outlaw and Bandit relationship
Imported - Needs Primary Verification
- Outlaw is described as a combined M50 and M100 two-channel architecture in one chassis.
- Bandit is described as an M50 (Rev. B) in an Outlaw-matching cosmetic scheme.
- The source indicates a believed 900-1900 serial span for these models but notes no official published production totals.
Source: Phoenix Gold Registry - Outlaw/Bandit
Open source page

Sources / Notes

Archived Phoenix Gold FAQ - M Amplifiers
Primary source used for M50 spec table values and product photo.
Open source
M50 Owner Manual
Primary manual source used for electrical specs and control-function verification.
Open source
M-Series Manual Index
Directory listing confirms archived M-series documentation.
Open source

Model Disclaimer Block

Repair and calibration information is provided at user's own risk. Verify all procedures before applying power.