Known Issues
- Age-related capacitor drift and noisy gain/input controls.
- Intermittent behavior from fatigued solder joints in high-heat zones.
Product Archive
M25
Entry M-series amplifier with Tri-Linear capability and one of the most-restored early Phoenix Gold models.
Category
Amplifier
Series
M Series
Era
1992-1995 (archived FAQ/manual sources)
Specifications
- Output Power (4 ohm @ 12.5/14.4V)
- 25/65 WRMS x2
- Output Power (2 ohm @ 14.4V)
- 70 WRMS x2
- Output Power (4 ohm bridged @ 14.4V)
- 140 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
- 750mA
- Crossover Frequencies
- 30Hz to 600Hz
- Crossover Slopes
- 12dB per octave
- Bass EQ
- 0 to +12dB @ 45Hz
- Minimum Impedance
- 2 ohm stereo nominal; 1 ohm stereo / 2 ohm bridged is current-limited
- Dimensions
- 8.25"L x 10.6"W x 2.0"H
Visual Identification Notes
- Manual cover and interior pages are included in gallery for visual reference.
- Use gallery page labels to compare control and terminal layouts across revisions.
- Confirm silk-screen and endplate details during intake photography.
Recommended Service Actions
- Perform full visual inspection before powering unknown-history units.
- Check supply filtering components and reflow suspect joints where needed.
- Document baseline measurements before and after service actions.
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
M25 amplifier photo
Archived M25 product photo from Phoenix Gold FAQ M Amplifiers page.
M25 manual cover
Owner-manual cover extracted from archived PDF for visual identification and layout reference.
M25 manual page 2
Manual interior page used as technical and historical reference material.
M25 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 pageM-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
Sources / Notes
Archived Phoenix Gold FAQ - M Amplifiers
Primary source used for M25 spec table values and product photo.
Open sourceM25 Owner Manual
Primary manual source used for controls/functions details and verification notes.
Open sourceM-Series Manual Index
Directory listing confirms archived M-series documentation.
Open source
Model Disclaimer Block
Repair information is provided at user's own risk. Verify all measurements and polarity before power-up.