Product Archive

FAS-2400 (Son of Frank Amp'n Stein)

Limited 'Son of Frank Amp'n Stein' 4-3-2 platform documented as combining MS275 and MS2125 sections, with companion FAS406A crossover references.

Specifications

Architecture: MS275 + MS2125 under one long special heatsink
MS275 Output (4 ohm @ 12.5/14.4V): 75/95 WRMS x2
MS275 Output (2 ohm @ 14.4V): 125 WRMS x2
MS275 Output (4 ohm bridged @ 14.4V): 260 WRMS x1
MS2125 Output (4 ohm @ 12.5/14.4V): 125/160 WRMS x2
MS2125 Output (2 ohm @ 14.4V): 255 WRMS x2
MS2125 Output (4 ohm bridged @ 14.4V): 510 WRMS x1
Companion Crossover: FAS406A, 18dB per octave slope (archived FAQ)
Case Dimensions: 25.5"L x 11.4"W x 2.4"H
Dimensions w/ flanges + terminals: 26.5"L x 11.4"W x 2.4"H

Visual Identification Notes

Period notes describe black base with violet/blue glitter clear-coat details.
Some units are associated with custom plexi panel and certificate of ownership.
Photograph all cosmetic cues before cleanup to preserve authenticity records.

Known Issues

Complex dual-amplifier layout can hide faults across linked signal paths.
Collector-restored units may deviate from original finish details.

Recommended Service Actions

Validate each internal amplifier section independently before full-system tests.
Archive condition/provenance photos before any cosmetic correction.
Log crossover/accessory presence separately from amplifier electrical state.

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

FAS-2400 amplifier photo
Archived Son of Frank Amp'n Stein reference image from Phoenix Gold FAQ MS Special Edition page.

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

FAS and SoFAS limited-series context
Cross-checked
- Frank Amp'n Stein (FAS2300) is described as MQ430 + MS2125 in one heatsink with an approximately 300-unit limited run note.
- Son of Frank Amp'n Stein (FAS2400) is described as a MS275 + MS2125 4-3-2 special platform with matching FAS406A crossover references.
- MS1000 is described as two MS2250 sections integrated in one long heatsink with high thermal/current demand cautions.
- FAS406A companion crossover values include 18dB/oct slope, 8V output level, and 100dB S/N in the same archived source.
Source: Archived Phoenix Gold FAQ - MS Special Edition
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
MS275 bridged value discrepancy across archived FAQ pages
Imported - Needs Primary Verification
- MS/MPS page lists MS275 bridged output as 280 WRMS x1 at 14.4V (4 ohm bridged).
- MS Special page lists FAS2400's MS275 section as 260 WRMS x1 at 14.4V (4 ohm bridged).
- This archive keeps the discrepancy visible and marks the bridged value for revision check pending additional primary evidence.
Source: Archived Phoenix Gold FAQ - MS Special Edition
Open source page

Sources / Notes

Archived Phoenix Gold FAQ - MS Special Edition
Primary source for FAS2400 architecture, finish notes, and power tables.
Open source

Model Disclaimer Block

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