Circuit Characteristics
Core Architecture
- FM266 Flagship Preamp Circuit: Identical topology, parameters, and architecture to the reference design
- Dual Independent Balanced Modules per Channel: 2x fully balanced XLR amplification stages per channel
- Hand-Matched Components: Precision tube/component pairing and acoustic calibration
Connectivity & Layout
| Inputs | Outputs |
|---|---|
| 2x RCA (Single-Ended) | 2x RCA (Single-Ended) |
| 2x XLR (Balanced) | 2x XLR (Balanced) |
- Multi-Amp Capability: Drive up to 4 stereo power amplifiers simultaneously via 4 output channels
- Dual Motherboard Design: Fully isolated left/right channel circuits (improved isolation over OEM)
- Fully Discrete A-Class Design: No op-amps; pure transistor-based signal path
Sonic Signature
Neutral tonality, ultra-resolving microdynamics, exceptionally musical presentation
Construction & Components
Chassis
- CNC-machined 8mm aluminum enclosure (Gold-red/Silver/Matte Black options)
- Schurter IEC inlet with gold-plated fuse holder
Analog Stage
- Volume Control: ALPS RK27 motorized potentiometer (IR remote/manual operation)
- Power Supply: Dual 50VA toroidal transformers (one per channel) *
- Critical Signal Path:
- Taiwan-sourced PTFE-coated OFC wiring
- Monocrystalline copper interconnects (72H burn-in processed)
- CMC pure copper RCA terminals (gold-plated contacts)
Component Highlights
- Military-grade resistors & sealed trimmers
- Latest-production audio-grade capacitors (Nichicon/Elna)
- Gold-plated 3U DIP8 sockets
- Hand-soldered with Alpha (USA) Sn99Ag0.3Cu0.7 alloy
Technical Specifications
Electrical Parameters
| Parameter | Specification |
|---|---|
| Input Sensitivity | 2.5Vrms |
| Input Impedance | 10kΩ |
| Static Power Consumption | 15W |
| Damping Factor | N/A (preamp stage) |
| Output Power | N/A (line-level device) |
| Power Requirements | 100-120VAC / 220-240VAC |
| Dimensions (W×D×H) | 430×310×95mm |
| Net Weight | 8kg |
APx555 Measurement Data
| Metric | Performance |
|---|---|
| THD | 0.0005% @ 1kHz |
| THD+N | 0.001% @ 20Hz-20kHz |
| IMD (SMPTE) | 0.005% |
| SNR (A-weighted) | 117dB |
| Channel Separation | -116dB @ 1kHz |
| Frequency Response | ±0.049dB (20Hz-20kHz) |
| Output Voltage | 7.6Vrms (max) |
| Gain | 11.6dB |
Quality Assurance
- Full AP Test Suite: Every unit undergoes APx555 testing including:
- Bandwidth verification
- THD/IMD sweeps
- Dynamic range analysis
- Channel crosstalk mapping
- 72H Burn-In Protocol: Pre-shipment stress testing under load
- Warranty: 5-year warranty on critical components
Structural Advantages
[Technical Appendix]
- XLR Pinout: Follows US standard (Pin 2 hot)
- Capacitor Aging: 48H forming process on all audio capacitors
- Resistor Matching: <0.1% tolerance across differential pairs
This translation maintains technical rigor while optimizing for:
- Industry-standard terminology (e.g., "toroidal transformers", "balanced XLR")
- Measurable performance claims aligned with AES/CEA standards
- Component authenticity for audiophile audiences
- Clear product differentiation points (Dual Mono design, AP-verified specs)
