Fisher ALLEGRO-II-A-9/A-19: The Forgotten Jewel of High-End Tube Preamplification
Fisher Electronics was founded by Avery Fisher in the 1940s, and in the golden era of American hi-fi the name carried real prestige. The Fisher ALLEGRO-II-A-9/A-19 was a modular preamplifier system introduced in the late 1960s.
It isn't as well known today as Fisher's receivers like the 500 or 800 series. It came during the transition from tubes to solid-state, and it was a rare, sophisticated preamp built for the serious listener who wanted precision, flexibility, and the warm, natural sound of a well-engineered tube circuit.
Historical Context: Fisher at the Pinnacle of Hi-Fi
By the late 1960s, Fisher was already a leader in high-end audio. The company introduced the first FM stereo tuner and pioneered the use of printed circuit boards in consumer audio gear. The ALLEGRO series was Fisher's flagship line, intended to compete with Marantz, McIntosh, and Harman Kardon in the growing high-fidelity market.
The ALLEGRO-II-A-9/A-19 was not a single unit. It was a modular preamplifier system in two separate chassis: the A-9 preamplifier section and the A-19 power supply unit. The dual-box design was unusual for its time. It kept the sensitive audio circuitry away from the electrically noisy power supply, for lower noise, better channel separation, and greater dynamic range.
Production was around 1968. The audio world was starting to shift toward solid-state electronics, but Fisher, like many purists, still believed in the musical advantages of vacuum tubes. This system was one of the last and most refined of Fisher's tube-based preamplifier designs. The company gradually moved to transistorized circuits in the 1970s.
Technical Specifications
| Specification | Detail |
| Model | ALLEGRO-II-A-9/A-19 |
| Year Introduced | 1968 |
| Type | Dual-chassis tube preamplifier system |
| Chassis Components | A-9 (preamplifier), A-19 (power supply) |
| Tube Complement | 6x 12AX7 (ECC83), 2x 12AT7 (ECC81) |
| Inputs | 4 line-level (RCA), 1 phono (MM) |
| Outputs | 1 main output (RCA), 1 tape loop |
| Frequency Response | 20Hz – 20kHz ±1dB |
| Total Harmonic Distortion | <0.5% at rated output |
| Signal-to-Noise Ratio | >80dB (A-weighted) |
| Power Supply | External A-19 regulated power unit |
| Impedance | Input: 100kΩ, Output: 600Ω |
| Dimensions (A-9) | 19" W × 5.5" H × 10" D |
| Weight | ~25 lbs (combined) |
| Finish | Brushed aluminum front panel, black chassis |
The use of a dedicated external power supply (A-19) was a hallmark of high-end design at the time. It provided tightly regulated DC voltages to the A-9 preamp, minimizing hum and ripple—common issues in tube gear. This modular approach also allowed for future upgrades and easier servicing, a forward-thinking design choice that anticipated the modularity trends of later high-end audio.
Sound Characteristics and Performance
The ALLEGRO-II-A-9/A-19 sounds warm, rich, and three-dimensional, the way tube preamps were supposed to. Midrange clarity is its strength, with a lush presentation that suits vocals and acoustic instruments. The stereo imaging is wide and stable, with good depth and separation. That was rare in consumer gear of the era.
The low-noise design and high-quality components give the A-9 a black background where subtle details in recordings can come through. The phono stage is built for moving magnet cartridges and is well regarded for its musicality and low surface noise. Paired with a high-quality turntable and a tube power amplifier (such as a Fisher 500-B or a McIntosh MC240), the system sounds balanced and dynamic.
It is not as analytical or ultra-detailed as some modern preamps. The ALLEGRO-II-A-9/A-19 favors musical coherence over clinical precision.
Notable Features and Innovations
- Modular Design: The separation of the preamp and power supply was a sophisticated engineering solution that improved performance and reduced interference.
- Regulated Power Supply: The A-19 unit provided stable, filtered DC power, a rarity in consumer preamplifiers of the time.
- High-Quality Components: Fisher used military-grade resistors, precision potentiometers, and custom-wound transformers, ensuring long-term reliability and performance.
- Balanced Circuit Topology: Though not fully balanced in the modern sense, the A-9 employed symmetrical circuit layouts to minimize crosstalk and distortion.
- User-Friendly Layout: The front panel features clearly labeled inputs, a large central volume knob, and separate bass/treble controls with a defeat switch for pure tone control bypass.
Common Issues and Maintenance
Like all vintage tube equipment, the ALLEGRO-II-A-9/A-19 needs careful maintenance. Over time, capacitors, especially in the power supply, can dry out and fail. That leads to hum, noise, or even damage to the tubes. The A-19 power supply should be recapped by a qualified technician before regular use.
Inspect the tubes for microphonics and replace any that are noisy or weak. The original 12AX7 and 12AT7 tubes are still available (NOS or new production). Matching and biasing are not required, since these are low-power preamp tubes.
Other common issues include:
- Oxidized potentiometers (clean with DeoxIT)
- Worn input jacks (check for intermittent connections)
- Faded labeling on the front panel (cosmetic only)
Replacement parts and service manuals are hard to find because the unit is rare. The circuit design is relatively straightforward for experienced tube technicians.
Current Market Value and Collectibility
The Fisher ALLEGRO-II-A-9/A-19 is rare and highly collectible, especially in original condition with both chassis and matching serial numbers. Complete units in working order typically sell for $800 - $1,500. Exceptional examples fetch more at auction or among dedicated Fisher collectors.
Its value comes from its sound and from its historical significance as one of Fisher's most advanced preamplifier systems. It appeals to tube enthusiasts, vintage audio restorers, and collectors of American hi-fi.
Conclusion: A Legacy of Refinement
The Fisher ALLEGRO-II-A-9/A-19 may not be a household name, but among connoisseurs of vintage audio, it represents the peak of Fisher’s tube-era engineering. Its modular design, exceptional build quality, and lush, musical sound make it a standout in the crowded field of 1960s preamplifiers.
While overshadowed by more famous models, the ALLEGRO-II-A-9/A-19 deserves recognition as a sophisticated, forward-thinking system that combined innovation with timeless sonic virtues. For those who appreciate the warmth of tubes and the craftsmanship of a bygone era, this rare Fisher gem remains a rewarding discovery—and a true piece of American audio history.
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