FM Acoustics FM 255 | Classic Series F10B

At AudioWWW , we proudly offer compelling trade-in value for pre-owned equipment, meaning from time to time we come across some great pre-owned items that we can put into the hands of our clientele! Each one of the items in our pre-owned/demo inventory has been vigorously tested and cleaned to ensure the utmost in quality. Please have a look at our selection, and be sure to check in regularly as we update the page on a weekly basis. Be sure to let any of our staff know if you have any questions or inquiries regarding any piece you may be interested in. Happy shopping!

FM Acoustics FM 255 (Line Stage / Preamplifier)

Key Features & Circuit Design

• Proprietary enhanced Class A circuitry. fmacoustics.com+1

• Exceptional rejection of interference, often quoted as ≥ 95 dB for common-mode rejection. fmacoustics.com+2fmacoustics.com+2

• True-balanced inputs and outputs; two balanced inputs and three unbalanced inputs. fmacoustics.com+1

• Discrete Class A tape send/return for auxiliary connectivity. fmacoustics.com

• Identical balanced signal paths to preserve symmetry. fmacoustics.com+1

• Modular design, with hand-selected, curve-tracer tested components. fmacoustics.com

• Low-impedance internal power supply, shielded transformer with dual shielding to reduce stray fields. fmacoustics.com

• Volume (level) and balance controls are precision mechanical type (not stepped or digital). fmacoustics.com

Published Specifications (for MKII / later versions)

• Gain (line): 20 dB HiFi Engine

• Signal-to-Noise Ratio (line): 120 dB HiFi Engine

• Total Harmonic Distortion (THD): ≈ 0.003 % HiFi Engine

• Channel Separation (line): ~95 dB HiFi Engine

• Output (nominal): 3 V (line out) HiFi Engine

• Maximum Output (preamp): 16 V (some sources) HiFi Engine

• Dimensions: 446 × 92 × 280 mm HiFi Engine

• Weight (unit): ~5 kg HiFi Engine+1

FM Acoustics Classic Series F10B (Power Amplifier)

Key Design Features

• Amplification uses fully discrete circuitry, with all stages hand-tuned and matched. fmacoustics.com

• All amplification in pure Class A until output, where Class A + AB operation is employed. fmacoustics.com

• Built-in, multiple automatic protection circuits for both amplifier and load. fmacoustics.com

• Designed to remain stable with complex and low-impedance speaker loads. fmacoustics.com

• Long burn-in (≈200 hours) and mechanical stress testing (50,000 vibration cycles) for reliability. fmacoustics.com

Published or Reported Specifications

• Power Output (per channel / stereo model):
   • 80 W into 8 Ω Hifido+2whatsbestforum.com+2
   • 125 W into 4 Ω Hifido+2whatsbestforum.com+2
   • 200 W into 2 Ω (reported) whatsbestforum.com

• Gain: ~26 dB Hifido

• Input Impedance: ~40 kΩ Hifido

• Dimensions: 446 × 100 × 300 mm (W × H × D) Hifido

• Weight: ~12 kg Hifido

11/10: New - Unopened Factory Shipment

An item rated as "NEW" must come in its factory-sealed box. The item should not have been opened or used in any way. The seller should clearly indicate if any warranty is included and specify whether it is backed by the manufacturer. Some manufacturers only honor warranties if the product is purchased from an authorized dealer, and others may offer warranties only to the original owner, even if the box has never been opened. If no warranty details are provided, it’s essential for buyers to inquire with the seller for clarification.

• Important Note: Items that have been opened for inspection or any other reason should NOT be listed as "NEW."

10/10: Mint - Essentially Never Used, Factory Fresh Appearance

The "Mint" grade is reserved for items that have been removed from their original packaging but have barely been used—typically less than a year since first use. These items should look like new without any visible blemishes, scratches, or discoloration from environmental exposure (e.g., oils from fingers, smoke, or household chemicals).

Key characteristics:

• Electronics: No visible scratches, nicks, or blemishes; connectors and plating should appear like new.

• Speakers: No signs of use, with perfectly intact grilles and flawless veneer.

• Turntables: Covers should be free of dust, fingerprints, or swirls.

Items at this level are rare, as very few pre-owned or demo products meet this standard.

9/10: Excellent - Perfect Physical Condition, Light Use

An item in Excellent condition will show signs of light use but will be in pristine physical shape. It may have been used occasionally but remains in near-perfect condition.

Key characteristics:

• Electronics: No visible scratches, but light dust may be present in crevices. Connectors may show slight use, but no discoloration.

• Speakers: Perfect appearance on the front face, with minor indentations on the back or bottom that do not affect the veneer.

• Turntables: Minor signs of use, like slight hazing on the cover or minor scratches on the headshell.

8/10: Very Good - Minor Flaw, Well-Maintained

A product rated 8/10 has been used but is still in great condition. It may have a few minor flaws that are noticeable only on closer inspection, such as small scratches on the top or sides.

Key characteristics:

• Electronics: Minor scratches on the top plate or sides (max 1/2" long), no major wear on connectors.

• Speakers: Slight discoloration along edges or minor scratches on the bottom.

• Turntables: Light haziness on covers, but no visible scratches on the main surfaces.

7/10: Good - Visible Use, Well Maintained

Items rated Good show more significant signs of use but are still in functional condition. They may have noticeable scratches, light wear on connectors, or slight damage to the body.

Key characteristics:

• Electronics: Visible scratches, some wear on the knobs and switches, no dents or bulges.

• Speakers: Minor scratches on the veneer, loose-fitting grilles, or light wear on speaker covers.

• Turntables: Hazy covers, some visible scratches on the tonearm or platter.

6/10: Fair - Noticeable Wear, Fully Functional

An item graded as Fair will show clear signs of use, including multiple minor scratches or even some major blemishes. Despite these imperfections, the item functions perfectly.

Key characteristics:

• Electronics: Major scratches (over 2” long), slight dents, or wear on the front facia.

• Speakers: Larger scratches through the veneer (up to 2”), or worn-out grilles.

• Turntables: Scratched covers or worn-out platter surfaces.

5/10: Average - Multiple Scratches, Well Used

At this grade, the item shows significant wear and multiple scratches. The physical condition may be rough, but the equipment remains functional.

Key characteristics:

• Electronics: Several scratches on the front and other surfaces, some rust or pitting on connectors.

• Speakers: Major scratches, broken or missing grille covers, visible damage on the cabinet.

• Turntables: Cracked covers, visible damage to the tonearm, or excessive wear on the platter.

4/10: Mediocre - Rough Physical Condition, Functional

This grade is for items in rough physical shape, though they still function properly. These items are typically used or aged but are not beyond repair.

Key characteristics:

• Electronics: Broken or cracked display faces, heavy pitting on chrome, or visible rust.

• Speakers: Dented corners or broken binding posts, but still functional.

• Turntables: Missing covers or severe discoloration from wear.

3/10: Poor - Heavily Used, Functional

Items in Poor condition show significant physical damage, but all functions still work. These products are far from "pristine" and may be for parts or temporary use.

Key characteristics:

• Electronics: Severe pitting or oxidation, dented and rusted parts, possibly missing knobs.

• Speakers: Major scratches or chunks missing, but drivers still intact.

• Turntables: Visible damage to tonearm, cracked covers, or other serious wear.

2/10: Very Poor - Heavily Damaged, Some Functional Issues

A Very Poor item is in terrible physical condition and may have functional problems. However, it might still have some usable parts or could be restored.

Key characteristics:

• Electronics: Major dents, missing knobs, non-functional buttons or switches.

• Speakers: Torn drivers, severe damage to the cabinet, or non-functioning grilles.

• Turntables: Warped platters, or tonearm with tight or wobbly bearings.

1/10: Shot - For Parts Only

Items rated 1/10 are in non-functional condition. They are typically beyond repair and can only be used for parts.