Single-ended-tüüpi ajalooliste Western Electric’u võimendite skeemilahenduse eeskujul konstrueeritud integreeritud võimendi lampidega 300B (triood) 2 tk., draiverid 6SL7 2 tk., 12AT7 2 tk., 274B 2 tk. KUULAMISVÕIMALUS!

Tõeline muusikaelamus sobivate hea tundlikkusega (soovitavalt vähemalt 88 dB/1W/m) lairiba- ja ruuporkõlaritega, näiteks Odeon Nova, Helix, Rigoletto 2020 ja Tosca 2020, Cube Bliss C, Cube Nenuphar, Auditorium 23 Hommage 755 JT. See võimendi on midagi erilist kirglikule muusikasõbrale, kes ei lähtu oma valikutes peaasjalikult tehnilisest spetsifikatsioonist. LM300IA ei jäta kedagi külmaks, sest sellega ei hakka igav, kui on valitud sellega sobivad kõlarid. “Tube rolling” erinevate kvaliteetlampidega annab üllatavaid tulemusi. Standardvarustuses on lambid Psvane 300B.

The Line Magnetic LM-300IA is a single-ended Class A stereo tube amplifier. It draws inspiration from the sonic tradition of Western Electric, Altec, and Jensen electronics. Equipped with carefully selected 300B tubes and meticulous handcrafted construction, the LM-300IA delivers sound reproduction rich in authenticity and depth. Designed for high-fidelity enthusiasts, this device combines tube technology with contemporary engineering for a listening experience that is both precise and engaging.

Architecture and Sound Design

The LM-300IA features a single-ended Class A architecture, a configuration prized by audiophiles for its unparalleled sonic purity. This approach favors quality over quantity, delivering 10 watts RMS per channel—a modest power output, yet sufficient to effectively drive medium- to high-efficiency speakers. Class A operation ensures uncompromising reproduction of the subtlest musical nuances, with harmonic distortion limited to 1% at 1 kHz.

The amplifier boasts a remarkably wide frequency response, spanning from 10 Hz to 50 kHz (-1.5 dB). This broad bandwidth ensures precise reproduction of upper harmonics and contributes to the sense of space and airiness that characterizes the finest tube electronics. The signal-to-noise ratio of 87 dB reflects a circuit carefully optimized to minimize unwanted noise.

The LM-300IA’s sonic philosophy is directly inspired by the legendary Western Electric, Altec, and Jensen electronics—iconic brands that defined the golden age of tube audio. This lineage translates into a warm, embodied, and musically engaging sound that transcends mere technical specifications.

The Magic of Carefully Selected Tubes

At the heart of the LM-300IA lies its meticulous selection of tubes, each chosen for its specific sonic characteristics. The output stage relies on two PSVANE 300B tubes, renowned for their exceptional musicality and their ability to reproduce voices and instruments with striking realism. These iconic tubes, direct descendants of the legendary Western Electric 300B, give the amplifier its distinctive sonic signature.

The input stage uses one Electro Harmonix ECC81 tube and two Tungsol 6SL7GXT tubes, while the driver stage employs two LINLAI 274B tubes. This carefully considered combination achieves a perfect tonal balance between analog warmth and transparency. Line Magnetic emphasizes that each tube is rigorously selected and matched to ensure optimal performance within each amplifier.

A particularly appreciated feature of the LM-300IA is its bias adjustment system (idle current) with a built-in ammeter. This function allows users to precisely adjust the operation of the 300B tubes for the best possible sound performance and to extend their lifespan. The metal protective cage surrounding the tubes can be easily removed to make these adjustments or to replace the tubes.

Transformers and Power Supply: The Foundation of Exceptional Sound

Transformers are a crucial element in tube amplifier design, directly influencing sound quality. Line Magnetic has paid special attention to this aspect by equipping the LM-300IA with specially designed toroidal transformers for the power supply and two wide-band EI output transformers.

A distinctive feature of the LM-300IA is the individual encapsulation of all transformers and capacitors, each installed separately within the chassis to minimize mutual interference. This meticulous approach reflects the attention to detail that defines the design of this amplifier and significantly contributes to its exceptional sonic clarity.

The LM-300IA’s robust power supply, with a consumption of 180 watts, provides a stable foundation for tube performance, ensuring preserved musical dynamics even during the most demanding passages. This generous power supply partly explains the amplifier’s ability to deliver remarkably rich harmonic sound despite its modest output.

Connectivity and Versatility

The LM-300IA stands out for its versatility, offering comprehensive connectivity to suit various audio setups. The amplifier features three RCA line inputs for connecting different sources, as well as a direct power amplifier input (Pre-In) that allows the LM-300IA to be used solely as a power amplifier.

A welcome feature is the presence of a subwoofer output (RCA), making it easy to integrate an active subwoofer to reinforce low frequencies. This is particularly useful given the amplifier’s moderate power, offering the possibility to extend its bass response without compromising its sonic finesse.

To ensure optimal compatibility with different loudspeakers, the LM-300IA provides separate outputs for 4, 8, and 16-ohm impedances. This flexibility allows precise adaptation of the amplifier to the characteristics of the speakers used, ensuring optimal energy transfer and maximum sound quality.

Volume control is handled by a high-quality ALPS potentiometer, renowned for its precision and durability. This potentiometer can be remotely controlled via the supplied infrared remote, adding a touch of modern convenience to this classically inspired piece of equipment.

Frequently Asked Questions

What types of speakers are best suited for the LM-300IA? With its 10 watts per channel, the LM-300IA is ideally paired with medium- to high-efficiency speakers (88 dB/W/m or higher). Horn-loaded speakers, high-efficiency models inspired by Klipsch or JBL designs, as well as certain efficient two-way compact speakers, make perfect partners. The amplifier offers outputs for different impedances (4, 8, and 16 ohms), allowing optimal adaptation to a wide range of speakers.

How do you properly adjust the bias of the 300B tubes? Bias adjustment is done using the built-in ammeter and a small screwdriver. After removing the protective cage and allowing the amplifier to warm up for 30 minutes, simply gently turn the adjustment screws corresponding to each 300B tube until the ammeter needle indicates the value recommended in the manual (generally between 40 and 60 mA). This simple operation should be performed about once a month or after replacing the tubes.

Can the LM-300IA be used as a preamplifier only? No, the LM-300IA does not have a dedicated preamplifier output that would allow it to be used solely as a preamplifier. However, it can function as a pure power amplifier thanks to its Pre-In input, which bypasses the preamplification stage. This flexibility allows the LM-300IA to be integrated into more complex systems or to use a specialized external preamplifier if desired.

What is the sonic difference between 300B tubes and other power tubes like KT88 or EL34? 300B tubes are distinguished by their particularly natural and musical sound signature, with exceptional harmonic richness in the midrange. Compared to KT88s, which generally offer more power and more dynamic extension at the extremes, 300Bs favor tonal beauty and the presence of voices and instruments. Compared to EL34s, known for their warm midrange but sometimes less precision, 300Bs offer superior transparency while maintaining a characteristic organic warmth.

Is it possible to replace the original tubes with other brands to modify the sound signature? Absolutely—this is one of the advantages of tube amplifiers. The original PSVANE 300B tubes can be replaced with other brands such as Western Electric, Takatsuki, Emission Labs, or KR Audio to explore different sonic nuances. Likewise, the input and driver stage tubes can be swapped to fine-tune the sound signature according to personal preferences. This flexibility allows for a personalized listening experience and is a valued aspect of tube amplifiers like the LM-300IA.

Technical Specifications

Architecture and Design

• Type: integrated tube amplifier
• Configuration: single-ended, class A
• Philosophy: inspired by Western Electric, Altec, Jensen electronics

Tubes and Configuration

• Input tubes:
  • 2 × ECC81 (Electro Harmonix)
  • 2 × 6SL7GT (Tung-Sol)
• Driver tubes:
  • 2 × 274B (Linlai)
• Power tubes:
  • 2 × 300B (PSVANE)
• Bias adjustment: via built-in ampermeter and screwdriver

Audio Performance

• Output power: 10 W per channel (class A)
• Harmonic distortion: 1% at 1 kHz
• Frequency response: 10 Hz – 50,000 Hz (–1.5 dB)
• Sound: rich, harmonic, full-bodied
• Soundstage: very well defined, with depth and distinct layers
• Timbre: realistic, expressive (vocals, piano, orchestra)
• Special features: slight background noise due to power supply

Connectivity

• Line inputs: 3 × RCA
• Direct amp input: 1 × RCA (preamp bypass)
• Speaker outputs:
  • Separate terminals for impedances: 4 Ω, 8 Ω, 16 Ω
• Active subwoofer output: 1 × stereo RCA
• Headphone output: front panel
• Connection quality: audiophile-grade RCA terminals

Controls and Features

• Volume control: motorized ALPS potentiometer
• Input selector: 4-position rotary switch
• Power-on delay: 30 seconds
• Notable features: headphone output (rare feature on tube amps)
• Optimal use: after warm-up and bias adjustment

Physical Characteristics

• Dimensions (W × D × H): 430 × 365 × 217 mm
• Net weight: 34 kg
• Power consumption: 180 W

General Information

• Manufacturer: Line Magnetic (China)