Air Tight ATM-3 | Ein Klassiker von AIR TIGHT, gut erhältliche Röhren, Triodenbetrieb, leistungs- und klangstark.

Impeccable harmony of art and sound

6CA7 output valves for high reliability and affluent musicality under triple push-pull configuration.
Selector between UL and TRIODE modes enabling to match the amp operation to type of speaker used, or the sound to your personal taste.
Bias adjustment enabling each and all valves to exhibit the same operational performance.
Removal of PCB’s for vivid, natural sonic reproduction.
Large power transformer with heavy-duty choke coil and reputed Tamura output transformer.
Muting delay system to protect output valves.

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AIR TIGHT's first monaural power amplifier in commemoration of its 5th anniversary.

6CA7/EL34 is used for the output tube, and triple push-pull is used to secure 100W or more by allowing extra space in the vacuum tube. In addition, by connecting vacuum tubes in parallel, internal resistance is reduced without increasing plate voltage, and high power is achieved.
This enables stable operation over a long period of time without applying excessive load to each vacuum tube.

Six vacuum tubes with the same characteristics selected by an aging machine are used for each vacuum tube. In addition, each tube is equipped with an independent bias check mechanism for long-term stable operation in the best condition, and can be checked and adjusted at any time by the volume and meter on the front panel.

Equipped with a switching circuit for UL connection and 3-pole pipe connection, the operating state of the output pipe can be switched according to the speaker and sound preference. The UL (Ultra-Linear) connection is designed to connect the screen grid of the multi-pole output tube to the tap located in the middle of the primary winding of the output transformer. In this connection method, the phase of the voltage of the screen grid is opposite to the phase of the voltage of the control grid, so it acts as a negative feedback to the output tube. Therefore, the amplification is lower than when the multi-pole tube is connected. However, due to the decrease in the amplification degree, the internal resistance of the plate rapidly decreases. As a result, it extends in the low-frequency range and exhibits the expression power of a vacuum tube. In addition, stable NFB is applied over all frequencies.

The 3-pole tube connection is 100% negative feedback applied to the screen grid of the UL connection. The plate internal resistance of the output tube is even lower than that of the UL connection, but the decrease in the output is also large. As for sound quality, the energy is stable inside and is applied to all bands, so sweet expressive power can be obtained.

High sound quality is achieved by finishing with 1.1 point wiring without using a printed circuit board.

A large transformer is used for the power transformer, making up a strong power source with good regulation.

We have adopted the highest-grade transformer manufactured by tamura Manufacturing Co., Ltd. with transformer technology that has passed the Defense Agency standards. This transformer is a large type matched to the low impedance of the triple push, and realizes a low frequency without distortion. In addition, the constant loss is marked as 0.25 dB, which is the lowest value for an output transformer. In addition, the adoption of the Orient Core eliminates frequency shift over the entire band.

Highly reliable parts are carefully selected and used.

In order to protect the output tube, it is equipped with a muting circuit that cuts off high voltage in the output tube for approximately 30 seconds after power is turned on.

Nur seriös gemeinte Preisofferten mit Absenderangaben und Telefonnummer bitte!
Only serious price offers with sender details and telephone number please!