Air Tight ATM-300R


The ATM 300R is one of the most iconic but also simple one of the best tube amplifier ever made – but that just my humble opinion 😉

The best about the 300R is that it also is the best Headphone Amp you will hear:

Yutaka made a Headphone Junction Box especially for me to run the AB1266 all other High End headphones: HJB-1

NEWSFLASH: I have a 300R incl Takatsuki Tubes in stock as of Feb 15, 2024 If that still shows as quantity 1, I still have it!


This is the certainly one of the very best if not the best 300b power amp at his price-point and far above it. The 300R drives efficient speakers like the Devore Fidelity Orang-Utan or the Avantgarde Duos magnificently.

But plug an Abyss AB1266TC or a HiFiMan Susvara directly on his speaker outlets and you won’t believe your ears.

I have those sets always on show using my very own SHIANA custom cotton cable made exclusively by SIN Audio.

Air Tight also offers upgrade Tubes from Takatsuki in a bundle.

Here is what Airtight has to say about the 300R

Abolishing Vanity and Extracting Musicality: Even now many audiophiles are still longing for 300B direct-heated triode valve. We too, were captivated by the charm of this valve. Our approach is to pull out the full potential of 300B valve’s musical soundstage without any additive coloration. As a result, we could achieve a goal of timbral purity and tonal realism by means of 300B’s idiosyncrasy. Detail Researched Design without Compromise In all of circuit design, manufacturing and choices of components, researches are done to details to realize the vivid music reproduction without tonal coloration. At the same time, the stability in the long term is also considered. Best obtainable electrolytic capacitors, coupling film capacitors and winding resistors were chosen. Traditional hand-winded plastic bobbin-less interlaminar transformers were employed for the power transformer and choke coil. They are made by an orthodox lacquer vacuum impregnation method to minimize the vibration and beats so that the musical signal modulation is prevented. Resistors and capacitors are installed on the pure copper sub-chassis board. Wiring and soldering are hand made by skilled workers. All for the peerless and sublime sonic quality. We chose rectifying tube 5U4GB to protect 300B for the purpose to prevent rectifying noise. Also slow starter circuit is for the protection of 300B. Monocoque main chassis made of folded and welded steel plate is for timbral purity. Electric welded stud bolt rewards firm electric conduction and fresh sound as well as clean appearance as none of the screw heads are visible at a glance on the surface.

Power Output :
9W+9W (THD<10%)
THD below :
1% (1kHz / 1W / 8Ω)
Input Sensitivity :
290mV (9W)
Dumping Factor :
7 (1kHz / 1W / 8Ω)
Frequency Response :
30Hz~40kHz (−1dB / 1W)
Dimensions :
Weight :

Additional information


Without 300B Tubes, With Electroharmonix 300B Tubes, Takatsuki TA-300B Tubes


Air Tight