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Nautilus
$12,000.00
The Nautilus is one of our flagship Personal Audio Tubed Integrated Amplifier.
The Nautilus Rev 2 includes 2023 tube cage. This change to the metal work allows us to delineate inclusion of the Gen 5 power supply and culmination of 2 years successive efforts to improve this amazing amplifier.
With the inclusion the new tube cage, the transformer cover was raised 2" to allow the cage to fully protect any KT-120/KT-150 tube. The resulting metal work and power supply changes have yielded our quietest Nautilus yet.
Many still love the sleek lower profile look of the Classic Nautilus and as such we allow you to order your Nautilus with the original metal work style or the Rev 2. The Classic Nautilus will additionally save you $1000 on the purchase.
The Story of the Nautilus is born of the same process that brought the Zions. We set out to build my private amps apart from ampsandsound. These were to be mine without branding and never to leave for demos. All too often, my own listening space was sacrificed for the need for demo stock. I chose the HK Cit II as my inspiration point. From that seed came my own Cit II Monos build on turrets just like the best amps of the golden age. Ampsandsound followed with the Sulo monos. The Sulo and Leeloo monos brought turret-based construction and our highest performance to personal audio, but the dual mono layout is not for everyone.
The Nautilus is a dual-mono amplifier built into a single chassis. We started with our most versatile circuit, the Mogwai, and set out to create two independent amplifiers that share only the input tube, volume control, and outputs. Each channel has its own power transformer and power supply, built on separate turret boards, with every part chosen for performance.
To support this design, we partnered with our CNC fabrication house to build a 12-gauge steel chassis with heavy bracing strong enough to carry the 44 pounds of transformers. In total, the Nautilus weighs 74 pounds before packing. A polished chrome cover finishes the build, protecting the transformers and giving the amplifier its distinctive presence.
The Nautilus follows a classic approach to amplifier design. It uses turret boards and true point-to-point wiring, with no silicon, ICs, or regulators. This method is demanding and expensive to build, but it connects the Nautilus to the tradition of legendary amplifiers. These were amplifiers made to be played and built to last a lifetime.
For flexibility, the Nautilus uses dedicated transformer taps rather than voltage dividers. This provides proper system matching across a wide range of headphones, with five selectable impedances available, along with a pair of 8-ohm speaker outputs. A simple toggle on the rear panel makes it easy to move between speakers and headphones without rewiring.
The heart of the Nautilus lies in its transformers. Custom-wound output transformers provide excellent frequency extension and a flat response, while input transformers handle XLR to RCA conversion. This lowers the noise floor, improves clarity, and extends bass response. We paired these with Jupiter copper foil in wax coupling caps, chosen for their ability to reveal fine detail. Volume control is managed with a 24-step stepped attenuator, ensuring precise channel balance.
The result is a reference amplifier that balances purity of design with an unmistakable American voice. The Nautilus delivers a sound that is intimate, powerful, and enduring.
The Nautilus utilizes a single-ended Class A operation with zero feedback to provide the essence of sound, strictly old-school SET sound.
Bench report with 12AX7 inputs with 5ARA4 recifiers and KT88's
Input sensitive: with 12AX7 input @ 1.4V P-P on SE input
Noise: @ 300ohm/HiZ 2.1mV RMS
Noise: @ 100ohm 1.5mV RMS
Noise: @ 32ohm 1.2mV RMS
Noise: @ 16ohm 1mV RMS
Noise: @ 8ohm LoZ 660uV RMS
Max Power @ 8ohm @ 8watts RMS with KT88s and 5AR4s
Max Power @ 32ohm@ 5watts RMS
Max Power @ 100ohm @ 6watts RMS
Max Power @ 300ohm @ 6watts RMS
Ultra-wide bandwidth; 10hz to 32khz @ 1 watt -1db
THD 1Watt @ 1.22%
THD 2Watt @ 1.84%
THD 3 Watt@ 2.45%
THD MAX @ 3.27%
Noise ACV=0.24mV
Compatible with nearly every headphone.
Power and Noise specs are dependent on tube selection.
Actual size is 14”deep, 18” wide and 8”tall. (70lbs)
Amp weighs in at 70lbs/100lbs shipped in a large Pelican style case.
Black Base/Matte Black Cover, Silver Mesh.
Additional colors are possible as a special order... please call or email for details.
All ampsandsound amps are handmade in Southern California with custom hand-wound output transformers and U.S. sourced parts.
Our amps are hand-made by a small team with quality being our first priority.
Additional colors are possible as a special order... please call or email for details.
Nautilus Positive Feedback Review
As both a reviewer and a consumer, I read a lot of reviews myself. I often see solid state amplifiers being commended for having tube amp like qualities in their mid-range presentation, or tube amplifiers being commended for having solid state bass or speed. I myself have used these same euphemisms to describe some of my all-time favorite amps and thought they made a ton of sense.
However, as I have worked on this review of the ampsandsound Nautilus over the past three months I have chosen to re-evaluate whether I should be using these euphemisms in my vocabulary, both as a reviewer and a consumer. The reason for this re-evaluation is that the Nautilus has presented me with an amplifier that has no compromises that would easily allow a listener to identify its underlying topology. I would describe it as not bright and edgy, nor warm and flabby, instead vocals are rendered with realism that is simply shocking, and the sound is extended from the deepest depths all the way to the highest peaks without a hint of fatigue. It is simply a reference class amplifier quiet enough to be used with headphones, and powerful enough to be used with mid to high efficiency speakers. It defies categorization, and even at its $9200 price tag it provides value for the money in spades, based on both its performance and its build quality.