Nautilus Flagship Personal Audio Tubed Integrated Amplifier ampsandsound

This is the place to discuss the Nautilus Flagship Personal Audio Tubed Integrated Amplifier AmpsandSound

“The Nautilus is our flagship Personal Audio Tubed Integrated Amplifier.

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 choice 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 brings the dual-mono layout onto a single chassis. We start with our most versatile circuit, the Mogwai, and go about creating two separate amps that share a single chassis. 2 Power Transformers, Separate Power Supplies, Chokes, and input transformers. The amps are built with separate turret boards with the one shared component being the input tube, volume control, and outputs. With the most substantial single chassis we’ve made to date, we were unconstrainted with parts selection and layout. We chose the most robust power transformer and widest/least distortion output transformers we could find.

The Nautilus’ hand build nature and part selection necessitated and hand fabricated chassis. We partnered with our existing CNC metal fab house to build a 12 gauge steel chassis with bracing that could support the 40lbs of transformers without a hint of strain. In total, the Nautilus is 55lbs before packing. We additionally choose to cover all the transformers and business end of the amp with a gorgeous chrome cover.

The Nautilus’ employs turrets and point to point wiring. There is no silicone, ICs, or regulators. This is a Classic design, decidedly prosaic. We consider this a standard-bearer of purest audio with an American sensibility. The Nautilus built in a way few modern amplifiers are. This is not due to intrinsic inferiority, but rather it is impossible to rush and is incredibly expensive to produce. Some of the most familiar tube amps ever produced utilize this method, including; McIntosh, HK, Leek, Quad, & Western Electric. These amplifiers demand to be played and built to last a lifetime.

The Nautilus does not use a voltage divider network but depends on transformers instead. We use multiple dedicated taps for headphones to offer a dedicated selection for the most comprehensive range of headphones.

The Nautilus has been described as a tube integrated amp for personal audio users. We mean by this, the Nautilus allows for five separate impedances to be selected for system matching and has a pair of 8ohm 5 way binding posts. The speaker vs. headphone output is selected with a small toggle switch on the back of the amp. This simple addition was not without compromise. You can choose between headphones or speakers without wiring changes to your system.

Transformers are one of the most special aspects of the amps. The Nautilus performance is made possible with custom wound ultra-high quality output transformers from Transcendar, which provide excellent frequency extension and a flat response.

Cinemag transformers are used as input transformers for XLR to RCA conversion.

The input of Nautilus unitizes input transformers for reduced noise floor, greater clarity, and sub-bass response.

For this reference amplifier, we paired the finest coupling caps, Jupiter copper foil in wax caps. The increases in micro-detail retrieval were remarkable.

Volume control is handled via a 24step stepped attenuator. This ensures precise channel matching.

The Nautilus allows for a wide range of tubes, including 6l6gc through KT90s. KT120s and KT150s are not compatible. The tube complement form factor is spec’d as a matched pair of 6L6GC STR or KT88, a single 12AX7, and two 5AR4 or 5U4 rectifiers.

The Nautilus utilizes single-ended Class A operation with zero feedback to provide the essence of sound; strictly old school SET sound.

Bench report with 5751 inputs with 5ARA4 reciters and KT88s

Input sensitive: with 5751 input @ 1.72V P-P

Noise: @ 300ohm/HiZ 1.33mV RMS

Noise: @ 100ohm 1.1mV RMS

Noise: @ 32ohm 650mV RMS

Noise: @ 16ohm 550mV RMS

Noise: @ 8ohm LoZ 430mV RMS

Max Power @ 8ohm @ 8watts RMS

Max Power @ 16ohm @ 5watts RMS

Max Power @ 32ohm @ 5watts RMS

Max Power @ 100ohm @ 6watts RMS

Max Power @ 300ohm @ 6 watts RMS

Ultra-wide bandwidth; 8hz to 26khz @ 1 watt

Actual size is 17.5"wide, 14.5"deep, 7" tall

Amp weighs in at 68lbs/93lbs shipped in a large Pelican style case.

Default color is Black base/Matte Chrome Cover. Additional colors are possible as special order… please call or email for details.

When order is placed it will default with Black base/Matte Chrome Cover.”


I wanted to get this thread going as I have the amp on loan/review from Justin and I will place some of my impressions as I go here, much of those impressions will be found in my final filmed YouTube review. If you have any questions please let me know!


This thread is just wrong… it’s like you guys are trying to do a hit job on my wallet… please dear lord I hope you hate it…


You could save some money and buy a mogwai SE, get upgraded jupiter caps in it and also ask for an upgraded attenuator or if possible a pre input and supply your own preamp. Not as gnarly but I bet will still be a dreamy amp. Just Non Beast mode. Bigger Ben looks like a great amp too that is just a notch lower than the Nautilus


Absolutely @Earmuffs If budget for the nautilus isn’t an option Justin makes many other incredible amps!


Everything Justin makes is top tier


That’s a gorgeous amp. Love the dedicated taps. I wonder how well it performs with the different impedances.

Looking forward to the review!


Sweet looking amp…


I have the Mogwai SE with Jupiter cap upgrade, and I’m so in love with it I wouldn’t spend any more to get a Nautilus. But the Nautilus looks mighty impressive.


I have had the mogwai SE previously and I will concur that its a fabulous amp to my ears. Had a great time with it. Didnt get rid of it because I didnt like, I just wanted to explore other types of tubes.


I wanted to give a small sound impression update!

I have been primarily listening to the Nautilus with the D90 as it is the more neutral of the DACS I currently own so, I can get a feel for the sound as well as the Verite Open I have in for review from Zach.

I have been listening via Roon with Qobuz and Tidal. I will also be adding my impressions soon with the bitfrost 2 as well as the Matrix Sabre X Pro and today I received the Hifiman HE1000se and will update with those impressions as well.

I have listened via all of the taps from low Z to high Z and have at the time of this post preferred the Verite on the Low Z-100ohm range the most.

Apologies in advance for anyone that wanted me to hate the amp, as that will not be the case.

Listening with the Nautilus is one of the most life like, organic, music listening experiences I have ever had when paired with the Verite Open. I am hearing more detail and micro detail in recordings that I have simply never heard before from vocals, background vocals, instruments etc. All the while the sound is presented in the most non fatiguing enveloping way.

Everything seems to fit cohesively where it should be on its stage. For example when listening with the awesome Pendant the music is presented with a more forward presentation, and as good as the pendant is at times the presentation can push the information in a very energetic forward way vs. the incredible delivery and layering the Nautilus presents.

Details on some tracks I didn’t hear when listening to the pendant presented themselves clearly and beautifully when listening to the Nautilus. Impact and bass is the most rich and enjoyable I have ever heard from the Verite.

Spending several hundreds of dollars to get some of the better tube options for the Pendant to get it to present the sound signature in a way I have most enjoyed from it, doesn’t get close in the audible bass or impact region compared to the nautilus with the VO. This is in no way a shot at the Pendant, let me make that clear that at the $1999 price and below the Pendant is one of my favorite amps I have heard yet. I am using the Pendant as a point of reference for some of my impressions.

Vocals are the best I have ever heard at this point in my head fi journey. Female and male vocals sound life like, rich with zero harshness or sibilance. The synergy is very real with the Verite Open and I am very excited to try this pairing with additional DACS.

The staging is beautiful allowing for the 3D qualities of the Verite to amplify, and this is with a DAC ie.Topping D90 that honestly stages smaller in size IMO for width and depth. I would imagine the Bifrost2 and Matrix Sabre Pro will only take things to the next level. I will go into more detail soon and add additional impressions soon, but I have to get my daughter ready for bed. Chat soon!


Thanks for posting and giving us stuff to chew on! Based on my listening with my ZMF Eikon and others with ZMF cans on other amps, low Z to 100 ohm outs have also been preferred. Looking forward to the next update.


That sounds like a very special amp.

How is it with other non-ZMF headphones?


I’d love to hear how it is with the Empyrean.


Listening to the the HE1000se now off the 32om output will give more impressions as I get more head time! I will also roll it woth the RAD-0, Empy, HD800 mod, and Eikon (when they get here in a few weeks) 6XX, Aeolus, Koss Porta Pro too :stuck_out_tongue_winking_eye:

@ValentineLuke @PaisleyUnderground


This one is critical.


I didn’t want to be presumptuous, but yes. This is the one I’m waiting for.


That’s the picture I want tho… Matrix + Nautilus + Porta Pro… headphones being at the “rounding error” level. :joy:


Nobody who buys an $8k amp is going to use it with a Porta Pro. That pairing won’t teach you anything useful about either one IMO.

@Superfly it was a joke Dave…