Justin Weber makes products like they used to and prices them so that todays audiophiles looking for superb performance can actually afford them.
Nautilus headphone/speaker amp
In the Positive Feedback review they summed with:
"The Nautilus is the best amp I have ever heard, it took my two favorite amps and made them unnecessary. I have not found an amp that can do what the Nautilus does as well as it does, irrelevant of price. It is a no compromise amp for headphones and higher efficiency speakers. It is heavy, it is big, and it is awesome in that all American muscle car kinda way. It was the dream of owning pieces of gear like this that got me into this hobby a long time ago, I just never imagined that it would sound this good.
Read the entire review at: https://positive-feedback.com/reviews/hardware-reviews/ampsandsound-nautilus-amplifier/
From the website:
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
Zion Mono amplifiers
$13,000.00 the pair
The new Zion mono amplifiers are a brand new take on the legenadary HK Citation 5. Using new components and far better parts in a mono application versus the stereo design of the original. The Zions are transformer balanced using 7581 tubes (6L6GC). They are fully tube rectified with a very powerful 32 watts with a frequency response of 2.5Hz-115KHz -3dB. There are no solid state parts used in these amps and they are built the way the originals were done, all by hand. Even the transformers are 200% larger than the originals.
They are very closely based on the Harmon Kardon Citation V.
The Zion's are monoblock versions of the Citation V with tube rectification.
The amps are wired with turret board and point to point, just like the originals.
Chassis work is the area that consumed development. We wanted the most rigid, robust chassis we could produce. As a result, the whole chassis is 12 gauge cold rolled steel. The amps include two mid braces. These not only allow for mounting of components but mechanically tie the top to the bottom plate. The chassis is rigid enough to be stood on without bending or deflection. The transformer's covers are of the same material and have a rib-plate to increase rigidity and allow for ease of mounting. All metalwork is powder-coated. Chassis and covers excluding parts are approx 25lbs per amp.
Transformers are one of the most special aspects of the amps.
We include input transformers for XLR to RCA conversion.
All transformers are 200% over spec'd. Filaments are spec'd at 8amps, and output transformers are rated for 60 watts.
The bench report is fantastic, 32 watts RMS
Ultra-wide bandwidth; 4hz to 115khz @ 1 watt
10hz to 110hz @ 10 watts
These amps are built in the same manner the original HK Citations were manufactured. They are over spec'd in every manner and intended to last a lifetime. Just like the originals, they are quiet, true to source, and have incredible frequency extension. They feel much more powerful than their output in large measure to their low-frequency extension. The sonic signature is true to source with mid-range warmth. They convey all detail present to the source input.
The Zion's are a 17 x 13 chassis and ship in 2 large Pelican style cases.
Mogwei Special Edition
Headphone and power amplifier
The Mogwai SE offers more than an entry point for tube amps, but a hybrid product, meant for both headphone and loudspeaker use. It ises Auricap coupling caps and is transformer input coupled for better sonics. It has adjustable output impedance of 8, 32 or 300 ohms depening on what you are running. Run your high quality headphones of hi efficiency speakers off the Mogwai and you will light up with a smile.
The Mogwei circuit offers the ability to roll a wide variety of tubes inexpensively and bring increased power to headphones without any sacrifice of design choices that conflict with our values.
The Mogwai combines the features of a full-sized two-channel power amplifier and headphone amplifier in a chassis that is suitable for a desktop use.
The Mogwai utilizes single-ended Class A operation with zero feedback to provide the essence of the Classic Wonder sound; strictly old school SET sound, without having to spend hundreds if not thousands of dollars on tubes.
The performance of the Mogwai is made possible with custom wound ultra-high quality output transformers from Transcendar, which provide excellent frequency extension and a flat response.
The Mogwai does not use a voltage divider network, but depends on transformers instead. They chose a 32 ohm tap for headphones to offer a dedicated selection for the widest range of headphones, and an 8-ohm loudspeaker tap to connect the Mogwai to moderately efficient loudspeakers.Volume control is handled by the ALPS volume pot to allow attenuation and simplify the signal path. Zero feedback on the outputs negates the need for a pre-amplifier; an iPhone can drive the Mogwai without issue.
Input tube: 6SL7 or equivalent
Output tubes: 6L6GC, EL34s, KT66, KT77, KT88, 6550s and KT90s
A personal favorite is the Tungsol 6L6GC STR. Warm, strong and tight bass.
Cathode Bias/automatic bias allows for easy tube changes without adjustment.
Compatible with 32ohm-300ohm headphones using the “32ohm” 1/4″ jack.
Headphones driven successfully or tested with the amp include, MrSpeakers Ethers, MrSpeakers Ether Cs, Audeze LCD-2.2F, Audeze LCD-XC, AKG240, AKG701, Sony MDRV6, Sennheiser HD650, Sennheiser HD800, Beyerdynamic T1-32ohm, HIFIMAN HE400i, HIFIMAN HE-400S, HIFIMAN HE-400
The Mogwai is handmade with pride in Southern California with US-sourced parts, including their precision transformers.
Input impedance is 10K ohm with alps pot
Input Sensitivity 2.6V for full power out with input transformers
Power as measured with El34 power tubes and 5U4 rectifier
8 ohm power: 2.8Watts RMS @ 1khz
Noise on 32ohm tapp @ 440uV RMS
32 ohm power: 3.6Watts RMS @ 1khz
Noise on 32ohm tapp @ 650uV RMS
300 ohm power: 4.2atts RMS @ 1khz
Noise on 300ohm tapp @ 1mV RMS
Power as measured with KT88 power tubes and 5AR4 rectifier
8 ohm power: 8.2Watts RMS @ 1khz
Noise on 8ohm tapp @ 440uV RMS
32 ohm power: 4.6Watts RMS @ 1khz
Noise on 32ohm tapp @ 720uV RMS
300 ohm power: 5.2Watts RMS @ 1khz
Noise on 300ohm tapp @ 1.3mV RMS
Lifetime warranty to the original purchaser with 3 year transferability
Kenzie tube headphone amp