Suolo Monos

Coupling Capacitor
Output Impedance

The Suolo Monos came about from a brainstorming session. We were looking to keep the tone of the Kenzie which is warm, musical and detailed with the flexibility of the Mogwai SE and its Tonal weight. Additionally we wanted to showcase our technical prowess, as we consider turret boards to be the highest art.

The Suolo Monos are a 2 chassis solution, isolating each channel to its own amp. The amps employ a new power transformer with provision for tube rectification from a 6CA4 rectifier.

The power supply is robust and utilized choke regulation.

We opted to use the ubiquitous 5751 or 12AX7 allowing for the widest range of tube rolling options.

Output tube is the 1626 WWII transmitter triode or use the 12B4 triode with adapter for more increase in power by 40%. The goal of the Suolo mono is to allow for a wide range of NOS tube rolling; old tubes do it better.

The Suolo Mono is one of the sweetest-sounding headphone amplifiers on the market yet brings you closer to the music, going from the 10throw to the orchestra.  The 1626 is commonly referred to as the “Poor Man’s 300B”; offering a similar level of warmth, texture, and soundstage depth.

Outputs are ¼” mono jacks for 8ohm, 32ohm and 300ohm as well as binding posts for use as a 2chanel mono block amp.

The build quality of the Suolo monos is Jewel like, though you will likely never see the effort which went into its production, turret boards predate PCBs and provide the greatest flexibility while providing a rigid mounting point. Turret boards were used in some of the greatest amplifiers made from Mcintosh and HarmonKardon and today ampsandsound made use as well.  

Input attenuation/Volume is handled by a 10K mono stepped attenuator for precise channel matching.

The Suolo Monos are SET Single Ended Triode with no feedback. Output is directly coupled to the transformer, no voltage divider network to degrade the sound.  The Suolo Monos have more than enough power to drive even the most difficult headphones. We chose 8ohm, 32ohms and 300ohm output taps to allow use with the widest variety of headphones; everything from Grado Labs, HiFiMan, Audeze, MrSpeakers, Sennheiser, and Beyerdynamic.

Cathode Bias/automatic bias allows for easy tube changes without adjustment.

Includes 1 Mono ¼” to Stereo ¼” Y-cable to allow immediate use

Supplied Tubes:
Input tube: 5751

Rectifier: 6CA4

Output tubes: 1626 or VT-137

Headphones driven successfully or tested with the amp include:

 MrSpeakers Ethers2, MrSpeakers Ether Cs, Audeze LCD-2, LCD2 Closed Audeze LCD-XC, Audeze LCD-X, Audeze LCD-3, AKG240, AKG701, Sony MDRV6, Sennheiser HD650, Sennheiser HD800s, Beyerdynamic T1-600 ohm, HIFIMAN HE400i, HIFIMAN HE-400, HE-400S, Grado Labs SR-60, RS1i

The Suolo is handmade in Southern California with U.S.-sourced parts and custom hand-wound output transformers.

Wood Chassis is available in stock Walnut/Ebony or Black Lacquer. 


Input impedance is 10K ohm with alps pot
Input Sensitivity 1V for full power out.
Frequency bandwidth 8hz -1db to 18khz -2db full power

8ohm power: 500mWatts RMS @ 1khz
Noise on 8ohm tapp @ 430uV

32ohm power: 400mWatts RMS @ 1khz
Noise on 32ohm tapp @ 570uV

300ohm power: 400mWatts RMS @ 1khz
Noise on 300ohm tapp @ 640uV