http://ampsandsound.com/ Mogwai Like many of our products, the Mogwai evolved from our earlier designs, borrowing from the Bigger Ben and Classic Wonder, while embracing the form factor of the Kenzie. The Mogwai offers more than an entry point for tube amps, but a hybrid product, meant for serious headphone and speaker use. Our 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 amp into a small amplifier package, weighing ~15lbs largely due to its over spec’d custom wound transformers. The Mogwai utilizes Single ended Class A operation with zero feedback to provide the essence of our Classic Wonder sound; strictly old school SET sound, while paired with a more accessible tube selection. The performance of the Mogwai is made possible with custom wound ultra-high quality output transformers from Transcendar Transformers providing amazing frequency extension and flat response. The Mogwai does not use a voltage divider network, but depends on transformers instead. We chose 32ohm tap for headphones to offer a dedicated selection for the widest range of headphones, and an 8ohm speaker tap to connect the Mogwai to moderately efficient speakers. The Mogwai displays its transformers prominently on the chassis to frame in the tube selections, which can vary from a 6L6GC to a KT88. Volume control is handled by the ALPS volume pot to allow attenuation and simplify the signal path… no preamp is needed. Zero feedback on the outputs negates the need for a pre, an iPhone can drive the Mogwai without issue. The Mogwai differs from the Kenzie as it aims to provide powerful output while remaining true to 50s tube ideals, and single ended sweetness. As with all ampsandsound products, we strive for a neutral, non-fatiguing sound, and demand that all our products be ultra-quiet in operation. Quiet operation is not just a goal but a guiding principle that shapes all design and implementation choices… from pots to resistors we strive for tube amps to never distract from the music. Input tube: 6SL7 or equivalent Output tubes: 6L6GC, EL34s, KT66, KT77, KT88, 6550s and KT90s 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. (Beyerdynamic T1-600ohm were used successfully but not ideal.) Headphones driven successfully or tested with the amp include, Mr. Speaker Ethers, Mr. Speaker Ether Cs, Audeze LCD-2.2F, Audeze LCD-XC, AKG240, AKG701, Sony MDRV6, Sennheiser HD650, Sennheiser HD800, Beyerdynamic T1-32ohm, HIFIMAN HE400i. The Mogwai is made with pride in Southern California with US sourced parts, including our precision transformers. Specs: Input impedance is 250Kohm with alps pot, .5v for full power. Noise with pot fully counterclockwise is 500 micro volts RMS Measured with 6550 output tubes on 1/4″ 32ohm optimzied headphone jack. 500mW RMS output 20 Hz (-2db) to 17.7 kHz (-3db) Measured with 6550 output tubes on 8 ohm tap. 3W RMS output 30 Hz (-1db) to 20 kHz (-2db) Please look at our news section for feedback from owners of the Mogwai. Mogwai Headphone amp – $1,700 with tube set. Kenzie Headphone Amp Like many of our products, the Kenzie Headphone Amp evolved from our earlier designs – in this case, rave reviews about the SE-84’s headphone section. The inevitable question followed; why didn’t we build a dedicated headphone amp? Why indeed? After some research, we came to the conclusion that the Kenzie amp using the much loved darling circuit was the right choice for us. The outstanding performance of the Kenzie Headphone amp is made possible with custom wound ultra-high quality output transformers providing amazing frequency extension. The Kenzie does not use a voltage network, and has more than enough power to drive even the most difficult headphones. We chose 32ohm and 600ohm to allow use with the widest variety of headphones. The Kenzie Headphone amp showcases the transformers on the chassis to frame in the amazing 1626 tubes in all their single-ended direct-heated bliss. We have included an ALPS volume pot to allow attenuation and simplify the signal path… no preamp is needed. The 1626 AKA Kenzie is one of the sweetest-sounding amps you will ever hear. The 1626 is commonly referred to as the poor man’s 300b; all the same great imaging, texture, and single-ended sweetness without the cost to break the bank. The 1626 is a WWII era tube used as a transmitter tube in radar installations. The design is shy on pure output, but is overflowing with texture and drive, and is paired with a massive choke and robust output transformers for ultra-quiet operation. As with all of our products, parts selection was crucial during this build and each chosen not for price, but for best quality and synergy. Input tube: 12SL7 or equivalent Output tubes: 1626 or VT-137 which is a WWII transmitter tube and characterized as sounding like a mini 300b. Cathode Bias/automatic bias allows for easy tube changes without adjustment. Compatible with 32ohm-300ohm headphones using the 32ohm 1/4″ jack. Headphones above 300ohms will benefit from using the 600ohm 1/4″ jack. Headphones driven successfully or tested with the amp include, Mr. Speaker Ethers, Mr. Speaker Ether Cs, Audeze LCD-2.2F, Audeze LCD-XC, AKG240, AKG701, Sony MDRV6, Sennheiser HD650, Sennheiser HD800 (though reduced volume), Beyerdynamic T1-600ohm, HIFIMAN HE400i. The Kenzie is made with pride in Southern California with US sourced parts, including our precision transformers. Specs: Input impedance is 250Kohm with alps pot, .5v for full power. Noise with pot fully counterclockwise is 5mV RMS (Average) All measured at 32 ohm tap. All power measurements in RMS 100mW 20 Hz (-1db) to 17.7 kHz (-3db) 150mW 20 Hz (-1db) to 14.8 kHz (-3db) 200mW 20 Hz (-1.25db) to 16.7 kHz (-3db) Please look at our news section for feedback from owners of the Kenzie Headphone amp. Kenzie Headphone amp – $1,500 with NOS tube set. Gizmo I picked up the Mogwai that was at CanJam SoCal. Really loving it! These amps deserve their own thread. I'd post a pic of it, but it's the one on the website and the pictures are way better than what I can take. Since I bought the prototype, I'm claiming the right of prima nocta... or something... and nicknaming my Mogwai "Gizmo." Reviews Kenzie Headphone Amp Positive Feedback Headphone.Guru mithrandir38 joespride Note that development continues over at ampsandsound, and additional amplifiers have come to be since the post was originally made. The following headphones amps are now being made by ampsandsound: Kenzie: Based on the Darling circuit. Now has a coupling cap upgrade option. Kenzie Encore: Bigger than the original, headphone jacks now up front. Now has 2 inputs and 1 preamp out. Also comes in a Deluxe version with input transformers and upgraded coupling caps. Mogwai: Headphone / speaker amplifier in one, old school SET sound. Coupling cap upgrade now available. Mogwai Special Edition: Not yet widely available. Includes a tube rectifier and moves the the headphone jacks up front. Agartha: Uses 300b tubes, SET sound. Cap and input transformer upgrades available. Leeloo: Uses 12AX7 for input and a pair of EL-84s for output. NOTE: You can talk to Justin Weber and order different output impedance on the headphone jack than what's listed.