The close of 2021 has brought out more than 18 months of a global pandemic. During these challenging times, we at ampsandsound strengthened our development efforts resulting in new generation of our classic amps.
Though octal input tubes provide a romantic character that had defined the ampsandound house sound, reminiscent of 1950s HiFi, the downside to this approach is a reduced noise floor and dwindling NOS options. With ampsandound moving to a 9pin front end, performance has been increased, NOS tube rolling has become nearly limitless, and yet we were able to enhance the sweetness and tone we are known for. The 9pin front end allows vastly increased options for tone rolling to find your balance and preference.
With our front end's new development, we have improved our amps further, including both subtle and significant changes alike. Notable takeaways include increased power output, reduced noise floor across all our amps, increased bandwidth.
Like many of our products, the Mogwai evolved from our earlier designs, borrowing from the Bigger Ben and the 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 both headphone and loudspeaker 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 two-channel power amplifier and headphone amplifier in a chassis that is suitable for desktop use.
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, 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, which provide excellent frequency extension and a flat response.
The Mogwai does not use a voltage divider network but depends on transformers instead. We 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.
The Mogwai displays its transformers prominently on the chassis to frame in the tube complement, 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. Zero feedback on the outputs negates the need for a pre-amplifier; 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 classic tube design. 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.
Tube Selection: 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.
The pictures at the end are representative of the Rev 2 Changes, including consolidation of the outputs to the front of the amp. These changes coupled with power supply improvements have greatly reduced the noise floor.
Wood Chassis dimensions:14.75" Wide x 10.75" Deep
Specifications: Noise floor is greatly reduced with Rev2. Input impedance is 10K ohm with alps pot Input Sensitivity 2.6V for full power out with input transformers
Power as measured with KT88 power tubes and 5AR4 rectifier 8ohm power: 8.2Watts RMS @ 1khz Noise on 8ohm tapp @ 350uV RMS
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