The Eddie Current Balancing Act
Editors Note: This article has been contributed by Ryan Clarin, otherwise known as recstar24 on the headphone forums. Ryan has brought a lot to the hobby in his forum dialog, and was one of the main instigators/organizers for the 2010 Chicago CanJam. I couldn't be more pleased to present you with his take on the Eddie Current Balancing Act headphone amp, and his experiences with Craig Uthus's fine products. Take it away, Ryan!
I would like to start by saying I am no stranger to Eddie Current – having owned numerous Craig Uthus creations throughout my headphone amp journey allows me the experience to say that no other manufacturer still in the business has been as consistent a home-run hitter in the tube amp department. Eddie Current has produced numerous tube amps that not only consistently sound good, but push the design envelope significantly over their peers while keeping cost within human reach.
A Little History
My first EC amp was the HD-25, which was Craig’s first foray into tube amplification under the Eddie Current brand name, moving away from the Moth Audio brand that he is famously known for. The HD-25 was a transformer coupled SET utilizing a single 6SN7 for input and a 6AS7 for output. The output transformers were custom made specifically for the HD-25, and the input tube was coupled to the output tube with special Eddie Current custom-made mineral oil impregnated polypropylene caps. The amp housed the power transformer in an external chassis to avoid hum pickup, and it all was packaged for a price of $595. It was a fantastic amp with build quality that was above and beyond an amp of that price, which allowed numerous tube-rolling options, sounded great with low impedance cans, and offered numerous inputs and preamp functionality.
My journey then brought me to Moth Audio, specifically the Moth S2A3. The amp featured a 6SL7 input tube for each channel driving a 2A3 direct heated triode, coupled to the load through massive Electra-Print transformers, and tube rectification utilizing the 5AR4 rectifier tube. The input tubes were inside the chassis, viewable through glass portholes on the front panel. The top panel was a polished metal similar to what you would find on a Lexus or Mercedes, and internally featured brass plates that adorned the transformers with instructions on rewiring the output transformer taps to change the output impedance. I was lucky enough to own the first one ever made, a real beauty of an amp that in addition to headphone drive, was capable of 3 watts of output for efficient speakers. The amp had every little detail covered, and cost was north of $3000. A lower cost version without as many of the bells and whistles was released as the Si2a3, which featured multiple inputs and was around $1895. I happened to own a version of the amp specifically customized for headphone usage called the si2a3/45H, which featured an outboard power supply housing the power transformer to avoid hum pickup with lower impedance headphones, as well as an upgraded power supply to bring the noise level to non-existent levels with headphone usage. The output tubes were switchable between 2A3 and 45 DHT’s.
Fate would eventually bring me the Zana Deux, a top-of-line statement output transformerless design with 3 inputs and 2 preamp outs, allowing it to become the centerpiece of an audio system that incorporates both speakers and headphones. It uses two 6C33C-B tubes, one per channel, a 6SL7 input tube and two 6DM4A damper diodes, as well as an external power supply to separate out the custom toroidal power transformer.
The Zana was meant to replicate the sound of the original Moth Xana, which at $7000 was a bit rich for most folks back in the day, at a more affordable price point of $2200, while offering more functionality as well as better low impedance drive. The amp had insane soundstaging and drive, while offering a sonic transparency that had no peer within the tube amp realm. The Zana was truly state-of-the-art and to my ears nothing out there at the time was even close to its sound. Little did I know that Craig was still working in the lab on something that would even surpass what the Zana had to offer…