ECP Audio L-2 Headphone Amplifier
Editor's Note: I want to personally thank Nate for writing this article. Both he and Doug are long-time headphone DIYers. Both are very competent headphone amp builders. Getting to read Nate's thoughts here is much like opening a little window into the heart of Headphonedom. I am very pleased to present Nate's thoughts on Doug's ECP Audio L-2 parafeed headphone amp. Thanks a bunch, Nate. (Next beer's on me!)
The ECP Audio L-2 Headphone Amplifier ($2495)
I met owner/designer Doug Savitsky (the man behind ECP Audio) long ago through the DIY Audio forum at Head-Fi. We shared a common love of building things and were both passionately involved in the headphone DIY community. It was at CanJam 2010 in Chicago that I got my first glimpse of where Doug's passion was going to be focused for the foreseeable future. At the time he'd made the decision to branch out from simply designing and building DIY projects for fun and have a go at a commercial venture. He had already been working with several designs and had the results along with him in prototype form. Based on the brief audition that I had with two of those prototypes I eagerly awaited the finished product and made a mental note to make sure that I got to listen to them.
Fast forward to late 2011 and ECP Audio's official launch of two headphone amplifiers: the DSHA-1, a fully differential (balanced) solid-state design, and the L-2, a single-ended-parafeed tube design. It has been my distinct pleasure to sample the L-2 for the last few months and in that time I've come to truly appreciate what ECP has accomplished with the L-2 and what an exceptional piece it is. I recently encountered Dieter Rams 10 Principles for Good Design and it struck me that it was the perfect analysis tool for this review. Don't worry, I won't use all 10.
Good Design Is Innovative -- "The possibilities for innovation are not, by any means, exhausted."
I've had the good (?) fortune to go poking around a fair number of commercial headphone amplifiers in my time in this hobby, mostly as a result of said amplifier suffering some sort of failure and me attempting to repair it for someone. What I've encountered in that time is a number of similar designs out there, each packaged by their respective manufacturer in slightly different ways. That's not a bad thing, per se, but it does mean that we as the consumer are not always experiencing the variety of amps we might think we are. In this respect ECP has chosen the road less traveled for the L-2.
The fully transformer-coupled (input and output) spud/parafeed design, utilizing a single 6S45pi tube for both voltage and current gain, is pretty unique and not something that I've seen from any other major headphone manufacturer. But the innovative tech doesn't stop there. Instead of using a typical approach, the L-2 implements modern parts like a shunt-regulated biasing arrangement along with a cascaded MOSFET plate load. Both address typical shortfalls in tube amplifier design that date back the better part of century. The over-arching premise here is that headphones are particularly sensitive and that noise introduced by the amplification stage is a direct detriment to successful performance. I agree, and to that end ECP has done a fantastic job with the L-2. I've used it with both closed and open headphones of varying impedances and sensitivities, and the claims that are made on ECP's website are accurate--flip the on switch and you are greeted with precisely nothing. Big plus up for the L-2, but wait, it gets better.
Good Design is Aesthetic -- "...well-executed projects can be beautiful."
The L-2 is, quite simply, beautiful. Some will call it plain, or perhaps industrial, but the approach that ECP has taken is extremely well executed. Buyers are permitted a choice of several exotic hardwoods for the side panels and the rest of the chassis is tastefully brushed aluminum with not a hint of bling save for the ECP badge located front-center of the top panel. I'd call the overall look "understated elegance." But rest assured, the beauty is not skin deep. I've had a peek under the hood and the care with which the circuit was arranged is evident. From the Lundhal input transformers, through the V-cap coupling caps, all the way to the custom designed Electra-Print output transformers, the L-2 is as pretty (to this nerd's eye anyway) on the inside as it is on the outside.
The power supply is a somewhat more utilitarian enclosure, constructed entirely of anodized aluminum with the power umbilical connection on the front and the IEC inlet around back. It also possesses the signature ECP badge on the top panel, which is a nice touch that ties the two pieces together. ECP refers to its products as craft-made and this should not be viewed as a sacrifice or compromise. If anything the build quality evident in the sample unit I was provided is easily the equal of any commercial product I've come across.