I'm thrilled to announce a totally new redesign of my all-time favorite headphone amp, the Glow Audio Amp One!
I still haven't had the pleasure of directly comparing it to a Woo Audio WA-6, but unless that were to radically change things, this is my absolute reigning champion desert island amp (assuming that island has an electrical outlet) for any and all headphones I use, especially my regulars an AKG K702 and Etymotic ER-4S.
You can read both my review of this amp with multiple headphones, (Denon 'Mark Lawton' D2000, K701, HD650, ER-4S, Audio Tech AD2000 and DT880/600), plus some workarounds for issues with previous older designs, at my thread here:
"But wait, there's more!"
Patrick at Glow Audio has also assured me that his team went way further than to just correct previous annoying little glitches for the 2013 - 2014 Amp One. (Which, it must be added, did not affect sound quality).
Instead, they've taken the opportunity to make the most of recent improvements in technology, and created some real boosts in the quality of the amp's reproduction as well. In addition, they made a radical departure with previous designs by removing the DAC features of the Amp One, which made it such a great value, and instead repackaging it as a separate unit.
This redesign allowed them to really focus on insuring the best sound quality from each product, without issues of space in side the amp's chassis. And better still, the stand-alone DAC which normally runs at $125 is being offered F-R-E-E with purchase of either their Amp One or Amp Two. And "free" is one of my all-time favorite words, (especially when it precedes the word "mojitos!")
So what you have, indeed, isn't merely a "revamp" but a completely redesigned headphone amp. And right now's a good time to give it a listen, if you haven't heard this awesome little guy yet.
Patrick says they are so proud of their new amp redesign, that they really want everyone to hear for themselves. So in addition to the free standalone DAC, Glow Audio is also for a limited time offering a free set of AKG M80 Mk II (list price $179), or Pioneer SE-A1000 (list price $159) with any Glow Amp purchase. Pretty cool, indeed.
And remember that the Glow Audio Amp One wasn't created only for headphones, but to run small high-end speakers, including some from Glow Audio created especially to be matched with this amplifier, which have gotten some great reviews over the last few years. This doubles your investment, in a sense, allowing you to run a pretty decent high quality system for small to medium sized areas that won't melt your wallet. (Though the Glow plus their matching speakers are loud enough I read to melt your face off in small areas).
I haven't had the chance to audition the speakers, but they are on my list of "things to buy when I have the cash," and when I do I'll post a review here to be sure.
So, on with the improvements!
1. The Dreaded Headphone Jack o' Doom
As a lot of people have written about, including yours truly, the original 2007 - 2008 amp design was a great sounding amp. Patrick at Glow Audio says most are still running strong and trouble free. But he and his team had to make some compromises to keep the price point they were shooting for, and about the most troublesome was the headphone jack.
The jack had to fit it into a pretty tight space inside the amp's chassis to incorporate their point-to-point design (I'm guessing here), and were unable to design a special jack because it would've bumped up the price substantially. Long story short, for some of us with that amp the jack had a tendency to come loose over time. (I didn't have this problem). For others, like me, some headphones tended to seat imperfectly in the jack, forcing the "rubber o-ring" workaround. (30 cents for a rubber plumber's o-ring, which when placed around the headphone plug at its base, created the perfect fit for the jack).
So, how did they solve it?
Patrick's assured me recently that all subsequent models of the amp use a much sturdier jack, able to provide a secure connection with any headphone, (and unlikely to ever come loose, of course). Simple enough, and a very welcome improvement.
2. Headphone Hum
The headphone signal in the Amp One is tapped directly from the output transformer, so the guys at Glow Audio have to step it down. In the original designs, the amp was calibrated to match with higher impedance headphones. The recommendation was 300 Ohm and above. For some of us with lower Ohm designs, like me, this created a humming problem. I solve it by simply adding a quality resistance cable to my cans, as designed for me by Armaegis. With the additional cable, the Amp One was deadly silent, and the music "appeared" to my ears as if out of the vacuum of space. Amazing, amazing sound, and I've never heard a tube amp that sounded that good.
In the 2013 design, however, a Hi/Lo impedance switch has been added so the amp's output can be tailored to match the impedance of whichever headphones you normally use. This isn't available on all headphone amps, but is certainly welcome when it is, and I'm glad the guys at Glow Audio decided to do this.
3. The DAC
As I mentioned, the DAC is now offered as a standalone unit for $125, but it is also included free of charge with the purchase of either the Amp One or the Amp Two.
The reason the Glow Audio team decided to do this, is that the DAC previously incorporated into the Amp One was based on technology available in 2007, when the amp's design was being planned. In order to fit the DAC circuitry into the tight space inside the chassis, this DAC was somewhat of a compromise. Compared with modern DACs, it wasn't the best sound quality. However, it was an easy plug n' play unit, allowing the amp to be used easily with digital sources such as your MacBook or whatever. They did upgrade the internal DAC over time, managing to incorporate a Burr-Brown unit and Glow's own gain stage design into the 2011 - 2012 model, but given the tight space there was a limit to what they could do.
For 2013 - 2014 the DAC is now being offered as a separate unit. Instead, an additional RCA input has been added to the amp (making a total of 2), and the new Glow Audio DAC is based on their own design. About the size of a deck of cards, it's USB powered and uses a Burr-Brown 2704 chip. Patrick says it's so popular they've begun offering it as a stand-alone purchase for $125, and it's very hard to keep in stock due to the quality circuit design and associated components, which make for a really awesome sound. They use KOA precision resistors, ELNA electrolytic capacitors, and a Simons MKT non-polar capacitor.
Patrick said their goal was to make it sound at least as good as any DAC in the $250 and up range, so they didn't scrimp on anything. He also mentioned that if you're already familiar with the $250 Dragonfly, they were shooting for this quality range or better in designing the DAC, according to their own specs, and feel they have really succeeded.
4. Tube Madness and Misconception
Finally, one of the main issues we all complained about with the Amp One's previous designs was its tube limitations. The original design could only use Russian or Chinese tubes. However, this was a misconception. This limitation was true only for one of the older Amp One versions, and even it could be addressed with minor modifications.
Patrick has corrected me that there up to now (Sept. 2013) there have been four production versions of the Amp One. Of these four, only the 2009/2010 units (series II) had the limitation requiring the use of Chinese or Russian power tubes. All other units including the 2007/2008 (series I), 2011/2012 (series III) and 2013/2014 (Ver. 1.3) all can use ANY EL84 power tube available on the market currently.
The new Amp One continues to keep the same cosmetic design, which I thought was pretty cool and retro, the way a tube amp should be IMO. It's also still hand-built, using point-to-point wiring. And Glow Audio claims there have been little improvements all along the way over the past 6 years besides the ones Patrick talked to me about, and I've tried my best to give justice to above.
I remarked on the new higher cost, and he reminded me that the cost of labor and parts has nearly tripled in China, as we in the US already know because so many of our businesses are "coming home..." to Mexico. (Thank you very much). However, he said sales are going well, and they're thrilled to keep serving the audio community with great products and personal service, and feel that in this design they are offering a product of superior quality. Patrick said he feels very strongly that this is their best amp yet, and thus they've made the DAC available free with purchase, and are currently offering the free headphones as well to get people off the fence and into enjoying their new Glow amp.
Based on my own experience with an older design, I would certainly agree, and am glad to present these improvements to you all of us here at Head-Fi. I am looking forward to buying a new 2013 - 2014 amp myself, and have scotched my up-til-now current plans to save money and get a hybrid instead. With all these improvements, I think the Amp One is going to be well worth the months of Top Ramen for dinner to come up with the cash.
If you haven't had the privilege of checking out the Glow Audio Amp One, do yourself and favor and arrange to do so. I know this amp doesn't get a lot of mileage here on Head-Fi, and personally I think that is a shame. It's an awesome product, offered at a pretty fair price-point considering it's sound quality.
In addition, the fact that it serves as a dedicated headphone amp, AND a high quality stereo amp for speakers, just takes its value that much further, and that's further indeed. All you need is a good source and some quality speakers, and you've got a full blown audio setup for well under 2k all told. (The Amp One itself is currently running $840 plus $40 CONUS, and that includes the standalone DAC and even a pair of AKG M80 Mk II or Pioneer SE-A1000 headphones they are throwing in as well).
To get more info, you can start with my review, linked above, and feel free to write Patrick as he's really great about responding to questions and concerns fairly quickly and comprehensively.
As I still haven't gotten the new model yet, here are just some photos of my original model. The new model keeps basically the same look, with an additional RCA input as mentioned and a Hi/Lo Gain switch. (I believe the "glowing light" around the volume knob which softly changes colors, and is pretty cool, now has an on/off switch).
Sorry I suck so bad at taking photos. The DAC picture is from the Glow site, as I don't own it (yet). I'll post new photos as soon as I get my new Amp One.
Edited by Kouzelna - 9/23/13 at 2:37am