HeadAmp GS-1 Headphone Amp/Pre-Amp

General Information

The GS-1 is based on a fully discrete, dual-differential design by Kevin Gilmore, a rare design to find in a headphone amp.

Latest reviews


Headphone.Guru Editor
Pros: Incredibly transparent and neutral amp
Cons: Getting one ASAP.
HeadAmp GS-1 – A Forgotten Treasure
So after hemming and hawing for several months about picking up a solid state amp to compliment my Woo Audio WA22, I finally made the jump. I was looking for a solid stage amp in the $700-$1200 price range. Amps I considered were the Violectric V200, Corda Classic, Audio gd Phoenix, SPL Auditor, Burson HA160, and HeadAmp GS-1.
Having a great sounding euphonic tube amp already, I was looking for a contrast that would be complimentary to that sound. I was looking for a neutral, transparent amp that was very true to the input signal from my DAC/Source (CDs played through my Cambridge Audio Azur 650C transport feeding my W4S DAC-2). All of the amps noted above seemed to fit the bill for transparency with a neutral sound signature.
Long story short, I decided to go with the GS-1 (w/ DACT Stepped Attenuator) in silver (not dust…err...I mean black) based on the Kevin Gilmore Dynalo. It’s been a staple around here for 6 or more years and has kinda fallen out of the headlines on Head-Fi. I was however intrigued by the discrete design behind the amp. No opamps or capacitors in the signal path. It’s a Class A (a must for me) solid state amp (JFET, Bi-polar transistors) with a 1 W maximum; a good amount of power for the headphones I have on hand (I no longer own the very hard to drive Hifiman HE-6s).
Upon first opening up the box, I can easily say that the construction is top notch. It is very well built, professional looking and solid. Justin has very commendable workmanship skills and product design. It’s got a very nice and sleek look about it and I like how it looks in my rack:

It’s got some versatility as well. It allows up to 2 separate inputs and can function as a pre-amp. Two headphone outputs are available (both are equivalent) and a two gain settings (1x and 8.5x).
Now, how does it sound?
Test Tracks:
Jazz at the Pawnshop
Copland: Third Symphony, etc. Eiji Que: Minnesota Orchestra: HDCD
Patricia Barber: The Premonition Years
Porcupine Tree: The Sky Moves Sideways
Metallica: The Black Album
The Sheepdogs: Learn and Burn
The Grateful Dead: The Very Best of (HDCD)
Miles Davis: Kind of Blue and Sketches of Spain
Louis Armstrong: What a Wonderful World
Rush: Fly by Night (2011 Remaster from Sectors I)
Headphones/IEMs used:
Full sized headphones: LCD-3, HD800, T1, Ed.8LE
IEMs: Westone 4, NuForce NX700, Hifiman RE0
Initial out of the box impressions were very good. First thing that got me with this amp is the absolute “blackness” of the background. If black is the canvass for an HDTV’s picture, then complete silence is the canvas for audio gear. And the GS-1 does this better than any other amp (desktop or portable) I’ve heard. I’ve owned some really good amps in this regard like the Meier Concerto or RSA Hornet, but none have come close to this level. I was able to plug in my Ed.8LEs (the most sensitive headphones I own) and heard nothing. Even my IEMs were completely silent on the Low Gain setting. Initially I thought the amp must be defective as I thought only the LED was ON. Then I pushed PLAY on my CD player and was amazed to find that the amp was indeed fully ON.
I would definitely describe the amp as very transparent and neutral. If you’re looking for an amp to “tune” your system (either for your headphones, upstream gear, or personal preferences) I would look elsewhere. I feel that the music just flows through the GS-1 like an open window of what the recording has to offer. Very little of the GS-1 is imparted to the sound.
First off, I am not a believer in burn in for amps/DACs/cables. But after some initial burn in, I found that the sound staging improved, the treble became smoother and the bass impact/detail tightened up. So I guess we’ll leave that to an Act of God. :wink: If you’ve heard the GLite (one of my favourite sub $500 solid state amps), the GS-1 has a similar clean tone, but from memory, the bass impact and definition is quite a bit better on the larger sibling. As well, the highs on the GLite could be a bit too tizzy for my liking (as could the Corda Concerto). The GS-1, in my rig, has very extended and detailed treble; without any sizzle on my HD800s or T1s. I think the best improvement (along with a bit more power) has to be the imaging over the GLite.
A few long term Head-Fiers have described a holographic sound stage and after some burn-in, I can definitely attest to that effect. While the imaging on my WA22 is slightly wider and deeper, I find it slightly more precise with the GS-1. Every instrument in Jazz at the Pawnshop was exactly placed in my mind’s eye, every clank of a dish or quiet background discussion by the audience was accurately placed in the pawn shop.
The bass on this amp is tight, deep and fast. The organic and earthy bass of my WA22 is outstanding and I do enjoy it very much. But the GS-1 plays Enter Sandman’s initial rumble very tight and fast without the tube bloom that I’m used to. It’s still impactful (though less than my WA22), fast and tight. A great counter presentation to my tube amp. Yet, it still comes off as very musical.
The mids are presented in the proper proportion to my ears, nice and very clean. My WA22 presents very organic/upfront mids. Some might say a bit too much or a bit too lush, but then others might say that the GS-1 has mids that aren’t organic/full enough. It’s really personal preferences here and both are very enjoyable and complimentary.
Amazingly it drove all of the headphones that I threw at it very well with plenty of head room; from my LCD-3s to my very efficient Ed.8s. Amazingly, being as quiet as it is, on Low gain, it was fantastic with my IEMs. It had a lower bass floor than my portable iBasso D4 Mamba or FiiO E5. I haven’t come across such a versatile amp that could drive so many different full sized headphones and IEMs.
Overall, this amp is one amazing choice for those looking for a clean and transparent amp that doesn’t add anything to the music; just amplifies the signal from your DAC0 to your headphones…period. If you’re looking to “tune” your system with a warm or bass-heavier amp, you’d better look elsewhere. But you’d be missing out on a true audiophile experience of very transparent fidelity and one heck of a headphone amplifier.
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Reactions: Savant
Nice review. Kind of the direction I'm looking to take. I'll keep the GS-1 in mind.


Pros: Sound, Build Quality, Looks
Cons: Wait Time
Amazing amp. Great Synergy with the HD 650's and the Denon D-2000. Drives both with authority and allows you to appreciate their individual sound signatures. Truly "wire with gain."


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