HeadAmp GSX-2 mk2 vs Pass Labs HPA-1
Apr 16, 2018 at 1:25 PM Thread Starter Post #1 of 14
Icenine2

Icenine2

Headphoneus Supremus
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Thinking seriously about buying one of these and am leaning toward the Pass. Any opinions? I'm sure some of you here have had both of these at some time and I'l like to read what you thought/think. Thank you!
 
Apr 17, 2018 at 1:38 AM Post #2 of 14
I vaguely remember people not giving the Pass Labs HPA-1 stellar reviews when compared to other high end amp.

The GSX-mk2 on the other hand retains its value pretty well & its incisive sound would par well with an LCD-2.
 
Apr 17, 2018 at 12:17 PM Post #4 of 14
wink said:
Get the Headamp..........:L3000:
Click to expand...

Well, I had the GS-X MkII and then purchased the Pass HPA-1. I did have both for awhile, and although I very much liked the GS-X, I thought the Pass worked for me a little better overall, so I sold the GS-X. Overall both amps are very good -- both are resolving, dead quiet, and generally neutral, however I do think the Pass may have a very slightly warmer (or "tube-like") sound, which I believe is a Pass amp characteristic in general. I'm admittedly still on the fence as to whether I like the Pass sound or the possibly more neutral GS-X. What I did not like about the GS-X were: 1) the stepped attenuator (steps too large), 2) gain control - only 3 steps (which I feel did slightly alter the sound at mid and high levels), 3) transient pop when turned off, 4) overall "footprint" (the 2 units were difficult for me place in a rather tight space with potential hum problem,) and 5) SE output did not sound quite as good as balanced. The Pass is not small amp either, but as a one piece unit, it was a little easier for me to place with my other equipment. I like the Alps volume control better too, although I would still have preferred a stepped attenuator with much finer increments. What not to like about the Pass: 1) it runs quite warm (class A), especially since the amp is supposed to stay on continuously, 2) it is only single-ended (not a big problem but I have balanced connectors that I would like to use), and 3) only accepts RCA (not XLR) input from DAC -- again maybe not a problem, but I would still prefer using XLR. So my bottom line is that I think both amps are very good, but also have their downsides.

Now along comes the new Benchmark HPA4, which is scheduled for delivery in June. I've always had a good experience with this company's products, so I suspect this will be a super headphone amp. More importantly (according to the published specs and functionality) it has everything that I like in both the GSX and Pass with few of the downsides: it accepts XLR inputs, has both SE and balanced headphone drive, small size and should run fairly cool, has remote control and touch screen functionality that includes balance, input (gain) adjustments, and importantly an extremely well designed all-analog stepped attenuator. The HPA4 is apparently very similar to their highly rated ABH2 amp, both of which use the THX technology. Of course, there are no reviews of it as yet, but since they have a 30 day return policy, I decided to take a chance and reserved one.

How does this relate to your query? Well if you can wait awhile, I would just go for the Benchmark -- if you like it a lot, forget the Pass or GSX MkII. I hope I will like it too. I do plan to keep the Pass for another set-up, but if all goes well with the Benchmark, it will likely be my major HP amp.
 
Apr 17, 2018 at 3:03 PM Post #5 of 14
Thank you for your input. I was not aware of the Benchmark being solo amp and not a DAC combo. I'd seen pictures but ignored them since I want a stand-alone amp. Thanks again and I will investigate. Based on what you've informed me about the other two amps confirms what I've thought about the Pass being the choice for me. Side-stepping about balanced/single ended: a non-issue with me since you get into the debate about amps being truly balanced which few are. I had a Woo WA22 which is supposedly balanced (not really and what a debate about that if you check the forum here) which I replaced with the single-ended Cavalli Liquid Fire which blew it away and has been my reference to this day. I always like the bigger impact a powerful SS amp has to offer. Thanks again for the heads up on Benchmark. I will check it out.
 
Apr 17, 2018 at 11:48 PM Post #6 of 14
Fwiw, while something being singled ended vs balanced do not make it inferior. Running the gsx mkii single ended does effectively tie one hand behind it's back. My understanding is with single ended inputs only half the amp is used. Anyone feel please correct me if I'm wrong.

I really liked what I.heard from the brief listening session I had with the gsx mkii with the hek and lcd3. I've never heard the pass labs amp but would really like to.
 
Apr 21, 2018 at 11:56 AM Post #9 of 14
Apr 21, 2018 at 2:11 PM Post #10 of 14
MacedonianHero said:
I would love to hear Kevin Gilmore's thoughts here. :)
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I believe that is a Harry Potter deal where we don't even mention his name here............:beyersmile:
Mac. I would totally trust anything you have to say. You have/had more equipment I've wanted than anyone else here! Back in the day we used to discuss out WA22's.

I would actually love to read what Mr. Gilmore would have to say on any amp. He cuts to the chase and knows everything about design and implementation where we get the TRUTH about what an amp really is.
 
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Apr 22, 2018 at 12:05 PM Post #11 of 14
Icenine2 said:
I believe that is a Harry Potter deal where we don't even mention his name here............:beyersmile:
Mac. I would totally trust anything you have to say. You have/had more equipment I've wanted than anyone else here! Back in the day we used to discuss out WA22's.

I would actually love to read what Mr. Gilmore would have to say on any amp. He cuts to the chase and knows everything about design and implementation where we get the TRUTH about what an amp really is.
Click to expand...

The PASS Labs amp sounded great when I heard it, but I'm still here with my GS-X MK2. :wink:
 
Apr 22, 2018 at 2:48 PM Post #12 of 14
The pass labs HPA1 headphone amp is a single ended only headphone amplifier. Running on +/-24V with jfet inputs and mosfet outputs. Biased well into class A. Fairly classic CFA configuration.
The GSX2 is a dual single ended amplifier wired as balanced output with a balanced input. Also capable of being used as a preamp stage. jfet inputs, bipolar outputs, biased well into class A.
Differential Complementary VFA configuration, dual mono power supplies.

Both are beautifully built with high end parts and designed to last a very long time. A lot different from so much of the stuff produced that is throw away product that runs way to hot, or uses split rail noisy switchers to
reduce cost etc, poorly anodized chassis or bad paint jobs...

I only got to listen to the hpa1 for a short period of time, so comparing to the gsx2 would be tough, but the sound signatures are far more alike than they are different. But the balance between 2nd and 3rd harmonic distortion
is definitely different over the entire frequency range primarily due to mosfet vs bipolar, and balanced vs unbalanced so depending on your favorite headphone you might like one a bit over the other.
 
Apr 22, 2018 at 10:38 PM Post #14 of 14
Thank you Mr. Gilmore. I loved reading what you know about both amps.
 
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