For Pass source gear (not first watt or other pass designs, use the other thread for that)
5 Likes
Alright then, so I think I have a more firm grasp on what the Pass Labs HPA 1 does to gear now that IĀ“ve had the ability to play different things through it. First of all in the past I had one on loan thanks to the veeery kind and generous Nick Mimi and even though it was in my care for a long time due to a very extended loan I donĀ“t know if it was the Bifrost that was connected to it or something else but when using it as an amplifier for the LSA HP 2 and the Jomo Brass Trinity I wasnĀ“t particularly impressed. It was only using it as a preamplifier for my Focal Alpha 80s (with the same dac, Bifrost 2) that I was able to get a wow type of moment and experience what the Pass is capable of. Now however a year later I bought my own Pass Labs HPA 1 and have it paired to both a different dac (Hiby RS6 line out) and have used it with different headphones (Fostex 900mk2 PW edition, ZMF Verite Closed) and only now a year later do I understand and love the Pass as a headphone amplifier! Ok so let me get into what IĀ“ve noticed!
Staging: Alright so this was the first thing I really noticed back when I had it on loan and IT STILL STANDS OUT LIKE FOOKIN CRAZY, the imaging is sooooo exact like you really really hear if vocals for example are dead center, slightly left, slightly right or of course all the way to the left basically lol (looking at you Beyonce - Halo) and itās been awesome! Really feels like the peak of hifi where it takes you to back when you just found out about imaging LOL. But more so than the imaging (left to right) I feel like itās placement is just so damn spot on, ltās probably a combination of the depth that the amp has and the width + imaging that makes the placement so realistic. It definetly is the closest thing ivāe ever heard to having the singers right in the same room with me when hooked up to the Focal Alpha speakers. Last thing about staging that I kinda mentioned in passing right now, depth is nuts it really gives music so much depth that you just would not know is possible and the layering with it is amazing. Listening to stuff like Matmos - The Crying Pill is legit terrifying LOL and show cases the abilities to stage in such an intrecate way.
Detail: Not much to write about here I guess besides notating the fact that the detail, or the way it presents it. I feel like because itās got such a wide stage and so much depth in addition to itās veeery neutral that itās detail really shines!
Scattered thoughts: Okay this amp is A FUCKING ANIMAL idk how I legit donāt know how it does it but it manages to somehow have the best bass Iāve ever heard and it always stands out. But things donāt end there as it also manages to have such a focus on vocals somehow!!??! AND THEN THE TREBLE IS NICE, POLITE BUT AIRY TOO. I donāt know how it manages to do it, have literally all the factors that I love in audio. The first thing I had noticed was the bass, i wouldnāt say that it adds extra bass nor anything but the subbass gets such a step up in texture and general resolution. But the mids are something I started to appreciate recently too because it reminds me of the RS6 in terms of how the mids are soooo sweet sounding without adding thickness, wetness to the sound signature like WA8 does. The mids are instead super sweet, detailed while still being very neutral and organic. Treble isnāt a big stand out but itās most definetly prominent, detailed as one would expect from a dang neutral amp imo.
Amplifier(Headphones) vs Preamplifier (2Ch): I would say that all in all you will see the same type of improvements accross the board, real step up in bass texture, detail. I would say that itās generally the case with mids too where they become more airy, organic but incredibly detailed and same with highs. Another thing I did notice however is that the amp generally brings a level of height that I havenāt heard on anything else really. We always hear and talk about width but height is something Iāve never experienced until I got this amp. Something else to note is that as a preamplifier it brings a type of heft to my speakers that Iāve also never heard on anything although based on what Darko apparently heās noticed preamplifiers typically bring that type of heft to most speakers so that was interesting.
Summary of my thoughts: The Pass Labs HPA-1 is a very neutral amplifier that somehow brings the best of all words as it manages to highlight a thunderous bass, beautiful dreamy mids, prominent but soft treble and also manages to bring the best imaging/accuracy while having both a fairly wide soundstage and a super deep soundstage in addition to also bringing the factor of height in sound. There is literally no negative that I can think of with this amplifier/preamplifier in terms of sound. I think it would have been really neat if they could have somehow added a control for volume seeing as it can be used a preamp but I do understand that the preamp was just a nice addition that I would have loved! After all it is still a super expensive product lol. Even though I have a tube based WA8 that I got for the VC (mostly for portability) in terms of sound and enjoyment i prefer the Pass Labs amplifier over the WA8 in general for just sound. Been lovely.
12 Likes
So 
for ZMFs?
1 Like
for the ZMFs indeed!
1 Like
2 Likes
It really has been surprising! I thought the wa8 would be easily more enjoyable but duuuuuuude Iām really really really loving it on the pass. Itās just so natural, still as organic as the wa8 but just neutral and way more detailed etc. Still sounds phenomenal on the wa8 tho! I look forward to upgrading tubes in it haha
2 Likes
I have to say that I really do like your listening space setup. It looks comfortable and Zen.
3 Likes
Thank you very much! I really believe in both decorations and setting the mood for certain things so I made sure to make this section real comfy! Itās still not fully to my liking, something like float Sammyās room really inspired me because it feels so like at home! Mine looks a bit more sterile than I would prefer but now that I got the gear down thatās the next step!
Gonna be replacing my chair, probably gonna eventually replace the furniture that the pass is on once I get a new dac too etc!
1 Like
Does Pass Labs have a house sound? My only experience is the X2.5 pre and the HPA-1 so Iām curious. (Iām not talking about the First Watt Nelson Pass stuff)
Yes, itās reasonably constant across most all modern pass gear
1 Like
PASS HPA-1 continues to perform at BEAST levels. Despite my affection for tube based amplifiers I absolutely love the fact that I almost never have to worry about powering this brute down, it just sits nice and warm ready for an input signal and snaps to attention w/ never a complaint.
The grip and control along w/ sheer grunt of the bottom end always pleases me. I believe the reason I donāt find any of my HPās lacking in bottom end is because of the quality of this amplifier. If a HP has any ability at all for bass the HPA-1 will bring it forth.
Midrange texture is exactly where my own personal preferences lie, and I seem to always compare the midrange quality of my tube based amplifiers to what the PASS does. This one simple fact alone negates all the $$$$ I have spent on every tube ever 
If I simply used those funds alone on my front end I think I could have found my personal HP nirvana a long while agoā¦
Lastly the most critical feature, the air and texture of the top end. My ears are older, abused and untrained. I think the DAC and cables play a critical role in what the top end comes off as on good quality amplifiers. I may be wrong and happy to take better educated correction to this statement. I again have NO complaints and have been fully satiated by the quality of the top end.
For those of you who have the experience and knowledge, when it comes to solid state HP amplifiers, what is the next level beyond this piece? Who makes a solid state beast that blows the PASS HPA-1 out of the water and will bring tears of joy to my eyes? How much DAC and streamer will this better piece require?
Iām genuinely curious, I just donāt have experience beyond what I know. 
and nothing I have read up until now has caught my attention.
13 Likes
Dibs on yours when you āupgradeā.
4 Likes
Nick doesnāt upgrade. He just adds another listening room. 
11 Likes
Selling stuff is such a pain, Iām so very OCD about packaging it costs me more money than itās all worth in the end and my returns are basically negligent towards the cost of any upgrades thusā¦Iām just pickier now if I want something new. Problem is I canāt stand having all this stuff sitting around collecting dust thus the need to spread it all over the house. Heck, if I had a dog house, the dog would have music tooš
All thatās left is the screened porch now. Iām trying to figure out how to get equipment out there and keep the elements off it 
5 Likes
Havenāt had the pleasure of listening to an HPA-1, but the solid state headphone specific options in that range and above do seem to get pretty thin compared to tube/hybrid options. I have a hard time imagining much better than my Crayon CHA-1, though, as long as itās not a synergy mismatch. The only headphone Iāve tried so far that isnāt the best Iāve heard it is the LCD-24, and thatās likely due to an impedance mismatch where the amp is designed around high impedance performance.
Iām sure it can scale higher, but my Berkeley Alpha Reference DAC (Series 1) is my āreasonableā stopping point, and Iāll probably end up with an Auralic G1/G2 or Antipodes S30/S40/K30 range server-streamer to replace my Pi2AES eventually.
For reference, the best SS amps I previously owned were XI Broadway, XI Formula S + Powerman, and Vio V281, and none are close overall.
4 Likes
Not experienced but would have guess the Hypsos/Oor and the Bakoon 13R as next level SS based on what I see thrown around here a lot.
2 Likes
Then, beyond those you can go on to the Crayon Cha-1, Mass Kobo 394ii, aic-10 (yes it has a single tube but itās a hybrid and mostly solid state).
Not my list.
3 Likes
Start using speaker amps. Skyās the limit 
4 Likes
Iām a big believer in integrated amps as headphone sources but theyāre not the most desk friendly of beasts.
1 Like
That is the same/similar conclusion i came to a long while ago. My test session w/ the Susvara made it clear to me that a HP properly built to handle a speaker amp is basically as good as it gets. I purposely had my builder attenuate my main speaker amp for that very reason after a lengthy discussion, damn it feels good to justify that expenditure, it was painful.
5 Likes