Review Bakoon HPA-21 test @ Head-fi.org
CanDude: Bakoon HPA-21 headphone amplifier, one of the best
The thread
Two high end Bakoon headphone amp Japan version discussion and appreciation thread was more or less hijacked for Bakoon HPA-21. I felt that one of the best headphone amplifiers in the world needed its own thread so please continue to post discussions, reviews etc. of Bakoon HPA-21 in this dedicated thread.
Review Bakoon HPA-21
Equipment
Samsung laptop, Windows 7, JRiver Media Center 17 with 112 dB Redline Monitor plug-in
Flac-files, mostly 16/44, some 24/44-96
Wireworld Starligth USB cable
Lynx Hilo DAC
Special Wireworld XLR to RCA cables*
Red Astrachan headphone cable with ¼” to XLR adapter cable
Toxic Silver Widow headphone cable
Audez’e LCD-3 (RMA’d)
Sennheiser HD800
HiFi Man HE600
Reference headphone amps:
Bryston BHA-1 with similar Wireworld XLR to XLR cables to Hilo, no ¼” to XLR HP adapter cable, i.e. balanced in and balanced out
Built-in headphone amp in Lynx Hilo (SE out)
* Explanation on the special XLR to RCA cables: Lynx Hilo only has balanced outputs and HPA-21 only has unbalanced RCA + SATRI-LINK inputs. I had the shop (Audio Concept) made me balanced to unbalanced cables according to Lynx recommendations: XLR pin 1 (ground) to shield but no connection to RCA, XLR pin 2 (+) to RCA center pin, XLR pin 3 (-) to RCA sleeve.
Redline Monitor
I always listen to headphones using the plug-in Redline Monitor from 112 dB. This plug-in fixes the stereo image so it more corresponds to listening to speakers, compare to the corresponding (analogue) functionality in SPL Phonitor. There are other plug-ins for this, but most are toys that totally change the sound. Tone Boost Isone is also good, but it changes the sound too much IMO. Head-fit and bs2b_vst use simpler crossfeed algorithms that affect the sound less but are not that effective. My current settings for RM is center level = -2.5 dB, soundstage width = 60 degrees and speaker distance = 2 m. The max setting for speaker distance amplifies high-mids (above 2 kHz) a very tiny bit, that suits LCD-3 well since it is a little bit attenuated in this area.
Of course you cannot use plug-ins like this if you still use CD players as your source. Most music is mixed and mastered using speakers, so things like reverb, which usually has a big stereo spread, gets too prominent when listening via headphones without crossfeed. To me that is an added effect, definitely not “bit-perfect”. Try this experiment: Listen only to the left or right channel with RM and then without RM (click on the RM icon or name for “intelligent bypass”). Which sounds most natural?
I have done all listening with Audez’e LCD-3 via the current output, unless otherwise noted.
Purpose
The purpose of this review is to compare Bakoon HPA-21 with my Bryston BHA-1. In February I was lucky to be able to listen to a pre-production unit at the Stockholm High End Show. That was the world premiere for HPA-21. Then I waited and waited, remembering the clear sound from HPA-21 and wondering how it would sound like with my own equipment and music. Last year I bought BHA-1 as a “good enough / end of the road” headphone amplifier, but if HPA-21 is clearly superior to BHA-1 I intended to buy it. From an economical point of view I hoped that the differences would be so small so that it would not be worth the money to buy HPA-21.
I have also done some comparisons with Hilo’s built-in headphone amp, which reminds of BHA-1, minus some power and other qualities of a dedicated headphone amp. Since switching between HPA-21 and BHA-1 involves switching XLR cables to the DAC plus switching the headphone cable’s XLR plug it was more convenient to just switch the ¼” plug between HPA-21 and Hilo.
I will not describe HPA-21 specifications or technical solutions here since this information can be found elsewhere. For more information on HPA-21, technical details etc. please see the review by Srajan Ebaen at 6moons and my previous posts about HPA-21 in this thread.
Arrival
Since there were some production delays my expectations rise for every week. Now it had a lot to live up to! Finally the shop got one of the first HPA-21 production units. Using an Esoteric CD player, Toxic Silver Widow headphone cable (kindly lent by Michael at Klutz Design) and my own LCD-3 headphones I listened to some CDs I know well at the shop. I recognized the clear sound I remembered from the world premiere at the Stockholm High End show. Robert at the shop also confirmed the differences between the current output and the voltage output.
Before leaving the shop, of course with HPA-21 and the Toxic cable with me, I tried the same setup with Sennheiser’s HDVD 800 amp, not using its DAC, driven unbalanced from the CD player and also unbalanced to LCD-3. So the setup was not optimal for HDVD 800. The sound was not bad but not in the same class IMO. The sound was kind of softer and “thicker”, maybe a little bit more low mids. Probably suits HD800 fine, though.
The only problem I have had with HPA-21 is that the nut for the left RCA socket was loose when I got home. However I could easily tighten it with my fingers and later Robert at the shop tightened it properly. Having looked inside HPA-21 he said it is very tidy built. I hope this mishap is just an isolated case. The HPA-21 has worked flawlessly ever since.
Sound
So how does it sound like? The first note I made at home was “Clear, dynamic, details, blackground”. I noticed details and low level rhythmic figures I have not noticed before in songs I have listened to for years. Reviewers always say that, don’t they! But it is true.
I also quickly noticed that there is no lack of gain! With Hilo line out trim level set to +0dBV (lowest setting) and HPA-21 gain set to high I always set the volume less than 12:00 when using LCD-3. For modern über-compressed music I set the volume as low as 07:30. With Resonessence Concero, which outputs 1.2Vrms, the volume is a little bit louder.
It actually feels a little bit silly trying to describe the sound in ordinary terms like bass, mids, treble etc., but here we go...
Bass
The bass is excellent! It has more attack/punch and it is also more detailed compared to BHA-1. Maybe this makes it appear a little bit more prominent. On Pink Floyd’s The Wall (remaster) you can clearly hear the sharp attack when the kick drum beater hits the skin and then the short decay of the vibrating drum skin. You can of course hear all this with BHA-1 as well, but everything gets a little bit “mixed up” and “fluffy”, more “boomm” where HPA-21 presents a distinct “Boom”. I heard similar differences when I compared the DACs Lavry DA11 (“boomier”) with Lynx Hilo (more exact and dynamic bass).
Mids
The mids is excellent! I noticed that the Hilo’s built-in headphone amp seems to have a tiny bit louder upper mids/lower highs. Reading my notes I cannot find any comment on differences in mids between HPA-21 and BHA-1. I do not connect the differences I hear with the terminology of “mids”, even though there are differences in the mids technically speaking. Hence, mids is excellent for both HPA-21 and BHA-1.
Treble
The treble is excellent! It is clean and almost “polished” with LCD-3. In comparison the Hilo amp is blunter with less attacks and, as already said, maybe a tad brighter. As for mids I rarely think in the terminology of “treble” when listening to HPA-21.
Dynamics
Dynamics is excellent! Notes hits you from nowhere with very “precise” attacks. Every note lives in its own space and is easier to discover, examine and enjoy than with BHA-1. When listening to electro-pop it can almost be too much with all sharp attacks. But then you just switch to the voltage output and everything softens up a bit, more like a “normal” amp. The sound of Hilo’s built-in amp and, to a lesser degree, BHA-1, can almost be perceived as being compressed compared to HPA-21. This makes it harder to match the levels by ear.
The rest
Imaging, blackground, micro details, PRAT etc., everything is excellent! Someone described another Japanese Bakoon headphone amp as having a “slight v-shaped tonality”. This is not true for BHA-21 IMO. HPA-21 and BHA-1 are both flat, but it is true that initially you may perceive HPA-21 as being more V-shaped while BHA-1 has a “fuller” sound. I recognize this phenomenon from when I bought my Event Opal monitors. The Opals’ have less distortion than some other monitors so they may sound a little bit on the “thin” side. But when you listen carefully everything is there, having the correct level. What’s missing is the distortion, which normally makes a more initially impressive sound. I have my own term for that type of sound, I call it “paper cone sound”. Think of the sound from an old speaker with a wobbly paper cone. It hardly sounds correct, but nice and “cozy”. Perfect for guitar amps!
BHA-1 is a very very good headphone amp! It definitely does not sound like a Marshall stack on 11 (or 1)... You have to compare these amps side-by-side to be able to describe all the differences. When listening only to HPA-21 it is an excellent amp. When listening only to BHA-1 it is also an excellent amp. It is when you switch between these amps that you start to notice, and also to learn and remember, the differences.
Note that HPA-21 is in the “output = input” category. If you want a colored sound to your taste or maybe to compensate for other components in the chain, if too many details distract you from the music or if you do not want the slightest hint of sibilance or edgy sound on badly recorded music, this amp may not be for you.
Music!
Now we are getting to the heart of the matter. HPA-21 presents all instruments, voices, tiny sonic and rhythmic details, effects, you name it, so naturally and clear! The music is just there for you to listen to. It grabs your attention. You do not listen to a DAC with a fancy headphone amp, you listen to the music, period. With BHA-1 you tend to listen to “technical” details, at least when reviewing, while with HPA-21 you soon forget about all that and listen to the music instead. Here are some comments from my initial listening notes:
Switching to BHA-1:
"Ordinary" again. Not bad though.
Not as clear.
Lots of details!
"Thicker", more of a "wall of sound" where everything gets mixed together.
Switching to HPA-21:
Precision! Exactness! Details! Calmness! Naturalness! Unsmudginess! MUSIC!
The following episode is typical for HPA-21. I had switched to BHA-1 and listened to Pink Floyd The Wall (remaster), 2nd record. Sounded really good! Roger's voice was maybe a tad brighter than I remembered from HPA-21. While listening to the record I also read a review. I saved half of the review for later. When I had listened through the whole record I switched to HPA-21 and matched the levels. I then listened to the same record again. I could not start reading the second part of the review since my attention was drawn to the music, even though I had just listened to the record! I noticed the more detailed kick drum, the clean sound, how I could almost touch all instruments, I noticed small details etc. Finally I managed to continue reading, but I was always present in the music in a way I was not with BHA-1. I also noticed my right foot started moving... This is typical for HPA-21, the music is just there and always grabs your attention.
A week later I listened to and viewed Peter Gabriel’s Red Rain from Growing Up Live from YouTube, first on HPA-21 (because I couldn’t stop myself), then on BHA-1, then once again on HPA-21. On a way too loud volume... It was ridiculous. HPA-21 presents a clean, dynamic, studio-like sound with you present at the concert. And the bass, wow! You feel the joy of the musicians, you’re inside the music. With BHA-1 you get most of the details, but everything is kind of mixed up into a mush and you are not at the concert in the same way anymore, you are listening to your headphones via a good amp. So you do not need high-res audiophile recordings to get the best out of HPA-21. Of course high-res classical music also sounds excellent via HPA-21 (I have listened to that too). But with HPA-21 you can easily concentrate on the music, resolution is secondary.
According to Bakoon the SATRI circuit has no slew rate and you get 1/10th of the headphone distortion with the current output. Now I know how thatsounds like.
Cons
If you forget to turn off the power when you do not use it for a while the batteries may be dead when you want to start listening again. Then you have to wait for the batteries to re-charge. You will soon make a habit to turn off the power when appropriate, but sometimes you will forget...
There are no balanced inputs. This is understandable since Bakoon have their own SATRI-LINK standard instead, but if you do not use other Bakoon products (like their upcoming DAC) with HPA-21 the preamp or DAC of your choice probably has balanced outputs at this price range. However sound wise this should not be a problem in most cases (for example my special cables are just 50 cm long).
Final words
If you read this you have most probably already read the review by Srajan Ebaen at 6moons. I agree with what Srajan says, but you need to listen to HPA-21 for a while to fully understand it.
Do I exaggerate? Not IMO. Magnifying maybe. I only try to describe what I hear. YMMV, of course.
Of course I bought it! I guess I will only use my BHA-1 when the batteries in HPA-21 are dead. Once again I have reached the end of the road when it comes to headphone amps, but now at the highest possible end. I cannot imagine how any headphone amp can be better than this! Different, yes, but better, no.
OK, one last analogy... Compare listening to music to looking out through a window. Some windows are dirty. Some windows are colored. Some windows have very old glass, and while very clear they distort the view in funny ways. Some windows do not distort the view in any noticeable way (like for BHA-1). But you still look through glass. Then you open the window. This is HPA-21. Welcome to the music!
I will add comments on using other headphones with HPA-21 (HD800, HE6, SP) and also comments on comparing the Red Astrachan and Toxic Silver Widow headphone cables (probably in another post).
