[kurochin]

  Might the current-mode suit orthos since they are more or less purely resistive loads, while dynamics are reactive? That would make sense and joins up with what majkel says.

After reading the Headfonia review, particularly the blurb at the end about the impedance curve effectively becoming the frequency response under Current mode, I'm starting to get a clearler picture on how the Bakoon drives different types of headphones.
 
In a recent PM exchange with a fellow Head-fier, I mentioned how I thought the HPA-21 was a very "reactive" amp when used in Current mode on dynamic driver headphones. On the ortho Audeze LCD-3 I had at the time, the Bakoon amped it in a very even, linear fashion. It didn't really change any part of the LCD-3's natural EQ in most cases. It just added detail everywhere and accentuated certain technicalities. In that sense, you could call it a predictable kind of amplification since orthos have near ruler-flat impedance curves, though the way the LCD-3 presented everything was still pretty stunning, particularly the depth and lushness at the upper mids.
 
The Fostex TH-900 however, responded quite differently. The mids gots raised up a bit more (though still a tad recessed, which I actually prefer), the upper bass came even more alive, and the treble got smoothed out quite nicely. It was a bit mind-melting, as I'd never heard any amp - I've tried a few (Burson, Violectric, Luxman, Fostex, Cavalli) - work the TH900 in that particular fashion.
 
I'm not the most technically minded Head-fier (nor do I want to be), but I checked out InnerFidelity's charts for the TH-900 just now; http://www.innerfidelity.com/images/FostexTH900.pdf
Look at the bright-magenta curve in the Electrical Impedance and Phase section. To my unrefined ears, that's almost how the Fostex sounded, or rather, how it reacted towards the Bakoon's Current mode. If anything, I'd say the resulting EQ was sort of an "average" between the Frequence Response and Impedance curves, if that makes any sense.
 
I never had the chance to try a HD800 on the HPA-21, but if it's impedance curve is anything to go by, results might be interesting; http://www.innerfidelity.com/images/SennheiserHD800.pdf
 
I kind of agree with Headfonia's conclusion, in that the HPA-21is not an end-game amp for every single headphone out there. For certain rigs and certain tastes, it could well be the best ever, but the way it reacts to different drivers/headphones seems to be quite unpredictable.
 
Just my uneducated 2 cents. Not worth much, but I reckon it might at least point the more informed folk in some direction.

 

[zenpunk]

I thought the HD800 sounded quite bad on the Bakoon, somehow congested, which must be the first time this adjective is used in conjunction with the 800.  

 

[CanDude]

^
"Congested"? You must really be damaged by in love with the normal trebly HD800 sound!

 
OK, it is true as kurochin suggests that HD800 sounds like it is eq'd like its impedance curve when connected to the current output of HPA-21. I tried to mimic the impedance curve in EasyQ to duplicate the sound through the voltage output and the Hilo's amp. Eq-wise I got kind of in the neighborhood, especially when listening to pink noise, but of course it is more to it than that. Think that eq combined with the clarity, openness and exact sound of HPA-21.
 
What you miss is perhaps the high mids that is a little bit attenuated compared to the normal HD800 sound. This makes some of the airyness that you are used to disappear and the sound a little bit more laid-back. Or something like that... IMO, YMMV etc.
 
HPA-21 is an amp for HD800 owners like me that don't like their HD800 because they are too trebly. However you will not get the sub bass impact of a planar, but you will get a very well defined bass that is easy to follow.

 

[Ultrainferno]

That does make me wonder why you would own or buy a HD800 if you don't like the its trebly character. That's like complaining your duck whistle makes duck sounds

 

[zenpunk]

Thankfully the HD800 wasn't mine. I have never liked that headphone anyway on any headamp I tried, though it wasn't too bad on the Bryston.

 

[CanDude]

For me HD800 were my main cans after HD600 and before LCD-2. Then HE-6 and LCD-3. I don't sell my old cans... Now I'm awaiting LCD-X.

 

[Junf]

Would you recommend a dac that flows well with Bakoon?

 

[kurochin]

^ Nothing too clinical. Anything made by Lavry or other "engineering companies" would be way too dry, unless you're the analytical (emphasis on anal) type of listener. Wolfson-based chipsets would fare quite well, I reckon, since DAC's that use them tend to have warmer and meatier signatures.
 
ESS-Sabre DACs tend to be hit-and-miss. Most I've heard tend to suffer from way to much "digititus", which combined with the Bakoon's linear and uncolouring nature, might give you tetanus in the long run. There probably are exceptions (I've read that the Mytek does a good job, though I've not heard one yet), but it's a bit of a gamble if you're buying based on web-reviews and/or head-fi.org opinion alone.
 
Budget is the key at the end of the day. If you don't want to break the bank, the Schiit Gungnir should be a reasonable fit. Less than $1K, and the Schiitheads say it can be upgraded in future. Not sure what chipset it uses (AKM, maybe), nor have I tried one myself, but an acquaintance whose opinion I trust speaks quite highly of it.
 
If you plan to spend the same amount of money the Bakoon costs on a DAC, then your choices open up a bit. Something like the PS Audio Perfect Wave or maybe the Auralic Vega.
 
Just my subjective opinion though....

 

[Junf]

^ Thanks for explaining for me. I was considering Invicta Mirus and Exasound E20 mk III. But I haven't got my Bakoon yet, so it's really hard to decide. I'll be using the Bakkoon with my LCD3, hopefully it will arrive this weekend.

 

[CanDude]

Lynx Hilo of course! ...but only if you want an uncolored sound...

It's made for mastering.
Lavry DA11 sounds old, colored, indistinct and a little bassy compared to Hilo. Like an old radio... some would say more analog...
I compared Hilo with Antelope Zodiac Gold + Voltikus. I preferred Hilo. The Zodiac had an added "warmth" in the lower mids that many seem to like. To me it's just coloration that destroys the sound.
IMO, YMMV etc...

 

[banger]

Well, I have had the HPA-21 for almost 2 months now, and this is what I have found. In a nut shell, am totally smitten with this
amp's current output. I assume it is fully broken in now as it has around 130 hours on it. Mostly burn in with different playlist I
assembled.
 
First, I will comment on the music portion before the headphones.
 
I listen to all types of music except for Classical, Country, and Rap.
 
I have a large collection of older 69/70's CD's that I have not touched for years, as you may know, many of them don't have very
good production on them. Aerosmith, Led Zepplin, and those type of groups. All I can say is WOW! What I couldn't stand to listen
to before, not because of the music, but the quality, is now very enjoyable! So much detail in the tracks now, that I never heard
before. Some songs that I thought were ok, started to reveal nuances that suddenly made them very good. I don't know much
about electronics and how this all works, except for what I have researched, but I do know what my ears like. And they love what
they are hearing now! I almost have to second guess myself in all the work I have put in to learning how to rip SACD's to DSD and
convert them to Hi Rez files.Although, they sound spectacular also. I have been switching between my Woo WA5 and the HPA-21.
I thought the WA5 with the Royal Princess 300B's were my shangri la, but not anymore. Now I feel a little guilty looking at it while I
am listing to the HPA-21, like I'm cheating on it!
 
I have tried the LCD-3's, TH900's, and my long neglected HD800's. The LCD-3's sounded better than ever before, again I am
not technical enough to write a paragraph about all the nuances that the HPA-21 changed, suffice to say they sounded great.
But that did not keep me from selling them. Sorry, but they are just not comfortable enough to me to wear for very long. And at the
end of the day they kept me for being able to just drift away in my music. Too heavy and the clamping pressure was a bit much.
Even though I had the latest version with the wonderful pads, it was just too tight.
 
The TH900's were my anti HD800 phones. They gave me the sound I was most comfortable with. Even though I really do love
the sound stage and super clear highs that the HD800's gave me, they always lacked the base impact I was looking for. The
TH900's just hit all the right spots well enough that I gave them most of my listening time. This was with my WA5. With the HPA-21
there was some change in how it presented the music, but to me they sounded kinda of close to what they normally sound like.
They sounded clearer, like a bit of previously unnoticed veil had been lifted.
 
I was very surprised to hear what the HPA-21 does to the HD800! It adds the bass I was longing for and tamed the irritating tinny
highs I would get on some recordings. I also takes some of the expansive air away, but not enough that it bothers me at all. They were
sounding very TH900 like, but with tighter base, clearer highs, and larger sound stage. I can't believe how good my
music sounds with the HPA-21/HD800. I can totally drift away now! When the selected music has finished playing,
it feels like I am jerked back to the real world, from some type of wonderful trance state. I know others that would disagree with this
conclusion, but we all have different ears, and we hear things differently. So, that does not bother me.
 
I am curious to see what the new Audez LDC-XC's would sound like as I am looking for a more isolating phone than the TH900.
Although it looks like they are even heavier that the LCD-3's. I might pick up a used pair off the For Sale thread one day.
 
Just when I thought I was totally satisfied with my upgraded WA5 with expensive tubes, which cost much more than this little wonder,
I have found something that easily eclipses it to me.
 
Things I don't like about it are pretty much what others have said. Not as pretty as my WA5 with tubes lite up at night. After all it's just a
small black box. I would rather it charged the batteries while I was listing to it, but I understand the potential noise that could be introduced
from that type of design. Having to replace the batteries at some time in the future, as they don't last forever, Why bother with a Voltage
output when I will never use it. And, while I was burning it in, which took a while because of the charge cycles, I was only getting around 7 hours
of run time before it switched off. There is no way my listening sessions would go even half that. I try not to tell my friends how much I paid
for it because they look at it and say "are you serious" ?,  and laugh, until they listen to it of course!
 
If anyone is on the fence about this amp, you should give one, that has at least it's recommended burn in time, a serious listen. But take
you time, grab some old CD's, and re-discover the music of your past.

 

[BournePerfect]

   might give you tetanus in the long run.

 
 

 

[zenpunk]

I was also surprised how much the HD800's sound was transformed through the HPA-21. Personally I didn't like it but the main thing is that your having fun.
I am rocking the TH600 with the Bakoon for the past few days and already considering upgrading to the Th900. 

 

 

[CanDude]

 

So I'm not totally wrong then...

 

[kurochin]

Lavry DA11 sounds old, colored, indistinct and a little bassy compared to Hilo. Like an old radio... some would say more analog...

 
Aside from indistinct, your impression of the Lavry is the total opposite of mine. More analog? The Lavry to me is the very definition of digititus. Flat, metallic and dry. It sounds like it was designed by soulless robots, and that's from the balanced output fed into a decent amp. My cheap USB bus-powered Bladelius and Halide DACs absolutely kill the Lavry in terms of "analogue" sound, even if they don't quite have it's resolution. If you're brave enough to plug your 'phones directly into the Lavry's headphone jack, I recommend you write a last will and testament first.