[MohawkUS]

"Strom-Amps" sounds almost simplistic, like "current driven amplfication".  Doesn't necessarily imply opamp chips, like trans-impedance or the sort.  Not sure I have anything against an opamp chip gain stage, per se, but it seems to me that their main advantage is in small size for portable amp products and such, with their down side in circuit inflexibility for signal control and/or conditioning, as opposed to discrete components which can be varied and positioned to optimize that particular signal gain circuitry.

Of course you can have a combination of onboard (chip) and off board circuits, but I would think a product of this caliber would be comprised of mostly discrete components,especially in the gain stage, and except for perhaps some auxiliary function chip modules doing straight-forward signal processing or conversion and the like.  The flip side of that is that you can bring a whole lot of transistors to bear using chip technology, like a bank of opamps for amplification control.

It's gratifying that they're duly impressed with the HPA-21, tho.

Pros & Cons. I would say op-amps can be machined more accurately eliminating the need to match components as is done with discrete designs. I would assume this would result in less money being spent on labor/throw away components and more on other parts of design. Graham Slee has written some interesting posts on why he uses op-amps in his designs and how a number of manufacturers just copy op-amp schematics using discrete components.

Based on my limited knowledge I would say that the ideal solution is probably op-amps made in house, built to the specifications of the product being designed(rather than the inverse situation with off the shelf chips.)

 

[audionewbi]

It is very pricy to develop and produce your own opamp.

 

[jacal01]

The only thing I can add here is that the HPA-21 is a Korean derivative product of the Japanese HDA-5210 amp with a unique current controlled gain circuit developed by Akira Nagai, which in its inception promptly earned him "enlightened" (satori) plaudits from his peers for his outside-of-the-box thinking, and so caused him to name his amplification circuit SATRI.
 
My point is I think it improbable that the exclusive SATRI circuit design is replicated via a configuration of off-the-shelf opamps.

 

[Hi-Head]

Headmania had a review on both, but not on the same time.

Exactly but the author claims the M9 tops the Bakoon especially for its greater musicality, I am absolutely speechless! If there is one single character describing how the Bakoon HPA-21 sounds it is its musicality, its ability to let you dive into the music! This however should not downgrade the performance of the M9 but without hearing both amps in direct comparison it will be impossible to come to such conclusion.
Wasn't there a review on Headmania as well in which the (same?) author preferred a Burson headamp over the Bakoon? How ridiculous.....

 

[kurochin]

Wasn't there a review on Headmania as well in which the (same?) author preferred a Burson headamp over the Bakoon? How ridiculous.....

 
I own a Burson Soloist. Yeah, it's a very good headamp, punching above it's price-point in combination with certain headphones, but it was clearly bested by the HPA-21 I auditioned. IMHO, of course.
 
Opinions come with the hobby. If they call it as they hear it, then more power to them, I suppose.

 

[Sonido]

Hate to suggest it, but money talks on those review websites.

 

[zachchen1996]

I'll wait for that I guess.

 
Don't like the wagnus anymore?

 

[audionewbi]

Cant lie, wagnus isn't quite what i thought it would be. I've considered getting the k812 for it.

 

[AppleheadMay]

A question about the Japanese Bakoon amp, more specifically about the volume control options.
Does anyone know the difference between the three types od colume control? I mean, what the hell is Winging Resistance or Non Induction?
 
 
 
From the site:
 

Variable Resistance(Standard)	1,290
Metal Film Resistance ATT	1,535
Winging Resistance ATT(Non induction)	1,790

 
And the explanation from the site:
 
The difference of each type is volume (attenuator) grade which is directly affect its sound quality. 
Non induction wing resistance ATT is minimum distortion, high resolution, rich bass range and dynamic sound but does not have any special character. Metal film resistance ATT is good separation of sound, rich mid-bass range. Both attenuators is generally less noise, high stability and rich information.

 

[mscott58]

   
I own a Burson Soloist. Yeah, it's a very good headamp, punching above it's price-point in combination with certain headphones, but it was clearly bested by the HPA-21 I auditioned. IMHO, of course.
 
Opinions come with the hobby. If they call it as they hear it, then more power to them, I suppose.

Just received my HPA-21 a few days ago and have been doing the A/B comparison thing with my long-time Burson Conductor (which uses the same amp section as the Soloist). I'm still using the Conductor as the DAC, which makes A/B very easy, as I just plug my LCD-3's in either the Conductor or the HPA-21, no other changes needed once the volume was equalized)! 
 
Have to say I'm very happy with the Bakoon. The level of detail this thing is able to extract is simply amazing. It's not just the things I couldn't hear before in the details, it's the tonal character of the instruments and the very texture of the notes. There's just more there, and it sounds better. (Can't believe I'm sounding like the type of professional reviewer who uses all these fancy words and expressions!) If I was a professional musician I think might even be able to tell what brand of guitar or bass the band is using, the image of the instrument and notes is just so clear. And of course there's the removal of an extra layer of "veil" that you don't know is there until you take the next step up the (very expensive) ladder. 
 
Totally agree with Kurochin - the Conductor is a great all-in-one box. However, the HPA-21 takes it even further.
 
Is is worth paying ~$3K for an amp versus <$2K for an amp/DAC combo? I'll say yes (especially as I got a great deal on my Bakoon!) but those looking for huge "knock you over the head" improvements might not see it. At this level of the game IMO it's not about huge step changes, but rather continued refinement, and in that area the HPA-21 clearly scores. 
 
Thanks
 
PS - I'm still getting used to turning off my HPA-21 whenever I'm not listening. Keep forgetting the batteries have to recharge!

 

[Justin_Time]

I'm still trying to decide if I should get the HPA-01 or not. My Ultrasones have a very flat impedance graph,



It's not perfectly flat as planars, but better than most dynamics. Has anyone tried the Bakoons with low impedance/highly efficiant dynamics? Other than the Fostex as I have seen some people use that combination and report exaggerated bass because of the impedance curve.


I'm sold on getting a battery powered amplifier as I've had persistent problems with noise in my audio equipment as well as non-audio related problems with the power delivery. I'm just skeptical that it's the best move to buy an amplifier designed for planars for a dynamic.

 
I discussed the Bakoon HPA-21 (not the 01) in a very long article posted here about a week ago.  Here is an excerpt specifically addressing pairing the Bakoon with various headphones:
 
 
"Bakoon HPA-21 ($2,900)— This diminutive amp (in size only, not in price) was a very pleasant surprise.  It truly excelled with the PS1000 and HD800, providing more vivid details than any other amps I auditioned with perhaps the exception of the GS-X Mark 2.  While the HeadAmp GS-X Mk2 is silky smooth, the Bakoon has vivid and warm details.  A touch of brightness remained with the PS1000, but the focus, center image and palpable presence within a big sound stage were so good that the vestige of brightness could be easily forgiven.   And then there was the bass:  slightly boosted to a tremendous impact!  With the HD800, there was added weight in the bass as well but with tight control and impressive dynamics.  And no annoying sibilance!  With the LCD3, the Bakoon produced a very seductive, liquid midrange and highly resolved details with just a hint of euphonic caramel-coating.  I still wished for more air and bigger sound stage.  The bass was punchier than with the HD800 but not the last words in tightness.  With the HE-6, the Bakoon was simply superb.  I found that unlike most other headphones, which preferred the Bakoon's Current Output, the HE-6 sounded better through the Voltage Output.  The midrange was seductively rendered, at once warm and open, with plenty of vivid details and spacious soundstage.  The sound was remarkably free of the hardness often heard with other amps. There was plenty of bass with the HE-6, but once again, I wished for a tad more impact here—this was another surprise for a SS design; perhaps a bigger power supply is needed. The Bakoon HPA-21 is a great choice for the PS1000 and LCD3 and among the very best with the HD-800 and the impossibly insensitive HE-6. But if thunderous bass is your priority, this may not be the amp for you.

 

NOTE:  The gain on the Bakoon was too high for the HD800 [and the Ultrasone 8] even at the low setting.  I reduced the gain from my Oppo 105 and PS Audio PerfectWave Mark II by about ¼ to minimize sound leak in the Off position (considered "normal" with the unusual design of the Bakoon) and achieved fine volume-adjustment. But the reduced gain was insufficient to drive other "sensitive" headphones like the Grado PS1000 and the Fostex TH-900. I had to fiddle with the gain again.  Very annoying, especially at $2,900!"

I have also listened to the Denon LA7000 (Lawton Modified), TH-900 (Lawton Modified), Ultrasound Edition 8 and 10 for a few months with the Bakoon HPA-21.  The sounds are consistently excellent.  The discussion above regarding the PS1000 and especially the HD800 generally applies to the Ultrasone 8 as well.  I want to emphasize that the added weight to the bass does not in any way detract from the clarity of the mid-range. You can hear more details, better delineated but never edgy, and  much improved depth.  Overall, the sound is a touch warmer, more dynamic and vividly detailed.  
 
But if you prefer a completely flat frequency response of the Ultrasone 8, the Bakoon HPA-21 is definitely not the amp for you.  I myself found that the typically "flat" sound of the Ultrasone 8 with many amps rather anemic and un-involving. The Bakoon HPA-21 is exactly what the doctor ordered for the understated sound of these headphones.         

 

[zenpunk]

While many seems to enjoy the HD800 out of the Bakoon, when I tried it I just thought it sounded wonky, same for the T1.
I also clearly prefer the HE-6 out of the current output.
But I agree with many that the Fostex TH900 through the current output is just a match made in heaven.
And to my surprise I realised recently that I actually preferred the Oppo PM1 out of the voltage output.

 

[Justin_Time]

  While many seems to enjoy the HD800 out of the Bakoon, when I tried it I just thought the it sounded wonky, same for the T1.
I also clearly prefer the HE-6 out of the current output.
But I agree with many that the Fostex TH900 through the current output is just a match made in heaven.
And to my surprise I realised recently that I actually preferred the Oppo PM1 out of the voltage output.

Zenpunk,
 
Very interesting observations.
 
Could you give some details on what was wrong with the HD800 wonky sound through the Bakoon?
 
I fully agreed with you about the Oppo PM-1:  it sounded better to me too through the Voltage Output--did you notice the huge drop in volume?
 
With all due respect to Oppo PM-1 fans--this is an observation, guys, no bashing intended as I own the PM-1 too--these cans sounded poor from either outputs.  The lack of transparency (not to be confused with brightness) and the poor resolution of details were quite apparent.
 
Just for grin, I hooked up the much-maligned and oft forgotten Ultrasone 8 and the improvement in sound clarity, inner details and (gasp!) soundstage over the PM-1 was shocking, out of either output of the Bakoon.  Once again it was not a simple increase in brightness as the U-8 trebles is never aggressive in that area.  Your comments?

 

[AppleheadMay]

   
NOTE:  The gain on the Bakoon was too high for the HD800 [and the Ultrasone 8] even at the low setting.  I reduced the gain from my Oppo 105 and PS Audio PerfectWave Mark II by about ¼ to minimize sound leak in the Off position (considered "normal" with the unusual design of the Bakoon) and achieved fine volume-adjustment. But the reduced gain was insufficient to drive other "sensitive" headphones like the Grado PS1000 and the Fostex TH-900. I had to fiddle with the gain again.  Very annoying, especially at $2,900!"

 
As I am considering the Japanese Bakoon, which seems to have the same volume control problem, I am worried.
In the other thread this has been said as well, not much volume control with the TH-900, some people use it at no more than 1 on the dial setting.
On the other hand, both the Japanese and Korean Bakoon amps are said to be just about the ideal amp for the TH-900.
IMO having so little volume control must be really annoying. And I do not want a dac with volume control, I hate multiple volume controls in the chain.
So how can an amp/phones combo with so little volume control be a great match? Not trying to be negative here, just looking for an explanation as I am really interested in this amp.

 

[Justin_Time]

   
As I am considering the Japanese Bakoon, which seems to have the same volume control problem, I am worried.
In the other thread this has been said as well, not much volume control with the TH-900, some people use it at no more than 1 on the dial setting.
On the other hand, both the Japanese and Korean Bakoon amps are said to be just about the ideal amp for the TH-900.
IMO having so little volume control must be really annoying. And I do not want a dac with volume control, I hate multiple volume controls in the chain.
So how can an amp/phones combo with so little volume control be a great match? Not trying to be negative here, just looking for an explanation as I am really interested in this amp.

Simple solution:  just turn down your DAC output so that you get virtually no sound leak at 0 volume and you get all the range of volume adjustment you like (7am to 7 pm).
 
By the way, in my experience, I rarely have to crank up the volume of any amp beyond 1 o'clock for most of my listening except when the amp is really under-powered for the headphones (e.g. most amps with the HE-6).