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kawo 10th February 2012 04:11 PM

HPA-2 Headphone Amp Kit (High quality & High-end components)
7 Attachment(s)
Interested in buying the HPA-2 headphone amp kit can be found in
HPA-2 could change the structure of the operational amplifier freely when the most of the pin which equivalent to 5534 can be used on the board. You could make changes to your own preference. To further experience the charm of HPA-2, it is recommended to use SONY PS-3 playback and high-class headphone, such as SONY MDR7506,MDR-7509,MDR-7510, MDR-7520, etc. For high-end use, Adam ProAudio product is recommended. You might be pleasantly surprised with this clever little high-end gadget. High-end components make HPA-2. WSC-1 is used to control the direction of audio signal routing. This resistance is only common in the high-end Hi-Fi, such as Jeff Rowland, Mark Levinson, etc. This resistance is short of low class device, even a headphone amplifier. Moreover, the HPA-2 collects more high-end components, such as Vishay RN55D, CMF55D, UXB 0207, MMB 0207, Precision Resistive GP1/4, Toshiba 2SA1930, 2SC5171, Neutrik NRJ6HM-1 jack socket,etc.


Vishay WSC-1 1%
Vishay Beyschlag UXB 0207 0.1%
Vishay Beyschlag MMB 0207 0.1%
Vishay Dale RN55D 1%
Vishay Dale CMF55D 1%
Precision Resistive GP1/4 0.1%
Evox Rifa MMK
Philips 116 Aluminium electrolytic
Nippon Chemi-Con Aluminium electrolytic
Texas Instruments LM317
Texas Instruments LM337
Analog Devices OP27
Toshiba 2SA1930
Toshiba 2SC5171
Alps RK097
Neutrik NRJ6HM-1


Level 20 Hz90K Hz -0.1,-0.06
10 Hz100K Hz -0.3,-0.1
THD+N 20 Hz40K Hz 0.03%
10 Hz40K Hz 0.05%
IMD 0.007%
Phase 1K Hz0.00
100K Hz1.1
Gain 7 dbm
S/N 95 dbm
Impedance 8Ω→600Ω
(Neutrik A2 and TT402 Audio Measurement System)

MrSlim 12th February 2012 01:27 PM

Care to share the schematic with us? DIY'ers tend to like that .
It looks interesting, but you will need to share more details, such as power supply requirements etc..

tornislv 12th February 2012 08:11 PM

Found your kit on eBay. Howewer without schematics it's a No Go. PCB and components seems OK, I do not intend to start discussion here about are they genuine etc etc. Please provide the schematic and I would possibly buy one set.

kawo 13th February 2012 04:24 PM

I later post circuit, HPA-2 circuit is simple and general, it is characterized in part of resistance in the audio circuit is very important, if with the PS3 play SACD, using MDR7506 obtained very good sound, the HPA-2 using the 18V-0-18V AC.

qusp 13th February 2012 04:40 PM

without schematic you wont get much interest here. also i think you have a different idea of what is high end

Ryssen 14th February 2012 10:27 AM

Yes. a schema would be..nice.

Is it class A? Do the output transistors get hot at idle?

tornislv 14th February 2012 12:23 PM

1 Attachment(s)
A quick reverse engineering based on photos published suggests the schematic may be smth like this:

kawo 14th February 2012 04:14 PM

Hi Ryssen
Yes,class A. At room temp. about 40℃

kawo 14th February 2012 04:15 PM

1 Attachment(s)
Hi tornislv
the schematic

kawo 14th February 2012 04:20 PM

Only one channel, its power is standard LM317 and LM337, 15V → 20V adj.

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