HPA-2 Headphone Amp Kit (High quality & High-end components)

[kawo]

Interested in buying the HPA-2 headphone amp kit can be found in ebay.com
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.

Features

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

Spesifications

Level 20 Hz→90K Hz -0.1,-0.06
10 Hz→100K Hz -0.3,-0.1
THD+N 20 Hz→40K Hz 0.03%
10 Hz→40K Hz 0.05%
IMD 0.007%
Phase 1K Hz＜0.00°
100K Hz＜1.1°
Gain 7 dbm
S/N ＞95 dbm
Impedance 8Ω→600Ω
(Neutrik A2 and TT402 Audio Measurement System)

[MrSlim]

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]

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]

Thankyou^^,
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]

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

[Ryssen]

Yes. a schema would be..nice.

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

[tornislv]

A quick reverse engineering based on photos published suggests the schematic may be smth like this:

[kawo]

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

[kawo]

Hi tornislv
the schematic

[kawo]

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