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kawo 10th October 2011 05:38 PM

HPA-2 headphone amplifiers
3 Attachment(s)
Level 20 Hz90K Hz -0.3,-0.06
10 Hz100K Hz -1.0,-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)

BionicSniper 11th October 2011 03:45 AM

looks very cool. Why a PowerPoll connector, and what is the DIN on the back.

kawo 11th October 2011 06:04 AM

In my experience, Neutrik PowerCon better than the IEC, output - when it is Pre-amp output.

kawo 11th October 2011 05:29 PM

3 Attachment(s)

Vishay WSC-1 1%
Vishay Beyschlag USB 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
Kemet tant
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
Neutrik PowerCon

sgrossklass 12th October 2011 04:05 PM

Seems like a good conventional single-stage (I guess?) concept, with nice quality parts and laid out very neatly.

But yeah, this power connector is like way over the top. Now Neutrik NAC3MPA-1s don't really break the bank at 3..4€ a pop, but let's be honest, people regularly run much more demanding loads using bog standard IEC jacks - like power-hungry PCs or PA power amps with hundreds of watts. I have never heard of them being any kind of problem. The money saved could have been put to good use for, say, squeezing in a second amplification stage - and that would have had clearly measurable benefits in real life.

kawo 12th October 2011 05:22 PM

Thank you for your guidance, but you said you have to have a first condition, that is to use a good quality IEC, it will be very easy to loose, is not it a load problem. Many broadcast equipment for the prevention of the above happen, they design will add a button on the IEC, in particular, SONY

kawo 12th October 2011 05:34 PM

3 Attachment(s)
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. Moreover, the power indicator could be changed to different colors. The size of the HPA-2 is small, wide 97mm, high 32mm, and depth 182mm. It just occupancy a few space at home or office. To further experience the charm of HPA-2, it is recommended to use SONY PS-3 playback and high-class headphone, such as SONY MDR-7506,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.

kawo 14th October 2011 06:31 PM

2 Attachment(s)
For the phase on the Hi-Fi, you can fix the next level or speaker, but on somewhat different in the headphone amp, headphone is fixed on the head.

lcsaszar 14th October 2011 06:54 PM

Those AD OP27s are a bit suspect... I have TDA1541As similarly engraved not painted that are fakes.

kawo 15th October 2011 03:02 AM

Please respect your comments.

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