HPA-2 functions is to be replaced OP, to arrive at their favorite sound in the original design using OP27, because it is relatively average in every respect. Contrast this to the OP to do it as an intermediate, the first two HPA-2, the signal from the same CD player with a headphone listening.
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For comparison, first we have to determine the replacement of OP after the DC, because DC is easy to burn a lot of headphone's, HPA-2 after unplugging about 100mV below the OP, and OP will be in the installation within 1mV, usually only 0.1mV, can be said that good in my hands the factory machines, some of them up 9mV, if you have an interest in measuring the headphone amp.
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First up of course, is the most widely used 5534, I specifically chose the products long before, 83 years new, early products often discussed on the network is better, I would like to try.
Summary ------ 5534 either high or low frequency OP27 are no obvious, clear 5534 is relatively soft, very comfortable, feel good to listen to folk songs, there is less fog, but it should be 5534's charm, but with my current 5534 Well there were heard out of it!
Summary ------ 5534 either high or low frequency OP27 are no obvious, clear 5534 is relatively soft, very comfortable, feel good to listen to folk songs, there is less fog, but it should be 5534's charm, but with my current 5534 Well there were heard out of it!
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I suppose you were writing in English, but I found my Canadian language skills stop helping me making sense out of your last few posts. I didn't realize English language they teach in China has departed so much from what they teach here. It seems either I should go to China and learn something new, or you could switch back to some less advanced English language and help people like me who have got stuck in the old time to better understand what you are writing. Thanks.
The metal work in your project looks very nice, would you consider organizing a group buy for only the mechanical items including the casing, the connectors, the power switch, and the volume knob?
The metal work in your project looks very nice, would you consider organizing a group buy for only the mechanical items including the casing, the connectors, the power switch, and the volume knob?
A customer in Hong Kong feel after use----Many thanks to kawoaudio building the excellent HPA-2 at very reasonable cost, this [FONT=新]＜[/FONT]$5,000 HPA-2 + Sony MDR-SA5000 combo has quickly become one of my reference systems for personal music enjoyment when I do not have to disturb others. The transparency and instantaneous transient response are not challenged by any of my other can/amp combinations and yet musicality has never been compromised, despite the Sony would sound too analytical and sometimes dull with other headphone amps.
Amongst all these, the better combinations are T1 + Cyber 20, HD600 + XP-7, K702 + X-Can V8 and the SA5000 + HPA-2. All have their different sound signatures with T1/Cyber 20 and SA5000/HPA-2 belonging to a group with cleaner, neutral and more accurate sound while the K702/MF and HD600/XP-7 belonging to a much richer and thicker sound. It is surprising that the more expensive Beyerdynamic T1/A1 combo doesn't even sound up to par with the T1/Cyber 20 combo and the greatest pleasant surprise is the Sony/HPA combo which gives taut and deep bass, clean and sustaining highs from the piano and violin and even mid range of vocal is sweet and soothing, though not as rich as the Sennheiser.
Amongst all these, the better combinations are T1 + Cyber 20, HD600 + XP-7, K702 + X-Can V8 and the SA5000 + HPA-2. All have their different sound signatures with T1/Cyber 20 and SA5000/HPA-2 belonging to a group with cleaner, neutral and more accurate sound while the K702/MF and HD600/XP-7 belonging to a much richer and thicker sound. It is surprising that the more expensive Beyerdynamic T1/A1 combo doesn't even sound up to par with the T1/Cyber 20 combo and the greatest pleasant surprise is the Sony/HPA combo which gives taut and deep bass, clean and sustaining highs from the piano and violin and even mid range of vocal is sweet and soothing, though not as rich as the Sennheiser.
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Kawo,
Your design looks very professional. I'm also very pleased that you are using a Neutrik connector.
I do have one suggestion though... Have you considered using National Semiconductor LME49720 opamps? These might not be great for the application, however they have gotten excellent reviews.
LME49720 - Dual High Performance, High Fidelity Audio Operational Amplifier
Your design looks very professional. I'm also very pleased that you are using a Neutrik connector.
I do have one suggestion though... Have you considered using National Semiconductor LME49720 opamps? These might not be great for the application, however they have gotten excellent reviews.
LME49720 - Dual High Performance, High Fidelity Audio Operational Amplifier
Thank you for your appreciation, in the HPA-2 can only be used on a single op amp, dual op amp can not be used with I being tested there ... OP07, OP37, PM1008, NE5534, AD844/883, A843BH, OPA627AP, OPA637SM . the best op-amp is OPA637SM, but with not enough on the HPA-2 stable, so the OPA627 is the preferred.
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