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Post by videoguy on Nov 8, 2016 21:06:11 GMT
Hi all: My AKHA journey started May 2015. As you might remember I revived this project as it is too important to let die. Had many interruptions along the way; ie many visits to the heart specialist w my wife etc. etc. The main question: Was it worth it? A resounding YES. You may recall I came up with an easy way to raise the operating voltage of the SCHA to +- 20vdc, a marked improvement to that amp.
Moving on: The AKHA is at an entirely different level. The first thing you notice is there is more air around the music. Dead quiet & free of distortion & the cleanest audio I have ever heard! The channel separation is improved with a wider sound stage. Had to have a friend evaluate stereo separation & sound stage as I have been virtually deaf in Right ear, most of my life. I am using a ladder type volume control. There are only 2 resistors in the circuit on each of 23 steps; this eliminates the choke point that series resistance string controls introduce.
I am listening thru modified Fostex T50RP Orthodynamics; they are a big improvement over standard dynamic driver headphones. Orthodynamic drivers are a wide range version of a ribbon tweeter; simply put they are a ribbon microphone in reverse. More later after the caps completely form etc.
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Post by videoguy on Feb 3, 2017 3:06:51 GMT
My AKHA now has had 100 hrs. of running time. There has been progressive improvement as the capacitors in the power supply are now fully formed. I have added an output impedance switch, having 4 positions, low, 65 ohm, 120 ohm & preamp output of 100 ohms.
For those members who bought boards & dual matched transistors; you need to build this amp., it is worth every bit of time & money required, for the build.
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Post by videoguy on Jun 23, 2017 15:11:04 GMT
For everyone who participated in the group buy for the AKHA headphone amplifier but have not built it; let me encourage you to get to work & build it. It has the cleanest sound of any amp. I have ever heard. It also has a lot more air around the audio than I have ever heard. It easily outperforms most of the high end units on the market.
As Sandy K. is no longer a member & cannot be contacted, I will be able to answer any questions you may have.
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Post by freddypipsqueek on Jun 23, 2017 15:19:21 GMT
I'm one of those with the kit (I have a spare Chiara as well) but little time. I will put some aside this summer. A.
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Post by videoguy on Jun 23, 2017 15:32:22 GMT
Hi Freddy: You will be rewarded w the cleanest, distortion free audio you have ever heard. Well worth the effort.
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