Dr Joe's bench while building a GT-102.
Dr Joe's bench while building a GT-102.
Dr. Joe was kind enough to send in this detailed review of the GT-102. He has allowed me to post it essentially verbatim on the web-site.
Everything supplied in this kit is of exceptional quality. These include all of the electronic components ... diodes, transistors, ICs, resistors, capacitors and circuit boards; the hardware ... gold-plated RCA input jacks, heavy-duty speaker output connectors, fused AC power line connector, LED lighted front panel switch, a variety of screws, nuts, bolts and wires, + a very precisely-fabricated chassis/case with mounting holes for over-sized heat sinks. Everything fitted together exactly as described in the construction manual and there were no missing parts or surplus. The use of Faston terminal connectors for the AC power supply connections further simplified the assembly. The only difficulty encountered centered around accurately identifying several of the electronic components due to their small size. Long gone are the days when a 10,000 mF, 63 VDC capacitor was the size of a pineapple juice can!! In any event, to minimize the risk of misidentifying several of the tiny components, a fluorescent or LED Magnifying Tabletop Lamp with a 4" 3-diopter primary lens and a 1" 12-diopter secondary lens proved very helpful.
The view inside the GT-102.
Having readily passed all of the recommended Power-On/Power-Off tests, I initially hooked up a pair of very sensitive full-range speakers to the amplifier outputs, powered up and allowed the amp to run for a couple of hours with no signal applied. During this initial "breaking-in" period, the measured DC voltage at the output terminals was less than 0.5 mv with no audible hiss or hum from either speaker. The amplifier operated very quietly and the case remained cool to the touch. This amplifier has been designed and built to last for decades. The layout and construction are very reminiscent of the power amps I built back in the 70s and 80's using only computer-grade components and still operational today.
The GT-102 amp was then hooked up to my workbench stereo system consisting of a fully updated/modified Dynaco PAT-4 Preamplifier, a Dynaco FM Tuner, a Sony CD/DVD Player, a restored Thorens TD-150 turntable, a Visio HDTV and a pair of Polk Audio Speakers + 12" Sub-woofer. On powering up, the accuracy, clarity, transparency and openness of the sound reproduction without any trace of "edginess" at the higher frequencies and great low-end reproduction, were all readily discernible and exceeded all of my expectations. The GT-102 amp was tested at low and moderate volume levels using a wide range of analog and digital sound recordings. I am still awaiting the opportunity ... once the house has been vacated! ... to assess the amp's ability to reproduce at higher volume levels, the DVD version of Drum Tao's "Drum Heart" concert hall performance. Based on what I have heard so far, the GT-102 amp should have no difficulty handling this task. It is the best sounding medium-power amplifier utilizing the more energy-efficient Class AB design platform.
Dan, great design and implementation. A few sample photos of the finished unit are attached.
GT-102, back view.
Hi again Dan ... I have finally had an opportunity to critically listen to the entire CD and DVD versions of Drum Tao's "Drum Heart" concert hall performance at sound levels comparable to the live performance, which I have had an opportunity to attend during their last North American tour. The recordings of this dynamic performance are of excellent quality and will test the entire dynamic range of an audio system, especially, the power amplifier. As noted in my earlier communication, the Akitika GT-102 power amplifier was an outstanding performer at the low and medium volume levels. Using the same simple equipment configuration ... a Sony CD/DVD player, a completely updated/rebuilt Dynaco PAT-4, the Akitika GT-102 Power amplifier, a pair of Polk Audio full-range speakers + a Polk Audio 12' sub-woofer and a Visio HDTV/HDMI monitor ... the DVD version was played at a live performance volume level. The Akitika GT-102 Stereo Audio Power Amplifier did not disappoint!
The performance of the Akitika GT-102 Stereo Audio Power Amplifier at a high volume level was truly outstanding ... effortlessly and seamlessly reproducing the wide dynamic range of complex musical passages without any hint of distortion, overload or breakup. The high end reproduction was very clean, crisp, transparent and accurate ... completely devoid of any signs of high frequency distortion, fuzziness, harshness and edginess. The low end performance was very powerful, tightly defined, dramatic and even palpable, and once again without any hint of boominess or distortion. The complete absence of any background hiss, hum or or other noise between pauses in the performance were readily noticeable and most welcome. This has been the only occasion during which I was able to listen and enjoy the entire recording without feeling the need to turn down the volume or to turn it off!
The Akitika GT-102 Stereo Audio Power Amplifier paired with a fully modified/updated Dynaco PAT-4 make an awesome pair which will outperform many much more expensive commercial options with very impressive wattage, harmonic and IM distortion ratings. The reason for this is that other lesser-known specifications, viz., the amp's transient response, damping factor, signal-to-noise ratio, etc., at normal listening levels, are more responsible for realistic and accurate sound reproduction than any of the former specifications. Your Akitika GT-102 Stereo Power Amplifier clearly has all of its operating parameters in the proper balance and sounds great. For those who do not have a Dynaco PAT-4 to upgrade, the Akitika PR-101 Stereo Preamplifier should be a very compatible companion for the Akitika GT-102 power amp.
Regards,
Dr. Joe
Classic Equipment in a rack.