PCB layout, wiring routes, grounding strategies, heatsinking, power transformers, and especially power-supply design, will affect stability, transparency of sound, and the ability to drive speakers. In using power op-amps, implementation is key. I've subsequently compared my Gaincard to one of its clones and one DIY version, and learned that all LM3886 op-amps are not created equal. After reviewing it, I bought the Gaincard and used it every day for 10 years with a pair of Rogers LS3/5a speakers. The 4706 Gaincard's high price, radical simplicity, and unorthodox power supply spawned concern among measurements-oriented audiophiles, but word quickly spread about how musically satisfying it could sound. The Gaincard, introduced in 1999, had only nine parts per channel, short signal paths, minimal power-supply capacitance, and, with only one of 47 Lab's Power Humpty power supplies, cost $3300 (a second Power Humpty cost an additional $1800). The roots of the storied LM3886 can be traced back to 47 Laboratory's 4706 Gaincard integrated amplifier, designed by Junji Kimura, which I reviewed for Listener magazine Robert Deutsch reviewed it for Stereophile in December 2001. Now, before you get your knickers in a knot about an "audiophile-grade" power amplifier based on a lowly op-ampinstead of this year's fashionable MOSFET, JFET, SIT, or bipolar deviceyou must understand that the AkitikA's LM3886 op-amp is notorious and fashionable. Note the three deep-finned heatsinks: one behind the rear panel, for the power-supply regulator, and two in a row along the inside of the left side panel, one per channel, to cool the two LM3886 power operational amplifiers. The first thing to note is the steel wall separating the audio circuitry from the toroidal mains transformer and regulated power supply. The GT-102's interior is spartan, but studying its layout gives the potential kit builder a good idea of how much screwing and soldering will be required to build it. On the rear panel are only an IEC power-cord inlet, two gold-plated RCA jacks, and two pairs of generic speaker binding posts. Its front panel sports only a logo and an illuminated, bright green plastic rocker switch for power on/off. The GT-102 is a class-AB, 60Wpc stereo power amplifier in a case made of relatively thin steel. So long as your kit is correctly assembled, we'll refund the price you paid, you just pay return shipping. If within 30 days of receiving the kit you aren't satisfied, return the kit. Which I did.īecause the GT-102 is available as a kit I begin my description of it by quoting AkitikA's "Satisfaction Guarantee" for this US-made amp: When I asked John Atkinson if I could review AkitikA's GT-102 power amplifier, he said okay, but suggested that, because he would be testing it on his lab bench, I should request the factory-assembled, pre-tested version ($488). For me, kits were the start of a new lifeone that led me to secret societies and darker corners of the audio underground. (I worshiped at the Philco 16B Tombstone.) Solder fumes, wire strippers, and building amps remain very appealing to me. By the late 1980s I'd advanced to building simple tube amplifiers from scratch, using parts cannibalized from antique radios. Next, I started reading Audio Amateur and Speaker Builder magazines, buying used test instruments, and modifying my Dynaco and Hafler gear. Yahweh, Bob Marley, and The Specials loved this potent lively-up system as much as I did.
To this day, Dylan and the Doors have never sounded better!Īfter moving to New York City, I built a solid-state Hafler DH-101 preamp and two (!!) DH-200 amplifiers, which I used to drive stacked pairs of Large Advent loudspeakers. I didn't want to take tubes to college, so I also built Dynaco's solid-state PAT-4 preamplifier and Stereo 120 amplifier, which I used to drive Dynaco's A-25 loudspeakers. He practically forced me to build a Dynaco (footnote 1) Dynakit Stereo 70 tube amplifier, as well as the matching PAS-2 preamplifier and FM-3 stereo tuner.
#Stereo power amplifier kit how to
He taught me Ohm's law, and how to solder, dress wires, and use a multimeter. When I was in high school, my best friend was a radar technician for the Navy. My friend wondered if I wanted to review the AkitikA amp (the name is a palindrome, based on a kit). (The studio guy bought his assembled and tested for $488.) Now, he likes the AkitikA more than his broke-down reference amp." So he went online and bought this 60W AkitikA solid-state amplifier to use while his big amp was being repaired.
An e-mail from an old audiophile pal: "Herb, my buddy owns a recording studio, and he told me one of his $10k reference amplifiers stopped working and the manufacturer said it would take months to be repaired.
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