The Scythe KamaBay Amp SDA-1000 amplifier offers an appealing combination of price and capabilities, an attractive exterior design and small dimensions. It can make a nice addition to a notebook that cannot provide the desired volume in headphones or help organize sound in a room where there are speakers without an amplifier. Unfortunately, several design slips do not allow this device to show its full potential.
The main problem is that the amplifier is not meant for speakers with an impedance of 4 Ohms. Moreover, Scythe somehow forgot to tell the customer about that. As I found in my tests, the amplifier could work with such load, but the high level of distortions deprived music from all beauty. For the amplifier to work normally with a load of 4 Ohms, two YDA138 chips must be used in monophonic mode while the included power adapter must have a higher rating.
The second problem was encountered when I tried to use the KamaBay Amp in my system case. Turning the amplifier on triggered the PSU’s protection and all the power noise is perfectly audible in headphones. The primitive adapter from a Molex connector to a round plug that goes into the amplifier is not enough. A full-featured LC filter that might suppress noise and limit the surge of start-up current is required. This reminds me of the "wonder cables" from OCZ we tested in our labs a few years ago.
Now, what about the sound quality of the Scythe KamaBay Amp? Comparing it with the amplifier of the Microlab Pro 3 speaker system, I found the KamaBay Amp to cope well with 8Ohm load. The only thing I can find fault with is that the medium frequencies are not exactly clear and the sound stage is flat as a wall. The KamaBay Amp did better as a headphones amplifier, delivering good dynamics and tonal balance, but of course it is no match to hi-fi models priced at a few hundred dollars. The lack of echeloning is its main problem, again. There is one oddity here, though. When you set the amplifier’s volume control at its maximum and lower the sound card’s output signal level, the KamaBay Amp sounds much softer and you begin to feel the sound stage. This raises my apprehensions about the quality of passive components employed in the amplifier’s input circuitry, and the third slip of its developers shows up.
For some unclear reason the amplifier’s chip has a very high gain setting: 30dB for the digital and 12dB for the headphones amplifier. This reserve of volume was not called for with every sound source I had. So, I guess that the lowest of the four gain settings available for the YDA18 chip (18dB for speakers and 0dB for headphone) would be quite enough. The developer might have provided a sensitivity switch for very quiet sound sources.
Summing everything up, I want to acknowledge the developer’s courage, promising concept and sparkling product design. At the same time, I wish the amplifier’s electronics were revised to correct the above-mentioned drawbacks. I guess, a Scythe KamaBay Amp SDA-2000 with two Yamaha chips and high-quality passive components inside, a miniature sensitivity switch at the back panel, and a “wonder” wire for connecting the amplifier to the computer’s PSU would be a much more desired product for many potential buyers.