The Aikido PH-1 phono stage returns. Building phono stage based on the Aikido topology makes perfect sense, as the Aikido’s low distortion, noise, and output impedance, without the use of negative feedback—all are highly desirable attributes in a phono preamp. The Aikido PH-1 phono preamp is an extremely flexible design, as a nearly infinite number of different Aikido Phono Stage configurations can be built on the PCB. Nonetheless, our goals always remain constant: high-gain, low-noise, and low output impedance. The input tubes provide the voltage gain in this preamp, while the output tubes isolate the input tubes from both the equalization network and the external load, and they deliver a low output impedance.
The Unbalancer-Two circuit accepts a balanced input signal and delivers an unbalanced, single-ended output. Besides performing the conversion from balanced to unbalanced, the circuit provides a little gain (usually, about 1.7 or +4.6dB) and exhibits an exemplary CMRR (Common Mode Rejection Ratio) and low output impedance.