Aikido and Tetra Phono-Stage PCBs and Kits

Phono Preamps
Despite predictions to the contrary, spinning black vinyl by the warm glow of vacuum tubes persists. In spite of the popularly-held belief that both LPs and tubes are dead, long dead—most believe that the vacuum tube died about 50 years ago and that the LP record died 25 years ago at the birth of the CD—both tubes and LPs grow more popular with each coming day. Tubes refuse to fade to black and solid-state audio gear is still embarrassingly being advertised as sounding tube-like; and Marantz once again sells turntables and new records are pressed daily.

Adding the Aikido topology to a phono preamp makes perfect sense. The Aikido’s low distortion, noise, and output impedance, without the use of negative feedback—all are desirable attributes in a phono preamp.

The Tetra phono stage combines the Aikido-All-in-One's power supply with the CCDA topology, a combination that allows an excellent tube phono stage to be made easily and inexpensively. The Tetra uses only four tubes, not the eight tubes that the Aikido phono stage requires. And it holds two power supplies, one for the high-voltage B+ and a low-voltage regulated power supply for the heaters. The high-voltage power supply is unregulated, but uses cascading RC filters to smooth away ripple. Of course, the power supplies require an external power transformer(s) with two secondary windings, one high voltage for the B+ voltage and one low-voltage for the heaters.

Tetra Sans PS & User Guide
The Tetra Sans PS phono stage uses two tube-based gain stages with a passive equalization network in between. The gain stage's topology is the Constant-Current-Draw Amplifier [CCDA], whose low distortion, fairly high gain, and low output impedance are desirable attributes in a phono preamp. The CCDA is a compound circuit that holds a grounded-cathode amplifier directly cascaded into a cathode follower. So what; what's so special about this obvious pairing? Its special status lies in the details.
$49.00
Tetra Phono Preamp PCB and Custom Kit
Combining the Aikido All-in-One power supply with the CCDA topology allows an excellent tube phono stage to be made easily and inexpensively. The CCDA’s low distortion and output impedance, without the use of negative feedback—all are desirable attributes in a phono preamp.
$49.00
Aikido Phono Preamp Kit
The Aikido phono stage requires a lot of parts, many sockets, resistors, and capacitors. Thus, this kits includes every thing needed to populate the PH-1 PCB, except the eight tubes.
$149.00
Blank Aikido Phono-Preamp PCB
Aikido phono preamp printed circuit board: This FR-4 PCB is extra thick, 0.094 inches (inserting and pulling tubes from their sockets won’t bend or break this board), double-sided, with plated-through 2oz copper traces, and the boards are meticulously and expensively made in the USA. PCB include 12-page user guide booklet.

$59.00