Page 2 - GlassWare Audio Design; PCB Features; Redundant Solder Pads; This board holds two sets of differently-spaced solder pads; Dual Coupling Capacitors; The boards hold two coupling capacitors, each finding
GlassWare Audio Design Warning! This PCB is for use with a high-voltage power supply; thus, a real shock hazard exists. Once the power supply is attached, be cautious at all times. In fact, always assume that capacitors will have retained their charge even after the power supply is disconnected or s...
Page 3 - Aikido Amplifier; Introduction to the Aikido; tracks these voltage changes symmetrically.
GlassWare Audio Design 2 The Aikido amplifier delivers the sonic goods. It offers low distortion, low output impedance, a great PSRR figure, and feedback- free amplification. The secret to its superb performance— in spite not using global feedback— lies in its internal symmetry, which balances imper...
Page 4 - Switch Rear
Remember, tubes are not yardsticks that never change, being more like car tires— they wear out. Just as a tire’s weight and diameter decrease over time, so too the tube’s conductance. So the fresh 6DJ8 is not the same as that same 6DJ8 after 2,000 hours of use. But as long as the two triodes age in ...
Page 5 - Heater Issues; V Heater Power Supply; Although designed for a 12V power supply, a 6V heater; AC Heaters; Filament Jumper Wire Schedule
GlassWare Audio Design 4 Heater Issues The board assumes that a DC 12V power supply will be used for the heaters, so that 6.3V heater tubes (like the 6FQ7 and 6DJ8) or 12.6V tubes (like the 12AU7 or 12AX 7) can be used. Both types can be used exclusively, or simultaneously; for example 6GC7 for the ...
Page 6 - AC; Power Supply
GlassWare Audio Design 5 DC Heater PS 300k 2W 100k 1/2W B+ B+ 4 300k 2W 100k 1/2W B+ 0.1µF 250V 0.1µF 250V AC 100100 Alternatively, you might experiment with floating the heater power supply, by “grounding” the heater power supply via only a 0.1µF film or ceramic capacitor. The capacitor will charge...
Page 7 - Tube Selection; tubes can extend the useful life of the tubes.
GlassWare Audio Design 6 Jumper J7 connects the PCB’s ground to the chassis through the top centermost mounting hole. If you wish to float the chassis or capacitor couple the chassis to ground, then either leave jumper J7 out or replace it with a small- valued capacitor (0.01 to 0.1µF ). Warning: if...
Page 8 - Configuring the PCB as a Line Amplifier; Typical Part Values
GlassWare Audio Design 7 Configuring the PCB as a Line Amplifier The Aikido topology makes a perfect line amplifier, as it offers low distortion, low output impedance, and excellent power- supply noise rejection— all without a global feedback loop. The key points are not to use capacitor C3. For gui...
Page 9 - Configuring the PCB as a Headphone Amplifier; Switch Front
GlassWare Audio Design 8 High transconductance output tubes are best for driving headphones, for example, the 6DJ8, 6H30, 12BH7, and ECC99. A coupling capacitor of at least 33µF is required when driving 300- ohm headphones; 330µF for 32- ohm headphones. Use a high- quality, small- valued bypass capa...
Page 10 - Assembly; with the aid of standoffs), then all the other parts—; Let me know what you think
GlassWare Audio Design 9 Assembly Before soldering, be sure to clean both sides of the PCB with 90% isopropyl alcohol, wiping away all fingerprints. F irst, solder the shortest parts (usually the resistors) in place, then the next tallest parts, and then the next tallest... Make sure that both the s...
Page 11 - -Pin Aikido Schematic
GlassWare Audio Design R4 R2 in out R8 R11 9 9 8 7 6 3 2 1 R3 R9 R1 C11 R5 R6 R12 R13 R7 C2 C12 in 9 9 B+ C1 R14 R14 R13 C1 C2 out out out 3 2 1 6 7 8 1 3 2 2 1 3 6 7 8 R1 R3 C11 R2 R5 R7 R11 R8 R4 R6 R12 R15 C6 R16 C5 R9 R10 R10 V1 V2 V4 V3 9-Pin Aikido Schematic (Rev. C) C12 J7 6 7 8 C3 C3 J8 J8
Page 12 - Top Side PCB Mechanical Layout
GlassWare Audio Design 11 Top Side PCB Mechanical Layout 6 4 9 1 2 8 3 7 5 V1 5 7 3 8 2 1 9 4 6 V2 6 4 9 1 2 8 3 7 5 V3 5 7 3 8 2 1 9 4 6 V4 OVERALL PC BOARD DIMENSIONS: 4.00" x 10.0" 8 MOUNTING HOLE LOCATIONS 2.00" 2.75" 2.75" 2.00" .25" .25" .25" .50" 1.00&#...
