Summary of Contents for Glass Ware Aikido Stereo 9-Pin PCB
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Page 1: User Guide
Aikido Stereo 9-Pin PCB Revision C USER GUIDE Introduction Overview Schematics Recommended Configurations Tube Lists Assembly Instructions 05/29/2008 GlassWare AUDIO DESIGN Copyright 2006-2008© All Rights Reserved... -
Page 2: Pcb Features
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 shut down. - Page 3 Making this mistake would be like thinking that the essential aspect of being a seeing-eye dog rested in being a Golden Lab.) The Aikido circuit sidesteps power supply noise by incorporating the noise into its normal operation. The improved PSRR advantage is important, for it greatly unburdens the power-supply.
- Page 4 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.
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Page 5: Heater Issues
PCB, as long as all the tubes used have 6.3V heaters (or 5V or 8V or 18V power supply can be used, if all the tubes share the same 5V or 8V or 18V heater voltage). Just use jumpers J1 and J4 only. Note: Perfectly good tubes with uncommon heater voltages can often be found at swap meets, eBay, and surplus stores for a few dollars each. -
Page 6: Power Supply
0.1µF 250V The power supply is external to the Aikido PCB and can be mounted in, or outside, the chassis that houses the PCB. The optimal power supply voltage depends on the tubes used. For example, 6GM8s (ECC86) can be used with a low 24V power supply, while 6FQ7s work better with a 250-300V B-plus voltage. -
Page 7: Tube Selection
GlassWare Audio Design 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). - Page 8 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 guidance on part values, look at the page 12, which lists several line-amplifier design examples.
- Page 9 C2’s position. Capacitor C3 can be bypassed by placing a small film capacitor across the leads of resistor R11. output Line Mute Headphones Switch Front Right HP Left Line Output Lt C2 Lt C1 J8 (& J9) Rt C1 Rt C2...
- Page 10 R16 = 100k *High-quality resistors essential in this position All resistors 1/2W or higher C1 = 47µF* Film for 300-ohm HP 470µF* for 32-ohm HP C2 = 0.47µF* Film or oil C3 = 10 - 1kµF, 10V Electrolytic "10 - 1kµF, 16V Electrolytic C5 = 1 - 10µF*...
- Page 11 GlassWare Audio Design...
- Page 12 GlassWare Audio Design...
- Page 13 10.4 20.3 91.8k 100k 23.1 27.3 1250 91.3k 100k 20.3 26.2 83.1k 100k 10.7 20.6 Output Output Zo Line Zo HP Gain in dBs Amp. 0.97 -0.24 0.97 -0.27 0.96 -0.32 0.96 -0.33 0.93 -0.59 0.93 -0.59 0.94 -0.56 0.94 -0.53...
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