In fact, a bigger difference than might be expect in normal tube gear. One inductor and one extra capacitor added to the simple power supply will make a big difference in performance. I have found that just about any choke, of any inductance or DCR, is better than not using a choke in a power supply, even if that power supply terminates in a voltage regulator. For example, chokes perform wonders in stripping away power supply blemishes. Even if the power supply isn’t regulated, a few small tricks will deliver big sonic gains. For although the Aikido boasts an excellent PSSR figure, I don’t want to tax it any more than necessary. However, I would prefer to be a bit more nervous. Thus, with an ECC86 and resistor R15 equals 100k, R16 equals 129k. However, those who have used the 6GM8 before tell me that it a clean-sounding triode.Īll that remains is to calculate the Aikido power-supply noise voltage divider resistor values. I cannot measure the distortion, as I have not assembled my unit yet. The output impedance will be less than 600 ohms. The total gain of a 6GM8-based Aikido line amplifier will be close to +15dB, which should work handsomely in most systems. In other words, although a line amplifier may not be voltage limit, it may current limited.) A low-output impedance is nice, but without the ability to deliver current into a capacitance-laden load, it is not enough. The faster you want to charge a capacitance, the more current you will need. (Driving capacitance at fast slew rates requires current. Nevertheless, as long as short, low-capacitance interconnects are driven, the bandwidth should not suffer too greatly.
It is about one fifth of the minimum I like to use in a line amplifier. Or does it? After staring at the heater schematic, I saw how the PCB could be used without any cutting of traces, although a few import details must be observed. However, the 9-pin Aikido PCB only allows the four tubes’ heaters to be wired in parallel or two heaters in series, but not all heaters in series.
24 VOLT TRANSFORMER RADIO SHACK SERIES
This bothered me, as all four heaters in series would require 25.2 volts, which would also work as the B+ voltage, so why not one power supply? Surely, one power supply voltage is easier to accomplish than two. Thus, I would need to supply 24 volts and 6.3 volts or 12.6 volts. Fortunately, it shares the same pinout as the 6DJ8/6922, so using it with the 9-pin Aikido PCB is no problem.Īt first, I planned to use two power supplies for the 6GM8-based Aikido: one for the heaters and one for the Aikido amplifier’s B+. Additionally, like the 6DJ8/6922 this little triode stows a grid frame, making it doubly rare. Unlike most triodes, it works quite well with only 12 volts on its plate. The 6Gm8/6N27P/ECC86 dual triode was designed to be used as an RF amplifier and as a self-oscillator mixer in a car radio, back when car radios held tubes.
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