what 8-pin tubes would you suggest for an aikido preamp?

[jarthel]

as title. thank you

not sure if this is relevant but: as for operating B+ voltage and such, should I use the table provided my mr. broskie? (there's a table of listed tubes with different B+ and resistor values somewhere in the site)

thank you.

 

[Tweeker]

Source, available B+ and are you using his PCB? How much gain do you need? If you uss 2 of the same tube and wire yourself, heater to cathode insulation issues can be solved by cross coupling (the tops in one tube, the bottoms in the other) and higher voltages used. Many octal tubes would like more than 150V anode.

If using not his values some will have to be derived yourself, which shouldnt be too big a deal.

Blog 64 has the biggest table of values I found there.

 

[Tweeker]

An dual cross coupled Aikido example, from Sylvania 6SN7GTA data.

B+=517V, rk=1,100, r15=77.7k. Gives a current around 7.5ma. mu=19.5 and rp= 8,250ohms. V anode=250.

This gives a Zo of ~1,490 ohms and a gain of ~9.1. Very low distortion. Heaters floated at 30 and 280 volts.

 

[jarthel]

thank you