• WARNING: Tube/Valve amplifiers use potentially LETHAL HIGH VOLTAGES.
    Building, troubleshooting and testing of these amplifiers should only be
    performed by someone who is thoroughly familiar with
    the safety precautions around high voltages.

Poll..anyone interested in an Aikido linestage PCB group buy?

Aikido 9 pin board values

re: the resistors marked as 300E & 430E on the aikido B9A boards ... is this value regarded as definitive if building up the board using the valves specified? ie: 6N1P & 5687. ... these r not common values & there's not much room to be using resistors in series. Wouls 470 & 330 be close enuff/ ... anyone experimented here?
cheers .... cb
 
May I drop in? If yes, let me know wich ones are the first steps
Ofcourse you may drop in. Do you have experience with building tube /valve amplifiers? Then you probably know which tubes you like...and the next step it to choose the board that will fit those tubes. You have a lot of choice these days. You could choose John Broskie's PCB's or ours. If you are interested in our boards. Just send me an email.
 
Octal boards.

Hello Bas,
The boards have arrived.Excellent quality and smaller than I imagined which will make for a better install.I'm grateful to you for the time and effort you have given us all.It may be a while before I get the project finished due to my hectic work schedule but I'll keep you posted with my progress.
Regards, Si.
 
Aikido PSU V 1.0

Hi Bas.I'm starting with the power supply first and I have a couple of questions.I need a B+ of 300V so can you suggest a ballpark figure for C1. I assume that the 250V secondary winding shown on the schematic is ok for a B+ of 300V. As I'm using one psu board per octal board can I omit R2/C4 from each board or would you leave them in. With regard to the heater bias, I'm using 6SN7's and I believe the maximum voltage difference between cathode and heater is 200V.Can you suggest values for R4/R5 that will give the required bias. Finally the heater bias take off point on the diagram goes to the centre tap of the secondary winding for the heater filaments, and I'm going to leave the heaters running ac.The 6X5 will have it's own heater winding and doesn't need biasing.Does that sound ok?
Cheers Bas, Si.
 
Another Aikido hits the tracks.

Hi Bas--just to report successful building of an Aikido with your boards. I used ECC85's and ECC88's as their fil draw was all my PS could allow. Bigger PS next step! Really want to use 6CG7/5687. [ECC85 gives a bit much gain for a line stage.]

But using cathode R's as per board, with well filtered 275V B+, I plugged in some ordinary tubes and away it went, first time. Great on the bench--1dB down at 65khz, 3dB down at 360khz(?), flat to DC, almost! Good square waves etc delivers over 40V, goes pearshaped about 45V. DC fils means no hum.....

But the sound! Amazing improvements all round--even bass seems better articulated; this is replacing the Conrad Johnson PV8 line stage--no slug as a pre. Transparency is what it's all about.

My grateful thanks again, to you, Bas.
Regards,
Ken.
 
Bas Horneman said:

It is not finished yet...ask me whatever you would like to be put in there and I'll finish it.


:cop: Compromised URL removed by Moderation


Thanks, there were some threads about the power supply and how to make it; perhaps these could be added; and then the rest of the assembly?

Its really well written but just when I am getting into the story it ends! I don't want mine to end there!
 
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