• 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?

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#343
Bas, I'm in the process of sourcing components for the amp, and was wondering about your choice of cathode resistors(430ohm).
Any reason why you chose 1w wirewound?
As far as I can see only 3mA runs through them, or am I wrong?
Any reason not to use carbon composite for the cathode resistors too?

thanks
Svein
 
#348
Nice

Hey, i really like the picture on page 1 of the preliminary manual. Bas, you are great, if I knew how to use a tube I'd go with all your stuff! I don't see anything in there about which pin on the tube is which, guess I'll have to figure that out.....
 
#356
WRL, there is a simple trick with express PCB.

They give you dots and a dark background to prevent you making the PCB's yourself when you print.
You can print the layout and then photocopy and tone down the contrast, the darkness in the background is gone completely and the tracks are still easily dark enough to make a pcb from.

The only catch is you still get the dots, they are quite spaced out though and small enough to just tippex out if they are impeding your layout.
I layed out a Quad 405-2 with the current limiting circuits on PCB with this program, it is very easy to use. 😉

Craig
 
#357
Ok..everyone who has paid, has had their boards shipped, and should have been notified. Please mail me if that is not the case.

Peter Menting's boards will ship today.

But I have plenty boards left. So I'd like everyone who has given up their name (as noted a few posts ago) to tell me if they still want the boards. Otherwise the boards will be sold to the folks that gave up their names in the 2nd group buy.
 
#358
hi bas, if at all possible, i'd like to purchase a pair of the akido boards, if any are left. let me know and and where to send funds

also thanks for previous suggestions given to me on another thread. i wound up refering my aikido ac filaments to @ 60v to split the diff. between top and bottom triodes, did some grounding changes and swapped the 100k safeties with 1m.

almost all noise is gone! a little residual tube hiss can be heard close to speaker.....

however i have another problem, which is fluctuating DC on out puts!? i noticed this because my amps have ma meters and they wiggle when aikido is hooked up(otherwise i would not have noticed so soon)-i got DC readings of 1mv to like 40mvs and infrequently a little more, negative readings as well that seem to mirror the + readings . these readings are with preamp warmed up. they seem to oscillate steadily up and down-anyone have enlightenment on this type of problem-!?

thanks! charlie
 
#359
Yeah, that software is kind of a pain. But if you want to get rid of the dots... just change the background to white and the traces to black... Then screen capture and resize in word or some other image editor. Despite this, the netlist function is incredibly useful.

-Wes
 
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