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    Building, troubleshooting and testing of these amplifiers should only be
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Glassware Aikido All-in-One (Octal) | ACF-2 Buffer

Hi,

I've got John's boards for the Aikido Octal (Oct 2018 design) linestage and ACF-2 buffer and while going through the design /parts realized all is not as it seems.

There are lots of errors in the documentation, not to mention missing part values and duplicates. I was wondering if somebody has already built the new 2018 boards ? Some help would be nice. Thanks.

Regards.
 
I can't speak to the ACF-2 specifically, but the Tetra Phono I built recently had a few resistors supplied that were different values than specified in the manual. It seems that Broskie is always tweaking the circuit values and this isn't always reflected in the manual.

Broskie sometimes forgets parts. Once he forgot the circuit board on one of my orders but after a few emails with "AIKIDO, UREGNT PCB MISSING" in the subject line he sent the board and his apologies.

Steve
 
Here is my part list for Aikido All-in-One version E: I have mentioned to him in September. I thought he would update :D

Here is my part list. Anyway, I use different PT, Edcor XPWR064 so my R12 wpuld be around 6.8K or 7K to get down to 300V with 5AR4. If you use Hammond 6K56VG as in the manual and 5Y3 then R12 can be around 100 to 1k ohm, I think 470 or 680 is perfect

I got my part arrived few days ago but may not start yet. If you question any part, let me know.

Mouser Electronics

Btw, that part list is for 6SN7. If you use different tubes, use the parts in manual to change. Ignore missing R or C, or extra parts in manual. For coupling cap C7, 1uF/630V should be fine. I ordered Jantzen 0518 1.0uF Z-Superior Capacitor to see how it sounds.

C6: The higher the capacitance, the lower the noise. That's why I get 10uF/500V

I like his PCBs but I don't know if I would buy again or not. Seem like all his manuals are missing something. And take a long time to figure out. It's not something that you can put together in a day and expect to work perfect.
 
Thanks Steve.

Hi Alashikata, I'm using the 6SN7s as well. Thanks for the list, will compare with mine.

I'm good now. Thank you.

My parts list was similar except for:
C18 3300uf /25v
C19 0.1uf /250

Can you help understand how these values came about? For C6 I was going to use 1uf PIO (K40-Y9). You've got 10uf - why, how?

Regards,
Sunil
 
At first, I was thinking the same as you. However, after compared Version A-C vs Version E, the design a little bit different by using the big Polypropylene (PP) cap. I saw a lot people using between 0.47uF to 0.8uF for C7 with version A-C.

Few parts may not show, that means I ordered from somewhere else
C7 = [FONT=Open-sans, sans-serif]Capacitor Jantzen Superior Z-Cap MKP 800 VDC 1.0 uF[/FONT]
I ordered directly from this store
https://www.audiohobby.eu/en/219-capacitors
 
R14 = 100K for Aikido Octal Stereo PCB - for Line Amplifier
R14 = 10 ohm for Aikido Octal All-in-One (Power Supply) - Look at page 10 House Ground

Better to read the manual at least 2 times or more. I've been reading over 5 times. You will find everything you need in there. Whatever the manual is, it's too general. If you don't skip any page in the manual you would be able to figure out all the parts. Pay attention on all the figures, only use the value that list on your PCB, not everything in the manual.
 
Thanks. This is ridiculous for a DIY'er.

I have to figure the same for the ACF-2 now..:eek:

Alashikata, thanks for the help with the Aikido All-in-One. I'll be starting the build soon.

Could somebody with ACF-2 (Cathode follower) experience help with

C3 (220-1000uf@16v) ?
C6 (22uf@400v) ?

From what I can see, C3 is in series with Pin7 of the heaters and C6 in parallel with C5 & C4. Is this right ? Will these values work ?
 
This is the reason I don't know if I ever buy his products again. At least, he should give a set of value that know to work properly then other options for people to play around. I believe all his manuals are like that.

I guess this is for experts than a regular DIY that has all the measurement and testing equipment. I don't have any testing equipment so I am doing the guessing only. Anyone doesn't have electronic skills, then this is not for them.
 
Aikido ACF-2

So, I've got this going. The board is populated, with both PS supply. The heaters are running at 5.95 /6.12V. The HT at the pins is 132V.

The tubes are 6SN7 - RCA Smoked Glass (Grey'ish). I'm also confused about the output cap C1. Thinking of 0.22uF (K40-Y9), since I have a pair.

Are these numbers fine ?
 
It depends....

It depends on the input impedance of the next stage. If it's low, 10K or lower, the low frequencies might roll-off too soon. If it's say, 100K or higher you might be OK. Try it and see.
The Broskie boards being very thick, makes it difficult to remove parts once installed. See picture, you might want to try this trick with the O/P caps that I used on Tetra phono board resistors. Just in case you want to change them out for larger ones later.

Steve
 

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The heater AC is 12-0-12 and HT is 130-0-130. R4 & R7 are 4.7K.

I was trying to keep the current between 8 & 10ma. Is that right ? Good /bad ?

I have a few amps (SS) and tube. The SS are all 50K input impedance.

Sansui999 /Sansui 9500 /Sansui D907 /Kenwood L-05 /Nakamichi PA-07 /Krell KST100

Brook 12A Clone
Elekit 8200
J.E Labs 2A3 S.E

Would 0.22uF be ok here. Not planning on any more SS, maybe a few more tube projects.
 
The Elekit amps are in essence power amps with a volume control at the input. Their gain is usually quite high so they can be used directly with a high level source. If you have the situation where you are using them at the bottom of the volume pot range then by inserting a resistor shown at the red X on the attachment you can get a more useful range on the volume pot and increase the input impedance.
 

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Ok, got it. The Elekit has worked well so far with various preamps, the vol. at 12 'o clock.

Should I just go with 1uf. Damn, this is hard to decide...

John B has a note on how to decide this. Going with 50k input imp. and a corner frequency of 3.18hz, 1uF will be fine.

I've got two pre-outs on the chassis. Can I hook up direct, in parallel from the board.