Thanks Kodabmx, I did. He hasn't replied. Will keep trying.
I have another of his preamp (Aikido Octal) in the same state and not sure if I should go ahead.
He's been quite busy lately, but he'll get to it eventually... Usually, I make the subject line "TUBES" so it stands out against all the spam.
one thing caught my attention, why acf2 between your amp and pre? Your pre can't drive the amp properly? One day will come you will get rid of the extra stages. You actually need your sources, source switching and your amp that's it.
Regards
Regards
Not doing small small half decent pre/ power etc you fix your pre for good. My suggestion for a ultimate pre will be dht tube loaded by line out transformer or parafeed output and pot in the input. Or direct input dht loaded with lineout transformer driving an AVC for volume control.
Regards
Regards
😀 Better late than never.
The problem has been fixed in the latest edition of the boards apparently.
The problem has been fixed in the latest edition of the boards apparently.
It's time to finally put my Octal ACF-2 to good use after leaving it part-finished for a number of years.I need to verify what I've already assembled and add the few required parts - the problem is I can't find the Octal version manual so I'm hoping for a little help.
I'll be using 6SN7s (well, actually 12SN7s). I plan to provide the tubes with +/-160VDC (i.e. after the power supply filters and noting the fix to the potential hum issue). Anyway, this post seems to have the parts list I need;
https://www.diyaudio.com/forums/tub...-aikido-octal-acf-2-buffer-4.html#post5705829
Does that look good?
I'll be using 6SN7s (well, actually 12SN7s). I plan to provide the tubes with +/-160VDC (i.e. after the power supply filters and noting the fix to the potential hum issue). Anyway, this post seems to have the parts list I need;
https://www.diyaudio.com/forums/tub...-aikido-octal-acf-2-buffer-4.html#post5705829
Does that look good?
That list worked for me. I ended with a 20K pot. Works well with my tube amps and a Sansui x701.
The gain on the pot is fine with Altecs. At 8' listening distance, 12 'o clock gets nice and loud, by 2 'o clock its roll 'n roll. Hope that helps.
The gain on the pot is fine with Altecs. At 8' listening distance, 12 'o clock gets nice and loud, by 2 'o clock its roll 'n roll. Hope that helps.
Thanks Sunil, I appreciate your reply.
Do you recall the B+/- voltage your using at the Aikido upper plate/lower cathode or are you able to confirm from your manual? I seem to recall that something in the region of +/-150VDC to +/-175VDC is about right.
I may use Medano's Muses based volume control or better still an Intect Audio autoformer volume control.
Cheers.
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How was your All-in-One (Octal)? I haven't built mine yet 😀 Just fixed other 2 tube amps. Maybe start it sometimes in Dec. when I take a month off.
Nautibuoy - The 20K pot is for the Aikido - All-in-one (Preamp with Tube PS). Just realized I replied to your ACF-2 question about the volume control. 😱
My ACF-2 (Buffer with Tube PS) was ~ 130v. Its best to read John's document and work it out. The buffer was made for the 4S preamp and works prefectly.
My ACF-2 (Buffer with Tube PS) was ~ 130v. Its best to read John's document and work it out. The buffer was made for the 4S preamp and works prefectly.
Great experience learning the basics and superb performance. Its dead quiet with Altec 604e which are ~ 100dB. I also got a 3KV stabilizer with built-in RFI filter 😀
Aikido Octal in a chassis finally !
Fired this up last year on a bare board. Finally got the chassis delivered in July. Up last Sunday.
Sounds just the same, ridiculous. Its been running a 300b (Tubelab) till now whose sound I really like.
I fired up a Tubelab 2A3 today and its got new company 🙂
Fired this up last year on a bare board. Finally got the chassis delivered in July. Up last Sunday.
Sounds just the same, ridiculous. Its been running a 300b (Tubelab) till now whose sound I really like.
I fired up a Tubelab 2A3 today and its got new company 🙂
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Too hot in garage so I am not doing anything at the moment. What is the voltage before R12 without tubes? Mine is 390vdc so still figure out what R12 needs to drop to 280vdc
So R12 for me reads 306 and 296v with 440R. I think the design shows 4K /6K, isn't it ? If I remember right, they were biased ~ 9ma, I used that to get at 440R.
They do get hot, so I used 2W resistors. Ok so far ~ 1000hrs +
They do get hot, so I used 2W resistors. Ok so far ~ 1000hrs +
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Great. I am working on the old box of satellite chassis so it will be less drilling. Anyway, I couldn't wait so took a few hours last night to to figure out.
It's depend on the PT, mine is 280AC@90mA so before R12 is 390vdc without load. 78vdc drop needs for 4 tubes. R12 at 130r is 285v so I decide to use 100r/3w for around 287v since I have many around. Whatever value in the table is hard to predict until you try couple to find out. I ordered 1k, 2k, 3k, didn't realize it ended up around 100r-130r ...lol... I think between 280v-300v is good. Doe it sound like $5k like someone mention? 🙂 I am gonna hook up later to see what the sound like.
Another stupid issue is tube sockets. It's hard to push down other brands such as OTK 6n8s except Tung-Sol 6SN7. That's the max I can push it down. When I compared the pins between Tung-Sol, it's a little bit bigger than Tung-Sol.
It's depend on the PT, mine is 280AC@90mA so before R12 is 390vdc without load. 78vdc drop needs for 4 tubes. R12 at 130r is 285v so I decide to use 100r/3w for around 287v since I have many around. Whatever value in the table is hard to predict until you try couple to find out. I ordered 1k, 2k, 3k, didn't realize it ended up around 100r-130r ...lol... I think between 280v-300v is good. Doe it sound like $5k like someone mention? 🙂 I am gonna hook up later to see what the sound like.
Another stupid issue is tube sockets. It's hard to push down other brands such as OTK 6n8s except Tung-Sol 6SN7. That's the max I can push it down. When I compared the pins between Tung-Sol, it's a little bit bigger than Tung-Sol.
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