Aikido Tubes

[beau2317]

I would set it up to rectify the 300V. That will give you about 1.4 * 300 = 420VDC. Then you can drop about 120V using RC filtering, which will give you a very decent amount of filtering.

For example, let's say that your stereo line stage will take 20mA for both output tubes, and say 10mA for the input tubes. So then you will need a total R of 140/0.03 = 4k6. That will disspiate 140*0.03= 4.2 W

So you could have say 2 x 2k2 5W resistors, with a capacitor after each. The more RC stages you have the better the filtering. Be sure to bypass the last capacitor (the closest to the amp) with a smaller film cap.

That's how I would do it. But others might disagree (that's the great thing about this board....ask a question and get 4 replies

If you are using a stereo PCB then that only has one B+ input so there is no need to make separate supplies for each channel (even if you are using two mono boards). The aikido's high PSRR plus the fact that it draws pretty much a constant current means there is not much point anyway.

 

[SY]

This circuit likes high supply voltages. Because of the good supply rejection, the compromise on separation is not too bad, so that's where I'd work the trade-off.

 

[2KW]

Thanks guys for all your help. There is a lot of 'discussion' going about on the sonic impact of transistor based regulation vs passive regulation. What is the general consensus on this with the Akido?

I'll stop asking questions, and start with the building soon

Thanks again.

Paul.

 

[SY]

I don't know about a consensus but I've built two versions, one with passive CLC and one with a Maida-style regulator. I'd challenge anyone to hear a difference. The whole point of the design is to minimize PS impact, so it's not (IMO and IME) something to obsess over- layout and grounding are the most critical issues, other than tube choice.

 

[minhaj]

Dear Paul,

My reply to post 36
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I recommend 10 ma min. specially for your case. Tube life for ECC99 should be 5000 hrs with 300 volt B+. You may expect 10.000 hrs tube life with 6 volt CCS heater. Put a CMC between your filter caps, given other considerations have been considered you may expect very good sonic.

I have zero experience about ECC99 sonic though.

AIKIDO is a totem pole aka sea-show aka give and take circuit, you do not need regulated PS. Give it a tube rectified, specially for your case because your source is CDP, your amp is solid state and your speakers are party animals (I hope you do not mind), choke filtered passive supply, and enjoy.

Meanwhile I wait until one day you wake-up and get into TT + Tube SE + horn loaded single driver speakers.

Regards

 

[2KW]

Thanks minhaj, No offense taken on the speakers, they are party animals! Especially with a 600W/ch amp.

On the Aikido cct the output cap is a 47uF film cap. Excuse my ignorance, but what is a film cap? some type of electrolytic? Could I use two 100uF in series ( to make a non polarised ) I try to steer away from electrolytics in the signal path but what other options are there for 47uF/350V ??

 

[beau2317]

Normally the output cap on the aikido is 0.47uF not 47uF

A film cap is typically a polypropylene film such as an Auricap or Wima. Specifically not an electrolytic.

You can start of just by using a decent quality polyprop cap from your local electronics store, but spening money on this part is worth it.

 

[2KW]

Ok, discovered the 47uF is for when using as a headphone amp. I have a supplier for Auricap. They're expensive but.....

Thanks.

Paul.