Which Aikido pre-amp PCB for a newbie?

[Brit01]

Maybe I'll have to choose the 9 pin Aikido kit then due to local market conditions.

Any advice regarding the rectifier on the power board?

Cheers

 

[regal]

I can't help there, probably best to stay to the design. Ebay should have the rectifier.

 

[kkwan18]

diyclub.com.uk

they got the LS-57(6X4,EL84,12AU7)powersuppy suitable for the 9pin Aikido preamps....

 

[Brit01]

diyclub.com.uk

they got the LS-57(6X4,EL84,12AU7)powersuppy suitable for the 9pin Aikido preamps....

I'm having difficulties locating it from this web site. Could you point me in the right direction?

p.s I've been offered a power supply board from a fellow member but this was originally for the 8 pin octal version.
Is the power supply board different for the 9 pin board??

Cheers

 

[kkwan18]

Choosing a 9 pin Aikido boards, you get lots more choose of valve combination, with 6.3v or 12.6v heater powersupply.

http://diyclub.biz/catalog/index.php?cPath=1_248_205_151_41_132

keith

 

[Brit01]

Hi Keith,

I would use this board with just the rectifier like 6X4 and use this to supply the Aikido board with the 12AX7 tubes?

I ask this because the board shown has places for the output valves EL84 and 12AU7.

This is a multi use board that can be used solely for power and for an integrated amp also?

As you can see I have a lot to learn here.

 

[kkwan18]

this ps board comes with 2X6.3(12.6 DCV) heater suppies, B+ 200 to 400DCV

 

[tinitus]

Thks Keith.

Seems to me that I'm going to need a lot of help here. I think the biggest challenge will be finding the parts down here in Uruguay. I could get my old folks to send them bit by bit from Birmingham.

Broskie sells board kits with all components

I think I would find a regulated power supply

 

[Brit01]

Broskie sells board kits with all components

The problem is customs in Uruguay. Anything over 50 bucks they hit you with taxes and broker fees tripling the price!!

The bare board from JB is under 50 bucks.

Can you give me an example of a regulated power supply?

Many thanks

 

[tinitus]

Cant you make Broskie ship in smaller bits or have him write value of 5o bucks
or have it shipped to your famely in UK, and they could send it to you

Regulated supply...im not so skilled and only know of THEL in Germany, and its a bit expencive

 

[kkwan18]

This board is use for power supply only, it provide 2 x 6.3DCV or 2 X 12.6DCV for heater , the B+ is from 200 to 400 DCV.

 

[Bas Horneman]

Hi Brit01,

Since you want to keep this whole project affordable. It would be best to build something like my simple power supply. You'll learn from it and will see that it is good enough. i.e. It is the type of psu you'll find in commercial gear as well.

Regulated power supplies can be better but not are not per definition better.

The nice thing about the Aikido is that you can start off with something like the 12AX7. And later stick in a more suitable tube.

Kind regards,
Bas

 

[Brit01]

Hi Bas,

I was in contact with Wendell a few times. He said he's got a power supply board to sell. Just following up with him to see if he still has it and it is suitable for the 9 pin board.

And later stick in a more suitable tube.

What are the downsides of the 12AX7 as you made the above quote?

Thanks

 

[Bas Horneman]

The 12AX7 is not perse a bad tube. I have not even ever used one myself. But it has a lot of gain so you'll hardly be able to use the volume knob.

And I've also read that it is not a great tube for the cathode follower position. (The second tube in the Aikido preamp is a cathode follower)

 

[Brit01]

ok that worries me now as i recently purchased a Carver power amp. Was planning to use the pre-amp with the Carver.

The Carver has huge amounts of power (375 watts per channel at 8 ohms) which I need to handle from the pre amp side. (currently using Carver CT-3 SS preamp).

Maybe the lower gain tubes, 6 series right?

 

[Bas Horneman]

The 6 series refers to the heater voltage. There is a lot of choice there so yes. I would say try the 6FQ7, 6GC7, 6DJ8 or 6N1P.

 

[Brit01]

Does JB Aikido ship to countries that are not on the drop down list on his website??

I've written to them a few times with no answer yet?

Want to know shipping costs to Uruguay. If that can't be done then UK will be ok.

 

[raypalmer]

Bas,

A question re your Aikido PS design:

Could you elaborate on "Value xx for c1 to arrive at correct b+"?? I catch your meaning, I just need help with the math. What value for C1 would be needed to run a 9-pin Aikido with 12v tubes?

 

[Brit01]

hi raypalmer,

Try the psudII software to simulate your B+ and ripple.

I built Bas's psu through trial and error but then downloaded this software just last week and it is superb.

I experimented with different Cap and Resistor sizes and it simulated a B+ of 228 V.

228 V was exactly what I got when I turned it on with only 20mV of ripple .

It will tell you what the max ratings are for the Tube rectifier. The 6X5 is easy to overload. 0.47uF for C1 gave me a reasonable B+.

I currently use a 6X5GT

Caps: 0.47/100/200
Resistors: 1K/500

load: 40mA
Tranny: 275V, 200mA, 51ohms(secondary windings)

 

[raypalmer]

hi raypalmer,

Try the psudII software to simulate your B+ and ripple.

I built Bas's psu through trial and error but then downloaded this software just last week and it is superb.

I experimented with different Cap and Resistor sizes and it simulated a B+ of 228 V.

228 V was exactly what I got when I turned it on with only 20mV of ripple .

It will tell you what the max ratings are for the Tube rectifier. The 6X5 is easy to overload. 0.47uF for C1 gave me a reasonable B+.

I currently use a 6X5GT

Caps: 0.47/100/200
Resistors: 1K/500

load: 40mA
Tranny: 275V, 200mA, 51ohms(secondary windings)

Thanks Muchly Brit


How do you find the ps's performance?