Aikido power supply

david C · Post by **david C** » Wed Sep 05, 2007 9:09 pm

now that I've got my TVC working I'd like to have a go at building an Aikido pre,

I can't see a problem with the Aikido but I don't know where to start with the power supply, I've got a 350-0-350 tx and I need 220vDC B+

I'd love some help

thanks

Post by **Nick** » Wed Sep 05, 2007 10:58 pm

Which aikido setup are you going to use that will need 220v?

I might be better trying to get a setup that needs about 300v with that transformer.

220v doesn't seem much for an aikido, 100v per valve.

david C · Post by **david C** » Wed Sep 05, 2007 11:08 pm

I read the B+ off the schematic,

so you view is not to play around trying to reduce the voltage but to start with a smaller tx,

I really would like to understand how a ps goes together

pre65 · Post by **pre65** » Wed Sep 05, 2007 11:12 pm

Hi David-the circuit i am using for the PT15 power supply is based on a Rankin amp using a 350-0-350 with a GZ34-20uf-14H-10uf and gives about 450v ht !!!

Can you link to the pre amp circuit you are considering ?

Post by **Nick** » Wed Sep 05, 2007 11:13 pm

Well, its only my bias, but the idea of increasing the source impedance of a power supply by adding resistance to burn voltage seems a mistake.

Why not use a 6n6p version, that would be happy with about 300v ish B+

The other option is get one of the little TX's that maplin did, that will give you 250v to play with. The other option is a pair of back to back TX's, take the heater supply from between the two TX's and the B+ from the final voltage from the primary (as was) of the second TX.

david C · Post by **david C** » Wed Sep 05, 2007 11:18 pm

thanks Nick
is that using toroidals like you did in your phono amp?

pre65 · Post by **pre65** » Wed Sep 05, 2007 11:19 pm

Hi David-have you got the Duncan Amps "PSU designer" program on your computer ?

If not,download it and get to understand it.

I don't pretend to fully understand it but it is a very useful tool.

david C · Post by **david C** » Wed Sep 05, 2007 11:23 pm

yeah Philip I've got it, I just don't understand it or how to make it work:(

simon · Post by **simon** » Wed Sep 05, 2007 11:56 pm

No time now David, but I have that exact same circuit as the Aikido in my phono, except for 6N6Ps instead of 5687s, and I've been running it with an HT of 250V to 280V without any problems so far.

There was a thread of mine at t'other place which discusses PSUD (and other things I seem to remember...). Don't know if you've read it but it may help.

http://wduk.worldomain.net/forum/showthread.php?t=2072

I'm not exactly the most qualified to help, but I'll have a go tomorrow if I can.

colin.hepburn · Post by **colin.hepburn** » Wed Sep 05, 2007 11:58 pm

david C wrote:yeah Philip I've got it, I just don't understand it or how to make it work:(

Hi Dave
Beginners guide to Duncan’s PSU II Designer
Click this link http://www.dhtrob.com/overige/updates_en.htm tip and tricks first link top of page this may help you with Duncan’s PSU II

Post by **Nick** » Thu Sep 06, 2007 7:33 am

Yes, like I did in the phono.

Remember you can also use the two TX's back to back to provide a stepdown. A 230:9 to a 12:230 for example, would give something like 150v. Bridge rect and cap from that would give something like 210v

Use tx's with two secondaries, and connect them together (tx to tx), then use the two 9v middle voltages to supply two 6.3 regulators for the heaters.

Andrew · Post by **Andrew** » Thu Sep 06, 2007 8:08 am

Nick wrote:Well, its only my bias, but the idea of increasing the source impedance of a power supply by adding resistance to burn voltage seems a mistake.

I would agree, unless its a lash up to try something out, and then a variac seems a better solution for prototyping.

I would also avoid multiple LC combo's and go for LCRC etc.

cheers,

-- Andrew

shaun · Post by **shaun** » Thu Sep 06, 2007 12:07 pm

hi dave

i'm using the aikido circuit you've posted but with 6n6p on the o\p with 220v B+. mine uses a series regulated psu and sounds pretty good in my set up.

you could try your 350-350v tx into a valve rectifier (gz34) into a choke and cap for a raw B+ of 300v then a steve bench style series reg. its what i have and works well.

take care

shaun

Post by **Nick** » Thu Sep 06, 2007 12:10 pm

you could try your 350-350v tx into a valve rectifier (gz34) into a choke and cap for a raw B+ of 300v then a steve bensch style series reg. its what i have and works well.

Yes, I would agree, that would be my preference, but I was staying on the simple side in my earlier suggestions

david C · Post by **david C** » Thu Sep 06, 2007 4:17 pm

so if I could get my head round the Steve Bensch series regulator and using 6n6ps in the Aikido I could have quite a good pre amp,

how do I find out about the series regulator?

thanks everybody*

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