Choke Tuning Advice Pleas

[colin.hepburn]

Choke tuning Advice Pleas
I have just built my new external PSU for my headphone Amp
CLCRCR
It’s built from 630volt solen Polypropylene Caps and Mills Resistors
With the help of Nick G and Steve

It is working grate now the Sound difference with this PSU is nothing more than jaw dropping
I am interested to now more about choke tuning i.e. what type and value of caps to use and if this PSU can be improved even more
The PSU and Headphone Schematic can been seen @
http://uk.msnusers.com/MyAudioPics/shoebox.msnw

[BOONDI]

Hi Colin, can't see the choke on the schematic m8, but here's a very rough formula for you....

divide 1.7 by the inductance of the choke in henries to find the capacitor needed in uF.

e.g. with a choke of 8H you would need 1.7/8 = 0.2125 uF.

so use a 0.2uf or 0.22uf. these can then be bypassed using a cap of 1/100 the value......e.g. 0.22uf bypassed by 0.22nf.

As they are small value, you can go for polyprops or black gates etc.....

Regards......Derek....

[colin.hepburn]

Hi BoonDI
Thanks for the reply
the PSU is hear
http://uk.msnusers.com/MyAudioPics/s...hoto&PhotoID=8

[BOONDI]

Ah I see said the blind man.....

So for 30H you should start at 56nF or the closest value. The only way to tell if you have the value right is to check the output with a scope, or extended listening tests, as the 1.7 bit is only an approximation. It should get you near enough tho....

Best....Derek.

[colin.hepburn]

As i have built my Psu Unit With 630volt solen Polypropylene cap would there be Any advantage adding bypass cap to it

[BOONDI]

Probably not Colin....... we are only trying to kill the 100Hz hum.....

[colin.hepburn]

Hi Boondi
Thanks
Don't have a scope so will be doing a lot of listening i will try some cap ether side of the 56nf and see

[colin.hepburn]

That the good thing there is no hum what so ever on the PSU

[BOONDI]

Originally Posted by colin.hepburn2

That the good thing there is no hum what so ever on the PSU

What do you mean Colin, that there is no hum before putting the cap across the choke?

or

The cap has cured the hum completely???

[colin.hepburn]

yes i have not add caps to the choke there is no hum /buzz just inky black silence i am still not sure what all the numbers mean in Duncan's PSU designer really mean