View Full Version : modular sb3 psu ....project

2007-12-03, 06:09
These are the basic building blocks that you require…they are not set in stone so any item maybe swapped for an equivalent.

RS Stock no. 494-9072 Manufacturer OEP Manufact. part no. PS4009 18

RS Stock no. 500-6031 Manufacturer Schurter Manufact. part no. KMF1.1121.11 20

RS Stock no. 223-7888 Manufacturer Nuvotem Manufact. part no. 0050P1-2-009 15 2x 9v secondaries

The three components are wire as shown …

The iec filter feeds the transformer primaries and one set of secondaries feeds the rectifier and voltage regulator.

The dc cable is then attached to the dc output of this stage.

All cable joints need to be covered with heatshrink or second best electrical tape.

Using your digital multimeter connect the probes to the dc plug then measure the dc output using an insulated screw driver adjust the output to 5v dc leave for a while switched on and then recheck to see if the dc has drifted [the ones I’ve built have not]

The unit can be improved by removing the single resovoir cap and replacing with a bank of parallel caps or one big one ….I’m running 25000uf at 63v of Panasonic fc’s.

Also you can fit descrete diodes in place of the bridge ie 30dq10’s which seem to work rather well.

If you in any doubt about building this …don’t do it ! Mains voltages can kill you or your gear if you get it wrong ! These parts are designed for 230vac and if you need to build one for different mains voltages then you will need a different transformer.

the rather small pic shows the three elements and how there wired up ....the cable pairs of each connection should be twisted together but you have no idea how hard that is to draw!
the white square represents the torroidal transformer which has been lost somewhere along the way.

All you then need to build is a suitable case....

2007-12-05, 13:36
Hi Zanash,

I have built a PS for my SB3 by using the already built Power-One linear PS. I just replaced all the caps with BGs but the output caps I used 2x McIntosh 15000mF/63V and replaced the diodes with soft fast 8A Hexfreds. The sound is good but has thin sound and clean background compared to the Channel Island VDC-SB (this had been built very simple but it sounds excellent with thick, more resolution and musical sound).

Do you think that I should use the toroidal transformer instead of EI transformer for main one since toroid has more low noise than EI. I have strong believe that any audio components have a great to an excellent PS always makes your music sounds lively.


Deaf Cat
2007-12-05, 15:12
wow! you guys sound as if you know your electronics, change this change that hay presto! sounds easy :)

I built using this 173-1604 from RS, and found it a little bit taxing but quite enjoyable.

Do you guys think that there is anything obvious that could be changed to improve the thing?


2007-12-06, 03:31
I prefer schottky to hexafred.....

I bet the problem lies with the blackgates.....I've never felt they were quite right for me and tend to use silmics or stargets

what size [va] is the transformer ....you need a least 50va but 75 is better! if I could have afforded the 150va unit thats what i would have used.

2007-12-11, 09:33
I have an SB2. It has a switcher inside somewhere. I use only the digital section and tap off the signals before the dac chip. Does anyone know if this internal switcher powers anything other than the analog section? thanks

2007-12-28, 11:51
If you use only digital part of SB2 and you taped off the signals before the dac chip do you hear any big differences? Would you please provide pictures or just say in words where you taped off the signals? I would appreciate your time. Thanks.

2008-01-04, 09:03
sorry for the late reply. Here's the thread:


There's a link in post #7 of linked thread to detailed instructions. Please review the "requirements" tab if you plan to implement the reclocking board.