Sjöström Audio DIY forum

Projects => Power supplies => Topic started by: framos on March 18, 2011, 03:02:17 AM

Title: SST02 and DCT02 questions
Post by: framos on March 18, 2011, 03:02:17 AM
I bought both pcbs and was going to start building the two when I came across this quote in the build (which I missed initially when I read) "pcb is not tested yet for 110-120 VAC".  I'm in the US, and we run 115VAC, so I cannot use it here?

I then realized that the DCT02 is also made for 230VAC.

This means I cannot use either with 115VAC?  If I can use them:

1) How do I wire the DCT02 for 115vc input?

2) Can I use the SST02 without any changes to the BOM?  How do I wire it from the 115VAC input?

Thanks.
Title: Re: SST02 and DCT02 questions
Post by: peranders on March 18, 2011, 06:17:21 AM
DCT02
If you read what I have written... Yes 0-240 VAC. It's about current, not voltage.
http://sjostromaudio.com/pages/hifi-projects/36/109-dct02-the-dc-trap-high-end-style?start=6

SST02
If you read what I have written... Yes, change C1 and C2.
http://sjostromaudio.com/pages/hifi-projects/36/108-sst02-softstart-for-toroid-transformers?start=2
http://sjostromaudio.com/pages/hifi-projects/36/108-sst02-softstart-for-toroid-transformers?start=5
Title: Re: SST02 and DCT02 questions
Post by: framos on March 18, 2011, 03:42:24 PM
Sorry PA, at my level of understanding of these things, reading is not equal to understanding.  I read both several times, I still don't know how to wire it...
I guess you can consider this your online tutorial or FAQ on "wiring the soft start and dc trap for dummies".

So I do this chain:

mains -> SST02 -> DCT02 -> Toroidal transformer -> power supply -> amp board,

My mains are three wires, ACL, ACN and ground.

mains -> SST02 wiring:

ACL -> SST02's mains-in L
ACN -> SST02's mains-in NC or N?  I did read the related threads in the forum but still not sure...
ground -> ?

My IEC has an on/off switch integrated into it, so I don't use the SST02's "switch" connector?

SST02's out would then only have L and (NC or N) depending on which one I used above?

I have a LED for the amp board's power-up, should I add a second led to know the SST02 is working and wire it to the "LED" connector of the SST02?

SST02 -> DCT02 wiring:

There's four connectors on the DCT02, I have three coming out of the SST02, L, N, NC or two if I only use one of (NC or N).

SST02 L ->  DCT02 Phase in
SST02 N or NC -> DCT02 Neutral
IEC ground -> Protective earth ?

DCT02 -> toroidal connection:

DCT02 phase out -> toroidal's ACL input
toroidal's ACN input is taken straight from SST02's NC or N out?

The SST02's NC or N connection does not run through the DCT02?

DCT02 is not grounded to the IEC's ground?

I understood the part on the  SST02 needing different capacitors for 110-120AC, but the "not tested" part.  To you it's probably in the context of "it's a tested design, it will work with the appropriate capacitors, it's just that no customers of mine have used one on 115AC".  To me "not tested" is in the context of "you go to the doctor for a cure for your illness and he gives you a drug prescription, which he immediately states that it has been tested on rats and it worked, but it hasn't been tested on humans yet, but go ahead and start taking it anyway".  Since I don't know what I'm doing here, I just wanted to verify that "not tested" is to be taken in your context and not mine.



Title: Re: SST02 and DCT02 questions
Post by: framos on March 18, 2011, 05:11:23 PM
Will this work as a cap for 110-120VAC:

http://www.newark.com/vishay-roederstein/f1772468-2000/capacitor-polyester-0-68uf-275v/dp/95F9074

Also, this is a lot longer than what it replaces, I don't think it will fit with the X4 connector in place.  If I'm ont using an LED with the SST01, can I skip installer the connector in X4 to get more room for the capacitors?

Thanks again.
Title: Re: SST02 and DCT02 questions
Post by: peranders on March 18, 2011, 07:43:38 PM
Quote from: framos on March 18, 2011, 03:42:24 PM

mains -> SST02 -> DCT02 -> Toroidal transformer -> power supply -> amp board,
Correct

Quote from: framos on March 18, 2011, 03:42:24 PM

ACL -> SST02's mains-in L
ACN -> SST02's mains-in NC or N?  I did read the related threads in the forum but still not sure...
ground -> ?
As I write the SST01 needs only LIVE and NEUTRAL to work and the ground connection is only a joint for incoming ground and further but if you have a power inlet I'll guess you already have grounded the enclosure. NC means Not Connected I used a 3-pole terminal in order to get creapage distance with 5 mm terminals.
Title: Re: SST02 and DCT02 questions
Post by: peranders on March 18, 2011, 07:51:09 PM
Quote from: framos on March 18, 2011, 05:11:23 PM
Will this work as a cap for 110-120VAC:

http://www.newark.com/vishay-roederstein/f1772468-2000/capacitor-polyester-0-68uf-275v/dp/95F9074

Also, this is a lot longer than what it replaces, I don't think it will fit with the X4 connector in place.  If I'm ont using an LED with the SST01, can I skip installer the connector in X4 to get more room for the capacitors?
I think you should turn them 90 degrees vertically and let one pin go into the pcb and the other via a wire to the pcb.
Title: Re: SST02 and DCT02 questions
Post by: framos on March 23, 2011, 12:18:05 AM
I found this one at digikey, it's roughly the same size as the original in the BOM, will this one work for 115vdc:

http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail&name=495-2323-ND

Thanks.
Title: Re: SST02 and DCT02 questions
Post by: peranders on March 23, 2011, 06:18:01 AM
They are OK.
Title: Re: SST02 and DCT02 questions
Post by: framos on March 28, 2011, 04:06:45 AM
 I started putting together the SST02.  I purchased the materials from the SST01 BOM, as there was no SST02 BOM that I could find.  I'm putting the diodes in an just realized that there is no reference to D5 in the schematic or BOM of the SST01.  The project article for the SST02 has a low-res diagram that seems to have D5, but I can't read what the value should be.  Did I miss something where  D5 is  mentioned in the documentation for SST01 or did I miss the location of the SST02 diagram/BOM?

Thanks again
Title: Re: SST02 and DCT02 questions
Post by: peranders on March 28, 2011, 09:08:25 PM
The documentations hasn't been uploaded yet. See email.
Title: Re: SST02 and DCT02 questions
Post by: framos on March 29, 2011, 02:43:16 AM
Thanks, got the email.  Since I purchased using the SST01 BOM, I have this for R1, is this ok or should I get the 7 watt one?

http://www.newark.com/vishay-draloric/ac05000001000jac00/resistor-wirewound-100ohm-5w-5/dp/01H0163?Ntt=01H0163
Title: Re: SST02 and DCT02 questions
Post by: peranders on March 29, 2011, 06:39:18 AM
4-5 Watt works for most situations.