DIY power supply for squeeze box

tanchiro58 · « **on:** 6 Apr 2007, 06:33 pm »

Hi Robert,

Why don't you purchase a brand new or an used SB3 and do some modifications by yourself like I did. In my opinion and my taste this type of modification can be compared as better than the one of RWA and/or Bolder Cable. I also did listen to analog mod of RWA and digital mod of Bolder Cable but I like very much Gary's modification by swapping the two tiny inductors at the coaxial digital part with a little transformer 1:1 ratio (bought at Scientific Conversions model # SC947-02) to lower the noise.

Good luck.

Regards,
Tan

robert1325 · « **Reply #1 on:** 6 Apr 2007, 06:55 pm »

Hi, thanks for the suggestion... do you have a link to some instructions?

This squeezebox is for my dad, he wants to replace his now sold Wadia CDP for a good squeezebox ( analog or digital with DAC)

crooner · « **Reply #2 on:** 7 Apr 2007, 01:01 am »

I'd love to see a link as well.
I'm considering Bolder's digital mod for my SB3, but I'm willing to heat up my soldering iron and do the mods myself.

Tan, did you replace the stock RCA jack for the coax out?

tanchiro58 · « **Reply #3 on:** 7 Apr 2007, 02:04 am »

Quote from: crooner on 7 Apr 2007, 01:01 am

I'd love to see a link as well.
I'm considering Bolder's digital mod for my SB3, but I'm willing to heat up my soldering iron and do the mods myself.

Tan, did you replace the stock RCA jack for the coax out?

Crooner,

Yes I did replace the stock RCA with a BNC (I will do a silver plated RCA to my other SB3).
First you need to order the SC947-02 transformer from Jon Paul at www.scientificconversion.com and find yourself either best quality RCA or BNC connectors www.digikey.com. When are you ready PM me and I will guide you step by step to mod your digital SB3. By the way you also need some of the 22-24ga copper silver plated wire too.

crooner · « **Reply #4 on:** 7 Apr 2007, 02:37 am »

Tan:
Thanks for your reply!

Looks fairly easy to get that transformer in there. Is the $100 minimum order still required?

What's the best source for the silver wire?

I really like the WBT 75 ohm RCA Bolder uses, even though a cheaper one will probably do...

I will PM you as soon as I'm ready to tackle the mod!!

Thanks again,
crooner

crooner · « **Reply #5 on:** 7 Apr 2007, 02:40 am »

oh, and did you replace any other components in the digital output signal path?

Bolder uses Black Gate NXs....

tanchiro58 · « **Reply #6 on:** 7 Apr 2007, 03:07 am »

Quote from: crooner on 7 Apr 2007, 02:40 am

oh, and did you replace any other components in the digital output signal path?

Bolder uses Black Gate NXs....

SC947-02 is the only one component to replace the two tiny inductors L8 and L9 right before the digital ouput. A transformer costs only $16.00 each plus shipping from Jon Paul in CA. I do not suggest to replace the transistors with BG NXs in digital path since there is more works and you could damage the PCB and other components. You can use the WBT Nextgen but it costs $48.00 each (copper only). For the wire I use a military 24 ga coaxial wire that I stocked before. The good and cheap source of wire is on Ebay. Good luck.

crooner · « **Reply #7 on:** 7 Apr 2007, 07:33 am »

Thanks again for the informative reply Tan!

I fired up my system tonight and man, I must say my SB3 is already sounding incredible as it is. Of course, I am using my custom linear power supply and the DAC60 with Siemens CCa must surely contribute to the fantastic sound I'm getting.

I'm guessing the improvements at this point will be marginal at best.

Did the transformer improve the sound tremendously or was the difference subtle?

krikor · « **Reply #8 on:** 7 Apr 2007, 01:23 pm »

FYI: the link is actually www.scientificonversions.com ... only one "c" between scientific and conversions.

One thing that caught my interest at the website was the "Dual Zo" 75 ohm to 110 ohm (coax to AES/EBU) transformer. Would there be any advantage to using this if your DAC has an AES/EBU input? Or is there more to it than just adding a xformer?

Hey crooner ... can you provide any details on your custom linear supply? I'm in the process of tearing apart an Elpac for use with my SB3, but I'd consider building from scratch if I had a design to go by. I'm comfortable with my basic soldering and assembly skills, but I don't entirely trust my design abilities.

Very timely thread as I've just started contemplating taking my iron to an SB3. Thanks!

crooner · « **Reply #9 on:** 7 Apr 2007, 03:44 pm »

Hi!

My power supply is based on the Power One HB5-3/OVP-A open frame unit. This is a quite robust supply rated at 3 amps max.

I added extra capacitance by means of a pair of Elna Cerafine caps for 16,401 uF total. Including a 1 uF film bypass. The smaller electrolytics in the PCB were also replaced with Cerafines. A 1 uF electrolytic was replaced with a film type of the same value.

All the wiring is by Kimber Kable.

The enclosure is by Context Engineering (less than $40 at Fry's). I drilled ventilation holes on the rear plate and added a Corcom combination fuse holder/switch/IEC connector (with EMI filter). I also installed a DIN connector for the DC cable going to the Squeezebox. A blue LED was affixed to the front panel.

To reduce mechanical hum I added damping material inside the case.

Here are some pics:

ctviggen · « **Reply #10 on:** 7 Apr 2007, 05:07 pm »

Yikes! That's more capacitance than in my power supply for my 40 watt/channel integrated amp! Have you looked at the output on an oscilloscope?

crooner · « **Reply #11 on:** 7 Apr 2007, 06:27 pm »

Well, it's only slightly higher than stock. I didn't want to go overboard precisely for stability reasons.
The stock cap was 10,000 uF. I have it running 24/7.

I haven't observed the output on a scope, but my ears tell me the improvement over the stock parts has been substantial. It is also rock solid stable at 5V, which I did verify with my Fluke digital VOM.

tanchiro58 · « **Reply #12 on:** 8 Apr 2007, 07:52 pm »

Quote from: crooner on 7 Apr 2007, 07:33 am

Thanks again for the informative reply Tan!

I fired up my system tonight and man, I must say my SB3 is already sounding incredible as it is. Of course, I am using my custom linear power supply and the DAC60 with Siemens CCa must surely contribute to the fantastic sound I'm getting.

I'm guessing the improvements at this point will be marginal at best.

Did the transformer improve the sound tremendously or was the difference subtle?

Yes, to my ears after swapping the inductors L8 and L9 with a transformer SC947-02 I can hear big differences between stock SB3 and this mod. Even friend of mine (F100) he has the same thought (he has compared between his RWA analog mod and Bolder digital mod). He stated that he is using the BNC cable between his mod SB3 and Paradisea DAC and tranny's SB3 mod beats RWA mod one easily but this mod is more involved, spacious and musical than the Bolder mod. PM him and you can ask his opinion. Good luck.

tanchiro58 · « **Reply #13 on:** 8 Apr 2007, 08:00 pm »

Quote from: crooner on 7 Apr 2007, 06:27 pm

Well, it's only slightly higher than stock. I didn't want to go overboard precisely for stability reasons.
The stock cap was 10,000 uF. I have it running 24/7.

I haven't observed the output on a scope, but my ears tell me the improvement over the stock parts has been substantial. It is also rock solid stable at 5V, which I did verify with my Fluke digital VOM.

Crooner,

Nice PS custom built. I have the same stock PS but I replaced BG and Auricap caps and Elna Cerafine 10,000uF/63v. I also replaced all wires and two Hexfred soft and ultrafast 600V/8A diodes and Furutech Rhodium IEC.

Where did you get the PS aluminum box? Do you have any website address? Thanks.

crooner · « **Reply #14 on:** 8 Apr 2007, 09:44 pm »

Hi Tan!
Thanks for the comments re the PS.
The Cerafines were surplus from a discarded Sony ES component.
The box is from Context Engineering, and around $35 from my local Fry's Electronics.

F-100 · « **Reply #15 on:** 10 Apr 2007, 02:37 pm »

Hi Crooner,
Here are some pics of Tanchiro58 and my DIY power supply. With all the upgrades, this power supply is rock solid.

This pic was taken before I added the bypass cap across the big Elna Cerafine 10,000uF/63v and replaced the two diodes with Hex Fred.

krikor · « **Reply #16 on:** 10 Apr 2007, 02:45 pm »

Crooner and F100 - thanks for the info and great photos of your power supplies. If my modded Elpac WM220-1950 (still in progress) doesn't do it for me, I'm going to give your approach a try.

Tanchiro58 - I'm REALLY intersted in doing the transformer mod. Is it very difficult to replace the L8 and L9 inductors? I may need some guidelines when I get around to this mod.

Thanks.

F-100 · « **Reply #17 on:** 10 Apr 2007, 03:09 pm »

Quote from: tanchiro58 on 8 Apr 2007, 07:52 pm

Quote from: crooner on 7 Apr 2007, 07:33 am
Thanks again for the informative reply Tan!

I fired up my system tonight and man, I must say my SB3 is already sounding incredible as it is. Of course, I am using my custom linear power supply and the DAC60 with Siemens CCa must surely contribute to the fantastic sound I'm getting.

I'm guessing the improvements at this point will be marginal at best.

Did the transformer improve the sound tremendously or was the difference subtle?

Yes, to my ears after swapping the inductors L8 and L9 with a transformer SC947-02 I can hear big differences between stock SB3 and this mod. Even friend of mine (F100) he has the same thought (he has compared between his RWA analog mod and Bolder digital mod). He stated that he is using the BNC cable between his mod SB3 and Paradisea DAC and tranny's SB3 mod beats RWA mod one easily but this mod is more involved, spacious and musical than the Bolder mod. PM him and you can ask his opinion. Good luck.

I fully concur with Tanchiro58 on the transformer upgrade. I highly recommend this mod, especially for the money.

JoshK · « **Reply #18 on:** 10 Apr 2007, 03:12 pm »

I am just wrapping up the finishing of a box I built for the PSU I made. So this thread is good timing for me. I am just putting the finishing pieces together on three projects, this being one, after which I will be ready set to start experimenting with some ideas.

PSU as it stands now is based on mgalusha's design, which can be found in his thread about the Felicia + Squeezbox PSU; 'Felicia Squeemore' or something like that. This is using the LT1085 regulator. Once I get things up and running, I want to play with some basic mods to the Squeezebox, the Dac 60 and the SB PSU.

Some ideas I really want to try out are with regards to different regulation circuits beyond simple 3 prong chips. Spruced up chip based regulators, and discrete versions as well. I built my PSU so the regulator is really close to nearby caps (particularly the output cap) so that parasitics don't play too much a role in stability, but still the regulator is attached via a euro-style 3 point molex. This way I can build circuits on breadboards with 3 pins to insert into the molex and easily change and try different ideas.

If I actually come up with anything that is an improvement on the basic chip reg, I'll be sure to share here.

Has anyone tried bypassing the reregulators/switchers inside the SB and build a linear supply for each voltage? That is another idea I'd like to play with. I have a 1u chassis that I'd like to transplant the SB into so that I can have room to try such things.

JoshK · « **Reply #19 on:** 10 Apr 2007, 03:14 pm »

At this point, I don't know if it is worthwhile, but if there is min orders or other impedances to ordering the tx's, do any of you guys want to get together for a mini-groupbuy on these transformers. I am willing to pick one up to test out.