"Cheap" replacement power supply for Squeezebox2

Music Machine · « **Reply #20 on:** 21 Sep 2005, 11:07 pm »

Here's a possibility. It's 5v 1.5a linear regulated. $17.50
The supplied plug fits the squeezebox2 and center is positive. Plug and play. Not much fun but so easy.

http://electronicsurplus.com/commerce/ccp78437-5vdc-40-1-5a-wall--power-supply-with-a-5---2conduc-wm075-1950-760-139895.htm

I got one of these about a week ago. It improved the sound top to bottom compared to the stock supply. No switching back and forth to be sure. I was sure the moment I played music. I'm using the analog outs and haven't tried a dac since I got this power supply.

This supply can't be optimal. Inside I found only a transformer, two diodes, regulator, and two caps. If some of you smart guys try this cheap easy supply you might be motivated to design a good diy we can all enjoy. I'm definitely not the guy, sorry to say.

Regards,
Music Machine

jonwb · « **Reply #21 on:** 23 Sep 2005, 03:16 am »

Well here's a picture of the unit I purchased:

Yesterday I finally got around to soldering on the plug from an old wallwart I didn't need anymore. Not pretty, I ought to redo it later. The unit itself is surprisingly heavy (no wonder it cost so much to ship). Both the cords in and out of the 'box' use fairly heavy gauge wiring.

So I was listening to my system last night, pleased with the improved sounds from my amp mods, when I remembered that I had the new SB2 power supply to try out. Since I thought things were sounding pretty good I frankly wasn't all that optimisitc that I'd notice a decernable difference. Well I was wrong... it took about 2 seconds to notice the improvement. The highs were noticably cleaner sounding... bass tighter, remarkably better actually. Far exceeded my expectations. Of course my expectations were probably low because the thing only cost me $15.

I haven't taken it apart, so I have no idea if there are parts to tweak inside the brick. Tomorrow I'm sending my SB2 off to Wayne (Bolder Cable) to get it modded. I'm also sending him my new power supply, I'm curious to hear what he thinks.

Thanks again for the tip Paul... I think this power supply is a no-brainer for someone who has an SB2 and can't swing the cost of Vinnie or Wayne's power solutions (maybe a stop-gap). Any tips on where one could purchase a 5.5mm power plug might be helpful.

Jon

Occam · « **Reply #22 on:** 23 Sep 2005, 04:29 am »

Jon,

You're quite welcome. Given some of the comments of today, the 'props' are greatly appreciated.

If that 2 pronged wall plug is unpolarized, you might try reversing it to see if you get any positive or negative subjective changes and note your preferred orientation.
I was familiar with the ps when I reccomended it. Josh has my unit (I don't even own a SB2) and his plate is quite full, to say the least. Good luck to anyone trying to open the unit. Its bolts are at the bottom of a 2 1/2" deep, 3/16" diam hole and the bolts have no slots. You'd probably need a specific, very thin bolt driver to get at them.

Glad it worked for you,
Paul

JoshK · « **Reply #23 on:** 23 Sep 2005, 01:33 pm »

Yeah, I am guilty of taking Paul's supply and not giving it the demo it deserves. My plate has become the table and the plate was long lost under the contents.

If you are looking for the little DC plugs, switchcraft has/makes them and many of the online electronics seller have them (try markertek, partsexpress, switchcraft themselves, mouser, et al). Wayne pointed that out to me a long time ago when I was looking for a DC plug. Can't remember where I ended up getting one....oh wait I think RS. Anyway, not hard to come by.

rme · « **Reply #24 on:** 23 Sep 2005, 02:04 pm »

any idea if the 1.5a is enough for the wireless sb2 while running both analog and digital output? I thought the stock sb2 power supply was 2a.

Davey · « **Reply #25 on:** 23 Sep 2005, 02:11 pm »

Yeah, it should be fine. The SB2 draws about 750mA. The non-wireless version probably a little less, but I'm not sure.

Cheers,

Davey.

Occam · « **Reply #26 on:** 23 Sep 2005, 06:29 pm »

A quick comment on the Hostflet linear table wart ps for the SB2. Jonwb's quote of $15 for the upgrade powersupply was the all in cost, including the cost of the ps, $1 per order handling charge, and the actual shipping.

If anyone in NYC is ordering that ps, I've a specific transformer that should provide the power conditioning fuctionality of Felicia. That added facility should cost about $15-20 for the transformer, caps, fuses, and housing. I don't have a SB2, so I'd like to test it locally prior to release on a Lab thread.

jonwb · « **Reply #27 on:** 23 Sep 2005, 09:34 pm »

OK, I got the thing apart.

It took a really small 1/4" drive deep-well 4mm socket (Craftsman #44401); then there are two snaps on the sides of the case halves that hold it together that have to be popped apart. You can see it in one of the pictures I put Here . I'll defer suggestions on what to replace to you experts.

Occam · « **Reply #28 on:** 24 Sep 2005, 12:08 am »

Dang Jon,

I'm impressed that you got that sucker open. Then again, my favorite tool is a butter knife.
I'm quite impressed by the internals. Thats a lovely split bobbin EI core transformer, the MJE305 on that big honking extrusion heat sink is a series pass transitor. What is that TI? dip ic marked? I'd think its controlling that pass transitor and its specifics would tell alot. The transformer alone, in small quanties costs more than the Hosfelt price for the whole ps.

TIA,
Paul

jonwb · « **Reply #29 on:** 24 Sep 2005, 12:30 am »

Quote from: Occam

Dang Jon,

I'm impressed that you got that sucker open. Then again, my favorite tool is a butter knife.

Remember where I said I'm a mechanical engineer? Taking stuff apart is my speciality

Now, what to make of the internals... that I leave for you guys to explain.

Quote from: Occam

What is that TI? dip ic marked? I'd think its controlling that pass transitor and its specifics would tell alot.

Sorry I didn't get a better picture of that IC. I'd check, but the unit is currently in the custody of UPS (until Wednesday). Perhaps Wayne can report back once he recieves the unit.

Occam · « **Reply #30 on:** 24 Sep 2005, 12:48 am »

Jon - Not a problem. From the pic I assume its a TI ua723 adjustable precision regulator driving the MJE305 NPN external pass transistor. The schematic will look very similar to -
http://focus.ti.com/lit/ds/slvs057d/slvs057d.pdf
page 7, figure 4.

But thats just an edumicated guess.
All in all, a competent, straightforward, well implemented, but 'long in the tooth' powersupply.
It might benefit with capacitive bypassing of the bottom leg of the voltage setting resistive divider, if it doesn't already exist. Similarly, upgrading the filtering caps, putting bespoke rectifiers... might provide a modicum of improvement. I'd think resources would be better spent 'Feliciacizing' it. We all have our own agendas.

rme · « **Reply #31 on:** 24 Sep 2005, 10:14 am »

As I need to replace the tip with the sb2 required one, and I don't have a meter, could you tell me which side of the cord is + on the DC cord side?

Is there any markings on the cable itself for the + side?

Is it on the left, assuming you are looking back at the transformer from the dc end connector.

Also, is it better to have as short a cable length on the dc side as possible or is it ok to run 5-6 feet long on the dc side?

Thanks

Occam · « **Reply #32 on:** 24 Sep 2005, 02:36 pm »

Hi thee down to your local RatShaque. Bring your SB2. Find the DC power plug that fits. They don't like you opening their blister packs, but they will let you do so. If they don't, buy a couple, open them, try the fit, and return the opened ones....
Buy a inexpensive multimeter from RS or Hosfelt. Measure your SB2 switching supply plug to find which is positive, the center or the outside. Circumcise you Hosfelt ps output cord and measure which wire is which and mark it with tape. Connect the plug appropriately.
Never, ever assume that whoever assembled the ps consistently physically oriented the cable, especially when the plug was already attached and it didn't make a difference.

Measure twice, cut/connect once!

With regards to output cable length - the shorter the better with regards to voltage regulation and noise, but this must be balanced against the fact that the minimal noise passing EI split bobbin transformer emits a greater magnetic field than an otherwise pos toroid. A foot should be fine, but its not enough of an issue that you should alienate your SO over it, or compromise your aesthetic sensibilities. Make it long enough so that it can be positioned so that it isn't obtrusive.

angelo · « **Reply #33 on:** 6 Oct 2005, 03:33 pm »

i just received my SB2 but haven't opened it yet. i want to build a linear power supply and i come up with this very simple design based on ON Semi Regulator handbook. Please give your comment or suggestion, i haven't assembled it yet but i already have the regulator and caps, still need to get a transformer.

here's the schematic:

thanks,

angelo

sleepysurf · « **Reply #34 on:** 6 Oct 2005, 08:42 pm »

I presume y'all are die-hard DIY'ers, but still might want to START with the off-the-shelf Elpac 1.5A linear supply, as discussed in this thread...
http://forums.slimdevices.com/showthread.php?t=16245

Perhaps it could be modded with even higher quality components.

I've been using the Elpac with my SB2 for a few days now... so far so good. This weekend I'll conduct some extended listening comparisons with the standard wall-wart.

angelo · « **Reply #35 on:** 6 Oct 2005, 08:46 pm »

i found a much better regulator for this application using LM350 http://www.national.com/ds/LM/LM150.pdf

it's prolly easy enough to build an all-purpose adjustable power supply using this regulator, the one that i have is in TO-3 packaging so i have to find the right heatsink for it, i didn't know before that the whole metal case of this packaging is the output

so disregard the previous schematic.

angelo

angelo · « **Reply #36 on:** 6 Oct 2005, 09:03 pm »

Quote from: sleepysurf

I presume y'all are die-hard DIY'ers, but still might want to START with the off-the-shelf Elpac 1.5A linear supply, as discussed in this thread...
http://forums.slimdevices.com/showthread.php?t=16245

Perhaps it could be modded with even higher quality components.

I've been using the Elpac with my SB2 for a few days now... so far so good. This weekend I'll conduct some extended listening comparisons with the standard wall-wart.

i'm still a newbie.
the 1st schematic that i posted can't provide enough current for the SB2, sorry for posting it. i'm building the Linear PS because i already have the components, i'm sure it'll cost a lot more than the Elpac if i have to buy each parts. The LM350-steel regulator cost ~$6 a piece.

the Elpac PS looks nice, i might buy one just for the hell of trying it.

angelo

TriodeGuy · « **Reply #37 on:** 7 Oct 2005, 02:31 am »

Just wanted to say that the power one supply mentioned at the start of this thread has been marked down to $2.50.

http://www.cascadesurplus.com/catalog/product_info.php/cPath/99/products_id/856

I bought five of these for my SB2 and future projects. It seems to be very well made. We used to use power one supplies of various voltage/power ratings in the lab where I used to work as an engineering tech. They're built like tanks and always seem to put out good clean power.

JoshK · « **Reply #38 on:** 7 Oct 2005, 03:30 am »

I say go for it Angelo! Sometimes it isn't the result that drives us, it is the journey. You seem to have the diy bug bad like me.

jakepunk · « **Reply #39 on:** 7 Oct 2005, 06:28 am »

I received my Hosfelt transformer today. It's the same one jonwb purchased. I spent some time this evening listening to brass choir (highs), Blue Man Group (bass), and Bach organ fugues (everything). My opinion is that the new brick has a positive improvement, but it is small. The highs are a little less shrill and the bass is a little tighter, but it was not an epiphany.

Here's how I look at it: the SB2 costs $293 (shipped) and the transformer is $15 shipped. $15/$293 = 5.1%. I think the improvement is on par with 5%, and a 5% improvement is OK with me.

P.S. I was surprised when I saw that the logo of the original manufacturer of the brick had been removed. You can see it in jonwb's picture on the previous page in this thread. What looks like black electrical tape in the upper left corner is actually a depression where a rectangular portion of the exterior has been excised.

(A brief note on the buying experience: Hosfelt's website does not encrypt your name and address during the ordering process, only your credit card info. You do not select a shipping method, they pick either FedEx or USPS on your behalf. You don't see the final shipping charge on the online order form, you get it on your hardcopy receipt. The brandname is excised with an exacto knife. My point is that everything turned out OK in the end -- I got the product I wanted -- but if you are used to having a squeaky-clean online ordering experience, then this one may make you a little uncomfortable.)