"Cheap" replacement power supply for Squeezebox2

Music Machine · « **Reply #40 on:** 8 Oct 2005, 08:04 pm »

You might be surprised after it burns in for a couple weeks. I have the same one from hosfelt but haven't changed the plug yet. Also have the more expensive and probably worse elpac. The elpac gave an immediately noticeable improvement from top to bottom. The stock supply yields a confused sort of rough sound that went away with the linear supply. I didn't use to have an opinion about power supply burn-in. Something happened. It was good.

Regards
Music Machine

sleepysurf · « **Reply #41 on:** 8 Oct 2005, 10:03 pm »

Well, after trying the Elpac linear PSU in place of the standard switching PSU, I can honestly say the improvement is minimal (using the SB2 analog out).

However, I downloaded the latest Slimserver Beta, which incorporates pre-amp volume control to allow direct connection to an amp.

After connecting the SB2 analog out DIRECTLY to my Sunfire Cinema Grand 200 amp (feeding Martin-Logan Aerius i's), I now have absolutely INCREDIBLE LUSH CRYSTALLINE sound like I've rarely heard before. I had no idea my Yamaha RX-V1000 (as Pre/Pro) had such a deleterious effect on the signal path.

At least for me, the GREATEST upgrade path for improved audio from the SB2, was to simply bypass the pre-amp stage altogether! I'm sure some other mods might tweak the sound even more, but I'm thrilled with the improvement thus obtained. Now, I just need to figure out how I can still utilize my RX-V1000 for Home Theater DVD playback.

rme · « **Reply #42 on:** 9 Oct 2005, 08:24 pm »

Paul,

Any issues with running the dc portion of the power supply line with my amplifiers ac power cord?

I don't know if this increases noise or if it is not a problem, but I am trying to bundle all power lines away from interconnects and speaker wires.

JoshK · « **Reply #43 on:** 9 Oct 2005, 09:16 pm »

RME: you talking about running DC power in along side AC power in? Like inside a cord? => not a good idea. will cause excessive noise. You have to seperate and shield the DC lines from the AC lines, otherwise noise on the AC line will couple to the DC.

rme · « **Reply #44 on:** 9 Oct 2005, 10:27 pm »

Quote from: JoshK

RME: you talking about running DC power in along side AC power in? Like inside a cord? => not a good idea. will cause excessive noise. You have to seperate and shield the DC lines from the AC lines, otherwise noise on the AC line will couple to the DC.

I was planning on just using a wrap or zip ties to hold the dc power cord along with (not inside) the ac cord so that they aren't hanging all over the place. The ac cord will be shielded however.

Occam · « **Reply #45 on:** 12 Oct 2005, 06:40 pm »

Well, I'm back from a week in Aruba celebrating my 30th anniversary (seems far longer

) with SWMBO ..... So I've caught up with the posts and will make a few comments

RME - Josh is offering you excellent advice. While a shielded powercord does offer some defense against RFI (radio frequency interference), it does little to stop EMI (the magnetic field produced by the ac cord which induces hum in other wires in close proximity). Please space the wires as far apart as is feasable as Josh suggests.

I've traced the circuity on the PowerOne ps from Cascade, and its pretty much the same as the Hosfelt supply. It uses the same TI 723 chip and topology. Its larger pass transistor and transformer may offer some benefits, but its flexibility IMO, the voltage adjustment and over voltage and current protection, isn't particularly germane. By no means do I mean to dissuade anyone from using it, but you'll have to house it, provide a grounded powercord (anything anyone builds MUST have a grounded powercord!) vs. the UL approved and housed Hosfelt supply, leaving the $2.50 vs $6.95 cost benefit of questionable merit.....

Would someone with the Hosfelt supply please, please try flipping the unpolarized AC plug and reporting any subjective differences? [it was I who originally suggested (I'm 'pmkap' on the Asylum) the Atari supply from Hosfelt for the DI/O and was amazed by the difference that the plug orientation made]

If someone has a Felicia or other powerconditioner and the Hosfelt supply, would you please report the effect of using a conditioner?

Thanks in advance,
Paul

jonwb · « **Reply #46 on:** 12 Oct 2005, 07:08 pm »

Welcome back Occam... I hope Aruba was nice!

Quote from: Occam

Would someone with the Hosfelt supply please, please try flipping the unpolarized AC plug and reporting any subjective differences? [it was I who originally suggested (I'm 'pmkap' on the Asylum) the Atari supply from Hosfelt for the DI/O and was amazed by the difference that the plug orientation made]

I will try flipping the AC plug when I get my unit back from Wayne (SB2 mods). Probably will be sometime next week. Because of the new caps (including some teflon jobbers which require extensive break-in), I will really only be able to comment on the sound differences between the two orientations. Maybe someone else would be more help (sooner).

Jon

rme · « **Reply #47 on:** 12 Oct 2005, 10:26 pm »

As always, thanks everyone for your posting feedback on my questions, you all are quite helpful.

Paul, you mention to ground everything, however is there a way to replace the standard cord on the Hosfelt with a grounded one and a place to effectively ground from inside the Hosfelt box?

Hope Aruba was enjoyable.

Occam · « **Reply #48 on:** 12 Oct 2005, 10:54 pm »

RME - There is really nothing to ground in the Hosfelt supplied powersupply. The metallic fixing bolts are substatially recessed (see Jonwb's post and link to his Gallery pictures) and the whole shebang is UL Class 2 certified (not requiring a grounded wall plug). If you want to replace the supplied non polarized 2 prong cord with a grounded shielded cord, you'd simply wire the hot and neutral wires to the same on the board and leave the ground and shield wires from the cord 'floating' by wrapping insulating tape around them. This would simply encase the cord with a 'Faraday cage', which maintains the ground at the plug end. As the supplied wall plug is not polarized, I'd simply note which plug orientation is subjectively prefferable (if any), and maintain that line and neutral orientation. [the narrow blade opening on the wall socket is 'hot' and the wider one is 'neutral']. As to whether changing the powercord would yeild any benefits, dunno .....

Regards,
Paul

angelo · « **Reply #49 on:** 24 Oct 2005, 04:06 am »

here are some pics of the ps that i'm building, w/o the transformer. i'm surprised RS don't carry transformers anymore

the wiring at the back is not well organized but it works, tested it using a bench supply to adjust the pot for 5V output. this is using an LM350 adjustable voltage regulator.

angelo

Occam · « **Reply #50 on:** 24 Oct 2005, 02:17 pm »

Angelo - Very nice! Star ground and all. I assume that blue box is a cap bypassing the resistor to ground from the adj pin per fig 3 of the National pdf?

JoshK · « **Reply #51 on:** 24 Oct 2005, 02:44 pm »

very cool angelo, let us know how it works out.

angelo · « **Reply #52 on:** 24 Oct 2005, 03:33 pm »

Quote from: Occam

Angelo - Very nice! Star ground and all. I assume that blue box is a cap bypassing the resistor to ground from the adj pin per fig 3 of the National pdf?

thanks occam, the blue box is actually a pot, the schem. that i use is at page7 fig. DS009061-1 plus two protection diodes. Thanks for pointing out that extra bypass cap, i used an old National applications guide book and i just notice it is not as updated as the online datasheet. I can add that cap with no problem.

angelo

Davey · « **Reply #53 on:** 24 Oct 2005, 07:22 pm »

Josh,

What kind of a turntable is that on your avatar?

Davey.

woodsyi · « **Reply #54 on:** 27 Oct 2005, 02:53 pm »

http://auctions.planettest.com/java/jsp/doorway_partnoH-P6289A_invid8078.htm

This is not necessarily cheap although you can get similar items for good price now and then on e-Bay. I had one lying around that I was going to use for my turntable but I never got around to soldering a DIN connector. So I tried it on SB2 last night. After double checking the voltage with a multimeter to be 5V, I just snipped the SB2 switcher off and connected the bare wires to the output connectors. The change made the music discernably meatier with more bass oomph. All other things are stock and I run digital out to my DAC. It's really convinient that I can flip back and forth between SB2 and CD since they are on different inputs on my DAC. Now that I know it works, should I change out the "stock" power wire and connector going into SB2?

JoshK · « **Reply #55 on:** 27 Oct 2005, 03:16 pm »

Quote from: Davey

Josh,

What kind of a turntable is that on your avatar?

Davey.

Its my homemade base + Teres kit. I need to finish the cosmetics but I need to finish a lot of things. Such is life.

Eli · « **Reply #56 on:** 28 Oct 2005, 03:21 am »

Quote from: Occam

5 VDC @ 1.5 AMP Regulated $US 6.95

Mfg. # - 7202C-3
5-13/16" x 2-1/2" x 2-7/8"
Input: 117 VAC, 60 Hz
Output: 5 VDC @ 1.5 amp. The enclosure and
cords are black. Regulated and filtered.

With the Hosfelt supply, if soldering on a new connector, would it be more advantageous to shorten the lead from the power supply to the Squeezebox it powers, or should the power supply be kept far away from the Squeezebox (and, I would assume all other components), such as on the floor?

angelo · « **Reply #57 on:** 28 Oct 2005, 03:28 am »

Sorry for being too slow to finish this project

here's another update, i just got the transformer tonight, it has 3 outputs (8/16/24 volts), so i'm going to use the 8VAC to provide ~11VDC input to the regulator.
And I have a SCHURTER "power entry module"

with line filtering.

and here's my layout, i'm adding a steel plate to block the EMI from the transformer, i'm not so sure how efficient this thing is but it doesn't hurt to have one.
cutting the hole for the power connector is a real PITA, i'm sure josh has said this many times. Good thing it came out preety nice.

I still have to add a cap, some more wiring connections, maybe an LED, and an output connector.

angelo

Occam · « **Reply #58 on:** 28 Oct 2005, 03:31 am »

Woodsyi - Thats one heck of a macho powersupply!

Very neat.

Eli - From page 4 of this thread -

Quote

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.

Once a thread becomes longer than a page or two, it becomes a royal pita to find info

Angelo - Very, Very Slick! Hurry up and finish so you can let us know what benefits your efforts yeild.

Al Garay · « **Reply #59 on:** 8 Nov 2005, 06:37 pm »

Any updates? Angelo?