[mgalusha]

I've seen the question asked of how much power the Squeezebox really needs/draws. I've also seen answers answers varying from 370mA to 1A. I decided to really find out.

I have two Squeezeboxes, both SB2 and SB3. The SB2 has been modified by Bolder Cables and is a wired model without the analog opamp. The SB3 is a stock wireless model. I mention this because the SB3 draws considerably more current than the SB2. I suspect this is due to the wireless intreface.

The results:

Code: [Select]


Squeezebox 2 Wired

Off/Idle
Brightness Full  777mA
Brightness 3/4   642mA
Brightness 1/2   576mA
Brightness 1/4   532mA
Brightness Off   510mA

Playing
Brightness Full  810mA
Brightness 3/4   671mA
Brightness 1/2   604mA
Brightness 1/4   560mA
Brightness Off   536mA


Squeezebox 3 Wireless

Off/Idle
Brightness Full  985mA
Brightness 3/4   895mA
Brightness 1/2   854mA
Brightness 1/4   830mA
Brightness Off   818mA

Playing
Brightness Full 1015mA
Brightness 3/4   916mA
Brightness 1/2   872mA
Brightness 1/4   847mA
Brightness Off   833mA


Both Squeezeboxes draw the same power when "off" or when on and idle. The conclusion is that "off" just changes the display.

The current draw when playing is only a little greater than when idle. I placed a 15Kohm load on the analog outputs and ran the volume up and down while playing. There was no change in current draw.

The display is certainly consuming a good portion of the current and dimming or shutting it off will leave more current for the rest of the device.

In my estimation a 1 amp power supply is usable with the wired model but not suitable for the wireless. I think a supply capable of 1.5 amp would be better for either device and mandatory for the wireless Squeezebox.

Edit: I used a Lambda industrial power supply for testing. It will deliver 35 amps @ 5 volts with > 1% regulation. I didn't want the power supply to limit the current draw of the DUT. I used a Fluke 8050A DVM for current measurements. I wired the DVM in series as it will read up to 2A directly thus eliminating the need to use a shunt. Resolution on the Fluke is .1mA. Readings were moving around within approximately a 5mA range. I used the middle value of the range.

Hope this helps.

Mike

[Scott F.]

I've wondered the same thing. Great info.

Thanks Mike!

[bubba966]

Thanks Mike!

Now I'm glad I didn't get a PS that was only rated for 1A but had the right plug and instead got a 2.3A supply that doesn't have a plug at all.

[ctviggen]

Are you sure those numbers are right?  This means that with the SB2 off but with full brightness (which is what I keep mine), the SB2 would burn about 93 watts.  That just seems high, especially since the SB2 never gets hot.  (Think about putting your hand on a 100W light bulb, then compare with the SB2 in idle.)  Perhaps the case doesn't transfer in/out heat, but those numbers are still kind of shocking to me.

[mgalusha]

Bob,

I'm 99% sure the numbers are correct. I was very careful when measuring them and did each one twice to be sure.

How did you arrive at 93 watts? 5V x 1A = 5W unless I've completely lost my mind.

Mike

[ctviggen]

Doh!  I'm an idiot!  You're totally right.  I was thinking AC (120V), not 5V.  Please ignore my idiocy.

[woodsyi]

Those numbers I am sure are accurate.  I uses a HP power supply that has VU meter for voltage and current.  At 5 VDC, running Bolder modified SB2 wireless the meter never goes over 1 amp -- runs between .6 to .8 amp.

[Vinnie R.]

I did a check with my cablibrated Fluke DMM and those numbers look pretty darn close to mine  

[JoshK]

Thanks for this Mike!

[Carlman]

I bought a pair of the ones Bubba (I think) bought:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7571275306

I'm trying to get a few PS's together to compare and see what (if any) real difference I can hear compared to stock.  Wayne of Bolder Cables is sending me one he made (a beta, basic version from a while back).

I'll report my findings when I hear them...

-C

[jackman]

I bought a pair of the ones Bubba (I think) bought:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=7571275306

I'm trying to get a few PS's together to compare and see what (if any) real difference I can hear compared to stock.  Wayne of Bolder Cables is sending me one he made (a beta, basic version from a while back).

I'll report my findings when I hear them...

-C

Carl,
have you seen this one?

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

[Carlman]

I've seen it... and man is that ugly.
I didn't want to get into building a case and such.  I don't mind a little soldering/wiring but I'm not going to build a case or have something that needs a case plugged into the wall in my house.

I'm up to 4 PS's to compare including the stock one... All of them are on the way.... or will soon be... and that's about all I'll want to compare.  I've also got the stock SB3 to compare as well to the RWA-modified SB3.  So, I've got a lot of comparing to do.

-C

[Dan Banquer]

If the power supply is drawing a maximum of about 1 amp steady state, I would design for 2 to 3 amps for those current surges that can very brief. National Semi used to make Linear 5 volt regulators that were rated for that, and they still do. The part number is the LM 123, a 5 volt regulator rated at 3 amps. It comes in T03 package and there are plenty of heat sinks that can be mounted on a PCB for T03 packages. The pdf is available on the National Semiconductor site, and I'll bet that the part is available from Digikey
Hope this helps.

                 d.b.

[skrivis]

If the power supply is drawing a maximum of about 1 amp steady state, I would design for 2 to 3 amps for those current surges that can very brief. National Semi used to make Linear 5 volt regulators that were rated for that, and they still do. The part number is the LM 123, a 5 volt regulator rated at 3 amps. It comes in T03 package and there are plenty of heat sinks that can be mounted on a PCB for T03 packages. The pdf is available on the National Semiconductor site, and I'll bet that the part is available from Digikey
Hope this helps.

                 d.b.

It would be hard to beat the price on the supply at Cascade Surplus. The ones on Ebay are pretty cheap too.

There's some good stuff at: http://www.surplussales.com/PowerSupplies/PowerS-3.html
You can really get carried away if you want.

[Dan Banquer]

Yep; Open frame switching power supplies are really cheap, so if the radiated and conducted noise & switching frequencies from the open frame switcher are not going to be an issue than by all means use the switching supply.  If that is going to be an issue than I would recommend a linear supply. It's your call.
                        d.b.

[jackman]

Yep; Open frame switching power supplies are really cheap, so if the radiated and conducted noise & switching frequencies from the open frame switcher are not going to be an issue than by all means use the switching supply.  If that is going to be an issue than I would recommend a linear supply. It's your call.
                        d.b.

Dan, is the one from cascade a switching power supply?  Do you think it's a step up from the stock wallwart?

Thanks,
Jackc

[Dan Banquer]

It certainly looks like a linear, and at a damn good price too.  According to Mike's steady state data this should fit the bill quite nicely, and having over voltage protection will protect the rest of the ciircuitry in the unit in case something blows.  Now all you need are some  SONICROCKS
                    D.B.

[jackman]

It certainly looks like a linear, and at a damn good price too.  According to Mike's steady state data this should fit the bill quite nicely, and having over voltage protection will protect the rest of the ciircuitry in the unit in case something blows.  Now all you need are some  SONICROCKS
                    D.B.

Forget the SONICROCKS, I'm going directly for that magic Clock!  Thanks.

J