A power supply for the Squeezebox

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pre65
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#16

Post by pre65 »

Mike H wrote:I think that's magnimous then. :D
Magnimous ?

You made that up. :lol:
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#17

Post by Neal »

Urban Dictionary:

1. Magnimous
It means big or fierce, it also is an accomplishment in a hearty manner, and over the top.
1.)"Wasn't that a redundant magnimous score??"
2.)"Last night was so crazy it was Magnimous, those kids were drunk on Absinthe"
3.)That man is so magnimous, he's like a giant...run.
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pre65
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#18

Post by pre65 »

Silly me, I referred to a "proper" dictionary. :lol:
The only thing necessary for the triumph of evil is for good men to do nothing.

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Mike H
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#19

Post by Mike H »

Arrrgh I spelt it wrong.

Should have been magnanimous, as thick persons bad word choice really means unanimous

Ah well another joke gone flat :roll:
 
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shane
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#20

Post by shane »

Can anyone point me to a reasonably simple circuit that would be a significant improvement over the SB3 wall-wart?
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Ali Tait
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#21

Post by Ali Tait »

Here's the John Swenson one. Not tried it myself but I've read good things about it-

http://home.comcast.net/~johnswenson1/stereo/SB_5V.GIF
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#22

Post by shane »

Thanks Ali. That looks do-able.
The world looks so different after learning science. For example, trees are made of air, primarily. When they are burned, they go back to air, and in their flaming heat is released the flaming heat of the Sun which was bound in to convert air into tree.
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#23

Post by little eddy »

I just seen this reference where he talks about two series regulators set to 8 and 5V respectively.

http://www.decdun.me.uk/sb3.html#sb3psu
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andrew Ivimey
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#24

Post by andrew Ivimey »

That looks nice and interesting - Ma Tuchly - this was the website that got me started on gain clones. I'll have a jolly good read when the sun comes up.
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#25

Post by Cressy Snr »

Here's the one I just built.

Mains transformer is 9V

Sounds lovely.

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#26

Post by Neal »

Steve some improvements you could try. Replace the 330R set resistor with a pair of standard green LED's in series...

Increase the output cap to 100uf, don't use a low ESR ;)

Ground the set resistor, its bypass cap and the output cap at the load, run the return back to the PSU 0v...

Better still use a pre-tracking regulator config, see data sheet. You need 5v headroom so you may need to go to a 12v TX... given the low value series resistors you are using I'd go to 12v anyhow.
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#27

Post by Cressy Snr »

Cheers Neal
Those LEDs will make a nice power indicator :)

I did originally have a 100uF on the output, but on the scope there was a low rate cyclical drift going on at about 0.3 Hz so in the end I used the more conventional small value cap and 2R7 resistor. The 100uF however was a low ESR Elna, so that might have been responsible for the VLF drift.
I'll try it again with a cheap cap instead.

All earth returns in the PSU are actually returned to the PSU 0V although the way I have drawn the diagram does not show it. The pre tracking option looks interesting. Is it yourself and Tony Moore who have this kind of PSU setup?

IIRC isn't it that "super-reg" thing that the Transporter had?
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#28

Post by Mike H »

I seem to remember shouldn't have a large value cap on the output of a regulator as it makes the regulator "struggle" to maintain the Voltage, so sounds like it was "hunting" ~ oops too high oops too low oops too high oops too low etcetera :D

You could however use a large value cap if you insert a small value resistor between it and the regulator as it gives it at least a few Ohms to "work with"
 
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#29

Post by Lee S »

Are you using the built in DAC, Steve, or an external DAC ?
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#30

Post by Cressy Snr »

Hi Lee, I'm using an external DAC....the Musical Fidelity M1.

The difference this high capacitance power supply makes to the overall sound of the Squeezebox is not subtle!
Even though I'm only using the digital output to an external DAC, the improvement in quality is astonishing.

Silences are totally black with this PSU, which indicates to me that the Maplin switcher I had must have been allowing hash to escape up its DC power lead to pollute the digital circuitry within the player itself.

Low-level resolution is greatly enhanced, allowing the spaces in which recordings were made to become almost palpable. The Miles Davis track Time After Time for example has all of the low level percussion details I heard via vinyl at Owston, fully resolved, where before they had been a bit vague. It is this microdynamic picture that the Owston setup did so well that is now available via my digital setup.

This is a major step forward for the sound of digital, in my system at least. The thing is, until I heard the vinyl played at Owston through Nick's phono, via my mono amps and James Quasars, I had been unaware of what had been missing from my own digital playback experience.

I can fully appreciate now what Nick was getting at when he talked about the elusive "magic" sound. Now I don't think for one minute that this is the last word in digital or it is better than vinyl at the top of its game, but it is still damn good compared to what I had before.
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