[JDUBS]

Hey Guys

I'm going to attempt to build a 5v linear power supply over the next couple of weeks.  It will either be used for my USB->SPDIF converter or my Squeezebox...likely the Squeezebox.

Does anyone have any internal pics of a supply they've built before?  I've seen schematics, but pictures are a world of help to a newbie DIYer like myself.

I'm looking forward to firing up the Weller 

Thanks,
Jim

[JDUBS]

Guys

Has anyone tried a bridge like this one?

http://www.referenceaudiomods.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=RAM_LV_Exotic_Diode_Bridge&Category_Code=DIODES&Product_Count=4

Outside of cost, is there a reason for the preference for using a quad of hexfreds?

Also from RAM, what about this voltage regulator?

http://www.referenceaudiomods.com/Merchant2/merchant.mvc?Screen=CTGY&Store_Code=RAM&Category_Code=SR

Really expensive vs. the commonly used LT1086 or LT1085 regulators....just curious if anyone has ever tried one.

Thanks!
Jim

[SET Man]

Hey!

    Well, I don't know about those stuffs you mentioned from RAM. They look interesting.

    But here is something you might want to consider for your Squeezebox.

http://www.welbornelabs.com/squeeze.htm

   Anyway, have fun and let us know how it turn out.

Take care,
Buddy

[gitarretyp]

Those voltage regulators don't supply enough current. I believe you need 1A minimum for the squeezeboxes. Their diode bridges are constructed from the surface mount diodes they sell (you can get the same thing from digikey, for example). They just string several together to increase the current delivery ability. I'm not certain of the efficacy of using the smaller diodes strung together.

[JDUBS]

Those voltage regulators don't supply enough current. I believe you need 1A minimum for the squeezeboxes. Their diode bridges are constructed from the surface mount diodes they sell (you can get the same thing from digikey, for example). They just string several together to increase the current delivery ability. I'm not certain of the efficacy of using the smaller diodes strung together.

Yep, good call.  I should have scrolled all the way down the regulator page 

I e-mailed the guys at RAM about the bridge and you're right...smd schottky's. 

-Jim

[JDUBS]

Hey!

    Well, I don't know about those stuffs you mentioned from RAM. They look interesting.

    But here is something you might want to consider for your Squeezebox.

http://www.welbornelabs.com/squeeze.htm

   Anyway, have fun and let us know how it turn out.

Take care,
Buddy

Hey Buddy

I had considered that...but really want to start fresh and pick out all of the parts myself.  The Welborne kit is a good deal, though.

Thanks for the suggestion!

-Jim

[JDUBS]

Hey Guys

What would be a recommended transformer to use in light of the fact that the often-used Tamura (PL30-16-130B) is out of stock everywhere I've checked?

I don't want to skimp on quality, so high-end recommendations are welcome.

-Jim

[mgalusha]

Jim,

A Hammond 185C12 would work nicely. Mouser has them in stock for $16.21ea.: http://www.mouser.com/search/refine.aspx?Ntt=546-185C12%09

This is 6.3V@4A, just fine for a 5V regulated supply for your SB. You will have about 9VDC before the regulator, so the regulator only has to drop 4 volts. This transformer will work for either 115 or 230V. You don't need 4 amps but the extra capacity won't hurt and the transformer should run a little cooler. The SB draws just over 1A at full brightness when wireless is enabled. Use at least a 1.5A capable regulator. The Linear Technology regulators are very nice. Have a look at the LT1085, it's capable of 3A and works very well. http://www.linear.com/pc/productDetail.do?navId=H0,C1,C1003,C1040,C1055,P1283

Don't forget to properly heat sink the regulator.

[JDUBS]

Jim,

A Hammond 185C12 would work nicely. Mouser has them in stock for $16.21ea.: http://www.mouser.com/search/refine.aspx?Ntt=546-185C12%09

This is 6.3V@4A, just fine for a 5V regulated supply for your SB. You will have about 9VDC before the regulator, so the regulator only has to drop 4 volts. This transformer will work for either 115 or 230V. You don't need 4 amps but the extra capacity won't hurt and the transformer should run a little cooler. The SB draws just over 1A at full brightness when wireless is enabled. Use at least a 1.5A capable regulator. The Linear Technology regulators are very nice. Have a look at the LT1085, it's capable of 3A and works very well. http://www.linear.com/pc/productDetail.do?navId=H0,C1,C1003,C1040,C1055,P1283

Don't forget to properly heat sink the regulator.

Great!  Thanks for the recommendation! 

What do you think of running two LT regulators in series?  I've heard it may be a good alternative to a Jung-style regulator without all the additional circuitry of the Jung.

-Jim

[JDUBS]

Ok, so I've been doing some more research.  How about this "super regulator"?

http://www.at-view.co.uk/alwsr.htm

I believe it will do up to 1.5 amps...although needs at least 5v great than the output voltage at its input.

Happy New Years!   

Jim

[mgalusha]

Hi Jim, you could run two LT regulators in series but you would of course need to set the output voltage of the first regulator at least 2.5 volts higher than the output voltage of the second regulator. So for the first regulator you would want about 10VDC on the input and 7.5VDC on the output. A little more wouldn't hurt.

The ALWSR is basically a very nicely done Jung Super Regulator. Assuming it can provide the current required I suspect it will be hard to do better without spending a lot of money. Hugh Dean is has an offering that is supposed to be stellar but it's far more expensive.

mike

[TomS]

I don't think you're going to get 1.5a, more like 200ma or so with the Jung SR's

[JDUBS]

Hi Jim, you could run two LT regulators in series but you would of course need to set the output voltage of the first regulator at least 2.5 volts higher than the output voltage of the second regulator. So for the first regulator you would want about 10VDC on the input and 7.5VDC on the output. A little more wouldn't hurt.

The ALWSR is basically a very nicely done Jung Super Regulator. Assuming it can provide the current required I suspect it will be hard to do better without spending a lot of money. Hugh Dean is has an offering that is supposed to be stellar but it's far more expensive.

mike

Great, thank you Mike!  The ALWSR does seem like a bargain.  I emailed them to confirm the current handling capability.

-Jim

[JDUBS]

I don't think you're going to get 1.5a, more like 200ma or so with the Jung SR's

Tom

Andy Weekes makes a comment here (at the bottom) regarding the power handling capability of "a" super-regulator:

http://forums.slimdevices.com/showthread.php?t=26937

I'm checking with the guys that sell the ALWSR to confirm with them that it can handle 1.5 amps.

-Jim

[JDUBS]

Guys

I got confirmation that the ALWSR will handle up to 1.5a assuming adequate heat sinking.

Sounds like a great way to go for "super" regulation at a very reasonable price!

-Jim

[JoshK]

Do we need super regulation for the SB though?  I forget what all our sagely Occam had to say on the matter (there is a post here that I started about SB mods), but I do believe the opamps and dac chip have onboard regulation.   Does this mean that the extra regulation would be moot?  Not sure.

You might try something clean and simple first, like the Hammond with a LT1085 (what I am doing) using good rectifiers (I chose an IXYS bridge from partsconnexion).   Take a look at the Linear Technology application note for the LT108x series (thanks Mike).  That is the simple circuit I built. 

[jonwb]

Take a look at the Linear Technology application note for the LT108x series (thanks Mike).  That is the simple circuit I built. 

Do you have handy a link to that application note?

[JoshK]

found it...

link

click on the datasheet on the top of the right column for even more detailed info and more application examples.  However, the simple application diagram pictured is sufficient.

[Occam]

Do we need super regulation for the SB though?  I forget what all our sagely Occam had to say on the matter (there is a post here that I started about SB mods), but I do believe the opamps and dac chip have on-board regulation.   Does this mean that the extra regulation would be moot?  Not sure.

Josh - I've been call many things here on the boards (many not overly flattering), but 'sagely' is a new one. Thank you.... I think?
I frankly don't know what specifically makes a good ps for the SB. But my own ears, as well as many I trust. Gary Bauer, Wayne, Hugh, etc...., tell me that although the dac and opamp are fed their voltages by intermediating switchers, a better external power supply has, in my experience, always led to better subjective performance.

I strongly believe that the raw (pre regulator) circuitry is also of critical importance in any power supply, so I'll make some comments while astride my hobby horse, eliminating noise as early in the supply chain as possible, if practical -

1. Every line fed component benefits from adequate powerconditioning of the raw ac. Even that wall carbuncle suppied with the SB benefits, even though post conditioning it will still spew rf. As to whether conditioning is best done internal to the ps, or via an external conditioner would depend on your level of masochism and the size of your wallet.

2. The choice of transformer is significant in both the amount noise passed from the AC mains, and the internally generated noise produced by the inductive leakage of the transformer interacting with the switching characteristics of the rectifiers.
The advantage of a toroidal transformer is that it has minimal stray magnetic fields and is less likely than other transformers to induce hum. Its low inductive leakage also minimizes switching spikes from interaction with the rectifiers. But the high capacitive coupling between primary and secondary as well as its high bandwidth also tends to pass along any crap that may be riding on 50/60Hz AC.
The split bobbin 'world power' transformers used by many are far better in regards to passing line noise. Their split bobbins minimize capacitive noise coupling and their construction also limits bandwidth. But their higher inductive leakage interacts with rectifier switching. Their construction also leads to a larger 'hum field', requiring more physical separation from other components, than required with a toroid.
My Candide recommendation would be a 'flat pack' semi-toroidal laminated core transformer like the LP-12-1900 Flat Head(tm) from Signal Transformer -
http://rocky.digikey.com/scripts/ProductInfo.dll?Site=US&V=595&M=LP-12-1900
available from Digikey, if they actually had them in stock.
Far lower bandwith and capacitive coupling that a toroid, and less hum field and leakage inductance than a typical split bobbin transformer.

3. As Josh mentioned, there are those nasty rectifiers that in conjunction with the transformers inductance can 'sing' (but they can't carry a tune). I personally like the Fairchild Stealth(tm) rectifiers, partially because their name evokes both military macho prowess and semi mystical Ninja power.

4. And then there are the smoothing caps after the rectifiers.

All these things impact the efficacy of your SB supply, and then it goes to the regulator....

FWIW,
Paul

[JDUBS]

Guys, not surprisingly, you've provided a wealth of informaion.  Paul, your sagely-ness is particularly appreciated in the parts recommendations you've provided.

Thanks again everyone!