σ11 - single rail regulated all discrete power supply

[n_maher]

When I found out that amb had designed a single-rail version of the σ22 power supply I thought it sounded just about perfect for my Squeezebox3 power supply project. Here are the preliminary results. This PS is actually for a friend but mine will be very similar with just tweaked casework. If you want more info on this PS have a look here.

I did just a little testing tonight and the new PS definitely seems to have helped the anemic base that the SB3 DAC has with the stock PS. More on that later when I can back to back it with the DAC I'm currently using.

[thrice]

Looks good nate!

[deepak]

Very nice Nate. Is there improvement using the SB3 as a digital transport?

[n_maher]

Very nice Nate. Is there improvement using the SB3 as a digital transport?

Haven't had a chance to do much in the way of comparative listening yet with the digital out but it can't hurt. There are certainly those that would claim that it helps but there are also those that say that transports don't matter at all. I can say that it definitely makes a difference with the analog output, with the stock power supply it was pretty bad. With the new supply performance seems much better and nearly on par with the DAC that I'm currently using.

[JBLoudG20]

Nate,

May I ask which model Hammond you used? Also did you use the small reccomended Avemco transformer that AMB suggests? Also, do you have a ballapark cost as compared to the STEPS. I'm debating which one to build if/when I build an M^3.

[n_maher]

May I ask which model Hammond you used?

Of course you can ask, it's a 1455N1601.

Also did you use the small reccomended Avemco transformer that AMB suggests?

Nope, it's a Avel Lindberg Y236001 (for 5V output). At higher output voltages (bigger trafo) you might want to seriously consider a bigger case. I'm not saying that you couldn't fit more in the case only that it already takes a bit of planning to do.

Also, do you have a ballapark cost as compared to the STEPS.

It's a little more expensive than the STEPS in my case. I'd put a STEPS at around $100 and the σ11 around $125. I'm sure in both cases you can build them for less, but that's a fair ballpark. There are pros and cons to both power supplies and neither is a bad choice. I think technically the σ11 has lower output ripple but the STEPS is pretty damn low to begin with.

Being the glutton for punishment that I am I'm actually working on three σ11's right now and another σ22. Lord have mercy on my wallet.

[JBLoudG20]

Damn I wish I had a bigger budget to work with. I'll probably go with a wallwart until I can afford to srop that kind of cash on a new PSU.

Thanks for the info!

[n_maher]

Damn I wish I had a bigger budget to work with. I'll probably go with a wallwart until I can afford to srop that kind of cash on a new PSU.

Thanks for the info!

Do yourself a favor and at least toss a TREAD on the output of whatever wallwart you use. If it were me (for an M?) I'd use a 24VAC wallwart with a TREAD set to 26V or higher depending on the opamps you're going to use. You might need a larger heatsink for the M?.

[JBLoudG20]

Larger heatsink for the M^3 or for the thread?

[n_maher]

Larger heatsink for the M^3 or for the thread?

The TREAD. The M3 could potentially pull enough current that if you're dropping a lot of voltage the stock heatsink might not be enough. You could of course go with a lower voltage wallwart (like 20VAC) which would give you a maximum output of closer to 24V which is a pretty happy number. What opamps are you thinking of running?

[JBLoudG20]

Yeah I thought you mean the THREAD.

If I actually come to build it, I have a few 637's. They are SOIC, so I'll browndog them to use for the L&R and probably get the 8610 on the ground channel.