New Power Supply for SB2

Wayne1 · « **on:** 23 Oct 2005, 11:34 pm »

I have been getting a bit a grief about the appearance of the power supply I have been building for the SB2

Finally, I decided to do something about it. I also had a customer who was willing to pay whatever it took

He wanted to have the option to use the SB2 on battery. I happened to have a chassis on hand that I thought would work out just fine for a PS with battery.

I decided to try to improve on a few things now that I had a bit more space to work in. I separated the transformer from the rectifiers and filter caps. There is now about a foot between them. That should reduce any problems from the transformer's magnetic field. I also increased the capacitance of the filter caps and added a film and foil bypass cap. I used the same values after the batteries. Yes that's right, batteries. I used two 5 Ah 12 volt SLA batteries with about 10,000 ufd of capacitance after them. I used the same bypass cap. This feeds into a switch which will then send the 12 VDC into the regulator. I also used bypass caps on the filter caps in the regulator. The regulator board is also physically a goodly distance from the power transformer.

The case it well ventilated, so it should not get very hot.

On the back I used the same ACME Audio Silver plated IEC and fuse holder as in the standard PS. The battery charger uses an XLR connector for input and the 5 volt DC output is the same 2.5 mm connector that is used on the SB2.

This is what the internals look like.

I haven't figured out the total price for this PS yet.

Is this something that you guys would be interested in?

The 2) SLA batteries should give it about 10 hours before it would need to be recharged.

I am also going to look into a smaller version of this case to use for an AC only version.

brj · « **Reply #1 on:** 24 Oct 2005, 12:38 am »

Looks nice, Wayne!

Is there a voltmeter or some other mechanism to indicate when to recharge the batteries?

What switch "flipping" is involved when running off of AC power, running off battery, and recharging the battery?

I remember reading in a thread that people were hearing a difference when running off of the battery, but leaving the AC charger still attached. Has that issue been examined in this implementation?

Thanks!

Wayne1 · « **Reply #2 on:** 24 Oct 2005, 01:13 am »

No volt meter in this one. I can add one. It just costs money

With this PS, there is a DPDT switch. The AC transformer is live at all times.

The switch changes between the 12 VDC from the AC source or the battery source. When the switch is in the down position the charger is feeding the batteries and the 12 VDC into the regulator board comes from the AC transformer and diodes and caps. When the switch is in the up position, a blue LED is turned on to indicate the 12 VDC is coming from battery.

I think that keeping the transformer away from everything will take care of the interference problem. I cannot say for sure. I just finished building it. The batteries are still being charged up. The owner is going to stop by later and pick it up. I am sure he will be posting his impressions of it.

mgalusha · « **Reply #3 on:** 24 Oct 2005, 02:30 am »

Looks very nice Wayne.

This will provide a great option. A killer linear supply and a battery supply. Is this kinda like having your cake and eating it too?

I am jealous, it makes my home brew add on to the old power supply look even worse than it already did.

Mike

zybar · « **Reply #4 on:** 24 Oct 2005, 02:51 am »

Looking good Wayne.

George

Wayne1 · « **Reply #5 on:** 24 Oct 2005, 04:34 am »

Thanks for the comments, guys.

Good looks don't come cheap

This PS will have to sell for about $500.00.

I am going to check with the case supplier tomorrow on pricing. This one was made with an anodized aluminum chassis.
I believe that the same size case is available in steel for a bit less money.

Turk · « **Reply #6 on:** 24 Oct 2005, 05:18 am »

Well, I picked up the power supply and plugged it in and on a prelim basis I think it and the SB2 are going to be marvelous. It's dead and I mean dead quiet. That's without switching to battery power! I will let it charge overnight. I hope to have some of the DAM gang take a listen when it's got some hours on it.

At this point it appears to be worth every penny and more. Pretend you didn't hear that wayne. Oh, and mgalusha built me a killer CPU that will hold about 80K songs. This is too cool for a non-techno type like me. Hats off to Wayne and Mike. With no real hours on it, it is superior to my $4K Exemplar Denon. I am really amazed. I was skeptical about a high zoot power supply until I heard it.

Will give a full report, soon.

Jerry

JoshK · « **Reply #7 on:** 24 Oct 2005, 02:22 pm »

FYI,

surplussales.com has a good selection of NOS volt meters at reasonable prices (~$35-80/ea). That is where I got mine.

Wayne1 · « **Reply #8 on:** 24 Oct 2005, 06:11 pm »

Jerry did call me up today and was positively GUSHING over the sound of the power supply. That was running on AC. He hasn't tried the battery yet.

I feel that a lot of the improvement has come from spacing the power transformer away from the regulator.

In light of Jerry's comments, I have ordered in some smaller cases to build strictly linear power supplies. They will have the improvement in the capacitor bypasses.

The case that Jerry has is roughly 12x12x3. The new case is 12x8x3.

The "Deluxe" linear power supply will sell for roughly $300.00.

The cases will not be delivered for 3 weeks. When they do arrive, folks who purchased the standard PS can trade them back in for the "Deluxe" model for the difference between what they paid and the price of the "Deluxe" PS.

The DAM might get together soon for another PS shootout. This time between stock SB2, the "Basic" Bolder PS. The "Basic" Bolder PS powered from bateries and Jerry's" Deluxe" with AC vs Batteries.

God, what a bunch of geeks

Turk · « **Reply #9 on:** 24 Oct 2005, 06:29 pm »

Whoa,

I am many things, but a geek? I can't reboot my computer without help

I am proud that I have no idea what is happening inside any given piece of electronics at any given moment

This is all a great mystery to me and I kind of like it like that.

However, I do know what I like when comes to listening and the SB2 and Deluxe power supply really have my attention.

Now, let me get back to my chickens

zybar · « **Reply #10 on:** 24 Oct 2005, 06:32 pm »

Quote from: Wayne1

Jerry did call me up today and was positively GUSHING over the sound of the power supply. That was running on AC. He hasn't tried the battery yet.

I feel that a lot of the improvement has come from spacing the power transformer away from the regulator.

In light of Jerry's comments, I have ordered in some smaller cases to build strictly linear power supplies. They will have the improvement in the capacitor bypasses.

The case that Jerry has is roughly 12x12x3. The new case is 12x8x3.

The "Deluxe ...

Sounds great Wayne.

I will wait to send mine in until the new cases arrive, but definitely reserve one for me!

Looks like size really does matter!!

George

Val · « **Reply #11 on:** 26 Oct 2005, 09:28 pm »

I like the non-battery linear PS option, my poor memory doesn't need more things to switch off or else.

Turk · « **Reply #12 on:** 26 Oct 2005, 10:34 pm »

Val,

My listening over the past 4 days confirms that Wayne's implementation of the Deluxe PS is close to battery with Power unplugged. In fact I have listened mostly to the SB2 powered in "no worry" mode, allthoughWayne integrated a blue light above the switch that has not failed to remind me to flip the switch.

Jerry

mgalusha · « **Reply #13 on:** 3 Nov 2005, 03:55 am »

Jerry brought his new power supply by on Monday night and I can confirm it raised the performance of the Squeezebox to a higher level. It removed some heretofore unnoticed grunge from the sound of my SB2. Very nice job Wayne.

I can see this is going to extract some additional funds from my wallet. Yes Wayne, I'll be calling you.

Mike

Wayne1 · « **Reply #14 on:** 3 Nov 2005, 04:40 am »

Thanks Mike, but that supply is SOOO last month

After talking to Jerry about your little listening session, I think I have come up with a few ideas to make it sound EVEN BETTER

I should be able to work up a prototype in a week or so. It will be BIGGER and EVEN MORE EXPENSIVE

How about a bunch of Jensen four pole electrolytics for a start

fly_fish_nz · « **Reply #15 on:** 3 Nov 2005, 05:15 am »

Hi Wayne,

Any thoughts on the quality of the SB3's power supply? Seem to remember reading somewhere that upgrading the power supply was one of the most notable changes.

C.

Wayne1 · « **Reply #16 on:** 3 Nov 2005, 02:56 pm »

The power supply that comes with the SB3 is the same exact one that comes with the SB2. It is a small switching supply. To my ears, it gives the SB a very harsh sound.

The main difference between the SB2 and the SB3 is the form factor, ie the case it is packaged in. The SB3 does use a linear regulator for the 3.3 volt supply, internally, that feeds the DAC chip and digital buffer chip. I change the supply in the SB2 so that a linear regulator is feeding the 3.3 volt rather than the internal switcher in the the SB2.

I have not received any SB3, yet. I hope to very soon. All of the power supplies that I will be offering can be used with the SB2 or 3 with no modifications.

fly_fish_nz · « **Reply #17 on:** 3 Nov 2005, 03:24 pm »

Wayne,
Thanks for clearing that up for me.