Taking orders :)

[mcandmar]

Sooo, any more teasing photos or tidbits of information for us? 

 

[Doc B]

PB has worked up a battery charging circuit. We're awaiting some new batteries in order to test how much play time we get from a full charge. The ones we have around are pretty long in the tooth and not holding charge too well.

 

[mcandmar]

Witchcraft.  I wanted diode tubes and iron and ominous humming noises when i flick the switch, not a freaking iPod 

 

[Grainger49]

I think he wants a Jacob's Ladder on the power supply.

It looks cool but will give you headaches.

 

[denti alligator]

I spend far too much time checking this thread. But I have to have something outside career and family to keep me in anticipation. I'm that boring, yes.

 

[Doc B]

We have worked out what should be the final small revisions to the DAC board. John will be working on getting these turned into a final prototype board in the next few weeks. Our battery supply test is on hold for a bit as we have had a setback with the existing prototype due to my trying to kludge together some temporary cables that seem to have killed our existing prototype. Yes, it was a very clever $1500 mistake that has thrown us behind maybe another four weeks. And people are always saying to me, "Doc your job must be so fun."

 

[Grainger49]

Sam,

Just set the forum as your home page (I did).  Then when you open your browser click on Unread Topics.  If there is an update it will show up there.

 

[denti alligator]

Sam,

Just set the forum as your home page (I did).  Then when you open your browser click on Unread Topics.  If there is an update it will show up there.

I do use the unread topics thread, but is find myself lying in wait for new posts. That's what I mean by anticipation. Lol

 

[2wo]

Hey Doc, I have a battery supply for another project. It uses a CTEK US 800 charger to keep the battery topped up, it works very well...John

 

[tdogzthmn]

What is the purpose of the batteries in the DAC circuit? 

 

[Grainger49]

It eliminates all AC.  AC can cause hum.  The electronics run on DC anyway.

 

[Paul Birkeland]

What is the purpose of the batteries in the DAC circuit?

The battery so far has sounded much better than the other supplies we have tried.

 

[mcandmar]

Assuming you are using a battery as a cleaner power source, how you are going to implement a charging circuit without introducing the noise you were trying to avoid in the first place?    I'm sure there is a simple way to do it, i'm just curious to learn...

 

[Grainger49]

The on/off switch changes from disconnected from the charger (on) to connected to the charger (off). 

 

[mcandmar]

Ok, that made me laugh out loud. What's that saying again "keep it simple, stupid"

 

[Grainger49]

I have an Ack! dAck! that has a four pole double position power switch.  In the on position the two 12V batteries supply plus and minus 12V to the DAC, the charging circuit is totally disconnected.  In the off position it connects the batteries in parallel and to the charger, the DAC circuit is disconnected.

You asked a technical question.  It takes a technical answer.

 

[mcandmar]

Thanks Grainger, i understood you the first time, my comment was in reference to the elegant simplicity of the solution.

My mind was trying to devise clever circuitry to separate the charging supply from the output when the answer was a DPDT switch, hence keep it simple..

 

[Grainger49]

Sorry!

 

[mcandmar]

Not at all, thank you for be so helpful

 

[Doc B]

Well, thankfully John saved my a** by managing to repair the prototype board we blew last week. We're still not taking orders, but here is a photo of the most recent prototype that we have been playing with. This is 90% of the way to what the final will look like, save for some changes to the positioning of the various ports and slots. The panel is 6" square. The light at the front is the charging light. When on, unit is charging, when off, battery is fully charged. The switches are on/charge, USB/SPDIF coax/TOSLINK, and filter selection (that on the chip or John's awesome sounding software filter). The little slot behind that is where the optional sample rate display goes. That's a heat sink for the charging circuit at the left center, The screw heads in the middle hold the battery under the chassis, and I think the rest of the stuff is pretty self explanatory. Some of this may shift around and there will be one more slot for "accessories" to be determined in the future - that's why I say it's 90% like the finished version.

Good news is that it sounds quite good even with the charging circuit active. Great news is it sounds fabulous running off battery only. We are exploring the notion of a standby mode that keeps the board on and warmed up while the battery trickle charges, for those who like to keep their SS gear on all the time, and possibly a fast charge mode for those who are impatient and don't mind replacing the SLA battery more often.