Killer front end...

[earwaxxer]

Alright, ... I'm semi coherent... Just a disclaimer... but still. I'm REAL impressed with this battery front end, a la Quickie. .. I tell you. The Q is not, by any means the weakest link. Everything cont to get better with it in the circuit. Anyway... Full digital front end with the Q. All battery. Awesome. The reason for the post. I just got a RCA to RCA adapter for the usb/spdif to to rca dac. Thus getting rid of the cable. All good....

[4krow]

heres the deal, the more battery run stuff the better.

[earwaxxer]

True Greg... Dollar for dollar, battery is definitely the best bet IMO. It gets a bit limited when you need major amounts of power. For the DAC and pre. IMO, its the way to go. Get a DAC that runs off a wall wart. Build a pack that does the deal. In the interest of disclosure though, the Wrd4snd USB/SPDIF converter sounds SOMEWHAT better with battery, though, not night and day. Same with the FiiO DAC. Not huge, but preferred for sure. Cleaner, IMO. I could live with both...

[4krow]

 Wasn't it the Boulder amp co. in Colorado that produced a battery powered power amp? Don't know the wattage.

[Grainger49]

Just for yucks, try this.  If you have a balanced battery supply, plus and minus the same voltage, put hand matched 10k, or 5k Ohm resistors, matched to the last digit on your meter, across the two supplies.  This will hold the voltage matched.  Then bypass each resistor with a nice film cap. A 0.1uF will be sufficient.  No need to match the capacitors.

Jumpers here are fine.  Let us know if that makes a difference.

[earwaxxer]

Hey Granger - If you could give some more info about what you are saying that would be interesting. Like, what does the resistor filter, and at what values etc. Paul had recommended putting a cap across the power supply in parallel. I tried that once and didnt notice any change. - thanks - Eric

[Grainger49]

The resistors lock the voltages, the capacitors will filter any noise. 

Do you use a balanced voltage power supply, like +/-9V?

[earwaxxer]

The resistors lock the voltages, the capacitors will filter any noise. 

Do you use a balanced voltage power supply, like +/-9V?

Balanced power is another thing I want to understand.. What would a balanced battery supply look like? - thanks much...

[2wo]

It would look something like this, if I understand correctly. If you were thinking well, there

[Grainger49]

John has it.  It is complementary voltages with a virtual ground between them.

[earwaxxer]

Cool! - thanks John and Granger - I will try that!

[najo49]

Eric, could you give me the name of the supplier for the DAC and the adaptor. Thanks Jann

[earwaxxer]

The DAC I got from Parts Express and the adapter from Radio Crap.

[ALL212]

Just for yucks, try this.  If you have a balanced battery supply, plus and minus the same voltage, put hand matched 10k, or 5k Ohm resistors, matched to the last digit on your meter, across the two supplies.  This will hold the voltage matched.  Then bypass each resistor with a nice film cap. A 0.1uF will be sufficient.  No need to match the capacitors.

Jumpers here are fine.  Let us know if that makes a difference.

Grainger - can something similar be done for the wall wart switching power supplies?  And, if so, do we need to consider the size of the resistor/cap in watts?  Those Pass amps I built have 19v, 2amp wall warts - keeps the build simpler and keeps those of us who can tell which end of the soldering iron is hot but not much more from killing ourselves on straight AC.  If Nelson Pass approves you have to approve    but I like to tinker!

[Grainger49]

Yes, it will work but I would go with a three pin regulator for the Pass amps.  Much better.  What I suggested was cheap for a battery supply.  It isn't really an active regulator.