Battery powered Aleph-J

[dmtparker]

I am still 'noodling' design options for building an Aleph-J that would run off my house battery bank (solar) which is 48VDC. The reason I am noodling instead of building is I need some additional parts that I cannot get here in Panama and have to wait until I go back to US later this month.
Anyway, I had been working on ways to get +/- 25V out of 50V (see other thread) when I finally realized that I can get +/- 25V directly from my battery bank. The bank is comprised of 24 - 2V cells (@800 Ahr - BIG batteries) . If I connect wires to the Neg of #1, the Pos of #24 and the Pos of #12 (which is also the Neg of #13), I will have +/- 24V (which is really more like 25-26V). Now my questions:

1. The Neg of battery #1 is connected to Earth ground by a big copper rod driven into the ground. The house AC is connected to same. The amp will not have a third prong earth ground connection (no AC), but should the chassis be connected to 0VDC (which is @ +24VDC to earth) or to -24VDC which is @ earth? Or should the chassis just float with no ground connection? Will the interconnect (RCA) from the CD player have any problems? Obviously battery operated mp3 players are no problem. What about "audio out" from a computer that is plugged in to AC?
2. Assuming I am getting +/- 25VDC from the batteries as described above, what do I need for capacitance? Obviously there is no ripple, but I have read somewhere that batteries are like "big, slow capacitors" and need something to "speed them up."

Thanks for help in figuring this out.
And just to show that I am not only "planning" things, I just finished a B1 preamp and a rehab of a Dynaco ST-70 that sound great together!

 

[Zen Mod]

no need for safety earth when you don't have lethal voltages

however , you need input xformer on it for galvanic isolation, if you are going to use mains powered non - floating sources

or use output xformer on source side ....... anywhere in the chain

 

[dmtparker]

no need for safety earth when you don't have lethal voltages

however , you need input xformer on it for galvanic isolation, if you are going to use mains powered non - floating sources

or use output xformer on source side ....... anywhere in the chain

?Galvanic isolation? I am familiar with that on a boat to prevent corrosion, but not in electrical circuits. I can see how a transformer would avoid any ground issue, but it strikes me as a "non-elegant" solution. I guess what I need to do is check the continuity between the "ground" on the output of the CD player or computer and "earth". I know many amps use a "ground loop breaker" consisting of diodes and a resistor to "lift" signal ground above "earth". Would something like that help?

 

[Zen Mod]

put on paper ( here , whatever) exact setup you are going to use and then I can elaborate on hard data


exemplary thinking :

whatever type of GND scheme for amp PSU you are going to use - assisted or ditto connected between two accu banks , it'll be generally on +24V , if lower accu is connected to house mains safety gnd

so , amp's audio gnd is on 24V ; say that PC is and must be on safety GND ........ with case and it's audio GND sitting on it

in that case , with amp being closer to my heart , PC audio GND is on -24Vdc potential

use DAC , double isolated PSU with no safety gnd connection , take PC to it through isolation xformer and voila!

etc.