Battery Power vs Grid Power

[rollo]

   Until the Rocky mountain show battery power was new to me.
   After hearing the Dodd gear with Bbattery powered Pre and Amps it got me thinking. The servo amps feeding the subs though needed every bit of juice from the Ubers and TWL cords.
  What are the advantages and disadvantages of battery power. Leave high powered amps out for now.
   I was unable to do a direct comparison of battery vs non battery power. So impossible to compare.
    Has anyone here compared the difference directly ? It just makes sense to me to have the front end at least on batteries. The p[reamp though makes the most sense as ground lops usually occur when the Pre is connected to the CDP or TT.
  Dynamics I guess was always the issue so I'm told. But but the dynamics at the show were staggering. Even though the subs were attached to the grid there was no part of the frequency range that over powered the oher.
   I was so taken by this a Dodd Pre is on the way for further evaluation. Dood makes a VG Pre but that is not the issue. it is battery power that is.
   Any experience out there to contribute ? Batteries or grid that is the question. I like both. 

[BobM]

I tried battery powered DAC's at one point and I found the following ...

- batteries tend to be "slower" than AC when power is needed.
- slower translates to less sharp and less crisp transients, and loss of micro and macro dynamic response
- there are ways to "speed up" the draw on a battery, like putting some caps across the line - drawing from the caps is much faster than drawing on the battery directly
- Now a DAC doesn't draw much power at all, but running a preamp on battery has to have more issues than a DAC
- a reliable engineer can probably design a "power resevoir" of some type in the power supply to help alleviate this slowness issue, and that's probably what Dodd and Red Wine have done with their wonderful sounding equipment.
- then there's also the drain issue of the battery running down, but they seem to last a long time these days (Viagara?). I bet most of these have an auto-recharging topology where the battery recharges overnight, or when they get low.

[richidoo]

Some batteries have extremely low impedance, especially Optima Red Top, it is comparable to an ultra high performance regulator like Hynes or Belleson. Not all lead plate batteries will perform as good. There was a graph of acid battery impedance/freq. on the DACT website years ago that showed normal lead acid batteries were far worse than DACT regulator, but could have been a junky small battery.  With large batteries comes lower impedance due to the larger internal surface area for the reaction. Higher cold cranking amps means low impedance. Deep cycle means higher impedance.

AC power supply is not a consistently low impedance and is noisy. Battery is consistent low impedance even at high current and almost silent. There is no sag.   But you are limited to 12V, fine for DAC, but usually not enough for amp.

Altmann BYOB amp sounded very good despite the amp chip which didn't look very good on the scope. It made only 10W at full power before clipping into 4ohm. I think the reason it sounds so good at lower power is the low impedance PS. They say we are listening to the power supply as modulated by the amplifier circuit.

[rollo]

  At the show PRAT was excellent with the battery powered Pre and amp [ 30W/ch]. Added into the mix was a PIAudio Battery Buss. 
   Rich in total agreement that we really listen to the power supply.
    OK so far possibly affects speed. The battery used lasted 9 hours. There was a charger hooked up and the battery. When the batteries went low after 8 hours only then could I notice that speed was an issue. Lost dynamics as well. It was obvious.
   When fully charged we got 7 hours of music without issue. No loss of transients or the like. I believe the Battery buss was responsible for that. As bob stated caps are used to speed it up.  The system was running off one battery and one Buss.
   


charles

[shadowlight]

If the issue concern is the dirty power, why not use power regeneration option?

[Face]

I have a Dodd 6H30 battery buffer pre, but powered by a 12v power supply.  It would be interesting and easy to compare differences between the two PS sources. 

[jbtrio]

I have a purepower 2000+ which powers my whole system. If I run it on pure battery power the background gets a little quieter. The sound is smoother but,  dynamics are a little diminished.  The differences are slight.
 It depends on what type of music your listening to, you might prefer battery over regenerated ac.
 

[rollo]

Good input Joe, thanks. I was wondering how the Car Audio guys get all that dynamic output using batteries.
    It appears they use large storage caps that are muck quicker than the battery. HMMMM!.


charles

[richidoo]

Optima Red Top batteries are extremely low impedance, they deliver current as fast as exotic audio regulators like Hynes and Belleson. Serious car guys use 2ga copper wire and copper. Storage caps help plate batt, but not as necessary with the wound cell type.

I heard that PurePower conditioner at a firend's house, it really sounded great, powering Edge 400W stereo into Legacy Focus SE 2.5ohms and we were pounding them. Some of the best bass I've heard. He had tried a bunch of different power boxes.

[topround]

I have heard subtle differences in the Darzteel preamp between AC and battery. In quiet passages you can detect a blacker background, it is subtle and with big pieces of music or loud music the point become meaningless for me when using battery as I think there is very little difference, but with an andante movement ..maybe it becomes useful. But the preamp is so quiet to begin with, even with AC power.

I am very intrigued by the Veloce preamp which is coming soon to a theatre near me.
It is supposed to have startling dynamics  and speed despite being battery powered!

[bpape]

A couple years ago at RMAF we tried a DAC on battery vs AC.  For a while, while the battery was fully charged, it sounded as you describe above.  After an hour or 2, it didn't sound as good as good clean AC did.  That may be something specific to the DAC we were using but it seemed to want 'full juice' to sound its best.  That may not happen with larger batteries.

I run a BPT battery supply to my Bolder modded Sqeezebox and have not noticed the same issue.

Bryan

[rollo]

Optima Red Top batteries are extremely low impedance, they deliver current as fast as exotic audio regulators like Hynes and Belleson. Serious car guys use 2ga copper wire and copper. Storage caps help plate batt, but not as necessary with the wound cell type.

I heard that PurePower conditioner at a firend's house, it really sounded great, powering Edge 400W stereo into Legacy Focus SE 2.5ohms and we were pounding them. Some of the best bass I've heard. He had tried a bunch of different power boxes.

   For the battery powered preamp it was suggested by Dodd to use a Powersonic battery. Is the Optima safe for in home use. Dodd mentioned something about  gas leakage ? Ordered a Powersonic 12021F2 and Cetek charger. A PIAudio battery buss is on the way
    I'll check out the Purepower conditioner, thanks.



charles

[jbtrio]

Correction: I stated I have the Purepower 2000+ my bad I have the single chassis 1500+. It has plenty of power to run my whole system. Only at 25% capacity with everything running.

Rollo, you should try and get your hands on one
I think they work great, maybe carry the line. 

[richidoo]

All lead acid batteries give off hydrogen gas. As long as it is ventilated and the terminals protected from shorting then it is safe. The Optimas are OK to install in any orientation because they don't leak. I think the electrolyte is gel, not liquid, but I'm not sure. There are some cool battery cases available to hide and protect the leads.

I used one with Battery Tender charger, it worked well. I put the tender on a wall switched outlet, left it connected to the battery all the time, just turned it off when I listened, and on when I was done. I couldn't hear any difference on or off anyway but some chargers will be noisier. It's expensive for only a 12V PS, but allows playing music in lightning storms which are every night in spring here. Very annoying.

[rollo]

Thanks  Rich & Joe. OK C-Tek 3300 charger has arrived. Now waiting for battery.
    Nervosa is peeking.


charles