I did a search on battery power supplies, but...

[carlosfm]

carlosfm and protos

Me?

I'm sorry but these last two posts seem to indicate that a complex load is entirely the responsabilty of the power supply and that is just not so.

I didn't say so.

The power supply is there to make sure that it provides enough energy to the amp circuit so that it can do what it was designed to do.

Much more than that.
In fact, it is one of the (if not THE) most important things on an amplifier.
It is my way of viewing things that the PSU is also part of the signal path.
And it affects the signal in a dramatic way.

If the power supply can do this without introducing noise or problems of its own then it is a good power supply.

Yes, but my point was: your super-clean super-regulated PSU may not be the one that sounds better on your amp.
There are other things besides noise.

I also don't like the inference that what is measured can never agree with what is heard.

Never was not on my words also.

 

[carlosfm]

Staying on-topic, does anybody know howcome Final Lab do only extract 10W out of 36 AAA batteries...

AAA or AA batteries?

 

[moamps]

... does anybody know howcome Final Lab do only extract 10W out of 36 AAA batteries in their Music -6 power amp...

from Stereophile:

"As you might expect, the Music-6 requires a bit more in the way of juice; its companion power supply, the Final Laboratory DC-6, is actually a pair of battery boxes, each housing a series-connected bank of 18 D cells, for a total of ±27V"

18x1.5=27

Regards,
Milan

 

[yldouright]

carlosfm
I took your post as a cavalier endorsement of what protos stated about the disparity of hearing and measuring. If that was not your meaning then soften my words to the extent that they weren't. Yes a power supply that makes noise or introduces time distortions is in effect making a signal but calling it 'part of the signal path' is not at all accurate. An ideal power supply should do nothing more than what I stated earlier and whatever it does more than that is usually not good.

 

[jacco vermeulen]

Funny thing is that so far no one mentioned the influence of the juice that flows out the wall socket.

I use four 1600VA separation toroids and 2 huge 20amp Shaffner filters to clean and protect the mains on my amp stuff.
I posted pics of them at the Pass monster thread.
My preamplifier runs on rechargeables and has no need for all the hardware, just a simple filter in front of the drop charger.

I read a piece of someone who did measurements on his wall sockets, mains have much more to offer you than just 50/60 Hz.
A battery powersupply has the best separation from the mains when you desire it, no connection at all.

 

[carlosfm]

Yes a power supply that makes noise or introduces time distortions is in effect making a signal but calling it 'part of the signal path' is not at all accurate.

It is, and even more so with op-amps, that's what we're talking about here. Power op-amps.

An ideal power supply should do nothing more than what I stated earlier and whatever it does more than that is usually not good

That doesn't exist.
"Providing enough energy to the amp" is not enough.

Here is a "special" unregulated PSU I made for the dedicated analog stage (with LM7171 op-amps) on my Pioneer DV-575.
You can spot too regs there, but I'm not using them.
It sounds so much better unregulated.

 

[carlosfm]

Does it have a snubber?
For line-level applications with op-amps, this works fine.
No noise, just pure, fast, crystal clean music.
Now you can tell me that with the regs it measures better.
But it doesn't sound better.

 

[yldouright]

protos

originally asked by protos
The problem here guys is that it is ok to measure battery supplies at a constant load such as for a class a preamp etc but what happens under more complex circumstances when we are talking about a class ab amp?

What happens with battery power is no different than what happens with transformer based power supplies, either regulated or not as concerns the load. Either the supply can deliver sufficient energy to the circuit driving the load in a timely and quiet manner or it can't. The circuit is managing the load and that is what needs the power. The signal is much happier unaffected by whatever is going on in the power supply.

 

[yldouright]

carlosfm
Yes, an ideal power supply doesn't exist and neither does an ideal component but stop obfuscating. Op-Amps are nothing more than amplifier circuits shrunk into a package. We work around what is not ideal with them and sometimes they are designed to work with components that are not ideal but the goal is the same; deliver in a timely fashion enough energy to the circuit to do what it was designed to do and do it with as little interference to the source signal as possible. Do you disagree with this goal?

 

[carlosfm]

carlosfm
Yes, an ideal power supply doesn't exist and neither does an ideal component but stop obfuscating.

I will.
This is my last post on this thread.
It's not worth the trouble.
You will never get it, and you will never try to understand what I was trying to say.
I don't know where I was "obfuscating", neither do I admit you to talk like that.

Op-Amps are nothing more than amplifier circuits shrunk into a package.

Of course.
But they usually have high PSRR.
You must make the best PSU you can for digital circuits, like digital filters, dacs, etc, not necessarily so for what we're talking about here.
It is not essential.

deliver in a timely fashion enough energy to the circuit to do what it was designed to do and do it with as little interference to the source signal as possible. Do you disagree with this goal?

No, I don't.
There's much more, but forget it.
You will never get it, even if I stick it on your nose.

 

[yldouright]

originally posted by carlosfm

You will never get it, even if I stick it on your nose.

LOL, well, forgive me my ignorance and say what that "much more" is. Most of the people on this website know the interrelationships of the components but I think it is a great disservice to espouse the idea that the power supply should be anything other than quick, quiet and stiff to a person who is just trying to get his amp to work. If we are talking about putting things in the power supply to compensate for attributes in an op-amp that is one thing but to describe it as "part of the signal" IS obfuscation.

 

[PauSim]

AAA or AA batteries?

Oops. A- on that

from Stereophile:

"As you might expect, the Music-6 requires a bit more in the way of juice; its companion power supply, the Final Laboratory DC-6, is actually a pair of battery boxes, each housing a series-connected bank of 18 D cells, for a total of ±27V"

18x1.5=27

Even I knew that one . Perhaps my post wasn´t clear. What I would like to know is: what chip accepts 27V and gives out only 10 Watts? If each bank consisted of two paralel groups of 9 cells ( 9*1.5=13.5) would be closer to lm1875 or similar specs. But then J Atkinson measured 16 or 17 Watts and that´s what puzzles me. Tda2006 ?

Thanks

 

[protos]

Yeah, it's a cheap trick. Just pretend that audio designers only measure with 8 ohms resistors. I've never met a serious designer doing this, but it is always quoted by those who know diddly of designing a simple piece of electronics in the first place.
Like saying that engineers listen with their meters or scope. It isn't true of course, but what's a little lie if it matches the self-delusional outlook of the would-be know-alls?

Jan Didden

Hey , let´s not get carried away here.I was referring to previous postings on this thread detailing measurements on power supplies.I NEVER said audio designers IN GENERAL only use simplistic measurement techniques.
Actually the point I wanted to make was that WE SHOULD measure these battery or AC ps under more complex dynamic conditions such as when an amp is driving a real speaker load.
ONLY THEN can start a serious discussion of which MIGHT sound better based on empirical scientific evidence.
AFTER measuring the various PS´s we could also , if we want and have the patience, measure various characteristics of the amplifier with the various PS´s connected to confirm that indeed the amp is performing better with a particular power supply.

HOWEVER, my impression is that at the end of the day most members here would choose the PS that sounds best to them.
Experience has shown that this MAY NOT ALWAYS be the best measuring one although it is more probable that it will be the preferred PS.

OK , let´s see how many disagree with that.

 

[Russ White]

stupid noob question

How do I wire my 4 12V batteries to get a positive and negative rails with ground on each? Does anyone have a simple schematic? I would like to test a battery PS with my BrianGT LM4780 boards, but I can't find an example of how the PS circuit would look. Sorry if this is answered somewhere, I could not find it.

 

[jacco vermeulen]

Ground on each i dont really get.

If you desire +/- 24 VDC you connect all batteries in series,
plus(+)of one battery connects to minus(-) of the next battery.
The common ground in the middle:

= +12- +12- +12- +12-
= +24Vdc___0___ -24 Vdc

For double +/- 12 Vdc the same but with 2 batteries:

= +12 - +12-
= +12Vdc__ 0__ -12Vdc

 

[Russ White]

If you desire +/- 24 VDC you connect all batteries in series,
plus(+)of one battery connects to minus(-) of the next battery.
The common ground in the middle:

= +12- +12- +12- +12-
= +24Vdc___0___ -24 Vdc

Thanks Jacco, that is exactly what I was looking for. In the case of Brians board there is a +g and -g pad, and I thought perhaps I had to treat these specially. Should I simply use the same ground for both?

 

[Russ White]

fuse and switch

Would it wise to place the switch and a fuse in the center at the same point (in series with batteries) where I get my 0V? Or is there some better way to wire up a switch for DC/battery power supply.