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Old 26th January 2007, 07:44 PM   #1
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Default Any consensus on implementing a battery PS for a Tripath amp?

Especially a 36 volt one for AMP11?

Thanks!

George
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Old 26th January 2007, 07:45 PM   #2
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Default A 41Hz AMP11 that is.

Beduh, beduh, beduh.
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Old 27th January 2007, 08:35 AM   #3
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36V doesn't sound like an ideal battery voltage to me.

The problem the more batteries you use, the worse your
ESR will get. This will slow down your dynamics.
That is one of the main reasons I've figured out when using
smaller batteries (10Ah resp 25Ah with 15-25mR) in my early T-Amp days. A SMPS, as you can read in quite some threads around here, would deliver more dynamics. However they won't deliver the black background.

For a T-Amp 12 V supply, I am running "one" Northstar 90 battery
with 2mR ESR, which is giving me real great results.

Keep also in mind that especially smaller batteries degrade
over a much shorter time-frame than the big ones, because
you need to reload them much more often.

Cheers
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Old 27th January 2007, 11:36 AM   #4
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Default Thanks!

Where did you obtain the Northstar?

George
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Old 27th January 2007, 01:44 PM   #5
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Online (Ebay-dealer) in Europe!

I think you'll find plenty of online-offerings in US. You'll save some $ in US anyhow. They sell at least 20% higher in Europe.

These beasts can draw quite some power, when charged.
Take a particular look at the chargers.
In any case it should support battery recovery charging.

It happened once that my battery ran down. It took some days, but it
happened. My first charger did not manage to bring the battery back
up again. Now I got a charger with a more intelligent charging mechanism, which works fine.

Be careful not to shortcut them! 4500A will melt horseshoes in a second!


BTW. I got a second one for my DAC!

With my battery-powered Notebook I am mainly fully independent from mains by now!

My sound background is as black as it can be -- I guess! Dynamics are overwhelming.

Cheers
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Old 18th December 2007, 07:37 PM   #6
Taipee is offline Taipee  United States
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Default Add some caps?

Hey guys, for low ESR.... let's look at another option:

If you use series SLA batteries, the ESR will go up...

but why not use a BIG yet good quality Electrolytic bypassed w. a hi-quality Film cap in parallel with the batteries?

This would give a potentially very low ESR for big instantaneous current demand and still allow higher voltages for running something like an Amp11

you could run 24V or 36V and benefit from all that sustained power + the current reserve, still with that black background.

Gotta say that even the small tripaths, running off a 12V SLA can sound really stunning... as implemented in the Maestro t-Amp (sadly no longer available) .... and this when playing into 4 Ohm speakers with an efficiency of 93dB at 1m at 2.83V... plays really quite loud in a 16' by 20' room... only occasionally sounds hard (clipping).

To put it simply, compared to even a good high current SMPS, SLA sounds flat out better, more detail, more dynamics, better imaging 3D, etc.... and kicks big time, with no current starvation "farts".

Try it, Yule like it (pun intended, as it's the season).

Can't wait to try this with a pair of Amp11s running w. 24V, should get about 45 to 50W per channel into 4 Ohms... or 36V, will get more than 75 Wpc !!
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Old 19th December 2007, 08:54 AM   #7
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Default Re: Add some caps?

Quote:
Originally posted by Taipee
Hey guys, for low ESR.... let's look at another option:

If you use series SLA batteries, the ESR will go up...

but why not use a BIG yet good quality Electrolytic bypassed w. a hi-quality Film cap in parallel with the batteries?

This would give a potentially very low ESR for big instantaneous current demand and still allow higher voltages for running something like an Amp11

you could run 24V or 36V and benefit from all that sustained power + the current reserve, still with that black background.

Gotta say that even the small tripaths, running off a 12V SLA can sound really stunning... as implemented in the Maestro t-Amp (sadly no longer available) .... and this when playing into 4 Ohm speakers with an efficiency of 93dB at 1m at 2.83V... plays really quite loud in a 16' by 20' room... only occasionally sounds hard (clipping).

To put it simply, compared to even a good high current SMPS, SLA sounds flat out better, more detail, more dynamics, better imaging 3D, etc.... and kicks big time, with no current starvation "farts".

Try it, Yule like it (pun intended, as it's the season).

Can't wait to try this with a pair of Amp11s running w. 24V, should get about 45 to 50W per channel into 4 Ohms... or 36V, will get more than 75 Wpc !!

Hi.

This is what I am saying all the time.
You could also start with low ESR battery. My Northstar NSB 90 comes with 2mR. This will be hard to beat with caps.
However it is a known fact that paralleling low ESR caps
speeds things up on poor ESR batteries.

Another issues is the ageing issue which comes with the batteries.
This will have an impact on the transient response over time.
On small ones it hits you even faster, since you have to charge them much more often.
From that perspective it's not a bad idea either to have a low ESR power reservoir and a sniffer ( e.g. 8* 470uF) in parallel.

In any case this will not be a low cost solution. A good battery, the caps and a good charger will cost you much more than the SMPS around here.

Just to mention it. You should also go for a good charger. This will
increase the liftetime of the battery.


BTW: Did anybody try DC-DC converters to get a higher voltage
from a 12V SLA?

Cheers
Klaus
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Old 19th December 2007, 10:59 AM   #8
Pano is offline Pano  United States
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Default Re: Re: Add some caps?

Quote:
Originally posted by soundcheck
My Northstar NSB 90 comes with 2mR. This will be hard to beat with caps.
Uh.... at what frequency? DC?

I've found SLA batteries not to handle HF very well. Doesn't matter for many things. Does for audio.

If you want to use batteries, just be aware that they have their limitations just like other power sources. But I like them, they work well. =)
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Old 21st December 2007, 06:27 AM   #9
Taipee is offline Taipee  United States
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Default Amp 11 assembly?

Hey Pano, I enjoy your comments, it's well thought out stuff.

I have a Question, and tried to email you directly, but cannot yet do this as am not yet with "full status"... so mebbe this way... I'm looking for someone who can assemble a couple of Amp 11s from 41Hz in exchange for trade or moderate cash .. my surface mount soldering skills would probably be ok but my eyes are not up to the task and I don't fancy buying a magnifying glass lamp that costs more than my amps!

Rather spend it on batteries and good caps...so...

I'm very intrigued by the possibilities of doing something as good as the RWA stuff, but at a lower (much lower) cost... and the Amp 11 uses the same Tripath....
Also, Autocostruire has a pre-built board using the 4x100 tripath, have you had a chance to compare that or the 2050 to the lower power tripaths and or the UcD?

If the 4x100 sounds as good then maybe that is the way to go: 4 channels at high power, can easily bi-amp and or parallel a la Winsome Mouse for more current (my spkrs are 4 ohm).... possibly no soldering at all, and i already have a pretty nice case ready (an old McCormack Line-drive passive pre) using a good quality Noble pot... just throw in the boards, hook up them batteries and smile while the feet tap. All of that with good WAF.

do you have any suggestions for pre-built or an assembler to help?
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Old 23rd December 2007, 01:19 AM   #10
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Batteries can be good. But they are not perfect and probably are not the lowest-noise power supply. See here:

http://www.tnt-audio.com/clinica/reg..._noise4_e.html
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