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Karma drives HD580

post #1 of 17
12/11/03 at 12:02am
Thread Starter 
I just received some Sennheiser HD580s and found that they can be successfully driven by the Karma portable to reasonable levels. Maybe not to ear-bleed volumes but certainly sufficient to listen casually. And sound pretty darn good.
Given that my pimeta only lasts around 5-7 hours on 2 9V batteries, this is a good thing to know that the "rechargable" karma can drive them independantly. I think the sound with the pimeta is much fuller but nevertheless, it's possible with the Karma.
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post #2 of 17
12/11/03 at 12:51am
That's good to hear.

That sounds like an awfully low battery life for an amp. Are you using alkalines? Alkaline have 3 times better battery life than rechargables.

Not only that, 9V Lithium batteries have close to 2X the battery life of Alkalines, giving you 6 times the battery life of rechargables.
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post #3 of 17
12/11/03 at 1:58am
Thread Starter 
Quote:
Originally posted by Fish Tank X
That's good to hear.

That sounds like an awfully low battery life for an amp. Are you using alkalines? Alkaline have 3 times better battery life than rechargables.

Not only that, 9V Lithium batteries have close to 2X the battery life of Alkalines, giving you 6 times the battery life of rechargables.
Thanks for the pointer. I am using alkalines but never considered lithium and didn't even know there was a lithium 9V battery replacement. If lithiums are less than 2X expensive it might be a good tradeoff. My experience with past 9V rechargables is that their lifetime is poor, I think the same as you're saying. There is also a dc in for a wall wart type of adapter which I should definately look into for at home listening.
My understanding about the poor batter life is because it's output stage is running class A (biased on all of the time) with several cascaded stages of buffers, all drawing current all of the time whether there's any sound coming out or not.
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post #4 of 17
12/11/03 at 10:20am
But at that rate of consumption, Alks get expensive not to mention VERY wasteful. Keep an extra set of rechargables on you, and you'll have plent of music on the go.

Just my humble opinion.

Scott
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post #5 of 17
12/11/03 at 2:33pm
Theresa,

Care to provide any more details on the sound of the Karma/Pimeta/HD580 setup? This is the exact system I'm planning to put together for office/home use (along w/ ety ER6's unamped for "on the go"). Does your Pimeta take DC as well as batteries? If so, any differences in sound between those setups?

Thanks for any info.
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post #6 of 17
12/11/03 at 4:45pm
At that kind of battery life it's possible that the current draw is *so* high that the battery is loosing efficency.

I'd try buying 2 of these guys and see what kind of battery life you get. It could be anywhere from 10-20 hours.
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post #7 of 17
12/11/03 at 5:03pm
Thread Starter 
Quote:
Originally posted by cmpatti
Theresa,

Care to provide any more details on the sound of the Karma/Pimeta/HD580 setup? This is the exact system I'm planning to put together for office/home use (along w/ ety ER6's unamped for "on the go"). Does your Pimeta take DC as well as batteries? If so, any differences in sound between those setups?

Thanks for any info.
In my opinion the sound is outstanding. I don't have a AC/DC adapter for my amp yet but am going to buy one soon (9V batteries are expensive and wastefull). It takes 24volts in, or rather a range and i'm not quite sure what that range is. Seems to me I remember that it goes all the way to 36 volts or so. I bought the pimeta fully built by Norm at Headsave.
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post #8 of 17
12/11/03 at 5:09pm
Quote:
Originally posted by Theresamarie1
In my opinion the sound is outstanding. I don't have a AC/DC adapter for my amp yet but am going to buy one soon (9V batteries are expensive and wastefull). It takes 24volts in, or rather a range and i'm not quite sure what that range is. Seems to me I remember that it goes all the way to 36 volts or so. I bought the pimeta fully built by Norm at Headsave.
Be sure of that range before you plug anything into it, I believe norm usually sells the 24V Elpac for that amp. It really depends on your usage, meI'll probably go with some 9V rechargable and just keep of charged ones on the ready (I already have a charger for my son's swing batteries, so a little more for 9V rechargables isn't a bad deal at all.)

Scott
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post #9 of 17
12/11/03 at 5:21pm
Here's the thing though. If she gets 5-7 hours with alkalines, and alkalines have 3X the capacity of rechargables.. what kind of battery life is she gonna get for rechargables? Pretty crappy battery life, in my opinion.

I'd try the two lithiums and see what you get outa those.
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post #10 of 17
12/11/03 at 5:24pm
Quote:
Originally posted by Fish Tank X
Here's the thing though. If she gets 5-7 hours with alkalines, and alkalines have 3X the capacity of rechargables.. what kind of battery life is she gonna get for rechargables? Pretty crappy battery life, in my opinion.

I'd try the two lithiums and see what you get outa those.
Where did the 3X the capacty of rechargables come from. I know plenty of people use NiMH on here with no problems, in fact that's what Norm sells to go with them.

Scott
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post #11 of 17
12/11/03 at 5:29pm
As you see on this page, in bold print.

http://store.yahoo.com/sterlingtek/9vnimrecbata.html

160mAH of energy!!

As you see right here

http://data.energizer.com/batteryinf...onsumeroem.htm

Everyday's batteries hold 625mAH.

As you can *plainly* see, rechargables are *far* inferior to Alkalines for capacity.
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post #12 of 17
12/11/03 at 5:31pm
It *is* possible, though.. that the alkalines are being drained so fast they are not operating at maximum efficency.

In such a case, rechargables might be able to provide half or even 2/3 or, in best case, equal energy to Alkaline batteries. Not likely to provide more than half, though.
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post #13 of 17
12/11/03 at 5:34pm
Quote:
Originally posted by Fish Tank X
As you see on this page, in bold print.

[url]
As you can *plainly* see, rechargables are *far* inferior to Alkalines for capacity.
Well one what have to see how they work in that situation as well. I dunno blowing through an Alkaline a day would get real expensive (well 2 a day for the Tempo). So, in that case I think the rechargables win out for bang for buck, no?

Scott
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post #14 of 17
12/11/03 at 5:36pm
Bang for the buck isn't the issue i'm raising. I'm concerned that a pair of NiMH 9V batteries might provide only 3 hours of battery life. Thus, you'd have to have 4 batteries just to keep up.

This is an energy sucking PiMeta from hell, though. I have no idea why the PiMeta suffers from such poor battery life. The Supermini, when using 9V alkalines, gets over 50 hours of battery life. Theresa gets 5-7.

Must be the buffers, as she said. But still, that's insane!

P.S. The Supermini gets 12 hours with a rechargable NiMH. It gets 55 hours with an alkaline.
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post #15 of 17
12/11/03 at 5:38pm
It doesn't seem like a PiMeta would be all that portable as well. I say the ultimate sollution is just to keep one amp for portable use (supermini) and one for home hooked up to a wallwart. A supermini will blow the Karma's amp out of the water (220+ mW of power) and still provide decent battery life (3 AA batteries provide about 90 hours of battery life)
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