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Post by MartinT on Aug 17, 2017 14:16:23 GMT
The Yuasa brand is very well known for small lead-acid batteries. A DAC should be largely a steady-state current draw, but there will be lots of small ripples which the low output impedance should suppress quite nicely.
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Post by ant on Aug 17, 2017 15:26:08 GMT
I have found yausa batteries on most of the motorbikes I have had and found them to be better quality when i have replaced batteries on the older bikes I had.
The output stage of a dac ( or anything else for that matter) will pull more current on a transient such as a bass drum ect, the more headroom you have in current capability from the psu wether smps, battery, pi filter, ect the better. A battery is theoretically best as there is no noise to filter from it, and the v/out doesnt fluctuate until its charge is almost depleted. A dac is not a steady current draw, apart from idling, as soon as you put a signal through it the current draw is all over the place above the idle current. It will draw whatever current is required by the signal you put through it. If the psu cant supply this current, you will get distortion. A battery will supply the current, it will just discharge faster the more current it is asked to supply
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Post by MikeMusic on Aug 17, 2017 16:10:42 GMT
Thanks both
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Post by MartinT on Aug 17, 2017 16:17:18 GMT
Thanks, Ant. I was thinking of op-amps being class A but a DAC chip has much more going on, as you say.
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Post by ant on Aug 17, 2017 16:58:27 GMT
No probs, you'd be surprised how much current a dac or phono stage or source component can actually draw, and this will also depend on the input impedance of the (pre) amp its running into. Again it's one of those things that are to some extent system dependent. A class a op amp output stage will want more current capacity again given its bias. A few years ago I was running a beresford tc7510 off iirc a dewalt drill battery and it made quite a difference for the better. I don't do it now, the missus wont let me have anything that looks lashed up any more :-)
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Post by MartinT on Aug 17, 2017 17:23:10 GMT
Hah - I don't mind lash-up for testing, but then I try to make it look tidy.
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