John Curl's Blowtorch preamplifier part II - Page 3221 - diyAudio
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Old 4th January 2013, 05:22 AM   #32201
qusp is offline qusp  Australia
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depends on the batteries. I have several battery packs with impedance less than 12.5mOhms and capable of 140A
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Old 4th January 2013, 05:45 AM   #32202
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Quote:
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depends on the batteries. I have several battery packs with impedance less than 12.5mOhms and capable of 140A
They all start out fine but dont end up that way in use over time.
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Old 4th January 2013, 06:51 AM   #32203
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They all start out fine but dont end up that way in use over time.
What kind of batteries are-you refering-to ? Acid, cadmium or lithium/ion ? (I'm more thinking to a preamplifier than a power amp, of course)
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Old 4th January 2013, 07:19 AM   #32204
qusp is offline qusp  Australia
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They all start out fine but dont end up that way in use over time.
yeah look i'm not sure you have used anything like what i'm talking about. with proper care in undervoltage protection and the use of chargers designed for them, quality LiFePO4 last for literally thousands of full cycles at much higher discharge rates than what we are speaking of here. i've been using the ones I have here daily for well over 18months and they still perform pretty much as the day I bought them. they are 2300mah. there are also higher capacity ones if need be, but for a preamp I could see them not needing charging for a week (24hrs of use at 100mA for example) so 1000 weeks is ~20years and they should still be sitting at roughly 90% capacity of new

Last edited by qusp; 4th January 2013 at 07:22 AM.
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Old 4th January 2013, 11:05 AM   #32205
gpapag is online now gpapag  Greece
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Don't forget Kelvin caps!
SY
What kind of animal is this ? (I searched but didn't find any explanation)

George
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Old 4th January 2013, 11:31 AM   #32206
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SY
What kind of animal is this ? (I searched but didn't find any explanation)
What ? You don't know ?
(i asked myself the same question)
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Old 4th January 2013, 11:40 AM   #32207
qusp is offline qusp  Australia
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4 leaded caps I presume, with kelvin connection
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Old 4th January 2013, 11:41 AM   #32208
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Originally Posted by gpapag View Post
SY
What kind of animal is this ? (I searched but didn't find any explanation)

George
Probably these:
http://www.nist.gov/calibrations/upload/tn1024.pdf

4 terminal = Kelvin connections.
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Old 4th January 2013, 11:51 AM   #32209
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Kelvin caps, I used them once, long ago.
However, Richard is correct. We both know from EXPERIENCE what a pain in the --- that batteries can be. We have both designed with batteries, they 'float' but give little more than that compared to a 1'st Class AC-DC power supply.
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Old 4th January 2013, 12:46 PM   #32210
SY is offline SY  United States
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Quote:
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4 leaded caps I presume, with kelvin connection
Exactly. Suppression Devices sells them at pretty reasonable cost. The advantages in power supplies are small but measurable.
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