mrarroyo
Been here a while! 
Our man in Miami!
Posts: 1,003
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Post by mrarroyo on Mar 10, 2011 1:08:50 GMT
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Post by 405line on Mar 16, 2011 12:58:24 GMT
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Post by 405line on Mar 16, 2011 14:28:02 GMT
Frequencies,vs impedance etc....a lead acid battery acts as both psu and filter due to its enormous equivalent capacitance...as far as I know it makes little if any noise, even when you place a charger across it.
Jeff Rowland you all may have heard of him, he knows a thing or two about amplifiers he makes audio gear for a living and sells this kind of gear for ££££'s. I don't think he would use this battery technology in a m.c preamp of all things if he thought it would add noise etc..I cant see much difference to what I have proposed.
In particular his sites says "Even when in AC mode, the power supply is simply float-charging the batteries while both, in parallel, supply juice to the circuitry. As a result, even while recharging the batteries, you'll still achieve almost all the sonic benefits of battery power".
Clean power
Any amplifier or preamp is essentially a DC power supply modulated by the AC signal. This makes the quality of the power supply a vital issue. You often hear sophisticated, well-designed AC supplies described as being "almost as good as a pure battery," and the best of these designs indeed come very close. Rowland uses the real McCoy.
Inside the chassis of the power supply, which handles both the Coherence and Cadence, a large potted toroidal transformer is mounted in a deep central well and flanked by a pair of Panasonic 12V, 7.2 amp/hour, rechargeable lead-acid batteries in their own machined corrals. These form a full-function, high-quality AC power supply that also acts as a sophisticated, microprocessor-controlled battery charger. The main technical advantage derived from a battery-powered preamp stems from its inherently low noise and very low source impedance, maintained over a wide frequency range. In addition, pure DC operation avoids the conducted and radiated noise typically produced by rectifiers and regulators.
In this design, the preamp and phono stage always use battery power. Even when in AC mode, the power supply is simply float-charging the batteries while both, in parallel, supply juice to the circuitry. As a result, even while recharging the batteries, you'll still achieve almost all the sonic benefits of battery power.
Lead-acid batteries lack the "memory" effect of nicads, but good design practice and battery longevity dictate that you not deep-cycle them. Rowland designed the system to prevent discharging below 50% of full charge. Once you've gone that far—which takes between 14 and 18 hours of pure DC operation—the charger automatically kicks in, and you're back in float mode without having skipped a beat. I found that if you run the Cadence and Coherence simultaneously, you should manually return the power supply to AC mode before going to bed to prevent automatic cycling. Otherwise, you may lose your memory settings after the charger reboots.
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Deleted
Deleted Member
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Post by Deleted on Mar 16, 2011 20:30:01 GMT
That's not completely true.
You can float 24 x series connected 2,200AH batteries (52.6V nominal) and still hear some fairly low level hum from the rectifiers.
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mrarroyo
Been here a while!
Our man in Miami!
Posts: 1,003
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Post by mrarroyo on Mar 17, 2011 0:47:51 GMT
I have two of the Red Wine Audio components and used to own two other pieces. They all sound fantastic although quite expensive.
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