Hi,
capdegat said:
As my mains is utter rubbish I've been looking at commercial stuff and its damn expensive . I was thinking along the line of using a sealed lead acid battery on a timed overnight charger which feeds a large dc/ac inverter during the day . I have done lots of backup systems before but not for my hifi . Has anyone tried anything like this before ?
I can think of two easy solutions. Some people I know use very large Pro Audio Amplifiers (> 500W into 8R and 2 Ohm load stable, bridgable - this gives up to 120V with well over 20A current capicity) and a simple generator as source to produce their regenerated mains for equipment converted to US mains input. This seems to work very well, but you need to house the amps far away as they invariably use very noisy cooling arrangements.
I personally would probably choose instead a "fill in" solution. This becomes complex to design, but requires fairly extensive electronic design.
You need a PLL which locks onto the mains frequency and produces a low distortion sinewave from that, in fact, it would produce what the mains should look like, constant voltage, low distortion.
This clean signal can then be compared to the actual mains and the difference derived. We then connect a transformer in series with the mains and drive it from an amplifier which amplifies the previously derived error voltage and thus "fills in" reduced voltage, bucks out excessive voltage and corrects for flattopping (high distortion).
The advantage is that you only need an amplifier powerfull enough to supply the difference between what the mains should be like and what it is, making the whole thing feasible for passive (quiet as no fans) cooling and fairly affordable.
Meanwhile I am working with a startup company on designing some high end audio gear which has the ability build in to work within tolerance and optimally from 205V - 256V mains voltage (and 96V - 135V) without using switched mode supplies and even without internal regulators for most of the audio circuitry, with DC filters.
Plus, we specified transformers which have electrostatic screens (and use some other tricks I am not inclined to divulge) . This makes the sensitivity of the gear to mains quality drasticallly less, at a notional increase in cost.
I suspect we could repackage the technology together with a "balanced power" insulation transformer build like our own mains transformer easily as a power conditioner, but our own gear does not need it and why should we entertain the competitions poor designs?
Ciao T