Re: Logitech Z506 power supply
Two STA540.
Satellite speakers are in single ended configuration, and most likely 4 ohms each, while the center uses two of the same drivers in series on a bridged amp. The subwoofer is 6 ohms, again run from a bridged section. I only have the sub and the sat with the controls, so i can't say for sure, but this is the usual configuration for these 5.1 systems.
It is little, when the speakers are shit like these...
I fixed up the power supply to the degree that i trust it now, so it'll be going back in. I replaced the 10 ohm resistor with a 3W one (original was 1W), and the snubber diode with a HER307 (3A, 1kV fast recovery). Finally, i replaced the 13v zener on the output with a 15v one, this now gives about 17.5V idle, and will help the amps have more dynamic range.
With a 12v, 40W lightbulb as load, output voltage is 14.55v. Previously it used to fall to around 13.8v with this load. Anyway, at this level the PSU has entered current limiting already. The hottest part is still the snubber diode, currently reading 86C after ~15 minutes of continuous load. A bit warm, but better than 106C that the 800 volt diode reached! The resistor does not go past 60C whereas it used to go to 90 previously.
In the subwoofer, the PSU will run a bit cooler than that due to air movement thru the port, and will not be asked to deliver full power all the time, so it should be good. I'll post some pics too.
Originally posted by momaka
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Satellite speakers are in single ended configuration, and most likely 4 ohms each, while the center uses two of the same drivers in series on a bridged amp. The subwoofer is 6 ohms, again run from a bridged section. I only have the sub and the sat with the controls, so i can't say for sure, but this is the usual configuration for these 5.1 systems.
Originally posted by momaka
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I fixed up the power supply to the degree that i trust it now, so it'll be going back in. I replaced the 10 ohm resistor with a 3W one (original was 1W), and the snubber diode with a HER307 (3A, 1kV fast recovery). Finally, i replaced the 13v zener on the output with a 15v one, this now gives about 17.5V idle, and will help the amps have more dynamic range.
With a 12v, 40W lightbulb as load, output voltage is 14.55v. Previously it used to fall to around 13.8v with this load. Anyway, at this level the PSU has entered current limiting already. The hottest part is still the snubber diode, currently reading 86C after ~15 minutes of continuous load. A bit warm, but better than 106C that the 800 volt diode reached! The resistor does not go past 60C whereas it used to go to 90 previously.
In the subwoofer, the PSU will run a bit cooler than that due to air movement thru the port, and will not be asked to deliver full power all the time, so it should be good. I'll post some pics too.
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