Hello,
I am building an amplifier which runs off 2x 48V 600W SMPS's.
When there is no audio coming into the amplifier, I am switching off the amps, to prevent any speaker hiss etc.
Anyway, the issue I have is, when the main load of the amps come off, the PSU's go into some sort of low power mode, and make alot of switching noise, that is very audible. The output stays at the right voltage, but the audible noise is just too much.
Basically what I want to do, is apply a dummy load to the PSU's, so they are always under some sort of load, whether its Amplifiers, or resistors, just so they remain quiet at all times.
I cant turn them off, due to the nature of the system, as that voltage is used elsewhere, but at very small current, so its not enough to load the SMPS's itself.
So I am wanting to put in some large wattage resistors, but I am unsure how you go about calculating what resistance would be suitable.
I have seen projects where people use old computer power supplies, and have loads on those, but some of those are as low as 10ohm, and pull about an amp or so.
I am just unsure to what level I need to go for 48VDC, to achieve what I want.
Any suggestions?
I was thinking that when I get my system to shut off the amps when the input signals go away, at the same time switch in the load resistors. That way, I guess the resistors will not be a factor when the amps are actually used.
Thanks in advance