So fellas, I just thought about the following design "feat" of the amp I'm going to build. The power switch turns on the mains to the transformer which in turn powers the rest of the amp. Say I have like 50000µF of caps in the power supply. Now if I switch off the amp, the mains get cut off BUT there is still plenty of charge inside the caps that may continue to power the amp for quite a while. How can I get rid of this? I want the amp to be dead silent when I turn it off.
Thanks, I got a private message that gave some insights how to do that: a set of relays that cut the power from the amp circuit as soon as the secondary's voltage is down.
If you are looking at relays to open the power rails, why not use the relay to simply open the speaker connection?
You should always have a bleeder across the supply caps. A bleeder is a large resistor that will drain the charge off the supply caps. Calculate the resistor following ohms law to ensure a current through the bleeder of about 10 mA.
To avoid the turn-on/off pops, use a relay on the speaker connection. Siemens makes some good ones. As does Omron. Look for one that can switch 10~20 A with gold or silver-nickel contacts.
~Tom
To avoid the turn-on/off pops, use a relay on the speaker connection. Siemens makes some good ones. As does Omron. Look for one that can switch 10~20 A with gold or silver-nickel contacts.
~Tom
I'd suggest you look at the possibility of using input mute as well.
Then you have a number of options that can be added later.
DC detect, triggering the input mute.
Higher voltage dc detect triggering the output relay with latch that requires operator action to unlatch, eg switch off power.
Then you have a number of options that can be added later.
DC detect, triggering the input mute.
Higher voltage dc detect triggering the output relay with latch that requires operator action to unlatch, eg switch off power.
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