Tindie Weblog | Hello-Fi Speaker Safety Board


After I began studying about this Speaker Safety module and the assorted chips it may well substitute, I had an “Aha!” second. I’ve a reasonably first rate Denon DRA-295 amplifier from the early 2000s, and when it first activates there’s a pause of some seconds earlier than an audible click on could be heard. This click on is a relay that disconnects the speaker outputs from the first amplifier circuit. I had by no means actually considered it earlier than, however once you activate older hi-fi amplifiers you sometimes get transient noise on the audio system. This isn’t nice, particularly if it has a big DC offset or instantly places an excessive amount of energy into your audio system.

So in some unspecified time in the future, amplifier producers began including safety chips that might look ahead to the facility provide to stabilize, and examine for no overvoltage or different points on the amplifier output earlier than energizing the relay and enabling output. This circuit may also reply rapidly sufficient to save lots of your audio system if the amplifier circuit will get broken and shorts the speaker output to the provision rails, for instance. This could rapidly consequence within the speaker coils overheating and self-destructing!

Nevertheless, the safety chips have been recognized to fail and a few amplifiers by no means included them within the first place, so you possibly can seize this module so as to add safety. This module is actually a duplicate of the TA7317 safety chip that was utilized in many amplifiers, together with high-end amps from Nakamichi. So so as to use it, you simply want an exterior relay and a pair capacitors and resistors. Fairly straightforward to put in, and an effective way to guard your hi-fi audio system from injury.


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