Power Amplifier Speaker Protection Circuit Schematic
While switching a power amplifier on, a loud thump sound is heard to sudden heavy discharge current through the speaker at the time of power on. This current may damage the speaker, especially in case of direct coupled amplifier.
| PARTS LIST | |
| R1 | 5KΩ Preset |
| C1 | 1000µF 25V |
| C2 | 0.1µF (104) |
| D1 | IN4001 |
| Q1 | BC107 |
| RL1 | 9V 500Ω Relay |
| LS1 | Speaker |
The circuit given here protects speakers from the current surge. When the amplifier is off, relay switch is also off. When the amplifier is switch on, R1 and Ci provide delay of a few seconds to switch the transistor on which energizes the relay.
BC107 NPN TRANSISTOR
Delay time is proportional to value of R1.
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Please send your ideas, which are very important for our success…
#1 by GreenDiamond on March 2nd, 2012
I am an idiot so I would rather not risk my speakers by making one myself so I am wondering where I can buy factory made units on line?!
#2 by Nkwenti on November 24th, 2011
I use C945 transistor for this schematic and it works well….thanks for the diagram sir
#3 by Yoram on November 3rd, 2011
Capacitor use is just fine do not listen to Pasanlaksiris advice!
#4 by sandra akoth on May 16th, 2011
please send me a 50w power amplifier design driven by a pre amplifier
#5 by pasanlaksiri on April 24th, 2011
Hmm hey, you better at least use 555 timer for this instead of capacitor.
#6 by Hotwaterwizard on March 30th, 2011
Nice circuit. I would love it if it could use a 12v Cube relay instead of the 9v relay