gres
Full Member level 4
It's a copy of radmor secure system, but with "present time" components, that works very well.
System is made to secure power amp and column loud speaker. Works with almost all kinds amplifier, all costs are very low.
Functions: eliminate "knocking noise" when you turn on / off amplifier,
Protect power amp against overheat ( it cut loud speakers when temp is more than 85 at radiator).
Protect loud speakers columns against DC at amplifier output ( when it recognize power amp damage, it cut speakers).
System can be plugged at any amplifier and amplituner.
Elements:
R1 and R2 -220Ohm 1/4W
R3 33k 1/4W
R4 22k 1/4W
R5 150 Ohm 1/2W ( when heating is to strong 1W)
R6 temperature-sensitive resistor NTC 4.7k with room temperature (22 0C)
R7 and R8 6,8k 1/4W
C1 and C4 -4,7uF 63V
C2 and C3 - 100uF 25V
D1 to D6 - 1N4148
D7 - Zener 24V 1/2W ( better 1W )
D8 and D9 - 1N4007
Q1 to Q3 BC547C
K1 - relay 24V with two pares of contacts that can be load 2A(20W) to 5A(+80W)
Attention: Presented board is without zener's diode (D7 ) andR5, instead of those I used LM7824 that makes the board easier.
Scheme ( version with zener's diode)
Scheme for PCB ( version with LM7824 stabilizer)
Text comes from: https://www.elektroda.pl/rtvforum/topic1509481.html?sid=cf3524dc0f882f7c35ecfb1dc77808dc