I have built this projekt on an veroboard,I use it on +- 12v with 12v relay.It works fine there is voltage at Q3 collector and the voltage is zero with DC at R1,it works fine,when the relay is NOT connected,if I connect the relay the voltage at Q3 collector drops to ZERO!!Remove it 12v again,i have tried different transistors,different relay´s the same zero volt with relay.It drives me crazy!!!
ryssen said:
It is a DC-detector circuit with input from both channel output of power amp.
Output of this, controls a relay circuit that turns off, if DC is detected
I only can say you should check that you have
- put together the correct points on these 2 circuits.
- mounted all transistors leads correctly - B,C,E
Maybe someone else can see from circuits what the fault can be.
http://sound.westhost.com/p33-fig1.gif
http://sound.westhost.com/p33-fig2.gif
The diode that is parallell with the coil in relay
is probably turned the wrong way.
This diode should NOT conduct any current!
It is only for get away with current transients going the other way. In the monent when switch on/off.
I really do not know why is zener diode D2 ????
Because normally only one diode is used, in opposite direction, like D1
across the input coil to relay.
I use 1N4148 for this.
You should measure the resistance of the relay coil.
And adjust R6 so that you get 12 volt across the relay coil.
U-supply = U-R6 + U-coil
If supply is 18 volt and Rcoil is 200 Ohm
then you make R6 = 100 Ohm. Will be 6V across R6 and 12V across Rcoil
Usupply/(R6+Rcoil) = Ucoil/Rcoil
gives that
R6 = ( (Usupply x Rcoil) - (Ucoil x Rcoil) ) / Ucoil
say
R6 = ?
Usupply = 18V
Ucoil = Relay voltage = 12V
Rcoil = 200 Ohm
R6 = ( (18x200) - ( 12x200) ) / 12
R6 = 1200 / 12 = 100 Ohm
The little black marked part of D1 should be connected to R6.
is probably turned the wrong way.
This diode should NOT conduct any current!
It is only for get away with current transients going the other way. In the monent when switch on/off.
I really do not know why is zener diode D2 ????
Because normally only one diode is used, in opposite direction, like D1
across the input coil to relay.
I use 1N4148 for this.
You should measure the resistance of the relay coil.
And adjust R6 so that you get 12 volt across the relay coil.
U-supply = U-R6 + U-coil
If supply is 18 volt and Rcoil is 200 Ohm
then you make R6 = 100 Ohm. Will be 6V across R6 and 12V across Rcoil
Usupply/(R6+Rcoil) = Ucoil/Rcoil
gives that
R6 = ( (Usupply x Rcoil) - (Ucoil x Rcoil) ) / Ucoil
say
R6 = ?
Usupply = 18V
Ucoil = Relay voltage = 12V
Rcoil = 200 Ohm
R6 = ( (18x200) - ( 12x200) ) / 12
R6 = 1200 / 12 = 100 Ohm
The little black marked part of D1 should be connected to R6.
Build PCB + it function !
Hello,
i build a PCB an construct 2 of it.
I will use them for the Symasym in Version5.2 Audio Amp from MikeB. Look at this forum !
I checked and messured all parts and it work perfect for me.
Hello,
i build a PCB an construct 2 of it.
An externally hosted image should be here but it was not working when we last tested it.
I will use them for the Symasym in Version5.2 Audio Amp from MikeB. Look at this forum !
I checked and messured all parts and it work perfect for me.
An externally hosted image should be here but it was not working when we last tested it.
What voltage using on your P33 speaker protection circuit
Hi dx.master,
I am very interested in your speaker project.
Version 1.03.
1) What is the voltage using for the circuit?
2) Have you test one channel with fault input and other channel is 180 out of phase? (One channel to +ve and other channel to -ve)
3) Have you test one channel with fault input and other channel is normal wave input?
4) What adjustment about your circuit?
Thank you for your help.
Dominic Ko
Hi dx.master,
I am very interested in your speaker project.
Version 1.03.
1) What is the voltage using for the circuit?
2) Have you test one channel with fault input and other channel is 180 out of phase? (One channel to +ve and other channel to -ve)
3) Have you test one channel with fault input and other channel is normal wave input?
4) What adjustment about your circuit?
Thank you for your help.
Dominic Ko
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