I built recently a DoZ preamp based on Rod Elliott kit (P37A) powered by his P-05-rev B power supply.
http://sound.westhost.com/project05b.htm
The PSU is a standard LM317/397 dual supply but with a twist - it has a AUX voltage output to drive a muting relay.
I had a turn ON thump so the relay was a must. However I did not have any turn OFF noise. I included an output relay where the output is normally shorted and the relay has a delay of around 0.5 sec, just enough to avoid switching noises.
The turn ON thump is gone but I have a sharp thump after switching preamp OFF - looks like from the relay itself. CAn I tweak my relay setup somehow to get rid of this? MAybe a capacitor across the relay supply to slow down its reaction.
http://sound.westhost.com/project05b.htm
The PSU is a standard LM317/397 dual supply but with a twist - it has a AUX voltage output to drive a muting relay.
I had a turn ON thump so the relay was a must. However I did not have any turn OFF noise. I included an output relay where the output is normally shorted and the relay has a delay of around 0.5 sec, just enough to avoid switching noises.
The turn ON thump is gone but I have a sharp thump after switching preamp OFF - looks like from the relay itself. CAn I tweak my relay setup somehow to get rid of this? MAybe a capacitor across the relay supply to slow down its reaction.