Hello,
My new DIY amplifier is sounding terrific! Still I have a tiny issue with a sizzling sound.
When noting is connected to the input connectors, I can hear a normal breath sound in the headphone. I used this setup to play with all the input cables and the AC cables of the toroidal transformer and also turn it from it's center to minimize the noises. Here is the final result:
The input ground terminals and all the PCB HQG ground connectors are connected to one common HQG screw to the casing. (Not all connected yet in this picture).
If I connect the speakers to the output with nothing at the inputs, there is absolutely no sound in the speakers. No breath, no buzz, nothing! When I connect the RCA cables to the input, same status, no sound. My actual cables are RCA Van Del Hull M.C. Integration Hybrid, Halogen Free type. As soon as I connect the other end of the RCA cables to the output of my Technics SU-9070 pre-amplifier, I can hear a little tiny "gresil" sound. I tried others cables with the same result. The French-to-English translation of the "gresil" French expression is "sizzling". I am not sure if the translation is right. It's not a hum (60 or 120 Hz), it's a little background noise. If I raise the volume, I can cover it with the music, by mean the noise it's not amplified or louder.
I also tried to connect the amplifier AC cable to another outlet, with the same result. Then I tried to connect the RCA cable to another output source, my TASCAM 122 MKII cassette deck. The noise is a little lower but still present.
The weird thing is that this sound was present since day one, but so low that I could forget it. But this morning, is it because it is raining outside, I was listening the FM radio and was able to hear it more in the background.
What would be the cure for this? I saw some schematic with capacitors between the input ground terminals and the casing. Would this be a solution?
Any suggestion is welcome ;-)
My new DIY amplifier is sounding terrific! Still I have a tiny issue with a sizzling sound.
When noting is connected to the input connectors, I can hear a normal breath sound in the headphone. I used this setup to play with all the input cables and the AC cables of the toroidal transformer and also turn it from it's center to minimize the noises. Here is the final result:
The input ground terminals and all the PCB HQG ground connectors are connected to one common HQG screw to the casing. (Not all connected yet in this picture).
If I connect the speakers to the output with nothing at the inputs, there is absolutely no sound in the speakers. No breath, no buzz, nothing! When I connect the RCA cables to the input, same status, no sound. My actual cables are RCA Van Del Hull M.C. Integration Hybrid, Halogen Free type. As soon as I connect the other end of the RCA cables to the output of my Technics SU-9070 pre-amplifier, I can hear a little tiny "gresil" sound. I tried others cables with the same result. The French-to-English translation of the "gresil" French expression is "sizzling". I am not sure if the translation is right. It's not a hum (60 or 120 Hz), it's a little background noise. If I raise the volume, I can cover it with the music, by mean the noise it's not amplified or louder.
I also tried to connect the amplifier AC cable to another outlet, with the same result. Then I tried to connect the RCA cable to another output source, my TASCAM 122 MKII cassette deck. The noise is a little lower but still present.
The weird thing is that this sound was present since day one, but so low that I could forget it. But this morning, is it because it is raining outside, I was listening the FM radio and was able to hear it more in the background.
What would be the cure for this? I saw some schematic with capacitors between the input ground terminals and the casing. Would this be a solution?
Any suggestion is welcome ;-)