I have built a few relay attenuators and I am very happy about the latest version.
However, one thing that I have not been 100% satisfied with is that there is no way of switching the relais during a zero crossing.
This can sometimes lead to glitches in the output, it is a common issue with all relay based attenuators and there is no easy fix for it.
Relais are just too slow and unpredictable for it to work.
I have thought about this problem for a long time and had a few ideas that I considered but nothing really seems feasible.
But then I got an idea.
What if you combine 2 relay attenuators and use an SPDT analog switch at the output of both.
The idea is that you start with the analog switch selecting Att. 1, this is your current volume setting.
You then change the volume of Att. 2, when that is done you wait for the zero crossing and the analog switch now selects the output of Att. 2.
Att. 2 is now selected and the volume level has now changed.
Now, if the analog switch is only allowed to switch between the 2 attenuators during a zero crossing, the final drawback with relay attenuators would be solved.
You continously switch between the 2 attenuators while you are changing volume, but only during zero crossings.
I have not done any schematic work yet, but I have a few ideas of how to implement it.
Am I totally crazy?
However, one thing that I have not been 100% satisfied with is that there is no way of switching the relais during a zero crossing.
This can sometimes lead to glitches in the output, it is a common issue with all relay based attenuators and there is no easy fix for it.
Relais are just too slow and unpredictable for it to work.
I have thought about this problem for a long time and had a few ideas that I considered but nothing really seems feasible.
But then I got an idea.
What if you combine 2 relay attenuators and use an SPDT analog switch at the output of both.
The idea is that you start with the analog switch selecting Att. 1, this is your current volume setting.
You then change the volume of Att. 2, when that is done you wait for the zero crossing and the analog switch now selects the output of Att. 2.
Att. 2 is now selected and the volume level has now changed.
Now, if the analog switch is only allowed to switch between the 2 attenuators during a zero crossing, the final drawback with relay attenuators would be solved.
You continously switch between the 2 attenuators while you are changing volume, but only during zero crossings.
I have not done any schematic work yet, but I have a few ideas of how to implement it.
Am I totally crazy?
Last edited: