10-12-2024, 08:00 PM
After a few checks I realised I needed to get the main amplifier of my noise generator together so that I could test things properly. I appeared to be getting uncertain operation. Today I put things together, apart from the noise generator board which I am still uncertain about. Things came together fairly well but I still got uncertain operation. The amplifier circuit appeared to have some form of parasitic oscillation. Although I have not used those particular components before I could not really see why I was having such problems. To cut a long story short, along with a lot of fiddling, the issue I finally found was a loose connection of the 0V socket on my power supply, resulting in a poor / intermittent ground. With the original noise generator circuit I finally got an acceptable output. It was in the region of lower tens of millivolts (the thing about noise is that specific amplitudes are indeterminate and, at this stage, I'm not getting into detail).
The next step, apart from sorting my PSU, is to finalise on the noise generator circuit. I think it better to use only one supply voltage so maybe the 24 ish volt noise diode will have to go.
Otherwise, in the past week, I have been looking into Spice models for valves. I came across this thread / site in which lots of information is discussed: https://www.diyaudio.com/community/threa...ls.243950/ . I have found models which seem to work as they should and others which may be iffy. There are other sites but most models that I am aware of are mentioned in this thread. Implementation is helping my learning of LTspice which cannot be a bad thing.
The next step, apart from sorting my PSU, is to finalise on the noise generator circuit. I think it better to use only one supply voltage so maybe the 24 ish volt noise diode will have to go.
Otherwise, in the past week, I have been looking into Spice models for valves. I came across this thread / site in which lots of information is discussed: https://www.diyaudio.com/community/threa...ls.243950/ . I have found models which seem to work as they should and others which may be iffy. There are other sites but most models that I am aware of are mentioned in this thread. Implementation is helping my learning of LTspice which cannot be a bad thing.
