Oh, I missed that, but it was 10 years ago and I haven't read everything on the board since I signed up. I'll read through more carefully, and may want to start a new thread similar to that.I have already experimented with the technique, but to remove crossover distortion:
https://www.diyaudio.com/community/threads/a-dive-into-the-past.252143/post-3839604
There are earlier, more detailed posts somewhere, but I cannot find them.
It should work for a transformer too, but the implementation is going to be tricky
I'm thinking the reason this technique was never used outside of magnetic tape recording) is it's usually "too complicated" (too much extra circuitry) and not enough benefit, though it was clearly needed for magnetic tape.
Yet another thought, dithering noise for lower bit depth ADCs was common to reduce sampling distortion before delta-sigma took over everything. AC bias does a similar thing, and I'm wondering if such noise (probably filtered so that it's all ultrasonic) could be used in tape recording as well as other magnetic-related applications. This seems off-topic for an oscillator, but maybe not.
Media Technology: I received the parts today
First quick check on a 15K resistor Distortion was high (off scale on the linear readout) and the excess noise index (Quan-tech 315C) was 20 dB higher than the Vishay foil. Really bad.
I will do a more detailed report later.
First quick check on a 15K resistor Distortion was high (off scale on the linear readout) and the excess noise index (Quan-tech 315C) was 20 dB higher than the Vishay foil. Really bad.
I will do a more detailed report later.
Another check of another 15K and a Yaego. The Dales are clearly defective. Both distortion and noise. The second 15K noise was 30 dB higher than the Vishay foil. The Yaego was about 10 dB higher than the Vishay, all measured at .1W. The noise problem suggest a real manufacturing problem, most likely termination but it could be flaws inthe laser trimming.
These instruments were created to weed out bad parts for high reliability applications, not for audio nuts BUT they are great for checking nonsense audio claims.
These instruments were created to weed out bad parts for high reliability applications, not for audio nuts BUT they are great for checking nonsense audio claims.
Thanks for running the quick test. Will be interesting to see the rest particularly the ones that seem to measure clean.Media Technology: I received the parts today
First quick check on a 15K resistor Distortion was high (off scale on the linear readout) and the excess noise index (Quan-tech 315C) was 20 dB higher than the Vishay foil. Really bad.
I will do a more detailed report later.
Correction: The Holsworthy are the YR1B. I think all of my previous posts had the series part number reversed.
Wow.Another check of another 15K and a Yaego. The Dales are clearly defective. Both distortion and noise. The second 15K noise was 30 dB higher than the Vishay foil.
Not bad for the Yageo considering the "60 dB" difference in price. IIRC the Vishay S102 is at or near the noise floor?The Yaego was about 10 dB higher than the Vishay, all measured at .1W.