In Reply to: RE: Sample Sine Wave posted by vinnie2 on February 23, 2019 at 17:56:28:
According to my simulation, your 845 is starting to pull grid current at about 3 volts output (about 1 watt) using your operating points. Your 6SN7 driver is not going to do its job alone. Your sine wave isn't clipping but it sure is producing harmonics (on paper). It would be interesting to see what the real harmonics would be using your OPT. Depending on your music source, your probably not picking up on the harmonics but they are definitely there according to your scope. What is your plate and cathode resistor values.
You should look into a UMC204HD and the free ARTA Software. You get a scope, THD, FFT along with many other features. Its easy to implement and setup, I set it up in an hour. It's not too bad and reads very close to my HP Distortion analyzer.
Edits: 02/24/19
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Follow Ups
- RE: Grid Current - deafbykhorns 14:56:39 02/24/19 (7)
- RE: Grid Current - vinnie2 17:59:00 02/24/19 (6)
- RE: Grid Current - deafbykhorns 06:00:36 02/25/19 (5)
- RE: Grid Current - vinnie2 06:44:26 02/25/19 (4)
- RE: Try the 300B with a good DHT - deafbykhorns 07:54:02 02/25/19 (3)
- RE: Try the 300B with a good DHT - vinnie2 09:19:20 02/25/19 (2)
- RE: Try the 300B with a good DHT - deafbykhorns 13:01:02 02/25/19 (1)
- thanks! nt - vinnie2 13:59:12 02/25/19 (0)