In Reply to: RE: SE 2A3 beta follower : spectrum graph @ 1W , finals biasing posted by smart845 on March 28, 2014 at 00:41:12:
I tried a 5K plate load for the 2A3. Didn't change anything else.
Here are THD measurements :
4.3% @ 1W , 3.1% @ 3/4W, 2.1% @ 1/2W and 1.15% @ 1/4W.
Spectrum at 1W RMS:
Fundamental : 1KHz sine wave @ 0dB
2nd harmonic : -28.41dB
3rd harmonic : -41.50dB
4th harmonic : -67.84dB
5th harmonic : -65.60dB
The performance is a little better, but still not optimal.
I will try again the 2.5K plate load and higher bias current.
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Follow Ups
- SE 2A3 beta follower : 5K primary THD measurements ... - deathtube 667 16:45:44 03/28/14 (4)
- RE: SE 2A3 beta follower : 5K primary THD measurements ... - Tre' 18:13:04 03/28/14 (3)
- RE: external AF generator vs. internal generator... - deathtube 667 07:19:21 03/29/14 (1)
- RE: external AF generator vs. internal generator... - Tre' 07:47:06 03/29/14 (0)
- RE: SE 2A3 beta follower : 5K primary THD measurements ... - dave slagle 20:38:31 03/28/14 (0)