In Reply to: Why do some people dislike UL? posted by Ray Moth on March 17, 2007 at 14:12:56:
...compared to either correct pentode operation (fixed, regulated screeen voltage) or triode (screen tied to anode) operation.My *opinion* as to why this is so comes from examination of the screen current drawn in UL mode. I placed a pair of scope probes in differential mode across the circa 1k screen tap to screen R and saw a very distorted waveform, hinting at a very distorted screen current.
To me, this distorted current must "mix" with the obviously less distorted anode current in the transformer itself - and either cancel or add (or both) at a microdynamic level signals - vanishing vital signal information.
This is my take on it.
Regards, Allen
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Follow Ups
- Because in my own extensive tests, it lost information... - Allen Wright 04:34:26 03/18/07 (16)
- NFB in general is problematical ... - Naz 17:30:00 03/19/07 (0)
- I totally agree. "it lost information" - JLH 07:03:35 03/19/07 (3)
- Excellent JLH !! (nt) - drlowmu 11:08:44 03/19/07 (2)
- Re: Excellent JLH !! (nt) - Ray Moth 19:17:52 03/19/07 (0)
- Re: Excellent JLH !! (nt) - Ray Moth 19:15:04 03/19/07 (0)
- Re: Because in my own extensive tests, it lost information... - Eli Duttman 05:36:29 03/18/07 (10)
- That sounds similar ! - cheap-Jack 09:41:35 03/19/07 (6)
- A good example of what I meant - Ray Moth 10:14:13 03/19/07 (5)
- No, U-L was invented by Alan Blumlein in 1937, - cheap-Jack 10:45:07 03/19/07 (4)
- Re: No, U-L was invented by Alan Blumlein in 1937, - Ray Moth 19:04:44 03/19/07 (2)
- Good question on "Ultra-Linear". - cheap-Jack 13:39:39 03/20/07 (1)
- Misinformation - fatbottle 03:46:15 03/22/07 (0)
- Now that's a ref. I'd really like to read! - Try-ode 11:07:10 03/19/07 (0)
- never had easy acccesss to such transformers - and... - Allen Wright 06:00:13 03/19/07 (0)
- also - Try-ode 06:06:31 03/18/07 (1)
- I don't - it's only used in pure triode amps (nt) - Allen Wright 05:58:46 03/19/07 (0)