I understand your excitement, but please keep flies and meatballs separately. Lovely non-linearities are good for effect boxes, while "audio enthusiasts" love them for something completely different: for absence of "non-lovely non-linearity". I (as one of enthusiasts for whom you are trying to speak) would prefer absence of that "lovely non-linearity" as well, but it is impossible, unfortunately.
Oops, please excuse me for being so far out - I'll put it down to tiredness... well, it is coming up to 3:20 in the morning here and I really should have been asleep long ago! Zzzzzzz...
I hope others take a guess at the source of the curves that you attached in post #28
It's a useful way to deal with an ill-considered 'test' (that relies upon a flawed premise and hence has no real credibility) that is purportedly masquerading as a useable procedure.
Never mind.
Gordy off to bed...
Let's not turn this into another tube vs SS debate. OT posts deleted.
I've seen some journal papers on microlithic vacuum tubes. There is even a small book out. All of the ones I saw were using point field emitters, which would be too unreliable for ICs. But that was 10 years ago. New developments like carbon nanofibers or tunneling emitters may have changed the game. The real money behind it is probably the flat screen video monitor research. Maybe we will be using flat screen monitors someday to make amplifiers. Interesting audio/visual effects too.
Edit: OOPs, Sorry, I made a goof on the mystery tube plot scaling data. It's plotted with 2 Volts per grid step, not 1 V. Mu of 10 then obviously.
Edit: OOPs, Sorry, I made a goof on the mystery tube plot scaling data. It's plotted with 2 Volts per grid step, not 1 V. Mu of 10 then obviously.
Last edited:
Straight curves or not if it is a triode it is not linear. Pick an operating point draw a load line. The straights (curves) are progressively closer together on the right side of the operating point and vice versa. The decreasing spacing of the curves means decreasing mu from the left side of the graph to right this is classic triode 2nd harmonic distortion.
BTW add a pinch of partial bypass to the cathode resistor and you can straighten any triode curve. Remove the bypass capacitor from a capacitor from a triode, if you put it on a curve tracer and the curves look like those of a pentode. Vary the value of the cathode resistor the rate of curvature will also change. I think that it is FM.
Also take a look at the old texts of pentodes turned triode. Convex curves of pentodes, concave curves of triode strapped pentodes and straight curves of ultralinear.
I would not be surprised if there was some of this Magic going on it the curves posted in this thread.
DT
All just for fun!
Many people believe that linearity which is achieved via local feedback (which would be the case for a perfectly linear triode) sounds different from equal linearity achieved through global feedback. Perhaps because local feedback tends to have a higher stability margin, or better transient reproduction due to the dominant pole being above the audio range. Don't ask me, I'm just suggesting that the two might not sound the same.
Yes we know, but above about 2mA those curves really are equally spaced! So just stay out of the sub-2mA region.
Member
Joined 2009
Paid Member
Pretty neat
Would you mind tracing the pentode curves? Datasheets seem to be lacking.- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.