I don't like to promote Bybee's devices. I just note what I hear, and my personal experience with Jack Bybee, himself. I haven't always trusted him, but I do, today.
I prefer to invest my efforts into making better amps and preamps, not just by measurement, but mostly by better sound quality.
Richard, in your previous work, you must have seen some effects that are not easily to explain, and they MIGHT still be classified, even today. This is an example of some such thing.
I prefer to invest my efforts into making better amps and preamps, not just by measurement, but mostly by better sound quality.
Richard, in your previous work, you must have seen some effects that are not easily to explain, and they MIGHT still be classified, even today. This is an example of some such thing.
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I have a couple different network analyzers which will measure the phase and magnitude thru and across the device. It turns up some unusual things that you dont know is there and having an affect.
BTW - after you listen... remove that big C and see if it contributes to the change you heard. It could be mostly the affect of the C across the line and not much more than that.
THx-RNMarsh
Ah found it, 65611. I thought it might be buried further back in the thread. Also when I first looked at that post the schematic seemed to be hidden, there was just the black backdrop curves.
For the same reason OCC copper wire isn't used in mainstream electronics, only "high end" audio where all the rubes are.
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Not true, Marce. For example,a local hspital has been usning one of my filters since 2002 (or 2003) to feed their instrument bench during operations, although I told them it wasn't medical electronics grade stuff. They swear they get more accurate and very stable (less last number twitching) with it after trhey recalibrate their instruments with the filter on line. A few private opticians use them for eye testing and measurement gear.
More to the point, far too few people outside audio even know such devices exist and are possible victims of various sellers. My sales papers clearly state that this is not medical electronics grade equipment and should not be used as such, but I can't stop somebody from buying one and using it outside his home.
Since every daddy loves his child, I am not the one who should be talkning about my own gear. I plan to see Nigel Pearson this summer, and I'll make sure he gets one and does his thing with it. He is not one to be fooled easily and he certainly can think in and outside the box, and that's all I am looking for, an open mind.
The collector loads are not equal anyway (the input impedances of the transconductance stages with Q17 and Q18 are not that high). But if you are concerned about d.c. balance due to power dissipation in the input pairs, you could retain the 470 ohm R's for the inverting input sides and bypass them with capacitors (EDIT: just saw Dimitri's last post). I suspect the power dissipation balancing will be a small effect. Due to the complementary design the imbalances ought to first-order cancel anyway. Right now you have some substantial local gains and consequent Miller (and voltage-variable) capacitance at the inverting inputs, which may account for some of the divider impedance effects on distortion.Yes.But unbalance the LTP ?
It may help to balance the input impedance (~100 ohms shown) with the divider impedance (either about <1175 or <47 ohms). Look at the distortion at the input bases.
I know it was a simplified example, but cascoding the input pairs ought to help if the input C effects are important.
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Bybee has been associated with a number of 'line conditioners' for the last 20 years. Some are 'passive' and some are 'active'. What I am testing is one of Jack's latest line conditioners, and it is entirely 'passive'. The previous Bybee line conditioner, was designed by Jack Bybee and a colleague of mine who I sometimes design with. He works full time in microwave analog ckt design, and does audio, just as an aside. He is now using the 'passive' device that I know have, and he sold his previous 'line conditioner' to my newest colleague in audio listening, completely independently of me, for about $7500. My latest colleague loves the line conditioner that he bought. I heard it in action about 2 weeks ago in his hundred thousand dollar ++ system, which sounds better than I have at the moment.
Will the latest 'line conditioner' make any difference? I don't know for sure, yet.
Will the latest 'line conditioner' make any difference? I don't know for sure, yet.
Diodes at copper crystal boundaries, how do those signals travel down a PCB. especially mixer desks, int' old days you struggled to find a manufacturer who could do the extra large PCBs).
https://www.google.co.uk/url?sa=t&r...EjrbdZBOFsmYhKNto4JOrEg&bvm=bv.91427555,d.d2s
dimitri, i was not working to optimize this amp. Just took an existing one in my LTSpice library as an example to illustrate what i said here:
http://www.diyaudio.com/forums/loun...torch-preamplifier-part-ii-9.html#post4301513
While this post was received like a blaspheme against the one and unique electronic religion by a brunch of good fellows, including Bonsai, jan.didden , SY, and, of course Wally. Followed by a big heckling throughout the kindergarten.
bcarso, I agree with you too, of course ;-)
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Yes, exactly. Going back to the aircraft analogy, getting them to fly safely is a multi-stage process: first decent wings and engines need to designed by people, engineers who specialise in those fields, as Jacco indicated. However, those same people are not responsible for integrating the components into the aircraft, and ensuring that the full package does its job - there are levels of engineering involved all the way through, over the entire journey of ensuring that a plane will do its job correctly.
I've chosen the path of being the integrations man, the one who makes sure that the final product, a plane, actually does its job well - which is getting passengers safely from one place to another. Everything else is of lesser importance, perfect wings and engines don't mean a fart if the plane crashes every time it tries to land ...
It appears the n.i. input distortion is negligible in closed-loop operation. I get comparable distortion results for the two different feedback divider impedances (for the higher one the feedback C goes to 40pF). I did an even more simplified/idealized sim with a perfect output buffer. A slight improvement for both high and low Z networks can be had by returning the collectors to the emitters-10 ohm R's of the transconductance stages.
But as you say, you're not trying to optimize the design, just show an effect.
EDIT: I guess the question is---is there a design of the input stage and possibly subsequent stages that would, except for noise, which is well-understood, yield identical performance for different feedback impedances?
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I saw that Audio Note was using some sort of squirrelly material in a top-of-the-line phono preamp, which was presented to me as an ideal by a friend. I also noticed from the pictures that the wiring had graceful curves which said friend tended to emulate in his own wiring. Oh well. I think I quipped that their copper foil, paper, and oil capacitors were the first I'd seen, in their fairly low values, that had so much leakage current that they practically needed a d.c. servo. It was said by AN that the important thing about them was their damping of piezoelectric effects.
I haven't laughed so much in weeks. The worry is that you are probably being serious.
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