Completely possible to do; Bonsai has a nice little writeup on a buffer using a LM4562 with a bit of pull-down to bias it class-A. Pity he never checks to see how the circuit performs without the pulldown bias.
http://hifisonix.com/wordpress/wp-c...niversal-Small-Signal-Class-A-Buffer-V1.0.pdf
In either case, the commutation of the output stage is certainly there, but I wouldn't exactly hold my breath for anything ground breaking to come of this line of reasoning. Small currents, low supply impedance (if you do your bypass per DS recommendations), and PSRR are all conspiring against it. Maybe useful for applications where PPM and sub-PPM performance is needed (and you're driving a relatively high impedance load). It's not exactly like the designers put garbage OPS in opamps nowadays.
I haven't seen much in the way of measurements as to its improvement (and each chip and circuit will show something different), even Nelson commented that it's a cute, generally harmless trick. Plenty of comments, but little in the way of characterization.
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Bear, is it really off topic?
You suggested to actually test some different ideas (chaining opamps and so on) but which way will that lead to some progress if no controlled listening test is done?
Wouldn´t any result just provide another round of discussion why "sighted listening" can´t provide more than anecdotical evidence or why it can?
Nevertheless i´d appreciate to have a seperated thread to discuss in detail about controlled tests and maybe to have an associated sort of wiki with confirmed basics and facts as this information will otherwise be buried in the usual wall of posts. 🙂
What many of you seem to be missing is that not doing anything at all won't advance the conversation any better.
Who could question universal wisdom? 🙂
But, if you have followed these discussion for years, you surely have noticed that nearly every thread containing anecdotical descriptions of sound alteration after doing ...... will inevitably morph into a discussion about science vs subjectivism and why listening (not controlled by protocol) will be selfdelusional.
Since i/we started with controlled listening tests roughly 30 years ago, i have shared some of our results and experiences as well. But unfortunately if nothing else helps in my case the card of "hidden commercial agenda" will be played, or the "it wasn´t published in a peer review journal" argument will be raised or whatever the master of hand waiving ceremony will consider as appropriate... 🙂
Maybe it will not work either, but i hope that more people doing controlled listening tests will help.
Dunno guys but I can feel a certain complacent attitude where some seem to think that we have reached a plateau stage, where we cannot possibly make any further "audible" improvements over the current status of the technology.
I challenge those who think so to post here a set of schematics over which no possible "audible" improvement can be made. For starters let's talk preamp + amp. Prefferably with opamps if they fit the bill.
I challenge those who think so to post here a set of schematics over which no possible "audible" improvement can be made. For starters let's talk preamp + amp. Prefferably with opamps if they fit the bill.
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Jakob, I'd first just settle for more people taking advantage of the tests available already! The QuantAsylum one I linked before, for example, isn't perfect, but it's something one can do from home and gets the ball rolling. (Find our abilities and limitations, to a degree)
That way you and I can sit here and battle back and about nonsense details and leave other poor people alone. 😉
Edit: https://www.quantasylum.com/content/Home/tabid/40/Post/342/ABX-Testing-and-Distortion
That way you and I can sit here and battle back and about nonsense details and leave other poor people alone. 😉
Edit: https://www.quantasylum.com/content/Home/tabid/40/Post/342/ABX-Testing-and-Distortion
Why do some here think nothing has been done. It would take about 5 min to find several 5 to 10 year long threads full of folks perfectly happy with little 8-legs phono pre's. Then if you want to spend some serious time google "op-amp rolling".
How is ABX relevant to Bear's proposal that, at his own expense in time and money, he chains 10 opamps and fools around with the resulting circuit? Isn't this a DIY forum where people are encouraged to experiment? Or has it degenerated into something where people are encouraged to experiment, but only with a small selection of "guru approved" circuits?
Great, for me that's good enough, but how does that appease Bear's itch to fire the soldering iron?
Can we keep in mind that it's about a hobby? I am not on contract with anyone about it, if I want to do something "useless" like blowing tantalum caps myself to see "which is better", I don't have to justify that in front of anyone? Isn't this the essence of a hobby? And maybe you're having a skewed view of it since you've done it as a daytime job for much too long?
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"WHAT IS WRONG WITH OPAMPS?"
Well, this fellow (https://www.bursonaudio.com/products/ss-discrete-opamp-v4/) seems to think HE knows:
"IC op-amps have so many faults they’re really just unsuitable for audio applications.
Op-amp Issues
• Not designed with a focus on sonic performance
• Highly inconsistent in quality
• Poorly construced and degrade the signal on all levels
• Suffer significantly from EMI
Listening to an IC op-amp is like hearing a concert through a keyhole, or admiring the Mona Lisa on a stamp! "
YMMV
Well, this fellow (https://www.bursonaudio.com/products/ss-discrete-opamp-v4/) seems to think HE knows:
"IC op-amps have so many faults they’re really just unsuitable for audio applications.
Op-amp Issues
• Not designed with a focus on sonic performance
• Highly inconsistent in quality
• Poorly construced and degrade the signal on all levels
• Suffer significantly from EMI
Listening to an IC op-amp is like hearing a concert through a keyhole, or admiring the Mona Lisa on a stamp! "
YMMV
You got to wonder if they know better and just play into the audiophool hysteria for an easy meal ticket or do they actually believe this garbage?
I just like building with tubes and I don't really notice their "deficiencies" enough to care.
Opamps, okay for medical and lab equipment but not good enough to pass your precious Justin Bieber CD collection through. Lulz.
I just like building with tubes and I don't really notice their "deficiencies" enough to care.
Opamps, okay for medical and lab equipment but not good enough to pass your precious Justin Bieber CD collection through. Lulz.
Nice. Reminds me of small portable radios and combo radio/alarm clocks. They still make the later, and they still sound the same. I bet they're IC based too
Okay, but there are also lots of people perfectly happy with cell phone audio through earbuds. Happiness is one thing, and the limits of human distortion perception is something else.
Regarding rolling, I did google it and see a lot of nutty stuff has been going on. However, Mooly's wav version sound files posted earlier in this thread did have slightly different cymbal sounds that were apparently opamp-related, even if not primarily due to particular opamps. It's just that opamps were the only variable that was changed and there was some slight change in sound.
The differences are probably not important for most audio purposes, but they apparently nonetheless exist. One crucial missing piece of information in Mooly's test setup was the failure to take distortion analyzer measurements of the circuit in each opamp configuration. We might have found that the circuit produces much more distortion than expected due to layout or other issues. That then might account for the cymbal sound distortion audibility.
IIRC there was no follow up at all with respect to possible mis-application, I remember at least one was near its drive limit.
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