Oh heck, flameproof underwear on. Whatever the the part is, null the input and output. If there's anything there, the parts are different or the implementation has something wrong with it. If there isn't, the parts will sound the same. I've yet to hear an argument for identical signals sounding different that didn't involve witchcraft, magic or smoke and mirrors.
The poll is set to close on 21st but the opamp disclosure came when voting and comments dried up.
The vote at that time is here,
http://www.diyaudio.com/forums/ever...tout-where-you-get-decide-12.html#post3701967
Does it taste nice
Yes, the 4562 is a very transparent and high performance chip.Have you tried the next challenge... click my signature line.
Personally, I've always like the sound of current feedback and some video op-amps, but they all seem to have high input bias currents which I assume is usually the cause of high DC offsets.
Also, when trying to use them in say line level audio applications, they do NOT like to have a volume pot in front of them as I typically get all sorts of "pops" and "cracks" when turning the pot(maybe DC going through the pot's wiper??).
I suppose if you know how to get around these issues, you could have a very nice sounding line stage, but I'm just not smart enough to know how to implement them in such a application.
Any DC through the wiper of a pot can cause problems. I guess each design case would have to be looked at individually but I suspect traditional AC coupling is the way to go. The low resistor values of feedback networks and input stages don't directly match well either to common pot values which tend to be 10k and above. Also, while you can directly couple many VFB opamps inputs to a pot with no stability worries, the change in impedance for the CFB would alter the stability tremendously as the pot is varied.
So each case needs an optimised design, possibly AC coupled and perhaps even a combination of VFB and CFB to get the best of both worlds, each playing to their strengths.
Another quick test for the crack listening team
http://www.diyaudio.com/forums/everything-else/249479-purely-subjective-test-do-you-prefer.html
http://www.diyaudio.com/forums/everything-else/249479-purely-subjective-test-do-you-prefer.html
Dear Mooly,
Thank you for this poll. However I just saw it today. It is clear that members like the OPA134 as much as they like the DIRECT. That does say alot. On the other hand probably the LM4562 is better at handling the loading the opamps were subjected to alternatively it did add some artefacts that were pleasing to the ear.
Have you tried this cute preamp
kind regards,
Harrison.
Thank you for this poll. However I just saw it today
. It is clear that members like the OPA134 as much as they like the DIRECT. That does say alot. On the other hand probably the LM4562 is better at handling the loading the opamps were subjected to alternatively it did add some artefacts that were pleasing to the ear.Have you tried this cute preamp
An externally hosted image should be here but it was not working when we last tested it.
. Your opinions will mean alot. Your quality contributions haven't changed since you became a mod. There is something fresh about you and your signature avatar.kind regards,
Harrison.
Hi Harrison,
Second order distortion is required when the system is too clinical and fatiguing. But as the system optimized and perfected, second order distortion is a liability. Because of that, your designs (such as SYMEF) will only be phenomenal at medium level. At high end level it won't have a place.
IME, the easiest way to get everything is through the speaker. If I want second order I will use XT25. But I have critiqued Anyone who thought ZD5 (with XT25) as top class. YG of YGA also once said that XT25 is (one of) the best tweeter in the world, but his best amp in the world didn't use that tweeter.
Just my opinion.
Second order distortion is required when the system is too clinical and fatiguing. But as the system optimized and perfected, second order distortion is a liability. Because of that, your designs (such as SYMEF) will only be phenomenal at medium level. At high end level it won't have a place.
IME, the easiest way to get everything is through the speaker. If I want second order I will use XT25. But I have critiqued Anyone who thought ZD5 (with XT25) as top class. YG of YGA also once said that XT25 is (one of) the best tweeter in the world, but his best amp in the world didn't use that tweeter.
Just my opinion.
False! That's a widespread myth. That will not help. It doesn't matter how much 2nd harmonic you add, fatigue will remain. It doesn't matter if you add it or not and how much you add it. 2nd harmonic is simply a result of for e.g. SE output stages. [An opamp output that is forced with a CCS to SE 'mode' is an SE output stage as well.] 2nd harmonic generation is not the goal. It's just a byproduct what will be easily ignored by your ear.
What sonically matters is that thermally you get a more stable system with SE output. Almost always with less thermal distortion. And that's the point. That's why the system sounds better, and the reason isn't the increased second harmonic. Like I said, it's just a byproduct. Add second harmonic to your music in a music editor and hear if it sounds better on a fatiguing system. It's not going to sound better, guaranteed. You can't mask thermal (and memory type) distortions with added harmonics. You have to improve your circuit. People only see increased 2nd harmonic on spectrum, and thinks there's a correlation. There's still an operational amp thermal test to go. Which will not be a THD-based measurement, but the actual voltage vs time after the signal is switched to zero.