Oh yes. The lm4562 is high sr too 20v/us. But equal to opa134. I don't know why I don't like it. Actually I like it but there was something wrong there. I will post a thread when I have the answer. May be that is how that chip sounds? Many loves it. Nevertheless.
I have explained this many times. I have built almost all the best amps in this site, but I use tda2030a in this test and in my speaker design. I have learnt that this is a useful process. It is easier to get to the best sound which will only sound even better with better amps.
I know what to expect from better amps, and I know what to expect from wav. But mind you, differentiating mp3 to wav is not easy. You can try it by yourself. But I know what to look for with the wav. I intended to use wav for believable soundstage test I mentioned earlier. And fatigue test too.
Well, now I know two things. 1) I might as well use two tin cans with a string between 'em, and save money on opamps. 2) This was fun- let's do it again!
Re the source- no it wasn't terrible, but it didn't have clarity I associate with a really good recording. Maybe I just like close miked stuff, or find it more revealing.
On the test circuit, it might be interesting to go with much higher gain on the opamps, attenuating the input as needed. IMO, the load isn't so important, though making it a bit capacitive might show up some shortcomings in opamps that do resistive with no problem.
Re the source- no it wasn't terrible, but it didn't have clarity I associate with a really good recording. Maybe I just like close miked stuff, or find it more revealing.
On the test circuit, it might be interesting to go with much higher gain on the opamps, attenuating the input as needed. IMO, the load isn't so important, though making it a bit capacitive might show up some shortcomings in opamps that do resistive with no problem.
I want to compliment Mooly with this test and Jay with his hearing ability.
In line with what Conrad mentioned: it would be nice to do it again, but with a really good recording. Unprocessed human voice (so not Ricky L. or other audiophile favorites like Diane K.) would give me the best cues.
In line with what Conrad mentioned: it would be nice to do it again, but with a really good recording. Unprocessed human voice (so not Ricky L. or other audiophile favorites like Diane K.) would give me the best cues.
Rerun
Yes.
I can do a loopback measurement looking like the attached graph - which is not too bad apart from the insertion of 3rd harmonic at -100dB. There is only one op-amp in this path and DAC and ADC are on the same clock.
I have some quad 741 some LME49710NA and JRC211
Just need some good audio samples and permission to post them...
An alternative might be to get a log sweep measurement of the op amp, calculate the impulse response and let people process sound files of their own choice perhaps.
Yes.
I can do a loopback measurement looking like the attached graph - which is not too bad apart from the insertion of 3rd harmonic at -100dB. There is only one op-amp in this path and DAC and ADC are on the same clock.
I have some quad 741 some LME49710NA and JRC211
Just need some good audio samples and permission to post them...
An alternative might be to get a log sweep measurement of the op amp, calculate the impulse response and let people process sound files of their own choice perhaps.
Attachments
Picked that one before I saw this reply - didn't know the vote was over. Somehow, I found that it had more dynamics in the lower end. But only by a hair..
Second for me was the orange 
It was fun. One idea for the future... maybe... would be to take the output from a "favourite power amp" actually driving speakers at a few volts level and compare against a "blameless" topology under the same conditions. Use the same set up as here to produce to .wav files. I wonder if that might hint at sonic differences we hear and be able to reproduce them.
The clarity thing... well that surely has to be the A-D process in the laptop. A top notch CD player isn't going to sound as good passing the analogue output through a laptop conversion process... but... it did make for an interesting and fun test.
Picked that one before I saw this reply - didn't know the vote was over. Somehow, I found that it had more dynamics in the lower end. But only by a hair..
Current feedback opamps don't seem to have made any impression in the audio field and yet I can't help but feel they could have promise in the right application. Maybe we should "mix and match" more using different devices according to their strengths.
A chain of voltage followers could be a good test too. Some opamps are reputed to be on the verge of instability (even though classed as unity gain stable).
I hadn't voted, but I liked the transparency of Apple the most, and thought that it was the direct sample. I probably need to look at the TLE2072 for future designs (I've never heard or used it before, but it does have a certain sonic similarity to LT1213 and LT1208). Other than that, I liked Orange - probably more than Pomegranate. I did not listen to Peach carefully enough.
The direct file was the Marantz players analogue output fed direct into the laptop. So yes D/A-A/D. I did it that way so that all the files were processed identically. Only difference was no opamps.
The master file HERE hasn't been processed or undergone any conversion at all.
Listening was the general idea really. Now you know which is which try the 741 vs something else of your choice.I hope you aren't accusing me of this.
I was trying to to extract the maximum data out of the test. There are so few attempts at Double Blind Listening Tests that you make every effort to rescue valid data from even wonky ones.
Sadly my efforts were at best a strategic withdrawal and finally all validity was lost when people started posting their results.
In my book (I was a true DBLT guru in my previous life) anyone publishing their results before everyone has done the test is seriously attempting to ruin it
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Mooly, would you do another run? We can change some small things without telling the listeners and get a good hook on the true golden pinnae and the deaf Golden Pinnae.
A second test, properly conducted can salvage and more than double the validity of our results for the first test.
We have to trust the listeners not to cheat eg look at the files with Audacity etc.
An example of the type of spanner that can be thrown in the works.
Now Jay is thought a true golden pinnae, the deaf Golden Pinnae will be VERY affected by anything he says in a second test.
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Please contact me offlist if you do intend to do another one.
Just curious, what Marantz player did you use? I don't want to diss any particular player that someone is getting joy and satisfaction from, but I've got a Marantz 5001 that does everything right technically except the emotional connection thing. It's so uninvolving I can't listen to it. I haven't had time to make measurements to say what the problem is, but the difference between that and my Kyocera is night and day, at least to me.
