As Jay indicated, very obvious differences - would be straightforward to rank them. But I don't quite see the point to the exercise, because the opamps have been loaded beyond the level which is recommended - therefore, they will display quite distinct artifacts, which would not be the case in normal use ...
The opamps being overloaded? I often see them driving headphones of low impedance or high impedance but high voltage.
If the circuit is similar to the practice then there is a point to this. Even if just to demonstrate what is wrong with the practice. I didn't expect positive ID via ABX.
How do the listening results correlate to measurements?
If the circuit is similar to the practice then there is a point to this. Even if just to demonstrate what is wrong with the practice. I didn't expect positive ID via ABX.
How do the listening results correlate to measurements?
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Fair enough. I skimmed the earlier posts and didn't pick the max 7.5mA output current for this exercise. Personally, I would always use opamps well inside their comfort range of working conditions - doesn't make sense to me to do otherwise.
Edit: Therefore, nominally somewhat surprising that the differences are so marked ...
Edit: Therefore, nominally somewhat surprising that the differences are so marked ...
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Frank, come on now. Is it just me or is this the exact opposite of what you wrote in the BFP thread earlier today?
No. The design of the circuit should be optimised in its internal world, that is, of all the parts making it up, making it as robust as possible, as glitch free as possible. Then, when it has to handle the external world it should be as bullet proof as one can make it, able to shake off any requests of its capabilities - think Hummvee here, vs. a domestic SUV ...
Excellent.
So rank them by the differences you have heard. Best and worst.or
if you just want a couple to compare then say which and I'll send you just those two.
Not really. The idea was simply to see if any audible differences were apparent to the listener, perhaps to describe what you hear and if you have a favourite then what it is that makes that particular device more appealing.
What did you hear with A ?
Clip C (similar "signature" as LM4562 in previous test). But it sounded fatiguing after half an hour, so it can't be LM4562 (which has crazy terrific THD at 0.00003%), unless fatigue came from something other than THD.
May be it is TLE2072 then because it has very high slew rate but in achieing it it seems to have sacrificed some other variables??? (It cannot be because C is so clean and TLE has poor THD/noise/CMMR). Never heard this opamp.
Then may be LM833P? (Never heard this either). It is hard to judge as I suspected the circuit can become a bottleneck (e.g. 390R loading) for some ICs.
This is interesting, but I think, I found out that distortion spectrum simulation (FFT) have very good correlation with sound perception. May be you can try that sometimes (I have lost my opamp models in a hard disk crash)
Compared to the others A seems more matte, somewhat more monophonic.
The others sound almost like an enhanced version of A. Don't know if it's tonal balance or phase or something else.
Will continue to listen.
OK, did a first run through of ranking - feeling a bit stale with the exercise, so will try again tomorrow when refreshed, and take a second run on it, see if my first impressions still hold.
I ordered on cleanness of tone along with dullness of presentation - the 6th choice was the dreariest and most irritating to listen to; the 1st had the most life, sparkle, the one that could be enjoyed on repeat.
First run:
1. D
2. E
3. F
4. B
5. C
6. A
I ordered on cleanness of tone along with dullness of presentation - the 6th choice was the dreariest and most irritating to listen to; the 1st had the most life, sparkle, the one that could be enjoyed on repeat.
First run:
1. D
2. E
3. F
4. B
5. C
6. A
Interesting! Then it should be A! It has that unique bass strength...
Surprisingly, musically (flow, pace, pitch, rhytm) A is the closest to what I have been familiar with (Mark Knopfler and Dire Straits is my favorite) except the bass of course, which is a bit of hard, typical of quasi output (but I guessed it was my speaker - a new design I'm not yet familiar with)
Initially I thought A was NE5532 because NE5532 usually sounds "correct" (and the hard bass reflected the poor THD), but A is not as boring as NE5532 so this is interesting.
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