Originally Posted by nick_charles
Not disbelieving you but...Thanks for that.
You did Blind tests right ?YES - Okay
You level matched to +/- 0.1db ?YES - Okay
You used the same track for each comparison ?YES - Okay
What was the switching delay ?How ever long it took to change the OP-A's After listening and taking notes on the sound, of each set!
- I hesitate to rely on my memory of sound more than a couple of minutes hence, I like using switch boxes so I can compare two items sync'ed
What were your expectations prior ? None, Just wondering what would be the audible difference (if any)!
How did you prevent opinion cross-contamination ? Didn't have any pre- opinions of the sound differences.
Why not measure the different outputs using the different op amps that would be **much** more informative and allow detailed comparisons Yes it would prove the output being some what different but when you don't know what set of OPA's your buddy changed and you heard a difference, then compared your notes from previous sounds in the same song, that's all I and my partners needed to pick what OPA's fit and sounded best in my system!, Sorry if this is not enough for you or others!
- I'd be tempted to throw a few non-change changes to see if null differences were detected, the problem with your protocol is that subjects know that something has changed
The number of times a night and day difference disappears when cues are removed makes it certain that sighted tests have extremely limited utility for verifying if perceived differences are real or imagined, amps that are wildly different often become indistinguishable, $12K CD players sound the same as $200 DVD players, boutique DACs indistinguishable from Digital EQs - this happens again and again and again. This is why when I read night and day differences elsewhere I just ignore them. Here however we expect a greater level of evidence and sighted poorly controlled comparisons are insufficient for that purpose.Not to be a smart ass, and dispute your words, but I've always thought highly of your post and the help you given many members concerning our hobbies Equipment! Haven't you ever noticed a HUGE/ or noticeable difference in any changes that you've made in any of your equipment? (Maybe night and Day) was the wrong words to use but it was clear-cut difference.
- When I turn the speakers (Wharfedale Delta 70) off and switch to headphones the headphones (whichever pair I plug in) always sound dull in comparison, when I switch between headphones yes they sound different. In the past I have thought I have heard big differences between digital/SS components, my external DAC (casually) sounds very different from my CD players' internal DACs , but that is due to notable level differences, when I level-match them I cannot tell them apart.
My damascene moment was comparing an anonymous Denon DCD560 with a budget but well-regarded Rotel RCD855, I genuinely believed that the Rotel was superior but rapidly switching between them I had to admit I could not tell them apart. This did not of course stop me from experimenting with many more different CD players at different price points in the following 4 years. What influenced my self-education was the switch box, I could set up two CD players with the same CD sync'ed and swap between them quickly where differences were detected I found that they were always due to level differences. If I recorded samples I could easily DBT them , but if I level-matched that capability vanished. So for me all CD players I have compared (and I have tested 7 or 8 so far) really do sound the same (when level-matched) of course that is me and a small sample.......
Certainly op amps measure differently, whether they are different enough to be audibly different in-circuit can only be judged on a case by case basis and with more rigorously garnered evidence.AGREE
I tried to answer your questions as truthful as I could. My answers in red type was the easiest to help you and others read my answers to your questions, which I find very pertinent to this topic.. what did you think of the web sites explanation of the difference in Op-Amps???