| Originally Posted by souperman /img/forum/go_quote.gif I'm using the OP275 as LR, AD8397's as buffers, and AD8656. Which of those is the culprit for the high pitched whine after I shut off the D1? |
| Originally Posted by StevieDvd /img/forum/go_quote.gif I'm getting close to having all my gear sorted now. I finally swapped the default opamps from my D1 with the AD8397 buffers and OPA2111 L/R and the difference between them is remarkable and more akin to my personal preferences. The soundstage is demonstrably wider but with no less detail and no discernable loss of highs or lows. In fact when I swap opamps I tend to make the first listen with a pair of sacrificial headphones (just in case) so grabbed the old AKG26P from my diy drawer. The opamp pairing above certainly kicked some life back into these old cans, though the bass was a tad overdone which is the cans fault (and why they are relegated to the drawer). I think I'll be leaving these opamps in for quite a while to see how they bed in and hold off the AD8066 for some time whilst I get used to the sound. The source for the D1 is an Iriver H120 using the optical out. Since it is for a work setup I'm still trying out different headphones to meet the work criteria. Unfortunately I get so many interruptions it means iem's are generally out of the question, as are most full sized headphones. I need a pair of small closed cans which don't fold up every time you take them off to respond to someone. I don't doubt that there could be a better pairing for my personal preferences but I'm not over keen on a massive opamp test. So I'd like to just add my thanks to Ron (Hiflight) for moving my D1 up several notches in quality and musical fit for purpose. I'm off to get one of those mini optical cables to tidy the setup a little. Thanks to the contributors of this thread and in particular to Hiflight - may your opamp rolling continue to even more dizzy heights. Steve |
| Originally Posted by Schalldämpfer /img/forum/go_quote.gif Oh goodness... newbie opamp roller here with a question. Where do I put in my opmaps? Currently I have... AD746JN0709, LME49720NA, AD746JN #0730, 6234, another LME49720NA, but on a raised platform and an OPA2111KP. |
| Originally Posted by Schalldämpfer /img/forum/go_quote.gif Oh great... do the hex bolts on the back need to be removed, too? I'm having a pretty hard time removing the casing. |
| Originally Posted by HeadphoneAddict /img/forum/go_quote.gif I forget, which opamp combo was the one that has the analog input matching the level of using the DAC? |
| Originally Posted by HiFlight /img/forum/go_quote.gif I spent considerable time this evening going thru my best-sounding single-channel DIP opamps, at least the ones that had performed exceptionally well in my Xin SuperMacro amps. I also re-installed the AD8397 buffers to provide the most output power for low-impedance phones, although I used my high-impedance HD-650s for the evaluations. Although the LMH6643 is a very nice buffer, the AD8397 is tops for current output capability. Either will work quite well. If output current is not a consideration, perhaps use of the LM4562 or LME49720 would be satisfactory or simply bypassing the buffers would be another choice. I just wanted the max possible output current to benchmark these opamps. No consideration was given to battery endurance when using these opamps. They all draw a fairly high quiescent current. The opamps evaluated, using 2>1 adapters, were: AD794, AD743, LT1028, OPA627 and OPA637. The LT1028 was immediately discarded because of consistant startup oscillation, (whistling that has previously been noticed and discussed with some opamp configurations) The OPA637 just sounded unremarkable. It is a touchy opamp, and doesn't work well with loads that exhibit high values of capacitance or with gains less than 5. Whatever the reason, it just didn't ring the bell! The AD743 sounded superb, as always, even though it is an opamp most commonly used in sonar and IR applications. It had the sweetest treble of any of the opamps. Nice smooth sound, not punchy but accurate, neutral, and very listenable. The AD797 had the most punch in the low end and the biggest sound. Soundstage was closer to the listener than the others. The OPA 627 lived up to its reputation...The bass was very detailed, kick drums really sounded like kick drums. Soundstage was slightly further away than the other opamps. Highs were very nice but not quite the equal of the 743. This opamp sounds its best with complex orchestral music or vocals, and did better than any of the others with pipe organ selections. These 3 opamps are probably too close in performance for me to call an overall winner, as each excelled in one particular area. I will probably listen to each for a more extended period of time before selecting my own personal favorite. At this point, however, for the type of music I most enjoy, the OPA627 is probably ahead by a nose! Addendum: I retried the above opamps using the LME49720 as buffers. IMO, there is inadequate output current when using this opamp as a buffer to drive inefficient phones to an acceptable level of volume. I then substituted the LMH6643 for the LME49720. It works well in all respects and requires only about 1/3 the current of the AD8397. I do think it is a little smoother than the 8397, but does not have quite the bass punch. I guess one could call it a little more neutral overall. Again, the choice of buffer really depends on the listeners preferences. |
| Originally Posted by Schalldämpfer /img/forum/go_quote.gif Whooo! I just installed them, and WOW! I DIDN'T KNOW HEADPHONES COULD DO THIS! Thank you for the instructions, HeadphoneAddict, and HiFlight! |
| Originally Posted by pianomav /img/forum/go_quote.gif Ok, I finally had the chance to switch the opamps on my D1 and all i can say is "WOW", what a big difference in sound quality! Makes me think on why ibasso wouldn't use these opamps right off the bat. Rolling the opamps is definitely a 'must' on the D1 to unleash its full potential, IMO. Thanks for the great info guys! Now time to enjoy this little gem... |
