Originally Posted by Alydon
Originally Posted by Shahrose
So Alydon, I tried the LM6172 in the buffer spot with 2xLME49720 and surprisingly, it sounds quite different from before. The bass no longer cuts out, and there's no unneeded warmth to the sound (still add warmth, but not excessively). I believe it wasn't making contact properly before because now it sounds great. I feel like it's a compromise between the sound of 3xLME49720 and 1xLME49720/2xJRC2114d without most of the drawbacks.
The 3xLME49720 have a larger/airier soundstage, but not by much and the JRC2114 have more solid and hard-hitting bass (a bit more defined too), but again, not by much.
The JRC2114 have this upper treble harshness that just seems to grate on you. In fact, I feel there's a lot of things wrong with the treble when I'm using those. They have excellent bass/midrange though, maybe the best of any opamps I've used.
Anyways, I'm keeping the 1x LM6172/2x LME49720 for now to test it further.
Upon further testing and comparisons with 3xLME49720. I found the LME49720 have a more realistic tone (because they don't have that lower midrange hump of the LM6172), however, their bass is slightly less defined and a bit less punchy than the LM6172. Also, the LME49720 sound a bit more distant, and smoother. In addition, the LME49720 have a wider soundstage than the LM6172.
I have yet to find the perfect opamp combination. What's important to take away from all this is, there is no one best magic combination. Everything has pros and cons and you have to find your own sound. I've tried my best to describe the sound differences among all these components. In the end it'll be up to the listener to decide which he/she prefers.
Edit: If you ever want to see what I prefer, just check my profile, because it keeps changing. After going through all of these opamps twice to verify the differences and make sure they were all seated properly, I've come back to the 3xLME49720s for their sheer soundstage size and depth and smooth tonality.
Good to hear you were able to solve the bass clipping/stuttering issues w/ the 6172 so you could get a chance to hear what it's really capable of,
even if you didn't ultimately keep it installed. I can understand though why you'd want to stick w/ the 3x49720 setup w/ the HD650's, since I understand those cans already emphasize the mid-bass a bit so the 6172 might be a little too much in that area.
However, to give everyone an inverse opinion....
...Ultimately with my rig, using a 6172 in the buffer sounds the most realistic to me.. In my setup, the 6172 has the most detailed, full-bodied, and visceral bass of any opamp I've tried (including the JRC2114, which by comparison had a smeared, boomy, and indistinct bass), whereas the 49720, though detailed, is missing the lowest bass registers and simply doesn't have the impact or imaging that the 6172 provides. This is especially noticeable with strings and percussion. There is also a little too much upper-mid/lower treble emphasis (1-2KHz) with a 49720 buffer that makes horns sound slightly “bleaty” and gives high strings and pianos a nasal quality that sounds somewhat off to me (though again I don't think that the HD650's would experience this).
Lastly, I personally prefer the more intimate soundstage that gives me the feel of being in amongst the musicians. The 3x49720's setup does have a larger soundstage and I can see where many might prefer it, but it made the musicians a little too far away and the music a little detached as a result to be ideal for me.
Overall, both opamps are excellent choices though and I'd still be quite content w/ a 49720 in the buffer if the 6172's didn't exist.
I strongly suggest to anyone that wishes to try their hand at opamp rolling on the STX that you try both
of these opamps in the buffer spot to find out which one you prefer since I don't believe one is superior to the other. I guess this goes to show how important system synergy and personal preference come into play in addition to the personal experience and compromise/balancing that Shahrose already mentioned...
However, since I don't seem to be able to leave well-enough alone,
I've been rolling opamps in my Corda Opera and I think I've found another one that I'd like to try in the STX as well: the LM7171. This is a single-channel opamp which means you’ll need to use two of them on an adapter. However, they seem quite promising given the results I’ve heard from the Opera.
So far in the Opera it sounds very similar to the stock 6171's that it comes with, but with the contrast turned up. It has a blacker background, and slightly better dynamics, deeper and cleaner bass, a deeper soundstage, and better imaging. The mid-bass hump is reduced as well. Once my adapters arrive in the mail I’ll test them out in both the buffer and I/V spots of the STX to see how they fare.