DJ, what values & brands did you use? In the meantime, I'll look up some notes that I have in a laptop left at the office and tell about "stage 1" later this next week.
Today, I was just starting stage 3. However, I made a boo boo with the soldering iron and damaged the red WIMA cap and stopped. [One freakishly nice hole on top of it proved that I still have the right skills to mess up this project grandly!
] Perhaps it was for the best. This, and what I relate below about "stage 2" is affecting the schedule of, and thoughts about, the mods.
Last night I had finished a week of break-in and evaluation of stage 2: changing the 2 caps that are near the PCM1793. These seem to be part of the output linkage from the digital side of the circuit board, not the analog side. I may have mentioned earlier my fear that this change could be a mistake. Fab_flix had replaced these with 4.7uF Black Gates. Yet, when I opened the M02 after ordering 4.7uF Elna Silmic-II, I found that the original factory values were much lower (
.33uF 50v). So, I had some misgivings.
Anyway, here is how things stack up thus far. This is with these Elna S-II caps in almost constant playback for 130+ hours plus some 7 hours' worth of deliberate pauses, distributed for effect
A. The first result of replacing these seems to be that imaging contrast suffered a little. Specifically, the respective "space slot" of each object [instruments/voices in 3D space front to back] is less obvious. I talking about spacing
contrast not the objects themselves. The objects remained as sharp as before.
For example, the singer in the foreground and the piano well back behind are not in a different position. They are still
where they were perceived before. Yet,
that depth does not
jump at you so quickly. This was an improvement that had been gained from the op amps...now it was lost when these caps came. My speakers (planars) image very well and these imaging changes tend to be easy to detect. Yet, even the
rinky dinky set of Sony wireless headphones that I have here (a friend borrowed my better ones...forever, it seems
) could show the loss.
To be sure,
imaging is not worse than when the M02 had no mods. Again, it simply is loss of an improvement that it got from the new op amps, when compared to my player. This perceived loss was evident from day one and never got better along the week.
B. Another negative impact appears to be a slight loss of
top end percussive "crystallinity" (say, triangles) and harmonic sheen of violins.
With stage 1, after the op amps replacement, for the first time ever, the analog outs of the M02 could almost always match the analog output of my Denon 3910 player on this count. The 3910, in this mode and playback signal path, uses the PCM1796, vs the 1793 in the M02. To make sure, I then rigged things for a "passive pre-amp mode" (straight from the Musiland > to power amps via the PLLXO.) No joy. This loss was evident from the start but became less pronounced after 50 hours or so...then it stabilized at a still insufficient level.
C. Almost forgot... I could never put a finger to it but decays appear to have been reduced. The issue is
so faint that I have no reliable way to be sure yet. Always present, from the beginning.
D. For now, I'll call this one a "positive": A VERY slight gain in warmth of the "good kind" showed up in a few pieces of music. This came very late in the game, after the first 100 hours or so.
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So...the problem could be
1.) the new, higher values,
2.) that these Elnas may be better than the Nichicon FG they replaced, but not in THIS particular role,
3.) that even 130+ hours break in is not enough for the Elna S-II ???
4.) a mix of these.... or
5.) Perhaps the moon was in a different phase this week
Now I am undecided as to how to proceed. The unit is open on the table...while I write this...and think this through even as I write.
- As soon as I heard the issues early in the week, I decided to order caps of original values...just in case. I found and ordered the same Nichicon FG (Fine Gold) .33uF/50v, like the M02 came with.
- The issue of the damaged WIMA 1uFcap almost threw a monkey wrench. Fortunately, I have some broken-in caps of the same value and whose behavior I know well...they are indistinguishable from WIMA
in this kind of role. I replaced the WIMA with one (and I ordered more WIMA for retro-comparo later, if needed). Note that this is where Fab_flix placed a large Mundorf cap as a final mod.
Part of me wants to take out the Elnas and put the "correct values" to see if that recovers the losses.
Or, I could just leave the Elnas on for another intensive week... and probably do nothing else but confirm that the cap I just used to replace the WIMA has no audible effect. However, I am also intrigued by that
warmth that was observed with the Elna S-II,
slight as it was, late in this test phase. Could additional break-in bump this up (wanted or not)?
Hmm, actually, there is additional logic to doing this ...
...many of the other replacement caps are also going to be Elna S-II. Yet, to my surprise (after I opened the Musiland) these would be replacing not "crappy caps", as someone may have said. Some of these in the Musiland are Nichicon KG, their best in the Muse line.
So, a line of thought is to NEXT -- a week from now -- replace the rest of the caps that
will not have Elnas. This would leave the rest of the Elnas for the very end.
What would be the point? Well, we may get further experience on Elna Silmic II vs Nichicon KG, something about which I can't find enough reliable details on the web. The fact
IS that right now the Musiland 02 with its original Nichicon KG caps ain't too shabby.
Perhaps your early input may steer my thoughts on this. You may have observations that could shed some light.
