Rerurn to Romy the Cat's Site
In the Forum: Audio Discussions
In the Thread: Initial thoughts about new/old Lamm ML2s
Post Subject: Curiosity (and bad AC) prompts discoveryPosted by Paul S on: 10/3/2008
Finally looking under the hood, for the first time, my immediate observations are similar to those expressed by Romy and others who've checked and reported earlier: Top-Flight construction; "more than adequate" (but not "premium") parts. My amps (#s 57 and 58) have .033 uF 1000V Electrocube 950s, and the larger 10 uF, 400V Electrocubes are 935s. I have made no attempt to trace the circuit(s) yet, but the layout looks very simple compared to my former pre/phono amp, the AI M3A (which I modified extensively).
Regarding the 935s, 10uF seems pretty big for a coupler, but at this point I would guess that is their function. Based on Romy's observations it seems like an obvious swap to make the 935s become 950s, and the clean, open layout makes it look like it should be easy to do this (with the board in place). In fact, now that I've seen it I am almost overcome with the urge to swap those 935s for something else, even though the plastic caps are probably all still working fine, electrically.
I did not see any ID/factory info on the BIG cap, which I presume is an oiler. I wonder if it is still working to spec. If it's a mil-spec poly, then probably, yes. I don't have a dedicated cap meter, nor do I have an ESR meter, for in-circuit checking. One thing for sure: I would not want to get zapped by a full charge from that puppy!
These amps have lots of decent electrolytic caps. I think of typical electrolytics as lasting 3 - 5 years, although some seem to "function" for over 10 years. Swapping electrolytic caps would mean pulling the board, which, as Romy has said, looks easy IF proper protocol is followed. I can't even guess if it would be worth the effort to do other than a straight new-for-old swap of the PS "lytics", but I have gotten sonic benefits from using especially swell 'lytics in cathode RCs.
At this point I caution myself to at least match or beat Electrocube's ESR and ripple with any prospective substitutes.
At this point, I admit that it is probably weeks of terrible electricity that are causing my itch.
I am also thinking of putting in an "audiophile" fuse (and not mentioning it here).
A great listening session would probably put the wood to my "curiousity".
Paul SRerurn to Romy the Cat's Site