Okay—big thanks ZM....so progress!...upper 150 gave me a beep to heatsink from drain...weird since I'm using ceramic pads and goop, I didn't see anything suspect but I swapped it out. Still didn't fire up after the replacement but I got an Iq blip on the meter when I probed the neighboring BD140 with a stick! I reflowed the pins and things seems stable. Cooking now. Offset is responsive as is Iq twiddler. To be clear, the soldering didn't look suspect anywhere....but that seems to have been the issue. Strange?
I did use a mirror!
I think it was a cold joint—failed with heat over time(?). Flex the BD140, Iq popped up on meter (otherwise zero).... reflowed.. now I did get beep between drain and sink on that associated mosfet...diode test seemed fine however.... so...? Just now banged it on for final final check. Iq was .99mV at first swtich-on now settling around .88mV which is where I left it last night... offset residing around .04mV...(that seems to float a bit though)...
We'll use them today and for a week—to remember what we all love—and then SS down for some of that "Pinpoint Machine" precision thing.
Scryer on deck.
I think it was a cold joint—failed with heat over time(?). Flex the BD140, Iq popped up on meter (otherwise zero).... reflowed.. now I did get beep between drain and sink on that associated mosfet...diode test seemed fine however.... so...? Just now banged it on for final final check. Iq was .99mV at first swtich-on now settling around .88mV which is where I left it last night... offset residing around .04mV...(that seems to float a bit though)...
We'll use them today and for a week—to remember what we all love—and then SS down for some of that "Pinpoint Machine" precision thing.
Scryer on deck.
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...Little update....
I had a second failure of the right channel. This all while using J2 Babel during transitioning Scryer (fabulous!) to SissySIT (42) (trying to be economical with chassis having made the most compact mono-blocks I can at this point)—this time it was the PSU that gave up some ghost! I believe that the PSU was the culprit from the start (I won't name names—but it's way overly complicated a PSU for it's desired intent)—and incidentally was the same PSU in right channel mono-block that lead to repeated failures of my first SissySIT (R3) attempt... To be fair, I have the left mono-block with no issues, same PSU, totally possible it's user/installer error someplace.... SO—
I put Scyer/Sissy swap on pause—not being able to live without J2 Babel!!—and put J2 Babel in the svelt monos with DIY Audio PSUs, previously powering Scyer. While at it, Semisouth down! (Thank you anonymous delightful parts donor!)
Bias process rock solid—zero issues—everything fired right up. Sweet music has been playing for a month now. I do believe the SS down maneuver is very worth it. Difference is subtle though.
Now—to ditch the old/failed PSUs—reconfigure previous superwide monos to svelte version with some panel changes—get some equally svelte HA! boards (already built) for PSU duties and finally, finally, finally, see if I can get the SissySIT magic into the room!
(J2 Babel though is a blessing blissout—thank you ZM! — my favorite amps to date)
I had a second failure of the right channel. This all while using J2 Babel during transitioning Scryer (fabulous!) to SissySIT (42) (trying to be economical with chassis having made the most compact mono-blocks I can at this point)—this time it was the PSU that gave up some ghost! I believe that the PSU was the culprit from the start (I won't name names—but it's way overly complicated a PSU for it's desired intent)—and incidentally was the same PSU in right channel mono-block that lead to repeated failures of my first SissySIT (R3) attempt... To be fair, I have the left mono-block with no issues, same PSU, totally possible it's user/installer error someplace.... SO—
I put Scyer/Sissy swap on pause—not being able to live without J2 Babel!!—and put J2 Babel in the svelt monos with DIY Audio PSUs, previously powering Scyer. While at it, Semisouth down! (Thank you anonymous delightful parts donor!)
Bias process rock solid—zero issues—everything fired right up. Sweet music has been playing for a month now. I do believe the SS down maneuver is very worth it. Difference is subtle though.
Now—to ditch the old/failed PSUs—reconfigure previous superwide monos to svelte version with some panel changes—get some equally svelte HA! boards (already built) for PSU duties and finally, finally, finally, see if I can get the SissySIT magic into the room!
(J2 Babel though is a blessing blissout—thank you ZM! — my favorite amps to date)
Not sure, lost the neg rail completely. Nothing visual that I can see—but I also haven't tried to sort it. I was going to pull the caps and put them in the HA! boards for PSU redo... but they are a tad light...even though they'd probably work. Now... add those extra fancy Ducati caps plus HA! per ZM protocol???
Well....Babelfish J2 Redux post PSU failure... was working great in new chassis with DIY store PSUs.... BUT...
Hum. Not a lot, I questioned if it was normal—for half a second, but more than tolerable and certainly more than the previous PSU'd version...or any ZM or FW iterated amp to date (My M2X amps are extremely quiet amps—faintest little sizzle sound if you put your ear ON the tweeter).
SO! Can't move on to SissySIT project—since this really bothers me sans B/J2 in play and I LOVE these amps....and this elevated noise floor was making me sad. But it's been fun listening to M2X for a week...
Perhaps HUM is due to "loud" trannies? Dunno, I hear it can be a thing—I followed normal prescriptions for build practices—I don't recall any noise from Scyer in exact same setup... BUT...
Having inclination—and HA! boards in the house, I retooled previous actual B/J2 chassis with original proven trafos (same spec as others connected to DIY PSU) making them a combined "rack" width with some new skinnier top and bottom plates—AND some ZM-fav Ducatis.... I figured why not—can't get worse plus...new never-before-done-by-me stuff—and at end of day—2 pairs of more or less matching monoblocks to continue to play around with.
Voila! Quiet amps! WooHoo!
No idea what's up with other monos... but I think I will finally install Sissy in them and see about quietness before further adjustments (another pair of HA! boards in stock, should the need arise).
Hum. Not a lot, I questioned if it was normal—for half a second, but more than tolerable and certainly more than the previous PSU'd version...or any ZM or FW iterated amp to date (My M2X amps are extremely quiet amps—faintest little sizzle sound if you put your ear ON the tweeter).
SO! Can't move on to SissySIT project—since this really bothers me sans B/J2 in play and I LOVE these amps....and this elevated noise floor was making me sad. But it's been fun listening to M2X for a week...
Perhaps HUM is due to "loud" trannies? Dunno, I hear it can be a thing—I followed normal prescriptions for build practices—I don't recall any noise from Scyer in exact same setup... BUT...
Having inclination—and HA! boards in the house, I retooled previous actual B/J2 chassis with original proven trafos (same spec as others connected to DIY PSU) making them a combined "rack" width with some new skinnier top and bottom plates—AND some ZM-fav Ducatis.... I figured why not—can't get worse plus...new never-before-done-by-me stuff—and at end of day—2 pairs of more or less matching monoblocks to continue to play around with.
Voila! Quiet amps! WooHoo!
No idea what's up with other monos... but I think I will finally install Sissy in them and see about quietness before further adjustments (another pair of HA! boards in stock, should the need arise).
