-heatsinks on BD - mount them in opposite way (rotate that most of length is going up), still enough meat for back of transistor(s)
that way no touching of resistors, even if BD are sunk all the way
-you have clear note on schematic that you don't need isolation for pair of BD - collectors are connected, just use thermal paste
- who drew these pcbs? they're Gorgeous
that way no touching of resistors, even if BD are sunk all the way
-you have clear note on schematic that you don't need isolation for pair of BD - collectors are connected, just use thermal paste
- who drew these pcbs? they're Gorgeous
I will need to acquire 680R resistor. 1/4 or 1/2 W?
Attached are the results from my simple transistor tester measurements of my 2SK2087Cs. The one on this troublesome board is either #2 or #5. Can’t see my label on it now. So I did not do a more thorough assessment of my little batch of 10 (of which I now have 2, 5, 1, 7 available).
#3 and #9 are in my TDV amp doing very well.
Thank you for the troubleshooting help.
Attached are the results from my simple transistor tester measurements of my 2SK2087Cs. The one on this troublesome board is either #2 or #5. Can’t see my label on it now. So I did not do a more thorough assessment of my little batch of 10 (of which I now have 2, 5, 1, 7 available).
#3 and #9 are in my TDV amp doing very well.
Thank you for the troubleshooting help.
Attachments
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can you measure voltage between mosfet gates, for max and min trimpot positions?
by measurement across R122, we confirmed that CCS side of current mirror is functional
now, observing voltage between gates, we'll know does other side of current mirror is working or not
all of that , presuming that there is no wrong resistor value somewhere ......
by measurement across R122, we confirmed that CCS side of current mirror is functional
now, observing voltage between gates, we'll know does other side of current mirror is working or not
all of that , presuming that there is no wrong resistor value somewhere ......
gate to gate voltage is not high enough nor is having enough span
3 things:
-check all resistors (values, position); that includes trimpot values
-take cotton swab, clean top of all 6 SMD bjts (those in current mirror), find good lens/loupe and check their markings; 3 same ones in positive rail, 3 different same ones in negative rail; that in case some bloody greenhorn behind Iron Curtain did solder wrong SMD part ......... if needed compare with good channel
-check position and value of all SMD resistors; those at rails are 470R, base resistors are 100R, in between mosfet gates are 6K8
nomenclature as per schm in #188
if nothing else, while you're staring at small ones and if you can't find my error, you'll find your own
3 things:
-check all resistors (values, position); that includes trimpot values
-take cotton swab, clean top of all 6 SMD bjts (those in current mirror), find good lens/loupe and check their markings; 3 same ones in positive rail, 3 different same ones in negative rail; that in case some bloody greenhorn behind Iron Curtain did solder wrong SMD part ......... if needed compare with good channel
-check position and value of all SMD resistors; those at rails are 470R, base resistors are 100R, in between mosfet gates are 6K8
nomenclature as per schm in #188
if nothing else, while you're staring at small ones and if you can't find my error, you'll find your own
@Samuel Jayaraj Scryer vs Sissy42 (42 essentially same as R3). Both having same OS, so differences in FE. Scryer has active FE w/ feedback; Sissy iron FE and no feedback. They're cousins for sure. Scryer is more transparent and a bit more quiet, which gives it a sense of having better dynamics. Sissy has more of the richness and virtue that comes with a passive FE and no feedback. I love them both immensely. If I want more resolving and transparent, I go Scryer; if I want more richness I go Sissy. Both have the SIT magic. Right now my favorite is Scryer....next month it could be Sissy, or Old Soul, or Singing Bush, or .....