Hello friends!
I am waiting for my Dumble board and eyeing over the schematics.
I have found some differences between the Layout and Schematic files,
R25 and R24 is rated at 1W on the schematic but 3W on the layout. Can we get away with 1W in that position?
R14 Rated 1W on schematic but 3W on layout
R16 Rated 1W on schematic but 2W on layout
R53-R56 Rated 2W on schematic but 5W on layout, i have a feeling that 2W is too low for this position
C26 Rated 50V on schematic but 25V on layout
I would just err on the side of caution and go with the higher ratings, but itwould be good for future builders to know the actual required tolerances
C16 & C17 is stated as 20uf on schematic but 22uf on layout
C4 is 0,047uf on layout but 0,05uf on schematic
C36 is 0,047uf on layout but 0,05uf on schematic
I suspect that there are no sonic differences between these parts, but since we are dealing with a "corksniffer" amp here it would be good to know what the original values are.
Perhaps you can enlighten me AA?
Tried to edit. Should say "looking at (and likely buying) the E12"
The cap values (in uF) reflect the difference between common values when Fender originally built these and the modern. Given that tolerances are typically 20%, the modern values are "correct" - at least functionally equivalent. You're looking at (and the E12 values - check out this link:
https://en.m.wikipedia.org/wiki/E_series_of_preferred_numbers
R25 and R26 should be 3W --> I've updated the schematics
R14 should be 3W --> I've updated the schematics
R16 should be 2W --> I've updated the schematics
good catch on the R53-R56. This should be 5W wirewound --> I've updated the schematics
C26 is perfectly fine at 25V --> I've updated the schematics. Note that this value is sometimes declared as 47uf @50V, but there seems to be a major consensus over the 100uf @25V
C16 & C17 should be 20uf, but 22uf is normally easier to source. I've updated layout and BOM
Lots of different opinion on C4: seems to be 0.05uF originally, but some sources report 0.047uF. In general, 0.047uF is normally way easier to source. I've updated layout and BOM. Same goes with C36.
Thanks for the feedback. Anything else, please let me know :)
Please re-download all the files, they should be now up to date ;)
Cheers from London
Thanks for the post Andreas, will have a look and report back!