Quick question about a discrepancy between the DMM and DMM reissue schematics vs. the Dirtbag. C50 goes from the NE570 pin 13 to ground and is shown as 100n on the BOM, in the vintage EHX DMM schematic it is shown as being tied directly to ground. Can anyone explain why it was added? Also the values for C4 (47uf) and C32 (22uf) are the same as the reissue, but twice the value of the vintage DMM's (22uf and 10uf respectively), I wonder if that change was made to mitigate noise/hiss, or if there was another reason for it?
C50 it extra power filtering, the Dirtbag was switched from -15V to +15 so pin 13 is now voltage instead of ground.
The value of C32 doesn't matter so much but C4 forms a high pass filter with R5 so the value does matter but it's effect will be minimal, 0.1hZ roll off for 47uF, 0.2hZ roll off for 22uF.
Thanks Scruffie!