I am in the process of populating a few VFE boards. One of them is the White Horse compressor. Smallbear is out of the Silonex NSL-32SR3 photocoupler. Mouser doesn't carry them. Allied and Newark both do though (too bad I placed a Newark order a week before I ordered). I had a pretty bad experience with Newark and would prefer not to go through them. Is there an equivalent part that Smallbear currently has in stock that would be a good substitute?
The R2 would probably be fine. It does not have as high of an off resistance as the R3 but I think it's close enough in this application. I forget what the difference is in response time between the three - that might be why he used the R3.
R1: 40R On, 500k Off
R2: 40R On, 5M Off
R3: 150R On, 25M Off
The decay response is a slower on the 32SR2 when compated with the R3 (80msec vs 10msec). That's if I am understanding your comment correctly. Both have a rise time of 5ms (the 32sr2 has a unit of Msec, but I assume that is just a typo for msec).
That said, I'm not sure if that difference would have a large effect here.