Many say 9-ME-BC + amphetamines are a bad combination since amphetamines block the dopamine transporter.
There is more nuance to it.
9-ME-BC uses DAT to go inside neurons however amphs do not block DAT like classic DAT inhibitors, its primarily via competitive inhibition and it doesn't lock DAT into 1 state like ritalin does. This is important because amphetamines their dopamine efflux still allows DAT to change conformational states. To simplify, amphetamines do not put DAT into a channel-like mode where dopamine is just flowing out, instead DAT shifts inward -> outward -> inward -> outward -> ...
Amphetamines do release dopamine in a channel-like efflux but this is only responsible for a small amount of the total released dopamine.
9-ME-BC can still use DAT, just less effectively.
However i would still never combine them anyways. 9-ME-BC is mid.