Yeah, I agree, I should have been clearer. I meant specifically that using a contract manufacturer has less visibility into the quality control than in-house assembly, (In china or the US or anywhere) and also there are lots of challenges giving a contract manufacturer very clear instructions as to what is a “good” quality passing unit. I work for a US based contract manufacturer, and this is a huge challenge, just getting good enough instructions to be able to provide the customer with exactly what they want. With your own assembly operation you can ostensibly have experts who know how to properly test and calibrate everything. I have not actually worked in that environment so I don’t know how successful that is with relatively low wage local employees under your own roof. But a lot of eurorack modular manufacturing works this way, with the original designer doing the final assembly and testing, and I think in that situation you are more likely to have a better product (without making super in depth testing and assembly documentation) than it being completely assembled by the contract manufactuer.
But setting up an SMD line is super expensive, so for a lot of people it makes sense to use contract manufacturers for the PCB assembly, but then do the final assembly, calibration, and testing in house, rather than use a contract manufacturer.
