I didn’t really think about the BOM cost of my programmable decade resistor until I was asked. Then I also wanted to know. It is fairly difficult to put a number to what I paid, since I had a lot of components left from other projects that I could use. This includes not only cheap chip resistors and MLCCs, but also connectors etc.
Normally I order from both mouser and digikey, but for some of the industry-standard components, connectors etc I use local distributors. This is why I’ll only give a very rough estimate for the per unit costs including taxes (not including any shipping costs). For some of the parts like the PCBs there is a minimum order quantity that will increase the cost in most DIY scenarios.
|1||ELMA Stylebox 15 Standard (not new)||50,00|
|2||Front & Rear panels (Aluminum PCBs)||5,00|
|3||Rotary encoder knobs and key caps||10,00|
|4||IEC power connector + Fuse||3,00|
|5||4mm banana sockets||8,00|
|6||Connectors, cables etc.||2,00|
|3||EC2-12NU relays (or similar)||73,50|
|3||STP16CP05 constant current LED drivers||10,00|
|5||Rotary encoder and switches||37,00|
Power supply board
|1||Power supply PCB||1,00|
|1||TRACO TMPW 10-115||19,50|
|1||NE-18 series power switch||8,50|
According to this calculation the total cost of the unit would be about 369 €. Quite a lot, actually. This doesn’t necessarily reflect what I paid for it though. One example: I bought 5 NE-18 type switches on ebay for about 2 € each. These are not necessarily the same as the ones provided by mouser, but both variants could be used.