Bidirectional Stereo Input Selector
1-to-4 or 4-to-1, a trouble-free audio add-on, suitable for beginners

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Materials
Gerber file
CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.
Elektor recommends the Elektor PCB Service service from its business partner Eurocircuits or AISLER as the best services for its own prototypes and volume production.
The use of our Gerber files is provided under a modified Creative Commons license. Creative Commons offers authors, scientists, educators and other creatives the freedom to handle their copyright in a more free way without losing their ownership.
Components
The BOM (Bill of Materials) is the technically exhaustive listing of parts and other hardware items used to produce the working and tested prototype of any Elektor Labs project. The BOM file contains deeper information than the Component List published for the same project in Elektor Magazine. If required the BOM gets updated directly by our lab engineers. As a reader, you can download the list here.
Want to learn more about our BOM list? Read the BOM list article for extra information.
Component list
Resistors (.25W, 1%):
R1,R7,R9,R11,R18–R21 = 100Ohm
R2–R5 = 1.2kOhm
R6,R8,R10,R12 = 390Ohm
R13–R17 = 1kOhm
R22 = 560Ohm
R23,R24 = 100kOhm
Capacitors
C1 = 0.1 µF 100V, ceramic disc
C2 = 10µF 100V electrolytic
C3 = 1000µF 25V electrolytic
C4 = 1µF 63V electrolytic
C5 = 10pF 100V, ceramic disc
Semiconductors
D1–D4 = 1N4148
D5–D8,D13 = LED, 5mm, yellow
D9–D12 = 1N4004
IC1 = LM7805CT
IC2 = CD74HC175E
Miscellaneous
F1 = fuse, 500mA, fast
K1–K10 = RCA (line) audio socket, PCB mount
Re1–Re4 = relay, DIL, PCB mount, e.g. MEDER type DIP05-2A72-21D
S1–S4 = pushbutton w. make contact
TR1 = power transformer, secondary 9V @ 2VA
Discussion (0 comments)
Steve Morgan 3 years ago
Andreu 3 years ago
Steve Morgan 3 years ago
Content Director, Elektor 3 years ago
Steve Morgan 3 years ago
Still not working. If you click on the "PCB Files (1)" Tab next to the default "Relevant Links (1)" Tab, and then click on the 120316-PCB.pdf link, you get the following message: " We're really sorry but this link seems to be broken.Unfortunately the requested page was not found. There may be an error in the url or the link may have expired. "
Is that what you did?
That one is still broken for me, the others work OK.
Regards
Steve
Content Director, Elektor 3 years ago
Steve Morgan 3 years ago