Article
USB Audio Recorder
A fully-featured sound card for the Universal Serial Bus
Many motherboards these days only offer limited space for expansion cards, and integrated sound chips are generally not so well suited to highquality recording. If a sound card is fitted in the PC, it is exposed to enormous levels of interference which does nothing for the audio quality. The solution is an external sound card, connected over USB.Installing an add-in sound card into a system is generally a lot of fuss. In order to transfer audio data digitally to the PC, either you will need an S/PDIF interface on the sound card or else you will be reduced to ‘grabbing’ the audio using the CD-ROM drive. If you want to make recordings using a notebook computer, you will have to be content with the microphone input or purchase an expensive PCMCIA sound card.
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.
PCB
Component list
Resistors:
R1 = 75?
R2 = 470?
R3 = 680?
R4,R19-R23 = 1?
R5,R6,R7 = 4k?7
R8,R9,R11-R14 = 22k?
R10 = 1k?5
R15,R16 = 22?
R17,R18 = 220k?
R24,R25,R28 = 10k?
R26,R27 = 100?
Capacitors:
C1,C32 = 10nF ceramic, lead pitch 5mm
C2,C9,C13,C18,C20,C22,C24,C36 = 10µF 25V radial, lead pitch 5mm
C3 = 2nF2 ceramic, lead pitch 5mm
C4,C6,C7,C14-C17,C19,C21,C23,C25,C26,C27, C33,C35 = 100nF (SMD shape 1206)
C5,C8,C10,C41-C44,C46 = 100nF
ceramic, lead pitch 5mm
C11,C12 = 22pF
C28,C29,C34,C37,C38 = 47µF 25V radial
C30,C31,C39,C40 = 10pF
C45 = 10µF 63V radial
C47 = 470µF 25V radial
Inductors:
L1 = 1µH5 miniature choke
L2 = 47µH miniature choke
L3-L8 = BLM31A601S (Murata, SMD shape
1206, Farnell # 581-094)
Semiconductors:
D1,D2,D3 = LED, 3mm dia.
D4 = 1N4002
T1 = BC547B
T2 = BC557B
IC1 = TORX173
IC2 = TDA1315H/N2 (Philips)
IC3 = UDA1325H/N106 (Philips)
IC4 = 74HC573
IC5 = 27C512-10, order code 012013-21
IC6 = LE33CZ (ST, Farnell) or LP2950CZ-3.3 (National Semiconductor)
IC7 = 7805
Miscellaneous:
JP1 = 3-way pinheader with jumper
K1 = Cinch socket, PCB mount (e.g., T-709G from Monacor/Monarch)
K2 = USB-B socket, PCB mount
K3,K4 = 3.5-mm stereo jack socket, PCN mount (Conrad Electronics # 732893)
X1 = 48MHz quartz crystal, 3rd overtone, parallel resonance
PCB, order code 012013-1
Disk, order code 012013-11
R1 = 75?
R2 = 470?
R3 = 680?
R4,R19-R23 = 1?
R5,R6,R7 = 4k?7
R8,R9,R11-R14 = 22k?
R10 = 1k?5
R15,R16 = 22?
R17,R18 = 220k?
R24,R25,R28 = 10k?
R26,R27 = 100?
Capacitors:
C1,C32 = 10nF ceramic, lead pitch 5mm
C2,C9,C13,C18,C20,C22,C24,C36 = 10µF 25V radial, lead pitch 5mm
C3 = 2nF2 ceramic, lead pitch 5mm
C4,C6,C7,C14-C17,C19,C21,C23,C25,C26,C27, C33,C35 = 100nF (SMD shape 1206)
C5,C8,C10,C41-C44,C46 = 100nF
ceramic, lead pitch 5mm
C11,C12 = 22pF
C28,C29,C34,C37,C38 = 47µF 25V radial
C30,C31,C39,C40 = 10pF
C45 = 10µF 63V radial
C47 = 470µF 25V radial
Inductors:
L1 = 1µH5 miniature choke
L2 = 47µH miniature choke
L3-L8 = BLM31A601S (Murata, SMD shape
1206, Farnell # 581-094)
Semiconductors:
D1,D2,D3 = LED, 3mm dia.
D4 = 1N4002
T1 = BC547B
T2 = BC557B
IC1 = TORX173
IC2 = TDA1315H/N2 (Philips)
IC3 = UDA1325H/N106 (Philips)
IC4 = 74HC573
IC5 = 27C512-10, order code 012013-21
IC6 = LE33CZ (ST, Farnell) or LP2950CZ-3.3 (National Semiconductor)
IC7 = 7805
Miscellaneous:
JP1 = 3-way pinheader with jumper
K1 = Cinch socket, PCB mount (e.g., T-709G from Monacor/Monarch)
K2 = USB-B socket, PCB mount
K3,K4 = 3.5-mm stereo jack socket, PCN mount (Conrad Electronics # 732893)
X1 = 48MHz quartz crystal, 3rd overtone, parallel resonance
PCB, order code 012013-1
Disk, order code 012013-11
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