High-End-Preamp, Part 2
Published in issue 332, May 2004
The modular design and flexibility of the microcontroller program allow the preamplifier to be built exactly according to the individual requirements of its user.The multitude of options for constructing your ‘personalised’ high-end preamplifier mean that you must read this second part of the article before you order the parts and take up your soldering iron. This is because your requirements determine how many circuit boards of which type you will need, as well as which components you will need. You can connect several volume controls in parallel as illustrated in Figure 1, in order to adjust more than two channels at the same time. If you do this, you must interconnect the CS, Mute, SCLK, +5 V and Ground terminals of the circuit boards. SADATO from the first circuit board is connected to SDATI of the next circuit board, and so on. This causes the volume level setting to be communicated to all of the circuit boards.
(main board, 020046-1) Resistors: R1 = 27Ohm R2,R9 = 47kOhm R3 = 8-way 10kOhm SIL array R4 = 4-way 10 kOhm SIL array R5 = 1kOhm 5 R6,R7,R8,R10 = 10kOhm P1 = 10kOhm preset P2 = 100Ohm preset Capacitors: C1,C2,C3,C20 = 10µF 25V radial C4-C11,C14,C15= 100nF C12,C13 = 27pF C16,C17,C18 = 2200µF 25V radial C19 = 100nF ceramic, lead pitch 5mm Semiconductors: D1 = low-current LED (+ 2-way pinheader) D2.,D3,D4 = zener diode 5V6, 1.3W IC1 = PIC18LF452-I/L (PLCC). Blank ICs: Farnell # 400-9654. Programmed ICs: order code 020046-41 IC2 = PGA2311PA from Texas Instruments/Burr-Brown or CS3310 from Cirrus Logic (Crystal) IC3 = SFH5110 (TSOP1836) (+ 3-way pinheader) IC4,IC6 = 7805 IC5 = 7905 T1 = BC550C Miscellaneous: JP1,JP3 = 2-way pinheader + jumper JP2 = wire link K1 = 3-way PCB terminal block, lead pitch 5mm K2 = = 2-way PCB terminal block, lead pitch 5mm K3 = 16-way pinheader K4 = 10-way boxheader, vertical K5 = 26-way boxheader, vertical X1 = 10MHz quartz crystal 12 solder pins External parts: LCD, 2x16 characters with backlight 12 pushbuttons for chassis mounting 2 Cinch sockets for chassis mounting, isolated and gold-plated Mains on/off switch, chassis mount IEC mains appliance socket, chassis mount Disk, hex and source code files, order code 020046-11 or Free Download. COMPONENTS LIST (relay board, 020046-2) Resistors: R1-8 = 10kOhm R9-R16 = 47kOhm Semiconductors: D1-D8 = 1N4004 D9-D16 = low-current LED T1-T8 = BC550C Miscellaneous: JP1 = 2- way pinheader + jumper JP2,JP3 = wire link K1 = 10-way boxheader, vertical K2 = 2-way PCB terminal block, lead pitch 5mm RE1-RE8 = RY5W-K (Takamisawa), Conrad Electronics # 502852 (5V/167Ohm ) 16 Cinch sockets for chassis mounting, isolated and gold-plated COMPONENTS LIST (asymmetrical PSU, 020046-3) Resistors: R1 = 0Ohm 1 5W Capacitors: C1-C4
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Please note. In view of the complexity of international markets, Elektor cannot guarantee the availability of components for this project.
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