PARTS LIST
ITEM PART NUMBER QTY
❑ Housing 103158** (Jameco) 2
❑ Socket pins 100766** (Jameco) 55
❑ Header 160882 (Jameco) 2
❑ PB switch 104-0013-EVX 4
❑ SPST switch 108-1MS1T1B1M1QE-EVX 1
❑ SPDT switch 108-1MS1T1B1M1QE-EVX 1
❑ Power connector 163-2325-E 1
❑ Power connector 1710-2532 1
❑ 3. 5 mm Phone jack 161-7300-EX 1
❑ XLR3-F 164-7133 1
❑ 1/4” Phone jack 16PJ022 1
❑ Phono jack 16PJ052 1
❑ 1/4” Phone jack 16PJ080 1
❑ 10Ω2W 282-10-RC 1
❑ 1K 292-1.0K-RC 10
❑ 1M 292-1.0M-RC 1
❑ 1.7K 292-1.7K-RC 1
❑ 100K 292-100K-RC 1
❑ 100 292-100-RC 2
❑ 10K 292-10K-RC 12
❑ 19.6K 292-19.6K-RC 1
❑ 2.1K 292-2.10K-RC 1
❑ 20.5K 292-20.5K-RC 1
❑ 3.3K 292-3.3K-RC 1
❑ 3.57K 292-3.57K-RC 2
❑ 332K 292-332K-RC 1
❑ 47K 292-47K-RC 1
❑ 5.49K 292-5.49K-RC 1
❑ 8.06K 292-8.06K-RC 1
❑ 9K 292-9.09K-RC 1
❑ 100Ω 30BJ250-100 1
❑ 2.7K 30BJ500-2.7K 1
❑ 42TL019 42TL019 1
❑ TS912 511-TS912BID 3
❑ FAN1616 512-FAN1616AD33X 1
❑ GF1A 512-GF1A 2
❑ 7805 512-KA7805ATU 1
❑ Socket 538-52437-3072 1
❑ Socket 571-5-104652-5 1
❑ 220 pf 581-08051A221K 1
❑ .0022 µF 581-08053A222K 1
❑ 470 pf 581-08055A471K 1
❑ 680 pf 581-08055A681K 1
❑ . 47 µF 581-0805ZC474K 8
❑ Enclosure 377-1163-ND (Digi-Key) 1
❑ 2N3904 625-2N3904 2
❑ 100 µF 647-UVR1E101MED 1
❑ 20K 72-T93YA-20K 3
❑ F-51553 805-F51553GNBJAEN 1
❑ Relay 806-9081C1-05-00 1
❑ 1.0 µF 80-C1206C105K3R 5
❑ 4. 7 µF 80-C1206C475Z4V 4
❑ ADS7816 ADS7816U-ND (Digi-Key) 1
❑ Microprocessor RCM4120 1
❑ SN74LVC1G66DBVR 296-13253-1-ND (Digi-Key) 3
❑ LED 606-CMD3750 1
160882 Headers are cut to size and require 100766 pins
and housing
** 100766 socket pins requires 103158 housing cut to size
The system needs about 55 total pins — this is equivalent to
two pieces each of 103158 and 160882
NOTE: All items are from Mouser unless stated otherwise.
A more detailed parts list is available at www.nutsvolts.com.
50
August 2008
away from the analog amplification stages as much
as possible; and (2) to enable the flexibility in the
audio processing so the builder can develop his/her
own circuit and control it from the system.
The processor circuit (Figure 5) shows the
connections from the microprocessor board to the
other circuits. The board also has the A-to-D
converter and the pull-up resistors for the switches.
The ADC is powered by the 5V regulator. As
such, its SPI output signal is a 5V logic level. The
microprocessor board I am using can handle only
3.3V input signals — that is why there is a voltage
divider on the output of the ADC.
I have selected a 2 MHz clock speed for the
SPI system. This is used for both the analog
converter and the display. The interrupt service
routine that is used to sample the input signal takes
approximately 12 to 16 µs, depending on the
processor you are using. This means that the
highest theoretical sampling frequency is either
80 kHz or 60 kHz. The fastest sample rate the ADC
will support is 200 kHz. This is equivalent to an SPI
clock rate of 3.2 MHz since it takes 16 SPI clocks
to read the converter. The display can handle about
a 7 MHz clock. So, I could increase the clock
speed to 3 MHz and get a 50% increase in the
sample rate. However, this is not necessary since
the system is designed for the audio spectrum.
All of the values can be modified via the menu
system can be stored in the Flash memory of the
microprocessor board. This includes the ADC
calibration, the frequency “window” you want
to view, sample size, etc. The current menu
system allows you to store up to 10 sets of these
values. There is a complete and detailed
description of the menu system on my website at
www.qsl.net/k3pto.
Some Construction Notes
A few comments about the BOM. Although
the BOM shows mostly Mouser part numbers,
many of them are available from other sources,
including Digi-Key and Jameco. If you want to save
some money, I suggest you search the sites for the
best prices on the higher cost items. Bear in mind
that these companies may have a minimum dollar
value for orders. Many of the parts for this project
do not have critical values. For instance, the gain
resistors in the analog circuit may be customized
for your application. The transistor type used for
K1 on the analog board and the backlight on the
digital board can be any small signal NPN or
even an FET (2N7000). The PCBs (three) can be
purchased from FAR Circuits as a set.
I recommend that you purchase two of the
LCD boards, as well as two of the LCD connectors.
