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Notes & Errata Tapped Horn Subwoofer, September 2021: the Altronics C3088 driver specified for this design has been discontinued. Wagner Electronics (www.wagneronline.com.au) sell suitable alternatives: the SB Acoustics SB20PFC30-8 ($55) and SB20PFCR30-8 ($56.50). These cost less than the originally specified driver and give very similar performance. The only design change required is to increase the diameter of the driver hole from 180mm to 187mm. Advertising Index Altronics...............................25-28 Ampec Technologies................. 11 Analog Devices..................... OBC Dave Thompson...................... 111 Touchscreen Digital Preamplifier, September 2021: in the circuit diagram (Fig.6) on pages 42 & 43, the Vdd pins of IC6 and IC7 are incorrectly shown connected to +12V. They actually connect to +5.5V. Dick Smith Contest.................... 13 Battery Manager, August 2021: in Fig.3 on page 72, Q2 has been incorrectly drawn with a P-channel Mosfet symbol. It is an N-channel Mosfet, like Q1 and Q3. The gate, drain and source pins are marked correctly. Emona Instruments................. IBC Bush VTR103 AM/FM radio, Vintage Radio, August 2021: in the circuit diagram (Fig.2) on pages 102 & 103, capacitor C11 should have been shown in series with L5, not L6. This means that C11 and L6 form a parallel resonant network, not series resonant as stated in the text. Also, the right-most label in the photo at the bottom of p100 is wrong. It is the VHF RF amplifier load coil, not the VHF antenna coil. Jaycar............................ IFC,53-60 Single-Chip Silicon Labs FM/AM/SW Digital Radio Receiver, July 2021: the specified 3.3V regulator for REG2 (LM2936-3.3) has swapped input & output pins compared to the footprint on the PCB. So if you use this regulator, install it facing the opposite direction to that shown in Fig.5 on page 68, or mount it on the opposite side of the PCB but with the flat side facing as shown. Also note that its part code is incorrectly written as LP2936-3.3 in the circuit diagram, Fig.3, on page 67. 7-Band Stereo Equaliser, April 2020: an error has been found in the 7-Band Stereo Equaliser PCB (01104202 RevB). There is a missing track between the 10nF and 2.2nF capacitors above IC7 – they should be in parallel, but only one side of the pair is connected. This causes the second-highest band to operate at the wrong frequency. If you have a PCB with this error, solder a short length of wire (eg, a component lead off-cut) between those two pads. This error will be fixed with the RevC PCB. CLASSiC DAC, February-May 2013: revised firmware for the DAC (0110213B.HEX) is available for download from our website. This fixes pushbutton debouncing problems and includes changes to the IR reception code to better reject noise. Also, some people have complained that one or more TOSLINK input LEDs light up when there is no signal present. This is usually fixed by adding 30pF ceramic capacitors across the empty pairs of pads near the TOSLINK receivers. The November 2021 issue is due on sale in newsagents by Monday, October 25th. Expect postal delivery of subscription copies in Australia between October 25th and November 12th. It is a great kit that Jaycar are still selling here in NZ. (B. N., Dunedin, NZ) • You can look up kit information via our Article Search feature (siliconchip. com.au/Articles/ContentsSearch). Enter the project name (or part of it) in the “Name” field but watch out for differences in punctuation etc. Searching for “Voltage Monitor” shows that there were two kits, DSE K4608 and Jaycar KC5424, both of which have been discontinued. We generally don’t sell PCBs for projects published before 2010 because many of them have been superseded now (there are exceptions). In this 112 Silicon Chip case, it has been functionally replaced by the 10-LED Bargraph from February 2018. This later version doesn’t require any special-purpose ICs and it is also very flexible in its configuration. We sell the PCB for it at siliconchip.com. au/Shop/8/3272 It should be possible to use that to do virtually everything the Vehicle Multi Voltage Monitor can do. You might want to read the article first to determine what parts you need. For example, the 10-LED Bargraph calls for 10 3mm through-hole or M3216/1206 SMD LEDs of unspecified colour, while the Vehicle Multi-Voltage Australia’s electronics magazine Digi-Key Electronics.................... 3 Hare & Forbes............................. 5 Keith Rippon Kit Assembly...... 111 Lazer Security......................... 111 LD Electronics......................... 111 LEDsales................................. 111 Microchip Technology.................. 9 Ocean Controls........................... 8 PHIPPS....................................... 4 PMD Way................................ 111 SC Christmas Decorations........ 69 Silicon Chip Binders................. 81 Silicon Chip Shop...........106-107 Silicon Chip Subscriptions....... 50 Solder Master.............................. 7 Switchmode Power Supplies....... 6 The Loudspeaker Kit.com......... 10 Tronixlabs................................ 111 Vintage Radio Repairs............ 111 Wagner Electronics................... 87 Monitor uses two yellow, six green and two red rectangular LEDs. As far as we can tell, you should be able to fit those same rectangular LEDs to the 10-LED Bargraph PCB (or use 3mm round LEDs with the same colour scheme). You will want to set up the 10-LED Bargraph in linear mode, using the 10 1kW resistors specified in the parts list, just like the Multi-Voltage Monitor. The only trick is that if you want to achieve the 9-16V range option offered by the Multi-Voltage Monitor, you will need to replace R1 with a 5.6V zener diode, with its anode connected to ground. SC siliconchip.com.au