FS: Input relay board with mute and optional digital potentiometer

[scobham]

Hi,

I have 4 x PCB's for sale out of the batch of 5 I had made. These PCB's are 100 x 160mm (but can be cut down) and support 5 stereo inputs. There is a mute relay as well. (Which should be engaged before switching the input relay to reduce audible clicks).

The schematic diagram is attached. A DS1882 digital volume control can be switched into the output by means of jumpers LN1/LN2 and LN3/LN4.
The transistors/relays can be driven either by a rotary switch or the PCB will accept an Arduino PCF8574 expander board directly onto the PCB and the I2C port drives both the expander and the Digital Volume control.

Here is the link to the expander board:

PCF8574 PCF8574T I2C 8 Bit IO GPIO Expander Module for Arduino & Raspberry Pi U | eBay

I use the 5th board and there is no hum so layout is good.

Schematics attached.

I don't need the extra boards so hoping someone will benefit. They are 5 GBP each and 0.88 GBP shipping in the UK. If you are not in UK provide your address and I will let you know how much to ship.