Macrofab Engineering Podcast

Podcast Notes Popping in last weeks audio was probably due to a cheap USB cable. Stephen and Parker recorded last week on a laptop with a USB powered mic preamp that has less then stellar power filtering and performance. Stephen is continuing work on his automatic brewing rig. Has a motorized ball valve to control the flow rate for proper mashing and cooling rates. Parker found the correct IC that is inside the Jeep radio. Part number TDA7340S. It is a 100% direct match to the pinout of the IC inside the radio. He found it by looking at ST's catalog of Audio and Radio ICs from that time period. To switch Audio sources to an external source, Parker is going to hack into the TDA7340's external effects loop. See Figure 1. The signal will probably have a DC offset since the IC is on a single power rail of ~9.4V. DC offset should be around 4.5V. The Bluetooth adapter will need to have a DC offset to match. ICs to switch the audio signals will either be a NJM2520D or a MAX4544CPA+. Shout out to Pat Hensley from Te