Signal Generator Circuit with Volume Control

This is the prototype circuit using the XR-2206 signal generation IC. D3 extracted a Toshiba TC9235P volume control IC out of a small Cambridge SoundWorks desktop radio found at a yard sale; the up/down control (silver knob) is out of a CD player. The XR-2206 has a pin dedicated as an amplitude modulation input and early testing shows it works very well. For use testing our amplifiers, filters and enclosure designs, we plan to build this into a portable instrument box.

Push Button Circuit Schematic

This is the circuit D3 designed for the new push button shown in the earlier post. It provides logic and timing for the blue blinking sequence (earlier video) and control lines for indicating charging (red solid) and errors (blinking red).

Push Button Switch

This is a new switch with blue and red led lighting that just arrived. D3 built a circuit to blink with a slow-on slow-off pulsing mode as seen in this video. This will be used to turn our speaker systems on/off. Working today on new functionality, the circuit design now has a start-up sequence that blinks 5 times when the button is pressed and then stays on. It also has a control line that turns the color to red and blinking that will be used as an error or out-of-range condition indicator.

120 Watts with Excellent Specs

Just arrived today from the UK: only $25 for a completely integrated 120 watt amplifier with very good performance characteristics. We had this up and running in short order with as much volume as we dared to push through our test speaker! Perfect for the signal chain feeding the larger speakers in our prototype design.

New Speaker Design

Snapshot of work in progress on new speakers. Intended as platform to test speakers, enclosures, ports, cross-over networks, filters, and amplifier designs.