Version 1.0 (in collaboration with Michael Mahon)
I was asked to provide some Drew ][ TDX cards for the GS laptop project (http://www.a2gs.com), and I decided to to do a new design that is more suitable for a portable computer. The current version includes a power amp, headphone cut off and volume control. Again this was a real learning process, and there will only be 5 of these cards made, with 3 going to the GS Laptop project for their initial prototypes. The digital potentiometers (DS1669) are expensive and add a considerable amount to the overall cost
Though the basics of the laptop card is the same as the desktop card the power amp, volume control and headphone support adds complexity to what is a simple design.
A new IC is currently being tested (TDA8552) that has all these features included in a single 20pin IC. This will reduce cost and complexity and I hope to have this all completed in time for the full production run of the GS Laptop.
A big thankyou goes to Michael Mahon for his continual help and patience. Without his help the laptop card would never have been completed. :). This has become very much a collaboration.