jasonhanjk 0 Report post Posted October 20, 2010 It's been a long time since I start a thread here. Very long time ago, I always wanted to redesign the basic cmoy into a robust amp with little component count. Today I just had it completed. Initial specification is very promising and now running in this amp. When most people build their Cmoy. The main problem they encounter is fluctuating half voltage. Adding an led will stabilize the voltage. Picture of the board will come soon. Share this post Link to post Share on other sites
Firefox 0 Report post Posted October 21, 2010 Hrmm.. That's an inverting configuration which can, on a simple design like this, sound much better than the non-inverting equivalent. As for the LED, calculations need to be made for the LED's Vf and the resistor value changed accordingly. Also, note that the Vf limits how low the battery voltage can drop before the V-gnd swings to the top rail. It might be better to simply implement an inexpensive opamp as a unity gain buffer to drive the virtual ground. The opamp presents a high impedance to the resistor ladder and that prevents the mid-point from fluctuating too much since the current fluctuations through the ladder is minimized greatly as opposed to charging/ discharging the capacitors directly. Alternatively, a simple transistor configured as an emitter-follower would also do well to isolate the ladder from the current fluctuations of the capacitors charge/ discharge. Share this post Link to post Share on other sites
SvenMZ8 0 Report post Posted October 21, 2010 same sentiment firefox. the current draw from such voltage splitting configuration is much higher, if used as a portable amp, the battery life is significantly reduced. Share this post Link to post Share on other sites
madcap386 0 Report post Posted November 13, 2010 Looks good... keep it coming! For me, i would bother too much on the rail splitting imbalance too much. battery life problem is pretty much negligible. Share this post Link to post Share on other sites