On Tue, Feb 5, 2013 at 2:49 PM, Harold Hallikainen wrote: > What are you driving with this? If the load is a relatively high impedanc= e > (20k or higher, I see two 1k resistors in series on each output), the > series resistance should have minimal effect. Ah, that must be it. I was experimenting with some low impedance headphones. I had considered adding a small headphone amp IC, perhaps that is the best way to deal with this. > Do you really need an LPF there? If not, you can save some parts and > possibly drop the resistor values. I think it's a good idea based on where the audio is coming from. The internal opamps are using switched capacitors instead of resistors, so I could see some of that noise coming out. > One concern, if your load is a low impedance, is what the chip can drive. > It may not be able to source or sink enough current for a low impedance > load. Makes sense. A headphone amp is looking like a better and better idea... > Finally, be careful about capacitive loads on op amps. The capacity along > with the output resistance will cause a phase delay in the output, which > is then additional phase delay in the feedback, which can make the circui= t > unstable. Ok, that makes sense. I suppose he was trying to compensate for this somewh= at. The chip is a CY8C29466 Cypress PSoC. Josh --=20 A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools. -Douglas Adams --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .