dreamie 0 Report post Posted April 10, 2004 haha.. gain problems i guess... don`t dunk the PIOs... they are good caps... I followed Cmoy's schematic exactly, except for the input cap. Share this post Link to post Share on other sites
dreamie 0 Report post Posted April 10, 2004 It sounds like a MALFUNCTIONING RADIO WITH EXTREMELY BAD RECEPTION!!! Lots of static like sound... ............ Could it be because of the PIO? Old caps sound like old radio... More like a wrong connection (or lack of) or solder bridge somewhere. Checked my connections and they are fine... Both channels have the same problem... and they are also wired the exact same way. (wired 1 channel at a time, not 1 component at a time) Share this post Link to post Share on other sites
hacknet 0 Report post Posted April 11, 2004 hmm... could you take a photo of board and post a copy of the version of the schematics you followed..? Share this post Link to post Share on other sites
dreamie 0 Report post Posted April 11, 2004 hmm... could you take a photo of board and post a copy of the version of the schematics you followed..? I have no access to a digicam atm... sorry! I followed the exact same schematic on Chu Moy's Portable Headphone Amplifier article posted on Headwize, only modification will be the absence of the switch (at the input) and changing the input cap value to 2*0.068uF. I'm having problems closing the tin can. My PSU board wont fit. Share this post Link to post Share on other sites
dreamie 0 Report post Posted April 11, 2004 Just read the article. (http://tangentsoft.net/audio/input-cap.html) it seems to only talk about the use of the input cap. . It did mention about the corner freq. to be below 20Hz... I did a calculation... 1/(1*(pi)*(100000*(2*(6.8*10^-8))) = 23.40513869Hz Could this be the problem? I guess I will scrap the PIO caps for other applications. (A NON-portable preamp perhaps) Share this post Link to post Share on other sites
hacknet 0 Report post Posted April 11, 2004 nope... its got nothing to do with the caps... 23hz rolloff is a very resonable figure. and it certainly would not induce static like distortion... Share this post Link to post Share on other sites
eyevancsu 0 Report post Posted April 12, 2004 Try cleaning the underpart of the amp. Get some alcohol and a toothbrush and clean the soldered part to remove debris or flux. Also, scratch in between the traces with a blade to make sure nothing is touching and shorting. This actually solved the problem on a recent amp, the sound was very staticky and fuzzy, but this cleared it right up. -ivan Share this post Link to post Share on other sites
dreamie 0 Report post Posted April 16, 2004 Hi guys! Tried the above stated methods and the problem still persisted. Have bypassed the capacitor and used a 0.1uF capacitor but this time it seems to only be worse. I hear a loud humming sound... there used to be music in the past. Have decided to scrap the whole thing and rebuild another one. Any recommendations on cheap capacitors? Thanks in advance! Share this post Link to post Share on other sites
hacknet 0 Report post Posted April 17, 2004 i got phillips MKP for sale if you want some. very raved over cap by the taiwanese... Share this post Link to post Share on other sites
dreamie 0 Report post Posted May 1, 2004 i got phillips MKP for sale if you want some. very raved over cap by the taiwanese... How much are they? BTW, just rebuilt my CMOY. It's working now, but the volume is extremely low... Using OPA627 directly soldered onto the board... Share this post Link to post Share on other sites
