huangyong 0 Report post Posted January 8, 2006 (edited) if you guys want to make PCB, pls use protel format. i will try to persuade digi01 to make for us at cheap price. Edited January 8, 2006 by huangyong Share this post Link to post Share on other sites
squalle 0 Report post Posted January 8, 2006 I was thinking making the PCB, DIY way I dont wan to make the cost increase getting factory produced will make the price go up and not to say digi01 sure wnana earn some Share this post Link to post Share on other sites
kross 0 Report post Posted January 8, 2006 squalle, your vol pot looks quite well built. how much you bought it for? anyway, i have tried removing my vol pot and fixing a fixed 100k instead but the buzz is still there, which really puzzles me. now i dunno whether it is the vol pot fault or whether the soldering is at fault. Share this post Link to post Share on other sites
Kippei 0 Report post Posted January 8, 2006 Is the 337 facing left or right.... If the correct orientation is face right, while i following the perfboard diagram. I think i soldered vout to R 11k Share this post Link to post Share on other sites
squalle 0 Report post Posted January 8, 2006 hahaha LM 337, looking at its labeling, it's A I O I did this SOHA till I remember that pin-outs Share this post Link to post Share on other sites
squalle 0 Report post Posted January 8, 2006 kross: check all ur AC line. dont let them get near, and also did u somehow put ur switch and it's wiring passing thru the signal part? and also chk for cold joint or cold connection. last time I've got the hum due to that is that hum or buzz? if more like buzzing, then more like there's a strong EM source nearby, i.e. the trafo Share this post Link to post Share on other sites
kross 0 Report post Posted January 8, 2006 haha...i also find it hard to find the problem. i have remove the hum from the psu by not using a too high voltage, around 24V. but the buzz from the vol pot is there, slight irritating sound by i turn the vol pot too small, ie, in the range of 10k and above to 100k. if it is only a few k then there is no buzz. hmm, maybe when i have the time i'll redo the soldering again Share this post Link to post Share on other sites
squalle 0 Report post Posted January 8, 2006 do u have other pot? might be the pot somehow and at the same time, recheck ur connection if u suspect something's loose, then you can try to pull it see if it comes off. good luck getting the hum off aint that easy even the culprit is simple things happened to myself before Share this post Link to post Share on other sites
squalle 0 Report post Posted January 9, 2006 kippei : for the DC blocker (that guy calls it Da Blok), you have to tape out the caps. at the top of the caps where the metal part is exposed, can cause short. haha. happened to me as I did not tape out properly and caused my house circuit breaker cut off Share this post Link to post Share on other sites
Kippei 0 Report post Posted January 10, 2006 How come the 560R can be taken off.. The 2k pot provide enough trim? Share this post Link to post Share on other sites
squalle 0 Report post Posted January 10, 2006 yup definitely I tried one side with 2*300R and one side just the 2k trimpot both can reach 40V. Share this post Link to post Share on other sites
Kippei 0 Report post Posted January 10, 2006 Darn... till the last moment i am short of a 2134... Share this post Link to post Share on other sites
squalle 0 Report post Posted January 10, 2006 how can you miss that? do you have other op-amps? see this config: http://home.swbell.net/acavalli/images/Cav...llower_1.00.gif if u're going to use 2227, gotta do that kinda config. a little change of where the signal is tapped from. putting 100k for the input resistance will lower the DC offset at the output DC offset will be problematic if you're using 2227 or NE5532 or some other op-amps with input bias current higher than 10pA btw, you do use jfets for CCS rite? Share this post Link to post Share on other sites
Kippei 0 Report post Posted January 10, 2006 yep... i found 2132.... now the tube lights up.... plate voltage... in mV range dc offset 12 volt... Share this post Link to post Share on other sites