kross 0 Report post Posted October 13, 2005 lol....ok..i volunteer to build and sell for US$39.90...takers anyone?? Share this post Link to post Share on other sites
matt.pimm 0 Report post Posted October 13, 2005 Damn, I cant even get parts that cheap in the UK! Share this post Link to post Share on other sites
kross 0 Report post Posted October 13, 2005 wau...serious? hmm...then why don't you buy from him? Share this post Link to post Share on other sites
matt.pimm 0 Report post Posted October 13, 2005 Cost of parts for me in the UK is £30.48GBP from Farnell excluding the PCB and case. This is about $53.49USD or $90.44SGD! Share this post Link to post Share on other sites
Kube 0 Report post Posted October 14, 2005 Wow..that's expansive...why not ask someone here in Sg to buy the stuffs from farnell then mail you? Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted October 14, 2005 I believe it's their taxes. Share this post Link to post Share on other sites
jasonhanjk 0 Report post Posted October 14, 2005 (edited) Whats the max cap value to recommend 10uF thanks jason. what about the 100V 1 uF caps? i used them, and can work but I dunno whether they will affect the performance or not. Have you tried with other cap? Try playing around with a few values. Ok...got round to getting a 2nd board and doing everything all over again, this time with more patience and experience, of course dry.gif Everything's set up for use (as in all connections made), flux cleaned the bottom thoroughly, jumpered the right and left channels where the pot's supposed to be...and still no.gif Strangely, when I put my fingers underneath the connections, I can sometimes get clear sound. How's that? Also, LM6181 can work in place LM6171. Here is the link to the datasheet to LM6181. Read the datasheet first and confirm whether are their pinout the same. http://cache.national.com/ds/LM/LM6181.pdf I try not to spoon feed you too much. For you board problem, what do you use as source and what is your headphone? Edited October 14, 2005 by jasonhanjk Share this post Link to post Share on other sites
kross 0 Report post Posted October 15, 2005 recently i have some oscillation, some kind of hissing sound on my headphones when i on the power. after that i must plug out and then plug in my headphone jack again to get rid of the hissing sound. how to solve this anyone? what is it due to? lousy soldering? Share this post Link to post Share on other sites
squalle 0 Report post Posted October 15, 2005 recently i have some oscillation, some kind of hissing sound on my headphones when i on the power. after that i must plug out and then plug in my headphone jack again to get rid of the hissing sound. how to solve this anyone? what is it due to? lousy soldering? I've got that prob initially. But as I've fixed the board + all the I/Os and the pot, the hissing and very subtle oscillation are gone now. I guess all due to the ground loop prob. as my casing is made of alu, somehow it helps to eliminate the ground loop now burning-in the amp hmm is there any need to burn-in an amp actually? anyway, here's the pic of my 1st DIY amp: lacking of the top part. havent finished yet Share this post Link to post Share on other sites
Kube 0 Report post Posted October 15, 2005 Nice! Where'd you get that alu. casing?!...Nice knob too As for my prob...source is a Zen micro, with the default earphones that came with it. Don't want to test with my hd280pro, scared it might get damaged or something... Share this post Link to post Share on other sites
squalle 0 Report post Posted October 15, 2005 alu casing was hand made. hehe still need to continue for the cover part.. knob was bought from koba hmm, I did my test run using a pair of earphones, very cheap one. haha 2 bux one. dun even wanna use the default ipod earphones u're still having the problem? pm me ur msn contact if u have one. I'll see if I can help you Share this post Link to post Share on other sites
kross 0 Report post Posted October 15, 2005 funny thing is the oscillation happen only for one of my better headphones. the cheaper earphones and headphones plug in don't have this problem. i off my mp3 player there is no such hissing. on back the player there is this hissing sound again. hmmm..wat could be the problem..can't pinpoint that the source is causing the oscillation right? Share this post Link to post Share on other sites
squalle 0 Report post Posted October 15, 2005 kross: do u have other source to use? CD player? hm, I've just found out that my first prob of oscillation was caused by defective op-amp. then out of the stash I've got I managed to picked out 2 of them that are defective. both gave the same type of oscillation, very very terrible distortion in the lower freq. the other chips are OK. btw, all chips I've tested all are of the same model, tho' in 2 different prod batches. I guess you might have same prob? Do you have other chips to try? one more thing, I've got a prob when I off the amp, with 0 source; then I'll have hissing and slight screeching noise on the headphone, no matter which cans I used. However, when I turn the amp back on, still no source, the noise is gone. Can I confirm with any1 here that this prob is due to my power supply? apparently not from batt. the power is being taken from power adapter of an external HDD casing, modified by adding 4,000 uF. Share this post Link to post Share on other sites
squalle 0 Report post Posted October 15, 2005 regarding the noise when my amp is off: It's confirmed that the culprit is my prev power supply. now running using the PSU of my PC Share this post Link to post Share on other sites
Kube 0 Report post Posted October 16, 2005 Somehow...I've got this feeling that I took too long to solder the jumper wires to my stereo female sockets....hence them getting burned, and hence bad sound. Can't be left over solder since I thoroughly cleaned the board until it was nice and shiny like before...used minimum of solder to solder the components on...maybe it's the lm6171 or the opamps I'm using...Anyway, waiting for the pot from federal to come...so no rush Share this post Link to post Share on other sites
