heady 0 Report post Posted April 19, 2007 Hiss can be due to different reasons. It can be due to your source. I had some MP3 players which had a horrible hiss when heard thru amps. The louder the volume is turned up, the louder the hiss is. Some times the hiss is due to the phones which are brighter and tend to emphasise the hiss. Or it could be due to the amp itself, due to bad soldering etc. Distortion when volume is turned up can be due to the amp itself, eg soldering etc or due to the phones not able to take the increased volume. Or simply the capacitors you used for the power supply not being able to supply current fast enough. So again, can be any of these possible reasons. Changing opamps will change the sound character. However, it requires that your headphones must be good enough to pick up these differences. Notice, I said character and not quality. To detect quality of sound, you not only require a good set of headphones but also experience. If you are newbie to hifi, then if the sound is clean and clear, it is good enough. More experienced listeners want to be able to differentiate where the different instruments are in the sound stage etc. Others will be more interested in life like sound, etc. All very subjective which is why there are many opinions on what is good. Re: the flux, this is mixed in the solder and help it to melt. It will appear as an oily liquid on the wires and circuit board. You should clean it off as it can cause short circuits to the amp. You can buy alcohol from the pharmacy to clean it off or buy flux cleaner from Sim Lim Tower. If you go to the soldering tutorials in Tangent's site, you can see how to clean the pcb. HTH. Ok, done up the cmoy up to the amp section and tested them with croc clips. the chips didn't blew, and sound managed to get through the amp...... however.... 1. there's a quiet hiss whenever it's on( i think i can fix this by using the R5) 2. there's ugly distortion when i turn up the volume. I'm not sure how to fix this distortion.. any advices on this? My current amp is using JRC5532D. The voltage between V+ n V- are equal. I tested with my px100, sportapro n one cheap headphone. Distortions happens in all headphones.... but not when i play it low volume.i use a single 9v battery Anyway, may i know what's this flux thing? is it thing that would stick to my board n is a bit shiny2? Do i have to get rid of it n if yes,how? One last question, would a cheap op-amp like 5532D cause significant changes to the quality of sound? Cause i dun hear much difference when i play it through the amp(at low volume though). Would really b interested to know... Share this post Link to post Share on other sites
n0on3 0 Report post Posted April 19, 2007 wow. thx a lot actually the hiss is not much of a problem, it's very very soft. I just noticed it cause it was very quiet when i tested it and no songs were playing. lol. once the song play, it's not audible anymore. I'll try to fix my soldering, hope it will help my distortion prob... or would adding an additional 9v battery help? Which would b the cheaper option for the flux remover? how much are they? Share this post Link to post Share on other sites
heady 0 Report post Posted April 19, 2007 wow. thx a lot actually the hiss is not much of a problem, it's very very soft. I just noticed it cause it was very quiet when i tested it and no songs were playing. lol. once the song play, it's not audible anymore. I'll try to fix my soldering, hope it will help my distortion prob... or would adding an additional 9v battery help? Which would b the cheaper option for the flux remover? how much are they? The alcohol is quite cheap, the flux remover I think was $12 a can. The only difference I can see is that the alcohol contains water, so you need to blow dry the pcb after cleaning and leave it to dry before turning it on. The flux remover dries faster but much more expensive. If your distortion due to the amp clipping (run out of steam), then increasing the power may help. But I am not sure that is the reason. You can try it, no harm. Share this post Link to post Share on other sites
n0on3 0 Report post Posted April 19, 2007 (edited) i already did some touch up on the soldering. the hissing is already gone The only problem left is the distortion. What's the symptom of clipping? Cuz currently nothing is overheating. Anyway, im going to add the extra power soon... but just to be sure... it's should b connected in series rite? Edited April 19, 2007 by n0on3 Share this post Link to post Share on other sites
n0on3 0 Report post Posted April 19, 2007 no luck... the sound still distorts badly.... hmm. i'll get a pic of it... will post in 15min.. Share this post Link to post Share on other sites
n0on3 0 Report post Posted April 19, 2007 er... strange... i can't seem to upload the pic... i've been waiting for 1/2 hour but nothing is uploaded... hrm.... o well. Anyway, after reading some posts at headwize, i think that it's possible to tune the gain to correct this distortion. RIght now, im using the default gain of 11. I read in one of the posts that I should reduce it to somewhre around gain 5... I'll try to do some math here... until then, im still hoping somebody would come up with other suggestions. Thx in advance. Share this post Link to post Share on other sites
heady 0 Report post Posted April 19, 2007 (edited) i already did some touch up on the soldering. the hissing is already gone The only problem left is the distortion. What's the symptom of clipping? Cuz currently nothing is overheating. Anyway, im going to add the extra power soon... but just to be sure... it's should b connected in series rite? Symptom of clipping is distortion. But it is not the only cause of distortion. Clipping normally occur in loud parts of the tracks. For higher voltage power supply, you put the batteries in, is series. Never use 9V batteries in parallel. You can get the exact reason why in Tangent's site. Long explanation. Give the lower gain a try. Edited April 19, 2007 by heady Share this post Link to post Share on other sites
n0on3 0 Report post Posted May 5, 2007 hmm... i already changed the gain to 5... but still no luck.... i read this article at tangent: http://tangentsoft.net/audio/hs-opamp.html after reading it... i suspect the problem of it all is all about my op-amp( 5532D) which is a bipolar amp. i also read a few days ago on one forum(forgot to take down the URL) that since 5532D is a bipolar amp, it might not work well as there might b DC offset or sumthing like that. Pretty much matches with my problem.... May I have some confirmation on this? or should i go lower with my gain values? or shld i go to get OPA op-amps through federal? Just got a pcdp with optical line-out. can't wait to hear how my DIYed amp would work(once it work properly of course, w/o the distortion) ...... Share this post Link to post Share on other sites
heady 0 Report post Posted May 5, 2007 Bipolar opamps are "no no" for the ordinary CMOY. They will oscillate in this circuit. If you read Tangent's instructions, he does give you a range of opamps to use but also warn against using bipolar unless you know how to modify the schematic to suit them. If you want to see what modifications are necessary, compare the CMOY with the PINT schematic. Even the PINT eventually was withdrawn by tangent because it was not reliable, ie some builders cannot stop if from oscillating. So, stay away from bipolar opamps. Share this post Link to post Share on other sites
n0on3 0 Report post Posted May 5, 2007 (edited) YAY! so my prob would b finished when i get OPAs? haha Ok then, im paying federal a visit next week. just in time after i finish my exams. haha. how long does it take to order? i dun have cerdit card so i cannot directly order from farnell. does federal charge any xtra? Which OPA would u recommend ? i read from many about 2134s, 2132s and 2227s. I would really like to have one which won't give much prob( as in less likely to give problems like osclitatting bla2.) hehe. Haha. looks like the farnell counter is nearer to my house than SLT is. lol. btw, is the student 10% disc available there? Edited May 5, 2007 by n0on3 Share this post Link to post Share on other sites
heady 0 Report post Posted May 6, 2007 Here is a link to a review of opamps you can use. Not just OPAs. Don't know about Farnell giving discount for students as I am not one. But don't have to go down to Farnell to order. Find the order number of the item by viewing their website. Then call up to order. If the items you ordered are more than S$30, they deliver for free. But if less than that, you can collect. They accept NETS. Share this post Link to post Share on other sites
blurgal35 0 Report post Posted May 17, 2007 hi n0on3, post up a pic of ur diy amp leh.. interested to see how it looks like.. i know nothing bout amps.. but by reading thru this thread.. the ppl here are very helpful.. seeing from nothing to SOMETHING.. n0on3.. hope ur 1st complete amp is a great success!! Share this post Link to post Share on other sites
n0on3 0 Report post Posted May 20, 2007 i tried to upload it, but looks like there's sum problem, i couldn't upload the pic. my browser just idled for 30min+ with no pic uploaded. It looks like it's gonna b done when i get d op-amp. i just had a couple of school and church camps for the past weeks, so I couldn't go to get the op-amps. going to get it within this week Btw, yea, i agree that d people here r very helpful Share this post Link to post Share on other sites
Fuzzy Fuzzbucket 0 Report post Posted July 18, 2007 i assembled an amp today cost me around $20... yah around there, and not bad for that price... now i dont have to save up for an amp. haha... there is hissing when used with some sources... i guess thats normal... Share this post Link to post Share on other sites
Jakko 0 Report post Posted August 24, 2007 just a few quick questions, 1) where can I obtain a PCB for the CMOY 2) failing that, can a copper pad board work as well 3) Or I am better off buying the board from Farnell as recommended by tangent? Share this post Link to post Share on other sites
