[tangent]

MFD is an abbreviation for "microFarad", not a capacitor type.

 

[TaffyGuy]

damn, thats what i thought at first, then i changed my mind. now i feel stupid...

 

[TaffyGuy]

well, the soldering is done on my cmoy, and there's good news and bad news.

the good news is that its much prettier than my other amp.
the bad news is that it doesn't work

with the ****ty resistor voltage divider i get +4.4V and -4.1V pretty consistangly with music playing which shouldn't be a problem, and since its consistant it could probably even be tweeked.

but i also have .6V dc on one of the output channels (.04 in the other...) so i guess i screwed up somewhere along the way. i'm not exactly sure what does this, but i guess i'll have to just follow it through with my voltmeter/ohmeter but i'm too god damned exhausted now.

even though no one gives a rats ass about a broken cmoy, i'm going to post pics because i can, and it's much prittier than my other one, which was my main goal, heh.

okay, no biggy, but if i obviously did something bad, go ahead and let me know. Oh and i had absolutely no idea of the pinouts on my output or pot which i pulled out of a broken sony cd changer, so i assumed they were "the usual" or whatever i thought was intuitive. (seemed to be okay from ohmmeter measurements but i don't know what i'm doing) so if that would make a difference... well you know. gah, i never ate dinner.

 

[TaffyGuy]

hey hey found a short, and it works now. from 0 to .02V dc offset and the voltage is swinging from 4.1 to 4.2 V on both channels now, not bad at all. these are low impedance **** phones though. i guess if i feel ballsy i'll plug in some real phones to test it out. seems like that opa2134 is quite a solid player. too bad no one seems to like it much. good enuf for now =)

 

[sil0nt]

Quote:

Originally posted by TaffyGuy gah, i never ate dinner.

How many times have we all been there?

 

[tangent]

Quote:

too bad no one seems to like [the OPA2134] much.

You should restate that: "Too bad if no one else likes it."

If the chip works for you, ignore us chip snobs. Don't feel pressured into spending more money than you have. There are well-respected DIYers here using TL072s and other ancient chips for cryin' out loud!

 

[Budgie]

The Grado RA1 uses a much older chip and alot of people think it sounds great.nothing wrong with that 2134.

 

[TaffyGuy]

yeah for sure... but i'm definately down to experiment with different chips and different designs. its just that this chip in particular seems to be so DIY friendly, and cheap too (good point) that its too bad it isn't also the best sounding, assuming it's not

but i'm still un-spoiled enough, having never actually used a *real* headphone amp, that this little guy still produces the best sound i've heard, so i guess i can only win at this point. hope i didn't put that 1/4'' jack too far away so that it doesnt fit in a pepermint case, i'll have to actually enclose this one, then it'll be as if i have a real amp!

and whats even better is that for some reason i have absolutely no hum this time, and i get negligant *thump* when i turn on/off the amp. i can barely even hear the hum when i'm touching the componants, so i must have done something better. also this time i can easily hear some problems when i use the cheapo batt eliminator... seems to induce some popping and stuff... not bad though, beats burning out a 9v when i want to listen to tunes in bed and dont turn it off.

haveing accomplished this all by myself, and haveing it not be a hideously ugly popping pile of parts this time, i'm even more excited to build bigger and better amps. i've also got about 5 people telling me i have to build one for them too, so i'm glad that this very inexpensive model actually works well (they'd probably be suprised when they realized how much the meta parts add to)