1bit

hi klernie, welcome to sgheadphone!

to troubleshoot the no signal problem on the right channel, the first thing come to mind is to check the connection for the right channel as also suggested by neutralzz.

there are two possibilities: one or more component of the right channel is shorted to ground, or some where along the right signal path there's a poor soldering. check for these problems using continuity tester on your multimeter.

i can't see clearly from the picture but the soldering on the pot looks suspicious to me, check for short from the wiper to the ground pin for the right channel.

if the connections in the right signal path is ok, check the soldering for the power and ground pin for the right channel opamp ic (but it looks alright from the picture)

if the connections on the pcb are fine, check the connection off-board i.e. the soldering on the input/output jack. the right channel could be shorted to ground there.

if there's no connection problem, the components might be faulty. check the opa2134 by interchanging it.

if the problem only persist on the right channel, the ground opamp should be okay as if it has gone kaput the left channel won't be working as well.

but i think the ground opamp that you use (lt1077) is not suitable as it can only source/sink 5mA

for the input capacitors (C1 and C2), i'd recommend you upgrade them to higher capacitances. with 0.1uF for C1 and C2 and 10kohm for R4 and R8, the cut-off frequency is around 150 Hz. you'll be missing all the bass like this.

0.1uF for the bypass capacitors (C3,C4,C5) would probably be enough

btw heady, how do you clean the flux off the pcb? where can you buy flux cleaner?

hi benny

i'm not sure where to find the turtle beach soundcard here in singapore

must be quite difficult to find, most of the soundcards sold in sls are creative sound blasters

you can check for yourself by downloading the price list from the shops at sls here

well if you're into turtle beach riviera (as you told in the other thread) because of its optical out and dolbydigital/dts pass through capability, you might wanna check out the audiotrak maya 5.1 mkii, it has optical out but it's not stated if it can pass through dolby digital signal

audiotrak prodigy 7.1 on the other hand has digital coax out with dolby signal pass through feature

you can get both of the audiotrak soundcards at cybermind. it's at sls level 4, if i'm not mistaken

well, just a precaution, i don't really have experience using them so you really need to research more.

just trying to help here

kross:

well, i've just read this, the thing about potentiometer is that it can't give a true 0 ohm. from the article, analog pots will always have a wiper resistance, basically the contact resistance between the moving part (wiper) and the stationary part where the log taper is located. it is said this resistance can be around 100 ohm.

so if you compare a direct line and through a pot set at max, there bound to be a small attenuation for the signal through the pot.

as the value is around 100 ohm it shouldn't have a big effect for audio application i think. it'll do have an effect for delicate frequency tuning application or some precision continuity tester (lol tried to design this once using a couple of trimmer and failed lol).

other than attenuation another effect that i can think of to sound is noise, but it should be barely audible.

squalle:

thanks for the info about the input offset current, now need to look at the data sheet more carefully lol

mm where did you bought your jap pressed cd btw?

is there a shop in singapore that sells them? or did you buy them online?

squalle: hi just wondering why we need to be careful as ad8397 is bipolar?

kross: well koba also sells a cheaper variant of the blue velvet for $15, i've been wondering how it compares to the one sold at farnell

in a high quality pots usually they are expected to have long life, smooth turning (doesn't contribute noise when you turn them while passing signals), true log taper, lower gang error for the entire range (differences in resistance between the right and left pots for dual gang pots)

i think the pot affects the sound quality by means of the taper and the gang error

check it out here, kross

i don't think it'll work like that sonical, the cable you've got is a wrong one.

you could follow siriuz's suggestions and buy two 1/4" mono to RCA and RCA to stereo.

here's just examples of the adapters:

1/4" mono to RCA

Dual RCA to 1/4" stereo

however you shouldn't connect this directly to headphone, a headphone amp is required.

here's the link to emu0404 manual:

emu0404 manual (pdf)

refer to page 7

hope this help

whoops

ok so siriuz finally explained it

my mistake i thought the outputs were both stereo

is the headphone you're using faulty? you can try plugging the headphone to other sources to check

you can also try using different headphone or speaker for your emu

if the problem's still there try checking the connection, probably the d-pad is not pushed all the way to the socket on the emu card

well that's what i can think you can try for the hardware side, if it's still there you should look at the software

check the driver and the output balance at the volume control panel

well from the link you gave the y adapter cable is a mono cable, that might explain why you only get sound from the left channel only.

why do you need the splitter cable anyway? you should be able to plug your stereo headphone cable directly to one of the two output jacks available from the emu to get a stereo sound.

but, isn't the idea of using an amp is not to use amplification from the pcdp?

Do you think 2 is enough, squalle? what's the source you use?

I'm using the line out from my pcdp but even after maximising the pot on the cmoy2 the volume is smaller than what is possible coming out from the headphone out.

Kippei, where did you get the casing btw? How much did it cost you?

Hi, I'd like to ask those who have built their cmoy2 amp: what's the gain setting you use?

I've just finished building mine and it uses the same part configurations such as listed in the guide (with gain=2) and found out that it's not enough for me. So any recommendation about this anyone?

well bringing up old topic should someone needs this info, i found the shop tubeamp was telling about, it's called continental electronics. nice shop, it seems to stock components for radio control hobby as well.

however, i can't find the other shop at jalan besar.

tubeamp, care to tell us more info about the shop?

whoa a little detour here

what's the advantage of having more than one soundcard in a pc system btw?

LemonT what are you doing with those soundcards anyway? can you use them simultaneously or is it for convenience: when you play games you use the output from one soundcard, play music use the other one?

kinda interested

where can we get the tubes in singapore btw?

Happy birthday and happy halloween guys!

wow SPAM in sgheadphones

oops forgot to ask, the alps pot you use did you by it from koba? (the one you're talking about in the other thread) how is it?

wow! congratulation kippei!

i still haven't finished my cmoy2 yet haha

your amp looks really neat

Well, went to federal yesterday and ordered the pot. The lady said to wait 4 working days.

Quite funny because if you check the farnell website Click here it is shown that they actually have the pots in stock.

Hopefully the pot will arrive next week.

Thanks for the info Kube

hi kube

which pot are you ordering from federal?

i'm looking for one as well right now. can i know the part/order number?

how do you order it actually?

hi kippei, is it you whom i met at koba last thursday?

if so, boy oh boy thanks a lot for your help there haha