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Cmoy Not Working

post #1 of 13
11/25/11 at 11:55am
Thread Starter 

Hi Guys,

 

I just finished my cmoy and it is not working at all.

i tried to desolder and clear it up and solder again but nothing change...

 

the only sound i heard from my IEM is only when i plug in the output.

 

i could use my dad multimeter but only if i know how and which pin to try out.

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post #2 of 13
11/25/11 at 5:11pm

It could be anything.  Try to post some pics that will let us see the circuit and connections.  There are many pairs of eyes around here and someone may spot something that you can't see.

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post #3 of 13
11/25/11 at 6:18pm
Thread Starter 

http://imageshack.us/photo/my-images/20/img00221v.jpg/

 

http://imageshack.us/photo/my-images/32/img00211i.jpg/

 

any kindda info that u guys need? or should i try to test out with multimeter?

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post #4 of 13
11/25/11 at 7:28pm

The caps in the right direction? Jacks wired properly?

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post #5 of 13
11/25/11 at 8:26pm

I know this will not sound encouraging, so I apologize ... but you may need to start over.

 

The proto board you used is not really conducive to Tangent's layout for the CMoy.  Those solder joints on either side of the opamp connections on the bottom are all connected and appear to be shorted - regardless of whether you have solder there or not.  Except for the center two long rows under the opamp, every row on each side is connected through all of the holes all the way out to the edge.  It's possible that you turned some of the parts at right angles to make this work (like the Wima's).  I'm not sure whether that would've compensated correctly, though, because the opamp connections are still the same direction.

 

Bottom line, I can't tell what's going on in the pics.  Maybe someone else can be of more help.

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post #6 of 13
11/26/11 at 6:10am

As TomB has pointed out, it is hard to tell exactly what is going on, however, I believe those long vertical traces are getting you in trouble. Unless you intended it, the wires/components at the top of the board are directly connected to the wires/components at the bottom of the board, thereby possibly causing issues.

 

Did you intend those traces to remain contiguous? If not, you may want to try and cut/separate them right as they go under the opamp. This would provide separate sets of pads for the top and bottom components/connections. This would be fairly straight forward to try, you just need to use a sharp knife and gently scrape off the copper between any two connected holes of the verticle traces under the opamp.

 

Again, this only suggested if you did not intend for the top and bottom connections to be made by the board traces.

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post #7 of 13
11/29/11 at 6:14pm
Thread Starter 

Hi guys.

 

I've rebuild the cmoy from scratch and it works.

 

But there is another issue with noise at high volume.

 

I've build 2 cmoy with diff schematic. 1 from tangent site. another 1 i will post it later.

 

I tried op-amp rolling with 2227,2134,4556,4562 and 2068.

 

Tangent Cmoy (1 9v batt) turn out to be damn noise after 3/4 pot turn at 3 gain on my denon. (2227, 4556, 4562 and 2068)

Only 2134 works without any issue.  (220uF ,0.1uf cap) (100k input res, 47ohm output res)

 

Another  cmoy which using 2 9v batt wont have those issue at all. 

 

 

Izzit something to do with the op-amp? or the input voltage and current?

 

 

Sorry for my bad english

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post #8 of 13
11/29/11 at 7:44pm

the noise you refer to may be a weak battery...mine sounds pretty bad when the battery gets low and try turning your input source down just a little and see if that helps...

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post #9 of 13
11/29/11 at 7:47pm
Yes, what is happening is called clipping, there isn't enough voltage to amplify the signal as much as you want it to. So the top of the waveform gets cut off or clipped. The 2134 has a lower voltage requirement making it better for single battery use.
Glad you got it working.
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post #10 of 13
11/29/11 at 9:33pm

Glad you got one working, too!

 

Agree with Vixr's and John in Cali's statements - low battery or clipping sounds likely.  Or it could also be as Vixr says - maybe your input source is too strong.

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post #11 of 13
11/30/11 at 10:47pm
Thread Starter 

You both are right. This only happen when i connect it to my CPU. But still, 18v cmoy sounds better for me.
 

Quote:
Originally Posted by John In Cali View Post

Yes, what is happening is called clipping, there isn't enough voltage to amplify the signal as much as you want it to. So the top of the waveform gets cut off or clipped. The 2134 has a lower voltage requirement making it better for single battery use.
Glad you got it working.

     Quote:

Originally Posted by tomb View Post

Glad you got one working, too!

 

Agree with Vixr's and John in Cali's statements - low battery or clipping sounds likely.  Or it could also be as Vixr says - maybe your input source is too strong.


 

I would like to get some suggest which 1 to chose between Objective 2 pr PIMETA for my next project?

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post #12 of 13
11/30/11 at 11:57pm
Depends if you want portable or transportable, pimeta is portable, o2 is transportable wouldn't really want to put an 02 in your pocket. Sound quality wise O2 should be better.
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post #13 of 13
12/1/11 at 8:41am
Thread Starter 

Planning for SOHA as well. LOL. i guess most of my projects will be naked. even both of my existing cmoys are naked too. Damn troublesome to get a proper enclosure for those..
 

Quote:
Originally Posted by John In Cali View Post

Depends if you want portable or transportable, pimeta is portable, o2 is transportable wouldn't really want to put an 02 in your pocket. Sound quality wise O2 should be better.


Any comment regarding crossfeed? i try it on my breadboard and the only diff i can noticed is lower the volume for more than 50%... nothing else... even foobar plugin works much better...

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