It was my cd player.
I changed the opa604 to opa627 and opa2134 to opa637 and the signal output caps are 2 2.2uf ero mkp caps and the signal caps are 2 axon 33uf film cap.
I think the opamps are ok as I got sound from the right channel, and the DCV of the coupling caps in left channel is higher then that in the right, is it the culprit? the problem may seem stupid as i am just a rookie to DIY, plz help
I changed the opa604 to opa627 and opa2134 to opa637 and the signal output caps are 2 2.2uf ero mkp caps and the signal caps are 2 axon 33uf film cap.
I think the opamps are ok as I got sound from the right channel, and the DCV of the coupling caps in left channel is higher then that in the right, is it the culprit? the problem may seem stupid as i am just a rookie to DIY, plz help
*LOOOL*
Sorry Ronardi, which CD player type was it exactly. Please supply a link to the schematics and datasheet or (if those aren't available) make a scan of the schematics and load the pictures up. You were using schematics, were you?
Why?
The OPA2134 is a dual opamp. The OPA 637 is not. How and why should that work?
Please make a comparison between your left and right channel: check every single solder joint, the orientation of every polarized component, check for solder residue that could produce shorts between copper traces, damaged components, etc.
Sebastian.
It was my cd player.
I changed the opa604 to opa627 and opa2134 to opa637 and the signal output caps are 2 2.2uf ero mkp caps and the signal caps are 2 axon 33uf film cap.
I think the opamps are ok as I got sound from the right channel, and the DCV of the coupling caps in left channel is higher then that in the right, is it the culprit? the problem may seem stupid as i am just a rookie to DIY, plz help
I changed the opa604 to opa627 and opa2134 to opa637 and the signal output caps are 2 2.2uf ero mkp caps and the signal caps are 2 axon 33uf film cap.
I think the opamps are ok as I got sound from the right channel, and the DCV of the coupling caps in left channel is higher then that in the right, is it the culprit? the problem may seem stupid as i am just a rookie to DIY, plz help
Hi Ronardi,
You cannot use a single opamp in a socket for a dual opamp! You will need two OPA637's and an adapter board. Also the OPA637 is not unity gain stable as the OPA2134 is. If this is all abakadabra for you first read a book about opamps or Horowitz and Hill, The Art of Electronics, Cambridge University Press.
You cannot use a single opamp in a socket for a dual opamp! You will need two OPA637's and an adapter board. Also the OPA637 is not unity gain stable as the OPA2134 is. If this is all abakadabra for you first read a book about opamps or Horowitz and Hill, The Art of Electronics, Cambridge University Press.
Hi Ronardi,
well, now that you answer my questions for details with a simple double post (?!), I'll just ask other questions.
If that means that you've built the player completely by yourself, I understood you right now. Otherwise, please write down, which brand and type or model it exactly is.
Secondly, please point on a schematic or provide one yourself. We can't help you out as long as we don't know what you're talking about.
What does that mean, Ronaldi?
Where do those coupling caps sit (schematic-wise, not when you look at the board)? Directly before the output? Or inside the I/V or buffer stages?
How much voltage do you measure (mv or V) and where exactly? Across the cap or between one of the cap's pins and ground, or where (across) exactly?
I assume: across the cap's pins. Did you do all the tests I suggested (solder joints, polarity)? Can you test the components for failures (caps, opamps, everything around them in the circuit)?
That may already be the explanation. As Elso pointed out, the opa637 isn't stable in the same environment as the opa(2)134! Why (exactly) did you choose the opa637, and why do you expect it to work (e.g. circuit gain is >5, compensation/bypassing provided etc.)?
Yeah! Sorry,
Sebastian.
well, now that you answer my questions for details with a simple double post (?!), I'll just ask other questions.
If that means that you've built the player completely by yourself, I understood you right now. Otherwise, please write down, which brand and type or model it exactly is.
Secondly, please point on a schematic or provide one yourself. We can't help you out as long as we don't know what you're talking about.
What does that mean, Ronaldi?
Where do those coupling caps sit (schematic-wise, not when you look at the board)? Directly before the output? Or inside the I/V or buffer stages?
How much voltage do you measure (mv or V) and where exactly? Across the cap or between one of the cap's pins and ground, or where (across) exactly?
I assume: across the cap's pins. Did you do all the tests I suggested (solder joints, polarity)? Can you test the components for failures (caps, opamps, everything around them in the circuit)?
That may already be the explanation. As Elso pointed out, the opa637 isn't stable in the same environment as the opa(2)134! Why (exactly) did you choose the opa637, and why do you expect it to work (e.g. circuit gain is >5, compensation/bypassing provided etc.)?
Yeah! Sorry,
Sebastian.
sek said:Hi Ronardi,
well, now that you answer my questions for details with a simple double post (?!), I'll just ask other questions.
If that means that you've built the player completely by yourself, I understood you right now. Otherwise, please write down, which brand and type or model it exactly is.
Secondly, please point on a schematic or provide one yourself. We can't help you out as long as we don't know what you're talking about.
My CD player is a Original(Made in China) A9.8 or "DaVinci", maybe you don't know much about this...
What does that mean, Ronaldi?
Where do those coupling caps sit (schematic-wise, not when you look at the board)? Directly before the output? Or inside the I/V or buffer stages?
two of them sits right before the dac chip and the other two sits before before the RCA anologue output
How much voltage do you measure (mv or V) and where exactly? Across the cap or between one of the cap's pins and ground, or where (across) exactly?
I assume: across the cap's pins. Did you do all the tests I suggested (solder joints, polarity)? Can you test the components for failures (caps, opamps, everything around them in the circuit)?
In fact, I do hope providing more details by, I just can't....My electronics knowledge(may not beyond the level of "common sense" much)is very limited. I modified the CD player by following someone's experience in other forum....and they say it's easy..so I did it..
That may already be the explanation. As Elso pointed out, the opa637 isn't stable in the same environment as the opa(2)134! Why (exactly) did you choose the opa637, and why do you expect it to work (e.g. circuit gain is >5, compensation/bypassing provided etc.)?
I chose the opa637 because someone using the same player changed the stock one to this and work well. I just follow...
Yeah! Sorry,
Sebastian.
My CD player is a Original(Made in China) A9.8 or "DaVinci", maybe you don't know much about this...
two of them sits right before the dac chip and the other two sits before before the RCA anologue output
In fact, I do hope providing more details by, I just can't....My electronics knowledge(may not beyond the level of "common sense" much)is very limited. I modified the CD player by following someone's experience in other forum....and they say it's easy..so I did it..
I chose the opa637 because someone using the same player changed the stock one to this and work well. I just follow...
two of them sits right before the dac chip and the other two sits before before the RCA anologue output
In fact, I do hope providing more details by, I just can't....My electronics knowledge(may not beyond the level of "common sense" much)is very limited. I modified the CD player by following someone's experience in other forum....and they say it's easy..so I did it..
I chose the opa637 because someone using the same player changed the stock one to this and work well. I just follow...
I think the advice from sek regarding thoroughly checking for shorts and dry joints should be you first step. Use an illuminated magnifier and remake any joint that looks less than perfect and run a blade between adjacent solder pads even if no short is visible. Always check the basics and assume nothing.
Apart from that have you got any pics of the internals of the player, it probably won't help but I'd be interested to see what's inside.
Apart from that have you got any pics of the internals of the player, it probably won't help but I'd be interested to see what's inside.
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