Member
Joined 2006
Hi Joe,
In the diagram you posted it shows 47 ohms while you suggest 3.3 ohms as the loads..
So using 3.3 ohms for that diagram should also work I suppose....
Have you tried using lower values, say down to ~1 ohms? Perhaps not good for DC offset/ drift issue without feedback, right?
Have you tried Ad844 for the 9018 chip btw?
Anything needed to be different if opa660 is to be used here?
Thanks!
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OPPO 105eu - broken playback
Unfortunately on dismantling and re assembling my oppo 105 eu I've broken it
The symptons are that the USB input and also SACD playback do not work though CD and blueray do, as does streaming via the LAN. My conclusion is that pcm data is OK , serial is not. On inspection on the main board L51 has burnt out. Can anyone advise of this component value please and if this is indicative of the above symptom, Your responses gratefully received.
Regards
Howard
Unfortunately on dismantling and re assembling my oppo 105 eu I've broken it
The symptons are that the USB input and also SACD playback do not work though CD and blueray do, as does streaming via the LAN. My conclusion is that pcm data is OK , serial is not. On inspection on the main board L51 has burnt out. Can anyone advise of this component value please and if this is indicative of the above symptom, Your responses gratefully received.
Regards
Howard
I built the circuit as shown and can't guarantee variations. It was fitted to an Oppo 105 and it worked as shown.
Re using other than 47R, the Z on Pin 3 is high, but Z on Pin 2 is low. In the circuit shown, R3 can be used to trim output to 0mA and no need for any output cap. Re using 3R3, then all the values would shift and can't predict, but gain set R5 needs to be a lot higher, so signal/noise ratio will be worse. Using 1R needs way to much gain, IMO.
Will OPA660 work with this circuit? Good chance it will, but need tweak R3 (DC trim) and set R5 gain. The advantage of the '660 is that the buffer section has no feedback, '860 does.
Yes, have tried '844 and arguably even lower noise than '860 and Pin 2 Z is nominally 50R. But '844 has low current and doesn't have the facility to bring it up like '860/861. I don't seem to find that Z value in the '860 datasheet, that's probably because it varies with the setting of current. BTW, '844 is only available DIL8 and not SOIC.
Cheers, Joe
.
Member
Joined 2006
L51 Burn Out
Here is a photo of L51 , at least where it was. On further inspection the cause was the flat flexible connector between the main and stereo boards . Some of the strands were doubled over and I guess shorted out .
Here is a photo of L51 , at least where it was. On further inspection the cause was the flat flexible connector between the main and stereo boards . Some of the strands were doubled over and I guess shorted out .
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From your descriptions and picture it looks to me that you "succeeded" to put a part of the digital 5v rail to ground. The L51 acted as a fuse (hopefully).
The only to try now is to put back the ferrite bead (not so important for moment its value), or just connect together that pads, to reestablish the 5v for that stages witch it miss it.
Before doing this operation I will want to measure on both pads of the former ferrite, trying to find the 5v on one of it. If found it, then short the pads, and power again, to see what happen.
There is a chance to everything may work well after this operation. If not, then it mean that the regulator or PSU which feed this line, did not tolerate the high current. As usually such power circuits, it have a protection for over current, over a certain level. Maybe that level was not reached, because the ferrite bead has burned out.
If you may find (less probable) more than 5v on the pads of the burned ferrite, then one should find out why it is higher voltage there, and so, no any reason to short or mount back a new ferrite.
So, just try it one way, is my advice. There is 50/50 percent to succed.
The only to try now is to put back the ferrite bead (not so important for moment its value), or just connect together that pads, to reestablish the 5v for that stages witch it miss it.
Before doing this operation I will want to measure on both pads of the former ferrite, trying to find the 5v on one of it. If found it, then short the pads, and power again, to see what happen.
There is a chance to everything may work well after this operation. If not, then it mean that the regulator or PSU which feed this line, did not tolerate the high current. As usually such power circuits, it have a protection for over current, over a certain level. Maybe that level was not reached, because the ferrite bead has burned out.
If you may find (less probable) more than 5v on the pads of the burned ferrite, then one should find out why it is higher voltage there, and so, no any reason to short or mount back a new ferrite.
So, just try it one way, is my advice. There is 50/50 percent to succed.
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L51 Burn Out
Thank You Coris, hopefully I can have a look at the weekend. Also thanks for confirming the role of the componenet, I thought this may be its purpose.
Regards
Howard
Thank You Coris, hopefully I can have a look at the weekend. Also thanks for confirming the role of the componenet, I thought this may be its purpose.
Regards
Howard
Find CFT and Joe's inputs interresting !
Could by any chance (stacked or not in regard to the I/V need) AD844 to be better than opa660 ?
Is 844 internally feedbacked while opa860 /660 are not in non-buffer use?
Someone nice linked me an american shop with the discontinued opa660 but due to EBay restriction I can't targett it ! Anyone to have the name of this parts shop (I believe it was in California) ?
Could by any chance (stacked or not in regard to the I/V need) AD844 to be better than opa660 ?
Is 844 internally feedbacked while opa860 /660 are not in non-buffer use?
Someone nice linked me an american shop with the discontinued opa660 but due to EBay restriction I can't targett it ! Anyone to have the name of this parts shop (I believe it was in California) ?
Bypassed L51 and now fully functional , thanks again for advice Coris
There is nice you got it back to life. You were lucky!
I think you may finally find a ferrite bead to fit the dimensions, and put it back in place. Few hundreds ohms or even 1k at 100Mhz it may fit enough good for the function there (DC resistance as low as possible - under 1 ohm, specified for a few hundreds mA).
Just arrived....
Very nice build quality Coris. And a custom made R-Core!
Will get this hooked up this weekend.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Very nice build quality Coris. And a custom made R-Core!
Will get this hooked up this weekend.
I have used Coris LPM for a few days now. It is fantastic and a must have add-on for anyone with an Oppo 105 player.
It is better than the Oppomod LPM. I found the Oppomod to be hugely better than the stock SMPS. But the Coris LPM is better again by degrees.
The video is clearer than ever, the sound is as pure as its ever been. Digital spdif output has been improved, which never makes sense for a mod like this, but so it goes.
If you have an Oppo 95 or 105 then I highly suggest contacting Coris to get one.
It is better than the Oppomod LPM. I found the Oppomod to be hugely better than the stock SMPS. But the Coris LPM is better again by degrees.
The video is clearer than ever, the sound is as pure as its ever been. Digital spdif output has been improved, which never makes sense for a mod like this, but so it goes.
If you have an Oppo 95 or 105 then I highly suggest contacting Coris to get one.
Well, thanks for appreciations...
A little observation about 95 model. I think it may be an issue the heat dissipation of this LPM for that model. I mean the enclosure of it is really full, and not so much place for a efficient airflow inside, and an good exhaustion of the heat. The fan approach Oppo have found out for that device is only a joke... The LPM is optimized for the lowest as possible heat dissipation, but at least it generate some heat anyway. For 95 model it may be too much, I suppose.
Everything it is all right for 103 and 105/105D models.
A little observation about 95 model. I think it may be an issue the heat dissipation of this LPM for that model. I mean the enclosure of it is really full, and not so much place for a efficient airflow inside, and an good exhaustion of the heat. The fan approach Oppo have found out for that device is only a joke... The LPM is optimized for the lowest as possible heat dissipation, but at least it generate some heat anyway. For 95 model it may be too much, I suppose.
Everything it is all right for 103 and 105/105D models.
I think I have to mention a detail for those who may use/install this LPM.
In some cases, because some mechanical tolerances for the player`s chassis, the LPM it can come too close to the lateral side of the enclosure, when is installed in place.
A contact between LPM`s heatsink and the chassis it have to be avoided, as it may introduce a ground loop into the system. Therefore when occur situations like illustrated in the picture here by, one should place a heat resistant isolation tape (or even a thin paper sheet) in the area susceptible to come in contact with the LPM`s heatsink.
In some cases, because some mechanical tolerances for the player`s chassis, the LPM it can come too close to the lateral side of the enclosure, when is installed in place.
A contact between LPM`s heatsink and the chassis it have to be avoided, as it may introduce a ground loop into the system. Therefore when occur situations like illustrated in the picture here by, one should place a heat resistant isolation tape (or even a thin paper sheet) in the area susceptible to come in contact with the LPM`s heatsink.
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There is the right way to do it (assuming you cut it the trace coming from the old oscillator). You should also chose the ground connection for the clock signal right beside the clock inserting point (available everywhere in the area), instead of that very long wire to a far away ground point.