Just started demolishing my old shed but ... did you or didn't you swap the 2 x 15v and 2 x 10V windings before meddling with the device? And how were the results ? It does not seem so as you suggested replacing 7815/7915 for 7812/7912. And no there are a indeed a few simple and little time consuming ways to solve the issues as suggested and absolutely no need to redesign/repopulate entirely. The current approach is not technical and/or logical by nature. Also the owner states he mostly uses it as transport but still the device is not corrected and instead a lot of things are added to .... include a second DAC and output stage.....so analog output and not transport use?!?
You don't want to give details but what can you expect then? What you can expect are general and not fitting suggestions. Same hit or miss as the approach.
Example: there is a recent car but not it is not under warranty anymore. It has a structural problem with the exhaust. Fitting an "improved" engine will not solve the exhaust issue. So have fun and I am back to work.
You don't want to give details but what can you expect then? What you can expect are general and not fitting suggestions. Same hit or miss as the approach.
Example: there is a recent car but not it is not under warranty anymore. It has a structural problem with the exhaust. Fitting an "improved" engine will not solve the exhaust issue. So have fun and I am back to work.
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I have already suggested in my first posts, the replacing of the original +/-15v regulators with +/-12v ones (keeping the same transformer wiring).
An alternative fixing of original fault is replacing the 2x10v transformer output with the (unused) 2x15v one (keeping the existent +/-15v regulators). The specifications for currents on these two transformer outputs, it fit well in both cases.
These two possible fixes it address only the original fault. To be improved further the functionality of this CD player it are necessary much extended "fixes".
For making the all necessary improvements, corrections, upgrades on board, the original PCB it should be redesigned for best results. This improvement solution it is not applicable so far, but not impossible. It best fit for the producer himself.
I do not expect or need myself details or suggestions for improvements for this device, as I know now very well what it should be done, and which it are the design issues.
The main purpose of this thread it was/is to warn the owners of this product, about the serious fault it contain...
An alternative fixing of original fault is replacing the 2x10v transformer output with the (unused) 2x15v one (keeping the existent +/-15v regulators). The specifications for currents on these two transformer outputs, it fit well in both cases.
These two possible fixes it address only the original fault. To be improved further the functionality of this CD player it are necessary much extended "fixes".
For making the all necessary improvements, corrections, upgrades on board, the original PCB it should be redesigned for best results. This improvement solution it is not applicable so far, but not impossible. It best fit for the producer himself.
I do not expect or need myself details or suggestions for improvements for this device, as I know now very well what it should be done, and which it are the design issues.
The main purpose of this thread it was/is to warn the owners of this product, about the serious fault it contain...
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That might be but you don't read posts obviously. If your intention is to warn the owners/users then the changes/improvements will make them drift away more from the real issue.
A. Your suggestion to use 7812/7912 is simply not valid. It will not be OK. Explanation is already given.
B. Swapping the metal connectors out of the plastic part is a 2 second job not necessitating any redesign/rework of anything else. Also already explained. Just removal of 6 metal connectors and clicking them in the other plastic part.... In post #22 and another one you indicate that current ratings are no issue.
So you haven't tried the simplest of things while they could have had the largest impact and so at lowest cost (ie. for free). Only after that a conclusion could have been made involving costly modifications. I suggest strongly to look carefully at the connectors only to conclude you can simply remove cable and metal part by pressing a kind of spring like piece. Effectively you can then put swap the red for violet, the grey for the blue one and the yellow for the other yellow one... Now you have 2 x 15V at the right connector. Done.
If there would be anything off one could also remove the original connectors from the PCB and crimp new ones to the cables (like Molex KK 0.100) The tool can be bought cheap for only this use. Or use Phoenix connectors with screwable contacts...
Meanwhile I wrecked my complete shed
A. Your suggestion to use 7812/7912 is simply not valid. It will not be OK. Explanation is already given.
B. Swapping the metal connectors out of the plastic part is a 2 second job not necessitating any redesign/rework of anything else. Also already explained. Just removal of 6 metal connectors and clicking them in the other plastic part.... In post #22 and another one you indicate that current ratings are no issue.
So you haven't tried the simplest of things while they could have had the largest impact and so at lowest cost (ie. for free). Only after that a conclusion could have been made involving costly modifications. I suggest strongly to look carefully at the connectors only to conclude you can simply remove cable and metal part by pressing a kind of spring like piece. Effectively you can then put swap the red for violet, the grey for the blue one and the yellow for the other yellow one... Now you have 2 x 15V at the right connector. Done.
If there would be anything off one could also remove the original connectors from the PCB and crimp new ones to the cables (like Molex KK 0.100) The tool can be bought cheap for only this use. Or use Phoenix connectors with screwable contacts...
Meanwhile I wrecked my complete shed
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The use of 7812/7912 is very valid in this case. It works very well. The current floating through the regulators is quite low and the stabilisation is done, resulting a much better functionality than the original one (not stabilised at all). Of course it can be used 7810/7910 as well.
I will recommend the alternative fixing (swapping the toroid windings), for the ones who may want fix this by themselves, as removing the 15v regulators from PCB is quite difficult.
More easy is cutting the transformer output wires and then solder it to the right places. Not necessary the replacement of the metal contacts into/from toroid connectors...
The most normal alternative to fix this issue should come from Roksan itself, by recalling the defective devices for fixing (for free, as in car industry cases). Or Roksan fixing it in that cases the users of this CD players will ask for...
I will recommend the alternative fixing (swapping the toroid windings), for the ones who may want fix this by themselves, as removing the 15v regulators from PCB is quite difficult.
More easy is cutting the transformer output wires and then solder it to the right places. Not necessary the replacement of the metal contacts into/from toroid connectors...
The most normal alternative to fix this issue should come from Roksan itself, by recalling the defective devices for fixing (for free, as in car industry cases). Or Roksan fixing it in that cases the users of this CD players will ask for...
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No! Using a 7812 with 14.5V input voltage is NOT correct designing. There is simply not enough headroom taking mains voltage fluctuations, ripple voltage and regulator drop into account.
With modern version 7812 the datasheet states typical 2V drop-out voltage which leaves only 0.5V headroom for ripple and mains voltage fluctuations in your case!
It would work OK when a preregulator produces a straight line DC 14.5V. But even then... Some 7812 datasheets state an absolute minimum input voltage of 14.5V ....
With modern version 7812 the datasheet states typical 2V drop-out voltage which leaves only 0.5V headroom for ripple and mains voltage fluctuations in your case!
It would work OK when a preregulator produces a straight line DC 14.5V. But even then... Some 7812 datasheets state an absolute minimum input voltage of 14.5V ....
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Yes! Input voltage required to maintain line regulation for 78xx/79xx devices, it is specified in respective datasheets for 1A. At lower current, the necessary voltage headroom it is much lower (headroom is proportional with the current required from the regulator device). This is logical as well... In this case we talk about doing a quick fix, adapted to an already designed circuit. This is not a new design...
For the currents necessary to the opamps (few teens mA), which it load in this particularly case the mentioned regulators, the 14,5v on input of the 7812/7912 regulators is more than enough to ensure a very good regulation, even with a moderate AC line variation.
One should be also carefully when lowering too much the power line voltages for these circuits as it are originally designed. Too low voltages on these power lines it may alter their designed functionality. These analogue circuits it are designed to work at +/-15v. This voltage it should be provided. Mounting 12v regulators instead, is an quick fix, which it may still ensure a good power environment. I appreciate 10v as too low in this case.
The best (DIY) fix in this case, is swapping the transformer windings, so that the +/-15v regulators it get the right and safe voltages on its inputs (2x15v AC instead of that original 2x10vAC), to ensure the regulation function for an output of +/-15v.
For the currents necessary to the opamps (few teens mA), which it load in this particularly case the mentioned regulators, the 14,5v on input of the 7812/7912 regulators is more than enough to ensure a very good regulation, even with a moderate AC line variation.
One should be also carefully when lowering too much the power line voltages for these circuits as it are originally designed. Too low voltages on these power lines it may alter their designed functionality. These analogue circuits it are designed to work at +/-15v. This voltage it should be provided. Mounting 12v regulators instead, is an quick fix, which it may still ensure a good power environment. I appreciate 10v as too low in this case.
The best (DIY) fix in this case, is swapping the transformer windings, so that the +/-15v regulators it get the right and safe voltages on its inputs (2x15v AC instead of that original 2x10vAC), to ensure the regulation function for an output of +/-15v.
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Hello. I have just bought one of these CD players and am concerned to read this.
Would the fault you’ve described cause the CD player’s toroidal transformer to buzz intermittently? I know all toroidal transformers buzz a little bit — but mine gets louder and quieter intermittently. A sound meter placed close to the unit reads anything between 10 dB when it’s operating quietly, rising to 21/22 dB when the buzz is loudest. I am no electronics expert; just wondering if this buzzing problem could be related to the fault you’ve discovered. Thanks. - James
Would the fault you’ve described cause the CD player’s toroidal transformer to buzz intermittently? I know all toroidal transformers buzz a little bit — but mine gets louder and quieter intermittently. A sound meter placed close to the unit reads anything between 10 dB when it’s operating quietly, rising to 21/22 dB when the buzz is loudest. I am no electronics expert; just wondering if this buzzing problem could be related to the fault you’ve discovered. Thanks. - James
No, the Roksan Blak CD players design/production fault reported her, it have nothing to do with the issue in your device. The intermittent audible buzz noise, generated by the toroid in your device, is caused by the residual low DC voltage, present on your main AC network.
Such issue is quite common, and it mostly affect the toroidal transformers. The more powerful is the transformer, the more disturbing become that audible noise. The cure is using a DC blocking filter, mounted before the toridal transformer in your device. For further details please PM me.
Such issue is quite common, and it mostly affect the toroidal transformers. The more powerful is the transformer, the more disturbing become that audible noise. The cure is using a DC blocking filter, mounted before the toridal transformer in your device. For further details please PM me.
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Hi!
I have a Blak CD player and i really don't have any issues with it.
I used it with Blak integrated amplifier on unbalanced analog input and i really like it.
Tried it with RME Adi2 DAC and i still like my Blak CD more, directly on RCA analog input to my Blak integrated.
Maybe it's just your unit faulty, or is something that you missed?
Bye!
I have a Blak CD player and i really don't have any issues with it.
I used it with Blak integrated amplifier on unbalanced analog input and i really like it.
Tried it with RME Adi2 DAC and i still like my Blak CD more, directly on RCA analog input to my Blak integrated.
Maybe it's just your unit faulty, or is something that you missed?
Bye!
The player worked despite the misplaced windings from the transformer. The reason I contacted Coris was that I felt something was missing. A cdp at this pricepoint should do better. Now when the power issue is fixed and Coris updated the power supply feeding the clock circuit, the player sounds pretty good on the rca output.
The stock xlr outputs of the Blak are just for show. They have just used an op-amp on the single ended output.
Now the PCM1794 module that Coris put in my Blak is just amazing. Highly, higly recomended. Compared to my Oppo 105 the updated Blak sounds clearly better.
But through the xlr Coris output it is on a whole nother level. Bass impact and depth is just ridiculous, I can physically feel the bass in my sofa from my small Roksan TR5S2 speakers. Dynamics are startling (litterally), the background is inky black...
I could go on, but the point is this player has taken quantum leaps in SQ.
The stock xlr outputs of the Blak are just for show. They have just used an op-amp on the single ended output.
Now the PCM1794 module that Coris put in my Blak is just amazing. Highly, higly recomended. Compared to my Oppo 105 the updated Blak sounds clearly better.
But through the xlr Coris output it is on a whole nother level. Bass impact and depth is just ridiculous, I can physically feel the bass in my sofa from my small Roksan TR5S2 speakers. Dynamics are startling (litterally), the background is inky black...
I could go on, but the point is this player has taken quantum leaps in SQ.
The design or production issue affecting this Roksan CD player model it not belong to an single device. It is a whole production batch issue at least. Such fault it should be cached by the final testing routines in the factory, but it was not. The devices were sold out so.
The fabrication fault in these devices, it not cause missing audio output, so the users are not aware about it, thinking that buying a Roksan device, that it will always have to sounds good, it have to be only of an exceptional quality product, and so on. Placebo and marketing the product, it work very well in all this...
The issue I have discovered it make the device functioning out of the advertised parameters. But who care about specified parameters, when the user it get audio signal on outputs? Who have measured the performances of a such device, and compared with what is specified in its datasheet? Have you?
The reported issue is not a fabrication failure for only one item, as the toroidal transformer outputs it have unique connectors which it cannot be swapped, by accident of an worker in production lines. That transformer provide wrong voltages, which it cause no whatsoever regulation in analogue power system. This is not acceptable for a device priced for many thousands bucks. However, one it get the audio output, and the common judgement in this is: as one it pay many thousands bucks, then one should for sure get a very well sounding and quality product. The documented report in this thread it just demonstrate the opposite...
If you may have the opportunity to open your device, measuring the in and out voltages on the analogue regulators, powering the final output stages, you will could then experience by yourself what about. If you may accept a such basic fault in your quality CD player, you have paid that high price for it, then it is up to you...
The above post/report (transformer audible buzz) it shows another example about how much Roksan it care about the quality of their products sold on markeds out there.
In the car industries, the producers are using to call back the fabrication faulty cars, and fixing it on their expenses. Roksan it seems not caring at all about such fabrication faults, even it are well documented...
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As i am looking to purchase one of these CD Players, I have reached out to Roksan UK (Monitor Audio now distributes this brand here) and they have informed me that they have resolved the concerns highlighted.
The design engineer is currently away on annual leave and upon his return he/she will send me the details.
Hope this helps.
The design engineer is currently away on annual leave and upon his return he/she will send me the details.
Hope this helps.
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