I can definitely agree with Ricardo that removing the dc blocking caps (the four Elna Silmics at the top right of the board) and bypassing the muting transistors is the first step.
Better electrolytics around upgraded opamps are also a must.
I know I'm re-covering old ground for most here, but I think it's great that this awesome thread is still attracting new interest and starting people out into great quality audio.
Cheers, Lee.
Better electrolytics around upgraded opamps are also a must.
I know I'm re-covering old ground for most here, but I think it's great that this awesome thread is still attracting new interest and starting people out into great quality audio.
Cheers, Lee.
HI All
Yep will start out with aforementioned upgrades
OK it’s up and running again but it seems to just sometimes start skipping on or around track 8/9 on any CD it seems but next time it plays fine any suggestions as to why this happens
Yep will start out with aforementioned upgrades
OK it’s up and running again but it seems to just sometimes start skipping on or around track 8/9 on any CD it seems but next time it plays fine any suggestions as to why this happens
colin.hepburn2 said:
Hi Colin, and welcome.
Good to see you have also been infected with the tweaking-virus 😉
And another player 'under the knife'... 😀
Try cleaning the metal guide rod that the laser slides over. Very often the grease is old and hard, and that prevents the laser from sliding smoothly.
Regards,
Ray
DOS Mighty DOS
Hi Ray
You where right (again😀 ).
After one week playing, the sound is now much more integrated, the dynamics are awesome as well as the bass information.
This proves that a CDP can sound as big as a good TT.
I am so amazed by these DOS results that I wonder if it is possible to build a similarly designed phono stage for the TT.
Regards
Ricardo
Hi Ray
You where right (again😀 ).
After one week playing, the sound is now much more integrated, the dynamics are awesome as well as the bass information.
This proves that a CDP can sound as big as a good TT.
I am so amazed by these DOS results that I wonder if it is possible to build a similarly designed phono stage for the TT.
Regards
Ricardo
Hi Ray/All
Have checked and cleaned laser guides left it playing all day all seems fine now will do some of the upgrades on it but I am considering a Valve/Tube output stage on this thing
You thoughts on doing this would be welcomed
Cheers
Colin
Have checked and cleaned laser guides left it playing all day all seems fine now will do some of the upgrades on it but I am considering a Valve/Tube output stage on this thing
You thoughts on doing this would be welcomed
Cheers
Colin
Re: DOS Mighty DOS
Ricardo,
If you think music sounds good now, just wait a month or so!
Steve
RCruz said:
Ricardo,
If you think music sounds good now, just wait a month or so!
Steve
Re: DOS Mighty DOS
Cool huh! 😎
The story that parts need breaking-in is confirmed again.
A similar circuit for a phono stage is a whole different ballgame. Signal levels are very small (noise!), and RIAA correction must be implemented of course. There are good discrete designs floating around, a search will probably produce some threads 😀
I tried a valve output stage in this player, and it sounded very good. There are some pictures somewhere here in this thread of an experimental test setup. But the FET stage sounded equally well, so I decided to build it with silicon. I'm a tube-man, but in this case it's much easier without the high voltage and heater supplies!
Regards,
Ray
RCruz said:
Cool huh! 😎
The story that parts need breaking-in is confirmed again.
A similar circuit for a phono stage is a whole different ballgame. Signal levels are very small (noise!), and RIAA correction must be implemented of course. There are good discrete designs floating around, a search will probably produce some threads 😀
colin.hepburn2 said:
I tried a valve output stage in this player, and it sounded very good. There are some pictures somewhere here in this thread of an experimental test setup. But the FET stage sounded equally well, so I decided to build it with silicon. I'm a tube-man, but in this case it's much easier without the high voltage and heater supplies!
Regards,
Ray
hi, i have bought some LM4562NA opamps, but i am not sure on how to fit them! could anyone help me on this? do they just slot into where the old opamps came out of. i have a cd63ki
thanks
chris
thanks
chris
Hi Colincolin.hepburn2 said:
Inittially, when I started modding this CDP, I also considered this option....😀
After some heavy modding, my CDP got so full inside I could not equate this option anymore.
Try the DOS and you will be amazed.
Of course, the results depend a lot of the previous modds... I have got two clocks and 4 additional PSU with dedicated TX....
Regards
Ricardo
Hi Ray/Ricardo
Yes space will by a problem though I do have a low profile 240/230 50mA Mains Transformer for the job so would help but the DOS looks good as well can I Buy PCB Board on its own or do I have to buy the full kit of parts
Cheers
Colin
😉
Yes space will by a problem though I do have a low profile 240/230 50mA Mains Transformer for the job so would help but the DOS looks good as well can I Buy PCB Board on its own or do I have to buy the full kit of parts
Cheers
Colin
😉
I don't think a tube output stage will offer much over a well fettled DOS, and definatly not when you consider the size of the job and the higher voltage psu etc
I found the FET DOS pcbs to be better than the transistor ones.
Brent
I found the FET DOS pcbs to be better than the transistor ones.
Brent
Hi Colin
Look here for a very good DOS: http://www.audioupgrades.co.uk/discrete.shtml
If you want to build one from scratch, you will need a PCB.
In Ray´s site you will find all the info regarding how to build one.
In alternative you may as well contact Lee Thomo😀 ... He made the wonderfull PCB for me and also provided all the matched parts.
Ricardo
Look here for a very good DOS: http://www.audioupgrades.co.uk/discrete.shtml
If you want to build one from scratch, you will need a PCB.
In Ray´s site you will find all the info regarding how to build one.
In alternative you may as well contact Lee Thomo😀 ... He made the wonderfull PCB for me and also provided all the matched parts.
Ricardo
Hi Ricardo
Thanks for the update on the DOS yep seen the details on ray’s site so ok there do you still have a contact link or email you can post or send me for Lee Thomo as I would like to see if he will supply me with the PCB and or some parts
Thank you
Colin
🙂
Thanks for the update on the DOS yep seen the details on ray’s site so ok there do you still have a contact link or email you can post or send me for Lee Thomo as I would like to see if he will supply me with the PCB and or some parts
Thank you
Colin
🙂
hi Colin
In this post you will find Lee´s contacts:
http://www.diyaudio.com/forums/showthread.php?postid=1627096#post1627096
I am sure he will be able to help you.
My DOS really transformed my CDP into a high end machine.... You will really like this mod.
Ricardo
In this post you will find Lee´s contacts:
http://www.diyaudio.com/forums/showthread.php?postid=1627096#post1627096
I am sure he will be able to help you.
My DOS really transformed my CDP into a high end machine.... You will really like this mod.
Ricardo
output caps
I have removed the electrolytic and ceramic bypass caps on the +5V digital supply lines for the decoder and DAC and replaced them with a 220uF Os-con in the place of the old ceramic - closest to the chip. I also replaced the series resistor with a 470uF/2 ferrite bead combination. The result was very good.
I am now thinking that I will supply each +5V with its own regulator – rayregulator – fed by new PSU / transformer, with one winding for digital and one for analog. I thought I would place the regulator into the holes vacated by the old electrolytic.
The only cap after the rayreg would be the 220uF os-con near the chip, i.e. no output cap on the reg. However, having read some of the earlier posts on this thread about low ESR caps on the output of LM317 based regulators, I am now wondering whether the 220uF Os-cons so close to the output of the regulator would cause any instability/oscillation problems for the regulator.
Should I worry about this or will it be OK?
Joe
I have removed the electrolytic and ceramic bypass caps on the +5V digital supply lines for the decoder and DAC and replaced them with a 220uF Os-con in the place of the old ceramic - closest to the chip. I also replaced the series resistor with a 470uF/2 ferrite bead combination. The result was very good.
I am now thinking that I will supply each +5V with its own regulator – rayregulator – fed by new PSU / transformer, with one winding for digital and one for analog. I thought I would place the regulator into the holes vacated by the old electrolytic.
The only cap after the rayreg would be the 220uF os-con near the chip, i.e. no output cap on the reg. However, having read some of the earlier posts on this thread about low ESR caps on the output of LM317 based regulators, I am now wondering whether the 220uF Os-cons so close to the output of the regulator would cause any instability/oscillation problems for the regulator.
Should I worry about this or will it be OK?
Joe
It's a fair concern unless you have more than ~0.2ohnms between the reg output an d the coscon in the form of PCB track ressitance; if you have a 'scope it would be worth looking at
There's a very easy wrok-around though - just add acheap electrolytic of at least the same (total) capacitance value at the regulator. Cheap, low quality caps can have significant ESR (especially the 'super miniature' variety) and adding this at the reg will look like a local snubber... shouldn't cost more than 20p or so 😉
There's a very easy wrok-around though - just add acheap electrolytic of at least the same (total) capacitance value at the regulator. Cheap, low quality caps can have significant ESR (especially the 'super miniature' variety) and adding this at the reg will look like a local snubber... shouldn't cost more than 20p or so 😉
afterthought - here's a bit more I wrote on the how& why low-esr caps can cause a problem:
http://www.acoustica.org.uk/t/3pin_reg_notes3.html
http://www.acoustica.org.uk/t/3pin_reg_notes3.html
Fully agree Martin (good article). When we designed our regs and clocks it was very important we followed the semiconductor spec sheets as very low esr caused some issues and wrong capacitance values caused other issues. One reason we stayed away from elcos. It really is a nightmare trying to design something when everything effects the other.
Having too big a cap value on a regs output can cause it's response time to slow (slug) this can rob the music of timing and dynamics.
Brent
Having too big a cap value on a regs output can cause it's response time to slow (slug) this can rob the music of timing and dynamics.
Brent