dem is on pin 16-17
I don't know sure, but like the pre '97, in holland manuf. (HSH) dacs more then these newer ones...
Glad you saved the 650 with all the good work on it Simon.
An externally hosted image should be here but it was not working when we last tested it.
I don't know sure, but like the pre '97, in holland manuf. (HSH) dacs more then these newer ones...
Glad you saved the 650 with all the good work on it Simon.
UV101 said:
philpoole said:
The chassis is plastic on the CD650, and I've not connected to safety earth (it's a figure of 8 lead so this isn't even possible). I can't imagine where neutral could've shorted to a signal wire, my work here has been pretty tidy/carefully done. No issues at all on my home system, and no issues on Brent's work system WHEN REVERSED. It is weird. We marked the fig 8 plug and socket for correct insertion. That should be fine for now.
jameshillj said:
Ok, I'll give this a whirl then.
Cheers,
Simon
On further thought... I have two additional transformers, and the Naim is tied to utility ground via a resistor. These seem the likely candidates for the joining of "potential", where the loop is completed on the mains side.
Of the additional transformers, the newer of the two is slightly different in that it's a split supply, using a centre-tapped transformer. I don't understand why, but I suspect this is somehow significant. The player has been used with the Naim previously, WITHOUT the 2nd added tx.
I'm definitely going to add an IEC socket to keep things nice and correct polarity-wise. And as I've run out of room inside for extra supplies I probably ought to migrate to the plywood board soon too.
I'm thinking of cutting some of the bottom panel off to gain access to the DAC's decoupling caps, without removing the main PCB (as this is where player's develop faults, when I play with them).
Simon
Of the additional transformers, the newer of the two is slightly different in that it's a split supply, using a centre-tapped transformer. I don't understand why, but I suspect this is somehow significant. The player has been used with the Naim previously, WITHOUT the 2nd added tx.
I'm definitely going to add an IEC socket to keep things nice and correct polarity-wise. And as I've run out of room inside for extra supplies I probably ought to migrate to the plywood board soon too.
I'm thinking of cutting some of the bottom panel off to gain access to the DAC's decoupling caps, without removing the main PCB (as this is where player's develop faults, when I play with them).
Simon
I gave the player a brief "detail test" this morning... I played Diana Krall - The Girl in the Other Room - Track 12/Departure Bay. This is a good test track for detail retrieval because it has some odd popping noises that a basic CD player will not reproduce. The number of pops you can hear (some are louder than others) is a very good indication of overall detail levels. I can now hear quite a few of them (originally I think the CD650 could find NONE of them). Certainly closing the gap on my old CD63KI...
Regardless of actual detail heard, I think compared to newer players like CD63 (newer being a relative term), these old 1541 machines will never give the in-your-face, analytical type of detail, even if it is audible. I could be wrong, and Jan/Tubee, I think, said his had started to develop this analytical tendency.
Simon
Regardless of actual detail heard, I think compared to newer players like CD63 (newer being a relative term), these old 1541 machines will never give the in-your-face, analytical type of detail, even if it is audible. I could be wrong, and Jan/Tubee, I think, said his had started to develop this analytical tendency.
Simon
Yeah Simon,
This 470pF styrene is for the 1541A chip, not sure about the other 1541 ("not A") version - this is just an interem improvement until you get the final DEM 352kHz reclocking thing going (the base capacitor value then decreases to about 68nF - see the EC Design info on the Ultimate NOS dac thread)
I use the styrenes here too, with rather good results, but a bit ugly with standing on end. [old Rifa pfe216 NOS - big things]
And if you want to do something even more ugly (!), add a 4nF styrene plus 0.15R (in series) across these as RC snubber network to dampen latching current pulse.
Curiously, the decoupling caps aren't all the same (pins 9 and 11 have twice the capacitance) and the pin 13 has the 10uF poly cap rather than an 15uF electro [as per Torben] - just a small thing.
And I think that there are a number of the small smd bipass caps all over the underneath that should also be upgraded to pp - I think you may as well get used to dismantling the pcb as there's quite a few things to do under there!
On another subject entirely, could you direct me towards where the DOS schematic is located in the 63/67 thread - I don't know where to start (please don't say "page 1"!).
Sorry to hear about your power cord problems - you got off lucky, methinks!
This 470pF styrene is for the 1541A chip, not sure about the other 1541 ("not A") version - this is just an interem improvement until you get the final DEM 352kHz reclocking thing going (the base capacitor value then decreases to about 68nF - see the EC Design info on the Ultimate NOS dac thread)
I use the styrenes here too, with rather good results, but a bit ugly with standing on end. [old Rifa pfe216 NOS - big things]
And if you want to do something even more ugly (!), add a 4nF styrene plus 0.15R (in series) across these as RC snubber network to dampen latching current pulse.
Curiously, the decoupling caps aren't all the same (pins 9 and 11 have twice the capacitance) and the pin 13 has the 10uF poly cap rather than an 15uF electro [as per Torben] - just a small thing.
And I think that there are a number of the small smd bipass caps all over the underneath that should also be upgraded to pp - I think you may as well get used to dismantling the pcb as there's quite a few things to do under there!
On another subject entirely, could you direct me towards where the DOS schematic is located in the 63/67 thread - I don't know where to start (please don't say "page 1"!).
Sorry to hear about your power cord problems - you got off lucky, methinks!
James,
Thanks for the tips. What do you think about PPS caps?
e.g. http://uk.farnell.com/panasonic/ecpu1c105ma5/capacitor-1uf-16v/dp/9694315?_requestid=272663
The price is good and I think they're physically small enough.. and 1uF is a nice size, it seems (I've been reading).
I'd also replace some of the other decoupling with these under the PCB.
Removing the board was fine originally, but now I have large output caps and regs that are soldered to the groundplane, with wires feeding those from separate psus, it's not a good idea to take the board out. Cutting an access panel away underneath might be an idea. I really don't care about the chassis, I'm thinking of binning it completely soon anyway.
Simon
Thanks for the tips. What do you think about PPS caps?
e.g. http://uk.farnell.com/panasonic/ecpu1c105ma5/capacitor-1uf-16v/dp/9694315?_requestid=272663
The price is good and I think they're physically small enough.. and 1uF is a nice size, it seems (I've been reading).
I'd also replace some of the other decoupling with these under the PCB.
Removing the board was fine originally, but now I have large output caps and regs that are soldered to the groundplane, with wires feeding those from separate psus, it's not a good idea to take the board out. Cutting an access panel away underneath might be an idea. I really don't care about the chassis, I'm thinking of binning it completely soon anyway.
Simon
Attachments
Hi guys, finally got some 5v SRegs on board.
1 on the DAC (also on its own PSU), 1 on the Filter and 1 on the decoder.
I have to say its lifted a veil again!
I always think a good test is to listen a low volume. If everything still jumps out at you then your on to a winner. I've got good comfortable powerfull accurate sounding bass and the depth and detail in the mids and treble are really coming out. The music is starting to feel alive!
Very satisfying
1 on the DAC (also on its own PSU), 1 on the Filter and 1 on the decoder.
I have to say its lifted a veil again!
I always think a good test is to listen a low volume. If everything still jumps out at you then your on to a winner. I've got good comfortable powerfull accurate sounding bass and the depth and detail in the mids and treble are really coming out. The music is starting to feel alive!
Very satisfying
Simon,
Thanks for the cct and info - rather different again!
About those caps - I don't have any first hand experience with the SMD variety but their specs seem to be not very impressive. It's not the larger capacity (except pin 12) but the type of cap that makes the difference and the better caps don't seem to come in smd as they're much larger build.
Can you drill some holes thru the pads and mount caps on the component side? or hang them below with the base cutout and tack them onto the pads?
Bit messy, I know, but with a bit of careful sleeving and stacking, you could fit some of those white axial Mundorf "audiophiler" 0.1uF PP caps under there. They came up quite well - not as clean or clear as the styrenes, but still quite okay, and manageable size.
When I tried the 0.47uF Wima mkp-10 all over the chip, i didn't get any real improvement over the 0.22uF except for pin 13 - different, but not better "IMO" (in my old and doubtful opinion!)
Sorry I can't be more helpful
The old Rotels have more room in them for mods but otherwise basically same cct. (the 855 and 955s) and NOS comes up better. I've made so many changes that the pads and thin tracks have long gone and back to direct wiring! My old DDAC board is in the same sorry state but went out on a loan and never returned!
Starting to do a new board with the local supplies, caps, plugins (o/p stages, clock, reclocking, etc) organised with enough room for the bigger caps - interesting!
Thanks for the cct and info - rather different again!
About those caps - I don't have any first hand experience with the SMD variety but their specs seem to be not very impressive. It's not the larger capacity (except pin 12) but the type of cap that makes the difference and the better caps don't seem to come in smd as they're much larger build.
Can you drill some holes thru the pads and mount caps on the component side? or hang them below with the base cutout and tack them onto the pads?
Bit messy, I know, but with a bit of careful sleeving and stacking, you could fit some of those white axial Mundorf "audiophiler" 0.1uF PP caps under there. They came up quite well - not as clean or clear as the styrenes, but still quite okay, and manageable size.
When I tried the 0.47uF Wima mkp-10 all over the chip, i didn't get any real improvement over the 0.22uF except for pin 13 - different, but not better "IMO" (in my old and doubtful opinion!)
Sorry I can't be more helpful
The old Rotels have more room in them for mods but otherwise basically same cct. (the 855 and 955s) and NOS comes up better. I've made so many changes that the pads and thin tracks have long gone and back to direct wiring! My old DDAC board is in the same sorry state but went out on a loan and never returned!
Starting to do a new board with the local supplies, caps, plugins (o/p stages, clock, reclocking, etc) organised with enough room for the bigger caps - interesting!
Interesting, jameshillj.
Don't get me wrong, I'm often the first to agree that capacitor type is often crucial, however I'm not so sure its the most important point with this application.
From what I've understood while researching this, from various threads and datasheets, the type is nice of course but, the size seems important for those on at least pins 12 and 18, maybe 11 and 19 (although I haven't tried 11&19), and the most important point is close proximity to the chip. Sometimes, I feel if the special caps are big enough so that they end up too far from the TDA1541A, then it sort of defeats the object.
I'd worry about cutting holes in PCBs when I could do the same with some smaller caps instead.
Mind you, I'm a right one to talk! I've only ever heard my TDA1541A with polyester decoupling caps (half of them tediously placed under the board to get as close to the chip as possible). Maybe cap type is more important than I realise?
Don't get me wrong, I'm often the first to agree that capacitor type is often crucial, however I'm not so sure its the most important point with this application.
From what I've understood while researching this, from various threads and datasheets, the type is nice of course but, the size seems important for those on at least pins 12 and 18, maybe 11 and 19 (although I haven't tried 11&19), and the most important point is close proximity to the chip. Sometimes, I feel if the special caps are big enough so that they end up too far from the TDA1541A, then it sort of defeats the object.
I'd worry about cutting holes in PCBs when I could do the same with some smaller caps instead.
Mind you, I'm a right one to talk! I've only ever heard my TDA1541A with polyester decoupling caps (half of them tediously placed under the board to get as close to the chip as possible). Maybe cap type is more important than I realise?
Yeah Phil,
It's always a question of different components and longer tracks and other compromises - plus I've no cct expertise about this either apart from some stubborn trial/much error (!) and access to some really good NOS bits.
This method comes from torben's idea to standing the axial PPs vertical with the high tails commoned up and looped down to the gnd connection with no real problems - I tried crossing these large caps across the dac chip to have a much shorter earth connection (a real mess) and no APPARENT improvement, but with a better o/p stage,etc,
Mind you, this may well be just another one of those stubborn trials/errors but I do like my delusions!!
Actually, I'm finally getting some idea what John of EC Design is getting at on the "Ultimate 1541A" thread and much of it can be directly applied to many of our older existing players - that basic CDM-4 transport is a really good unit, too.
It's always a question of different components and longer tracks and other compromises - plus I've no cct expertise about this either apart from some stubborn trial/much error (!) and access to some really good NOS bits.
This method comes from torben's idea to standing the axial PPs vertical with the high tails commoned up and looped down to the gnd connection with no real problems - I tried crossing these large caps across the dac chip to have a much shorter earth connection (a real mess) and no APPARENT improvement, but with a better o/p stage,etc,
Mind you, this may well be just another one of those stubborn trials/errors but I do like my delusions!!
Actually, I'm finally getting some idea what John of EC Design is getting at on the "Ultimate 1541A" thread and much of it can be directly applied to many of our older existing players - that basic CDM-4 transport is a really good unit, too.
Yeah, it'd be great to have some actual comparisons, decent caps, versus size, versus location, but I think that would take time and effort, and would take all the mystique and deliberation out of it
John's ECDesign thread is good, although too big now. I'm not sure I agree with the fundamental theory per se, but it did inspire me to build my first DAC (In fact there's a picture of it deep somewhere inside that thread - quality ), and there is a phenomenal amount of info on 1541.
However, there are other threads too. DEM reclocking, TDA1541 info's a good one, decoupling caps, IV stages on the forum if you look.
John's ECDesign thread is good, although too big now. I'm not sure I agree with the fundamental theory per se, but it did inspire me to build my first DAC (In fact there's a picture of it deep somewhere inside that thread - quality
), and there is a phenomenal amount of info on 1541. However, there are other threads too. DEM reclocking, TDA1541 info's a good one, decoupling caps, IV stages on the forum if you look.
philpoole said:
Hi guys. It won't be me that does these comparisons
It's time, effort, money and probably a dead player. There isn't a crystal clear consensus about TDA1541A's decoupling caps. Some like 1uF, some like 220nF, most say only the MSB pin is critical... and then it might be 1uF, 4.7uF in film or 15uF in os-con etc etc.!!
Some say type or size isn't important, some think both are - for tuning to taste.
I picked a 1uF PPS because it comes in low voltage, small size SMD and is cheap. It's also a good dielectric and tried in this or similar applications by at least a small handful of very trustworthy people.
I don't think I fancy drilling holes in this old board, but I'll have a look and see if any work-around or drilling is possible without risking damage.
Those Mundorf "audiophiler" caps you refer to James - those will be MKP. A decent cap and I can get a good price from Lee on them. I just don't know if it's worth it....
I've not touched the decoder's PSU, or the -5V or -15V on the DAC yet (surely all much more important), nor have I re-clocked the DAC directly or got a nice output stage on the go yet. That said, I want to improve the decoupling sooner rather than later... ceramics
Simon
UV101 said:
I feel like this is a competition now
It's a shame you don't live closer to me, I'd love to compare. Lee's '94 was wonderful last time I heard it. I think with a '94/Philips equiv. and basic/cheap model like the 650 they sound very different at first (650 being very poor in comparison) but after "full" mods I think they'll be very similar. CD85 would need some drastic action to reach the very top though, it has about NINE op-amps!!! lol
Isn't it quite surprising that we all are quite comfortable spending a ludicrous amount of time and effort on 20 year old players because they just sound better than all the newer multi purpose devices available today, except the most expensive ones.
When they said years ago that these Phillips chips were the best and most "analogue" ever made (with perhaps the PCM63 for company), I doubt they ever expected the type of refinement we're looking for and now getting with these electronically old age machines! And many of the power supplies that we take for granted will never see service in even good quality commercial products.
Mind you, without the web and sites like this one, much of this wouldn't be possible for most of us.
Thank you everybody ... Jh
When they said years ago that these Phillips chips were the best and most "analogue" ever made (with perhaps the PCM63 for company), I doubt they ever expected the type of refinement we're looking for and now getting with these electronically old age machines! And many of the power supplies that we take for granted will never see service in even good quality commercial products.
Mind you, without the web and sites like this one, much of this wouldn't be possible for most of us.
Thank you everybody ... Jh
Hi Simon,
Was only by chance that I ended up with the phillips player. I was looking to buy a new player which gave me a bit of an immediate budget advantage when I decided to mod an older player rather than get ripped off by MF!
What started as a bit of a play, has turned into a quest!
I can't take anything away from all the dedicated people on this forum who have allowed me to study their experiences and make informed decisions and get very quick wins.
I have to say listening much louder this morning its absolutely awesome. I love the sound the TDA makes, the SRegs, splitting the PSU's and rails allow the detail and dynamics to come flooding out. I am now at the point where I have everything I could have ever wanted in the sound (but now I want more!!LOL). I'm going to continue to work on the 5V side for now but I also want to address the other rails. I also will get the DOS accross for a listen in time.
I'm sure we'll meet at some point!
Was only by chance that I ended up with the phillips player. I was looking to buy a new player which gave me a bit of an immediate budget advantage when I decided to mod an older player rather than get ripped off by MF!
What started as a bit of a play, has turned into a quest!
I can't take anything away from all the dedicated people on this forum who have allowed me to study their experiences and make informed decisions and get very quick wins.
I have to say listening much louder this morning its absolutely awesome. I love the sound the TDA makes, the SRegs, splitting the PSU's and rails allow the detail and dynamics to come flooding out. I am now at the point where I have everything I could have ever wanted in the sound (but now I want more!!LOL). I'm going to continue to work on the 5V side for now but I also want to address the other rails. I also will get the DOS accross for a listen in time.
I'm sure we'll meet at some point!