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Thread: Marantz CD52 MKII mods

  1. #1
    Join Date: Jan 2010

    Location: Oxford

    Posts: 871
    I'm NotSoPissedOffNowCosMyHiFisUnpacked.

    Default Marantz CD52 MKII mods

    This is one that I've not had a play with at all yet. I've had several goes at the CD50 which uses the TDA1541 dac, CD850 and I owned a CD850MKII from new for about 18 years all of which use the later swing arm type laser assembly from philips, the CDM4.

    I thought i'd start this thread to show the mods progress and explain some of the rationale behind some of the changes that will be made. I'll lay my cards on the table now, I've no intention of keeping the player at the end and I will offer it up for sale (in the appropriate forum section) for a sensible price that reflects the cost of the parts plus a few beers. I'm not looking to spend hundreds but I do expect to make significant improvements within a reasonable budget.

    Hopefully the thread will be informative and therefore my approach acceptable to the community. As previously stated in other threads, I do this because I can and I really enjoy it! If I can fund my obsession by selling at the end of the project then happy days

    There is plenty of information relating to these players on the internet. The player is Pre the KI Signature badge. That doesn't mean "he" wasn't involved! Indeed all of the SE range are his work. From experience I can tell you that in general, the SE versions are mainly about a few capacitor changes and bracing the actual cases. I have read that in some SE models the transformer is constructed using higher quality materials but I cannot confirm this. Certainly in KI models, the mods are SE plus a toroid transformer most likely of a higher VA plus copper chassis plating and a shiny badge!

    Since I'm likely to change and improve most of what the SE would offer, I've started with a basic CD52MKII as the only reason I can see for using an SE would be for perception.

    I've got hold of a reasonably priced player that works other than the drawer loading cog which is a common problem on all CDM4/19 transports. A replacement made from a more modern plastic is readily available for 6 on ebay. This is one time I'm glad our friends from the other side of the world are happy to 'clone' everything! The original part went out of production many years ago! For a test listen, the drawer can be manually operated.

    I'm not going to washy word audio reviews at every stage of this project but I will give a very brief overview at the start and finish of the project. To start I need to verify that everything work as it should and that there are no actual faults with the player (other than the loading cog). I have a couple of test CD's I know very will with a mix of tracks on them so having listened to them to verify functionality I can also comment generally on the sound. What I will say at this point is that the sound is quote flat compared to what I'm used to. Its quite a warm sound but lacks sparkle and accuracy. Something I'm sure I can improve to a reasonable degree. Don't get me wrong, I'm sure the standard sound would suit many, its just not good enough for me out of the box and I know it can do better.

    Here's the player in the flesh during test this morning. I've already removed the offending loading cog and ordered a replacement which will come with a new belt too.





    Here's the offending cog. As you can see, its stripped most of its teeth. The theory offered on the internet is that the grease philips used has reacted with the plastic and made it go soft. I can tell you it feels more like hard wax now than plastic although I'm not convinced by the theory about the grease! Having owned an 850MKII from new, I can tell you that you push the drawer to close. This is bound sure to stress the gear as its work ratio means that the motor spins hundreds of times to move the drawer from end to end. just pushing the drawer 1 cm is likely to require the motor to spin 3 or 4 times. This will put far too much pressure on the fragile teeth of the old cog. Armed with this information, even with the new cog, I'd recommend using the play button to close the drawer



    Next up will be some investigative work in the core power supply to see what can be done to improve things immediately before and after the voltage regulators............
    Ian
    http://www.hifisounds.co.uk

    Photo bucket - loads of mods!

    SL1200- DIY PSU- DIY FET int regs-Denon DL103 by Expert Stylus Company on Isokenetic stabiliser & Sumiko HS-12 shell- Achromat - Isonoe feet, Meridian 200 Phono satge, Junson JA-88D, Audio Aero Capitole CD/ DAC, extreme modified Marantz SA7001, Squeezebox Touch modded to death!, Focal 826WSE- Kimber 8TC, Kimber and CAT5 attenuated DIY Interconnects, Kimber mains

    "Leave Nothing as Standard"

  2. #2
    Join Date: Jan 2010

    Location: Oxford

    Posts: 871
    I'm NotSoPissedOffNowCosMyHiFisUnpacked.

    Default The Tear down!

    To get to the cog for replacement and the main board for mods,we need to completely dismantle the player. Same principle applies to most of the CDM4/19 based players by Marantz and Philips.

    There are 5 screws in the top cover which we need to remove 1st. 4 cross heads on the side and 1 torx on the back in the middle. Undo all 5 and remove the lid lifting the back of the cover 1st up and backwards.

    Next turn the player upside down. We need to remove the bottom cover.
    There are 8 torx to remove to release the bottom plate.



    Next we need to remove the on/off switch bar. This is done by disconnecting the bar from the actual switch then lifting up and back to remove it from the front panel.









    Next we need to remove the front cover from the CD tray. From the top of the player, you can just push the tray out a bit. You need access to the underside of the tray to remove the front of it. There is a tab that needs to be pushed out very gently to allow the front to slide across and off. Should be reasonably obvious from the pictures. The tab is at the top of the 1st 2 pictures.







    From the top again, you can now unplug the 2 white plugs from the display and headphones

    Now you need to remove the 3 torx screws from the top of the main front panel assembly. Ensure the CD tray is fully retracted inside the player. Release the tabs on each side of the player and release the front forward from the top. once free, it should just lift out from the bottom.





    Now you need to remove the CD tray. Lift the clamp mech to the vertical position and just withdraw the tray from the player. You may need to move the clamp up and down in order for the tray to clear the transport and come tight out.





    Now you can see the broken cog which needs to be removed. By applying pressure to the mounting on the transport side, you can move it enough to free the cog......easy!!!







    Putting it back is just the reverse! I don't suppose my replacement will be here for several weeks so i'll just keep the screws safe and proceed to remove the main board for mods........TBC
    Ian
    http://www.hifisounds.co.uk

    Photo bucket - loads of mods!

    SL1200- DIY PSU- DIY FET int regs-Denon DL103 by Expert Stylus Company on Isokenetic stabiliser & Sumiko HS-12 shell- Achromat - Isonoe feet, Meridian 200 Phono satge, Junson JA-88D, Audio Aero Capitole CD/ DAC, extreme modified Marantz SA7001, Squeezebox Touch modded to death!, Focal 826WSE- Kimber 8TC, Kimber and CAT5 attenuated DIY Interconnects, Kimber mains

    "Leave Nothing as Standard"

  3. #3
    Join Date: Jan 2010

    Location: Oxford

    Posts: 871
    I'm NotSoPissedOffNowCosMyHiFisUnpacked.

    Default

    OK Now to get the main board out ready for some pre mod investigation.

    From the top, we need to disconnect the loading motor.



    From the back, there are torx screw to undo by the output phono's in the middle and by the mains socket. From the bottom there are torx screw in the PCB and 2 larger black cross heads either side of the transformer to remove. Once these are out there are 2 tabs to press to allow to board to move out. Press the tabs to start the board moving but only move it enough to ensure its mechanically free. There is still a cable to the spin motor and ribbon the laser to disconnect.

    This picture shows 1 of the tabs.



    When the board is free, we need to locate the ribbon. You can access the ribbon from the side. The white collar on the plug needs to lift away from the the PCB to release the cable. Its a bit of a fiddle the 1st time you try to do it. Be very careful not to pull on ribbon until the collar releases or you could damage it. Its very fragile! Once release you need to access the spin motor connector from the front. Its got a tab on the PCB side that needs pressing to release the plug.





    With both of these released, the board will come out of the player and leave you with this



    I would now put all the mechanical bits back together for safe keeping.
    You will notice a white mech under the transport. This will just fall out. Make sure you dont loose it because its part of the drawer proximity mechanism!


    I've now got the main PCB out. The first thing I noticed is that the transformer runs warm. This suggests to me that its working quite hard. This is a sure sign that things can be improved with bigger transformers. I've yet to decide if I'll take this route due to the likely value of the player after some mods.





    Now we can start to identify components and possible upgrades
    Ian
    http://www.hifisounds.co.uk

    Photo bucket - loads of mods!

    SL1200- DIY PSU- DIY FET int regs-Denon DL103 by Expert Stylus Company on Isokenetic stabiliser & Sumiko HS-12 shell- Achromat - Isonoe feet, Meridian 200 Phono satge, Junson JA-88D, Audio Aero Capitole CD/ DAC, extreme modified Marantz SA7001, Squeezebox Touch modded to death!, Focal 826WSE- Kimber 8TC, Kimber and CAT5 attenuated DIY Interconnects, Kimber mains

    "Leave Nothing as Standard"

  4. #4
    Join Date: Jan 2010

    Location: Oxford

    Posts: 871
    I'm NotSoPissedOffNowCosMyHiFisUnpacked.

    Default Power Supply Mods

    Made a few changes to the power supply.

    First off I identified the audio analogue supply. There is a separate winding on the transformer dedicated to this which is pretty normal. The winding supplies the rectifiers which in turn supply +/-24v dc to the +/-15v regulators via smoothing capacitors. I've seen anything from 470uF right up to 9400uF per rail as standard for this job in CD players and DACs. This is a quick win normally governed by space. Here I've gone from standard 470uF up to 2200uF Panasonic FC (great pre reg where space is an issue) The rectifier is replaced with 11DQ09 schottky type. Post the regulators were some rather weedy 47uF caps. These have been replaced with 470uF Rubycon ZLH low impedance, low ESR caps which I often use on analogue rails.

    Next to address is the +/-10v. The same principle can be applied here but due to the heavy load put onto the positive rail (its used to supply the 5v reg which supplies most semionductors in the player) I've gone from 4700uF to 6800uF. Again we could go bigger but space is a issue. On the negative rail from 1000uF to 3300uF. Schottky diodes replace the original bridge too. Post regs I've gone from 47uF on the negative rail and 220uF (Black Gate!!) on the positive to 470uF ZLG again. These mods bring the PSU's closer to that of a much more expensive player. The restrictive part of the PSU is now the transformer which we may address later depending on budget. We'll save the Black gate for later!



    I've also identified all of the local PSU caps around the DAC, filter, receiver, ram etc for swap out later. AS usual, I'll go for solid polymer on any digital rails and standard construction low ESR (probably Rubycon ZLG) on analogue rails.

    Next easy win is the opamps. As standard, the PSU caps are Elna Simlic so not bad. I've swapped out the standard opamps for gold rolled pin sockets so I can play with opamps. I've popped some LME49720HA for now just to see where we end up. I've also swapped the green Nichicon BP elco's blocking DC on the output for some MKP type. It may be that we don't actually need any at all but I'll measure the DC offset and check later.



    I also have a few 11.2896Mhz oscillators so I paired one up with one of my regs and couple of nice caps a 470uF Nichicon solid polymer bypassed with a 1uF PPS on the reg and 0.1uF PPS on the oscillator. Should be a pretty good clock.



    Its starting to sound quite acceptable! The clock makes a big difference on this chipset and right now, its only clocking the DAC. I will direct clock the filter and decoder chips later which should improve things again.

    I've also been looking at low noise LDO chip type regulators. I would like to separately regulate various components including isolating the DAC analogue and digital rails as I think this will bring vast improvements, but thats another job for another day. I'll leave this lot to settle for a few days
    Ian
    http://www.hifisounds.co.uk

    Photo bucket - loads of mods!

    SL1200- DIY PSU- DIY FET int regs-Denon DL103 by Expert Stylus Company on Isokenetic stabiliser & Sumiko HS-12 shell- Achromat - Isonoe feet, Meridian 200 Phono satge, Junson JA-88D, Audio Aero Capitole CD/ DAC, extreme modified Marantz SA7001, Squeezebox Touch modded to death!, Focal 826WSE- Kimber 8TC, Kimber and CAT5 attenuated DIY Interconnects, Kimber mains

    "Leave Nothing as Standard"

  5. #5
    Join Date: Jan 2010

    Location: Oxford

    Posts: 871
    I'm NotSoPissedOffNowCosMyHiFisUnpacked.

    Default

    Here's the PSU updates on the circuit diagram

    Ian
    http://www.hifisounds.co.uk

    Photo bucket - loads of mods!

    SL1200- DIY PSU- DIY FET int regs-Denon DL103 by Expert Stylus Company on Isokenetic stabiliser & Sumiko HS-12 shell- Achromat - Isonoe feet, Meridian 200 Phono satge, Junson JA-88D, Audio Aero Capitole CD/ DAC, extreme modified Marantz SA7001, Squeezebox Touch modded to death!, Focal 826WSE- Kimber 8TC, Kimber and CAT5 attenuated DIY Interconnects, Kimber mains

    "Leave Nothing as Standard"

  6. #6
    Join Date: May 2008

    Location: A Strangely Isolated Place in Suffolk with far away trains passing by...

    Posts: 14,328
    I'm David.

    Default

    I do hope the mech lasts so you can enjoy what you've done

    One comment (second hand) about the output chips. There is usually a lot of ultra high frequency "noise" around CD players of this period and putting even wider bandwidth op-amps in may not bring about any improvement, as all they're going to do is reproduce the hash better as well as being more sensitive to the power supply and whatever that's doing in this once cheapo player. I appreciate it's all part of the fun, but I thought I'd mention it in any case - this from someone who did all manner of unmentionables to a daily used QED Digit with Positron and a.n. other supply for a Caiman I was told to leave the 5534 output chip alone since it's more than good enough for this duty and it sounds great to me, the supply adding making a substantial difference to the presentation, removing the "bitstream plumpness" it used to suffer from.
    Tear down these walls; Cut the ties that held me; Crying out at the top of my voice; Tell me now if you can hear me.....................

  7. #7
    Join Date: Nov 2010

    Location: Yorkshire

    Posts: 6,609
    I'm AnDreW.

    Default

    Ian, fantastic thread, I love reading threads like this, keep up the good work.
    SS CD Teac VRDS25X(Mega Modded) DAC Caiman SEG+Anker PSU DECK 1210 Mat Analouge Studio Crystal Mods MN Base/Bearing/Platter+Ebony arm Board Feet Isonoe PSU Paul Hynes SR7EHD-27XL/DCSXL Ag DC lead/Jaeger(low-impedance) connector/3 StageRegs/Recapped PCB+No Pitch/Strobe/Light ARM SME V(Kondo Ag Rewire&Tags) MCOrtofon Cadenza Black CABLES Arm Yannis SPD-4 IC Yannis 222 Litz+Ag bullets Power WAR PRE ATC SCA2 SPEAKERS ATC 50ASL STANDS Atacama PHONO Sugden Masterclass PA4 SUT Ortofon ST80SE POWER PSAudio P10

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  8. #8
    Join Date: Jan 2010

    Location: Oxford

    Posts: 871
    I'm NotSoPissedOffNowCosMyHiFisUnpacked.

    Default

    Thanks for the input guys

    I've not had a CDM4 fail on me yet. This is the 7th or 8th player with that mech that I've had including the CD850MKII I had from new which I finally sold about 4 years ago. They do all suffer with the loading gear issue and also a failed cap on some of the earlier machines (a blue 33uF Philips axial jobbie) that causes read and tracking issues. The cap is a different make on this model but I will get to it later when I recap the rest of the player.

    With respect to the opamps, I've changed opamps on many players now and by the time the PSU including local decoupling caps have been changed and the filter treated to some better components, I've yet to hear an adverse reaction to these HA's that I've got fitted. The LME47920 is one of the best opamps for audio in my opinion but as I have stated, I've fitted gold rolled pin sockets to allow for opamp rolling and I've got a few options that I'll try when I've finished the rest. I do appreciate that if the filter is poorly designed then there is potential for issue. The HA's are expensive and may not ultimately fit the budget and depending on other work in the whole output stage my be a little OTT

    I'm trying to keep the thread as informative as possible just in case someone else fancies tackling something similar. The principles are the same for pretty much everything. Its all about the PSU, reducing noise and separating PSU rails to keep the noise from one part of the player effecting everything that shares that rail. As an example, there are several things on the +5v rail including the CPU, DAC analogue, DAC digital, digital filter and SPDIF driver to name but a few. Digital rails are especially noisy. Even fitting separate basic regulators (7805 @ 22p each) to each individual device supply pin in place of the original shared for everything will stop noise from one device being transferred around the original 5v rail. I describe this as separating the noise domain. In many players each device is fed via a supply resistor which can be removed making it easy to fit independent regs. There are some chip type regulators available now with very good noise figures which are very cheap. These are what I will use in this player. I have my own discrete low noise regs but I'm looking to complete as cheaply as possible and I'm very confident I can achieve a very high level of performance using good quality LDO low noise chip type regs.

    I'll post the details of each section I change and show how I work out that cap does what job (analogue/Digital) and what I change it to along with my opinion on why. I'm now waiting for supplies before I move on but I'll show some of my working's out over the next few evenings :-)

    Ian
    http://www.hifisounds.co.uk

    Photo bucket - loads of mods!

    SL1200- DIY PSU- DIY FET int regs-Denon DL103 by Expert Stylus Company on Isokenetic stabiliser & Sumiko HS-12 shell- Achromat - Isonoe feet, Meridian 200 Phono satge, Junson JA-88D, Audio Aero Capitole CD/ DAC, extreme modified Marantz SA7001, Squeezebox Touch modded to death!, Focal 826WSE- Kimber 8TC, Kimber and CAT5 attenuated DIY Interconnects, Kimber mains

    "Leave Nothing as Standard"

  9. #9
    Join Date: Jan 2010

    Location: Oxford

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    I'm NotSoPissedOffNowCosMyHiFisUnpacked.

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    I'm in shock!!!! Exactly 1 week after ordering the loading gear, it arrived from China!

    Only took a few seconds to fit and now we have a fully functioning tray
    I cleaned and re greased the teeth and gear with some silicon grease.







    I've also been working on the distribution of the +5v rail within the whole player. I stated previously that it would be good to try and seperate the "noise domain" by individually regulating each power supply pin rather than having everything share the same single regulator. In this player, each pin is separated by a feed resistor in order to address this issue (well to a very small degree).

    I've now got the details together to seperate the 5 supply pins for the DAC, the digital O/S filter (if it stays) the Decoder, the RAM for the decoder, the SPDIF driver (if it stays) and the CPU. I'll use low noise regs for everything except the CPU which just needs putting in it own noise domain. I'll sort some pictures explaining what I mean a bit later.
    Ian
    http://www.hifisounds.co.uk

    Photo bucket - loads of mods!

    SL1200- DIY PSU- DIY FET int regs-Denon DL103 by Expert Stylus Company on Isokenetic stabiliser & Sumiko HS-12 shell- Achromat - Isonoe feet, Meridian 200 Phono satge, Junson JA-88D, Audio Aero Capitole CD/ DAC, extreme modified Marantz SA7001, Squeezebox Touch modded to death!, Focal 826WSE- Kimber 8TC, Kimber and CAT5 attenuated DIY Interconnects, Kimber mains

    "Leave Nothing as Standard"

  10. #10
    Join Date: May 2011

    Location: Glasgow

    Posts: 6,158
    I'm Brian.

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    Fantastic thread Ian. I had a CD67 SE which I loved and did some very basic mods . I would have loved to had the skill to do something like this . Very interesting.

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