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Leestereo's Restoration and Upgrade Of A Marantz 2325

Discussion in 'Marantz Audio' started by Leestereo, Nov 18, 2015.

  1. Leestereo

    Leestereo Super Member

    Messages:
    2,142
    Location:
    Ottawa, ON
    AK member "ragstoriches" brought in a very nice Marantz 2325 for some restoration and upgrade work.

    The restoration/upgrade included the following:
    1. Replacement of the power supply electrolytic capacitors with low ESR types (increasing capacity where appropriate and physically possible).
    2. Replacement of the signal path electrolytic capacitors with film types (whenever possible) or bi-polar electrolytic types.
    3. Upgrade original polyester film capacitors to polypropylene film types (as appropriate).
    4. Replacement of the signal path ceramic capacitors with C0G types.
    5. Replacement of the failure-prone 2SC458 and 2SA722 transistors.
    6. Replacement of the output relay.


    Power Supply & Relay Board (P800)

    The P800 board contains the regulated power supplies as well as the protection circuit.
    [​IMG]

    P800 board in original state
    [​IMG]

    Components removed
    [​IMG]

    Board cleaned of glue residue
    [​IMG]

    Restored and upgraded board
    [​IMG]

    The DS-131B dual diodes, H808 and H809, were upgraded to high current, soft recovery types:
    NXP BYQ28E-200,127. The capacitor C803 is the main filter for the regulated supplies and the original 470µF/63V capacitor was replaced with a 1200µF/63V low ESR type. Similarly, capacitor C806 filters the 35V and 19V supply, and the original 220µF/63V capacitor was replaced with a 680µF/63V low ESR type. The large 150 ohm/5W dropping resistor, R801, that feeds C804, was replaced with a physically smaller 150 ohm/7W one to allow better air flow around the surrounding components. The C804 capacitor that filters the 14V supply was replaced with a 680µF/63V low ESR type. Capacitors C805, C807 and C809 are on the base of the regulator/pass transistors and were replaced with low ESR types: 470µF/35V, 330µF/50V and 22µF/50V, respectively.

    Capacitors C811, C812 and C813 are used in the protection relay circuit and were also replaced with low ESR types: 22µF/63V, 47µ/25V and 220µF/35V, respectively. The protection relay (L801) was replaced with an OMRON LY2-0-DC24, which is a drop-in replacement for the original type.
     

     

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  2. catrafter

    catrafter Marantz Specialist Subscriber

    Messages:
    6,212
    Location:
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    Looks great!
    I like to replace the underrated 2SD331 voltage regulator transistors with MJE15030 types.

    Tom
     
    Mike Sweeney likes this.
  3. KutzlerTrans

    KutzlerTrans Jennie & I with Buddy and Barney. Subscriber

    Messages:
    2,990
    Location:
    Wisconsin
    Nice Work!
    What is the idea/reason behind raising the UF Value of 803/4/6?

    R804 looks a bit hot.

    Hey Ben, When you get time, Please give us part numbers for the C0G Ceramics and the brand you chose. Thanks, John
     
    Last edited: Nov 18, 2015
  4. Leestereo

    Leestereo Super Member

    Messages:
    2,142
    Location:
    Ottawa, ON
    Thanks for the kind words, Tom and John, much appreciated.

    John: C803, C804 and C806 filter the raw DC and increasing their capacity reduces the AC ripple and provides a bit more power reserve. Regarding C0G capacitor brands, I have previously used Vishay, Murata and AVX to good effect; I will typically order the 5% tolerance and 100V ones from Mouser.
     
  5. hirscwi

    hirscwi AK Subscriber Subscriber

    Messages:
    1,731
    Location:
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    Another fine project! Thanks for sharing it with us. Hope all is well up north...
     
  6. Bert 1100

    Bert 1100 Super Member

    Messages:
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    I love theses threads by Leestereo, always plenty to learn from them, thank you !
    :lurk:
     

     

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  7. Leestereo

    Leestereo Super Member

    Messages:
    2,142
    Location:
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    Thanks for encouragement, Bill and Bert; more than happy to share my projects.
     
  8. Leestereo

    Leestereo Super Member

    Messages:
    2,142
    Location:
    Ottawa, ON
    Main Power Capacitors

    Original Panasonic 15,000µF/70V capacitors

    [​IMG]

    [​IMG]


    Replacement United Cheimicon 18,000µF/75V capacitors
    [​IMG]

    [​IMG]
    Note that the ground plate was installed inverted with the replacement capacitors (due to the shorter height of the screw mounts).
     
  9. KutzlerTrans

    KutzlerTrans Jennie & I with Buddy and Barney. Subscriber

    Messages:
    2,990
    Location:
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    Thanks!, I ordered a few of the C0G's in 100v.
    Its odd they used 500 volt ones in the feedback loop.
    I also decided to add the PW series caps to my stock of parts. I will now have the 680 and 1200uf ones in stock.

    Is it me, or does everyone feel like its christmas when we open them Mouser packages?:banana:
     
    wurlyman likes this.
  10. gslikker

    gslikker Super Member

    Messages:
    2,160
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    I know the feeling :) Nice work, indeed!
     
  11. SoundOfSound

    SoundOfSound Super Member

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  12. Leestereo

    Leestereo Super Member

    Messages:
    2,142
    Location:
    Ottawa, ON
    Phono Stage (P400)

    [​IMG]

    P400 board in original state
    [​IMG]

    P400 board restored/upgraded
    [​IMG]

    The stock capacitors in the input high-pass filter (C401, C402) were 1.0µF tantalum capacitors and these were replaced with 1.0µF Panasonic polypropylene film capacitors. The electrolytic capacitors C403/C404, which determine the low end roll-off of the RIAA equalization, were originally 47µF/16V polarized low leakage types. Their replacements were bipolar Nichicon ES capacitors of the same capacity. The local filtering/decoupling capacitor, C413, was a 100µF/35V and was replaced with a 270µF/50V low ESR type (note that the voltage rating should be increased since this capacitor is subject to ~34V). The original polyester film capacitors at the output, C414/C415, were upgraded to polypropylene film types. The failure-prone 2SC458 transistors (H405, H406) were replaced with KSC1845 transistors (note that the pin-order for the original 2SC458 is "BCE" whereas that for the KSC1845 is the common standard "ECB"). The 1S-2473 diodes (H407, H408) were replaced with 1N4148 diodes and the failure-prone VD1212 dual diode (H409) was replaced with a pair of 1N4148 diodes in series.
     
  13. KutzlerTrans

    KutzlerTrans Jennie & I with Buddy and Barney. Subscriber

    Messages:
    2,990
    Location:
    Wisconsin
    Good info here. Thanks!
     
  14. Lavane

    Lavane AK Subscriber Subscriber

    Messages:
    7,569
    Location:
    northern cal.
    I always replace those flat gray film caps. Very dull sounding. Those new screw tops fit very nice.
     
  15. Rasputin47

    Rasputin47 Woad

    Messages:
    570
    Location:
    .on.ca
    Great thread.

    I just "finished" restoring my 2325 but after seeing some of these ideas I think I will be making a few more changes
     
  16. Leestereo

    Leestereo Super Member

    Messages:
    2,142
    Location:
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    Thanks for the compliments, everybody.

    Rasputin47: I know exactly what you mean about going back to "finished" projects...always new things to try out.
     

     

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  17. Leestereo

    Leestereo Super Member

    Messages:
    2,142
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    PREAMP/TONE BOARD (PE01)

    [​IMG]

    [​IMG]

    The 680pF ceramic capacitors (CE01, CE02) at the board input were replaced with same value C0G types. The 1.0µF polyester film capacitors in the high-pass input filter, CE05 and CE06, were upgraded to 1.0µF Panasonic polypropylene films. The emitter-bypass capacitors, CE09 and CE10, were 100µF/10V electrolytic types and their replacements were low ESR types of the same capacity. The capacitors in the feedback loop, CE11 and CE12, were polarized 10µF electrolytic types and their replacement were bipolar Nichicon ES capacitors. The output capacitors of the first gain stage (CE13, CE14), were 3.3µF polarized electrolytic types and these were replaced with WIMA stacked polyester film types of the same value.

    The capacitors (CE33, CE34), in the high pass filter for the second gain stage, were 1µF tantalum types and these were replaced with WIMA stacked film types of the same value. Similarly, the polarized 3.3µF capacitors at the output of this second gain stage, CE35 and CE36, were upgraded to stacked film types of the same capacity. The final output coupling capacitors of the preamp/tone board were originally bipolar 4.7µF electrolytic types and the replacements were stacked film types of the same capacity.

    The local DC filtering capacitor for the PE01 board (CE39), was originally 220µF/35V and the replacement was a 470µF/35V low ESR type.

    [​IMG]
     
  18. KutzlerTrans

    KutzlerTrans Jennie & I with Buddy and Barney. Subscriber

    Messages:
    2,990
    Location:
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    Have you ever compared the 4.7 films.
    Kemet. ,Wima, etc. Its too bad panasonic discontinued their films. they never made a small 4.7 or 3.3 under 100v though.

    You crack me up, tossing bigger uf ratings in their. Heck if i'd a known i could get away with it, it could have saved me a lot of time waiting for an order to come in.
    The FG'S are shorter and fit great. That is not a PW.... What is it?
    I just got the new C0G's today,and man are these things little.

    I restored my 2325 in the shop a few years ago, when i was just learning, and i think i will be going into it again, due to a loss of highs on full throttle. (half volume) The hpm200 suck the guts out of it. I intend to use the bigger sizes posted here. they just came today also.

    You guys talked me into ordering a boatload of 250v 1uf's

    Keep up the Nice work:thumbsup:
     
    Last edited: Nov 21, 2015
  19. runningdog

    runningdog AK Subscriber Subscriber

    Messages:
    396
    Location:
    Sonoma, CA
    That is so clever! And the way you rotated the caps 90 degrees puts the upside-down plate in-line with the chassis, contributing to a clean look. I did one this way just now with your photo for reference. Thanks!
     
  20. Rasputin47

    Rasputin47 Woad

    Messages:
    570
    Location:
    .on.ca
    I just added a lot of those to my next order as well.
     
    Last edited: Nov 22, 2015

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