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2270 Late Model - Lacks Depth

Discussion in 'Marantz Audio' started by Osibisa, Oct 12, 2018.

  1. Osibisa

    Osibisa AK Subscriber Subscriber

    Messages:
    318
    Location:
    New Jersey
    I understand that the sound signature may vary from unit to unit but this one just doesn't go as deep on the low end as my mid production unit, or any of the other receivers I own.

    This one went through the standard recap of power supply (PW), main caps (LKG), preamp, and power amps using the same Silmic II components yet while clear and concise, low notes just don't have the deep dive as my other 2270 or the 2275 & 2325 either. Not talking boomy or wall thumping by any means, just deep.

    I listen to orchestral and symphonic music during the day at low to semi-moderate level and there is an expectation that when hearing a string instrument hitting a low note I should be drawn in. Not happening.

    This morning as a test I split the receiver feeding the pre-out from the 2275 into the amp-in of the 2270, results yielded full bodied sound which eliminated any issue with the 2270's amps.

    Swapping in the opposite direction gives me the same clear sound sans depth.

    What I don't understand is why this is occurring given the preamp is of the same design and the same components were used with very different results. I could see if one channel had the issue, however both channels are balanced.

    Any thoughts?
     

     

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  2. sp58

    sp58 Member

    Messages:
    68
    Location:
    Germany
    After recapping let em play and wait - caps need time for reformatting, even foilcaps used as coupling-caps
    Good luck
     
    UncleBingo likes this.
  3. Osibisa

    Osibisa AK Subscriber Subscriber

    Messages:
    318
    Location:
    New Jersey
    Yes, but for just about 12 hours a day for three weeks?
     
  4. sp58

    sp58 Member

    Messages:
    68
    Location:
    Germany
    Listen to it and let us know when sound changes.
     
  5. Osibisa

    Osibisa AK Subscriber Subscriber

    Messages:
    318
    Location:
    New Jersey
    I think you misunderstood me … I have had it running for about 12 hours a day for three weeks.
     
  6. Stratman

    Stratman New Member

    Messages:
    37
    How big did you go on the main caps?

    I have a 2270 and 2275, both newly refurbished. I think the 2275 has more thump, but I still get a lot from my 2270 and it's a lot more clear/tight.

    My tone board for the 2270 was Wima films wherever possible and a few Nichicon FG and Muse. I think it sounds fantastic and I'll probably keep it over the 2275. The 2275 has more detail in mids and feels like it's much more powerful, but is a little fatiguing.
     

     

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  7. Dingman

    Dingman Do you know where your towel is? Subscriber

    Messages:
    2,389
    Location:
    Des Moines, Ia
    I think you've done well on the divide-n-conquer. It's obviously in the pre-amp of the 2270.
    I can't even start on why it's not the same as your other 2270. Have no idea.
     
  8. Osibisa

    Osibisa AK Subscriber Subscriber

    Messages:
    318
    Location:
    New Jersey
    I'll have to accept the fact that it has its own unique signature, not unpleasant just different.

    Stratman - it has a pair of Nichicon 10,000 uF caps.
     
  9. willyrover

    willyrover Super Member

    Messages:
    3,120
    Location:
    Hamilton
    I have both the 2270 and the 2275. They do sound very different and the 2275 definitely packs more punch than the 2270.
     
  10. Leestereo

    Leestereo Super Member

    Messages:
    2,093
    Location:
    Ottawa, ON
    In the 2270, it is worthwhile to upgrade the signal path capacitors on the tone control board (P450) since the tone controls cannot be "defeated" and hence are always in the signal path (there are garden-variety/regular ceramic capacitors that are particularly poor sounding); details regarding upgrading the P450 board can be found by clicking here.
     
  11. Osibisa

    Osibisa AK Subscriber Subscriber

    Messages:
    318
    Location:
    New Jersey
    Excellent .... coincidentally I read that thread last night!
    I'll get this scheduled with my next parts order and will report the results (fingers crossed).

    Would you happen to have the part numbers available?
     
    Last edited: Oct 15, 2018 at 1:46 PM

     

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  12. Leestereo

    Leestereo Super Member

    Messages:
    2,093
    Location:
    Ottawa, ON
    0.022µF: MKP2D022201B00JO00
    0.01µF: RDE5C1H103J1P1H03B
    0.0068µF: RDE5C1H682J1P1H03B
    0.0022µF: RDE5C2A222J1S1H03A
     
  13. Osibisa

    Osibisa AK Subscriber Subscriber

    Messages:
    318
    Location:
    New Jersey
    Appreciate the info!
    Thank you.
     
  14. Stratman

    Stratman New Member

    Messages:
    37
    For what its worth, I did that mod on mine as well as Leestereo's preamp mods, and I'm a big fan.
     
  15. Osibisa

    Osibisa AK Subscriber Subscriber

    Messages:
    318
    Location:
    New Jersey
    Did you notice any tonal difference after doing P450, or did you do them both at the same time?
     
  16. Stratman

    Stratman New Member

    Messages:
    37
    I did them at the same time. It was arguably the easiest board to make changes to.

    I just hooked up my 2270 after listening to the 2275 for the past few weeks. Yeah, there's less bass. I don't know if you'll be fully satisfied but on the 2270 with the loudness button pushed, or turning bass tone control to 3 o'clock makes it fairly comparable to the 2275 on my unit.
     

     

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  17. Osibisa

    Osibisa AK Subscriber Subscriber

    Messages:
    318
    Location:
    New Jersey
    My parts order is expected to arrive today, so in preparation I have P450 ready to be upgraded.
    What caught my eye is this revision (Rev 3) has two straps installed on the bass pot (R469) that do not appear in the SM or on pics I've found on the web.
    One pic I saw was a Rev-2 that did not have it and I really don't want to pull the covers off the other 2270 to see what's inside.
    I'm speculating that those straps may be influencing the tonal response of the bass pot.

    IMG_0602.JPG

    EDIT - What I thought were straps are actually 560k ohm resistors. I lifted one leg and performing a listening test before proceeding with the cap changes.
     
    Last edited: Oct 20, 2018 at 12:21 PM
  18. Osibisa

    Osibisa AK Subscriber Subscriber

    Messages:
    318
    Location:
    New Jersey
    Well I detected a slight improvement but not enough to write home about.
    Reattached and installed new caps per Leestereo's suggestion.
    As a test, cranked up this CD …

    613H8b0+YtL__AC_US218_.jpg

    Receiver easily handled the pipe organ on track two, which was heard but not felt. I would have been blown out of my chair if it was played through any of my other amps.

    This concludes my attempt to improve low end sonics.
     
    MBuras likes this.

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