Marantz 2275 Restoration - 1974

Discussion in 'Audio Visual' started by aokman, Oct 25, 2009.

  1. OP
    OP
    aokman

    aokman Member

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    Well so this worklog has finally come to an end...

    Has been a great adventure restoring this amp and certainly had its challenges :)

    Final calibration results were after 1hr of amp warm up time

    Power supply: 34.9v
    DC Offset: L = 0.2mv R = 0.1mv
    Idle Current: L = 9.9mv R = 10.1mv

    Now begins the hunt for my next big amp restoration project while listening to this wonderful amplifier, hopefully i can track down another Marantz :D

    [​IMG][​IMG][​IMG]

    [​IMG][​IMG][​IMG]

    [​IMG]
     
    Last edited: Nov 25, 2009
  2. MUTMAN

    MUTMAN Member

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    great result. looks fantastic
    :thumbup::thumbup:
     
  3. ford ftw

    ford ftw Member

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    You have inspired me to recap my Marantz pm-243 (no idea of the year can't find any info on the internet).

    Edit: have you considered swapping the transformer for a toroid? I've heard they are a lot better for amps as they produce a "cleaner" power supploy resulting in cleaner sound.
     
    Last edited: Nov 26, 2009
  4. Oblong Cheese

    Oblong Cheese Member

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    Dude that looks brilliant! Better than a lot of modern systems for sure.

    As someone who has grown up almost entirely within the digital music age, these old amps are quite fascinating to me. I would love to own one, but they're so expensive!
     
  5. OP
    OP
    aokman

    aokman Member

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    yes im finding that out now, they really aint that expensive if you find one in a salvo shop or something but people on ebay seem to think they are worth a fortune just because they are old lol.
     
  6. Bion1c

    Bion1c Member

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    excellent job mate wd :thumbup:

    it almost looks better with the cover off !

    ill be keeping me eyes out at any salvos i end up in from now on :)
     
  7. OP
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    aokman

    aokman Member

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    cheers :) i love the look with the lid of personally :)

    Just started cranking it up tonight took it to 70% with Tiesto and god it almost deffened me. I cannot believe the 2 amp modules were only getting warm running it this hard!
     
  8. 3Tone

    3Tone (Banned or Deleted)

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    Very good test material I must say! :thumbup:
     
  9. itachi46

    itachi46 Member

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    u see how massive those heatsinks are? XD btw i figured out what i blew out its the 2 power transistor and the 2 NEC transistor...
     
  10. OP
    OP
    aokman

    aokman Member

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    Yeah they aint that big though there just isn't much heat output because it calibrated down as tight as i can get it :)

    On another note my next project has started, i scored a Marantz Model 32. Very rare and ive just started restoring it...

    It is quite possibly the best small amp ive seen from then build quality wise, only 4 electrolytics plus the main filter caps. The rest are film capacitors and very pricy Silver Mica capacitors...

    [​IMG][​IMG][​IMG][​IMG]
     
  11. THeX

    THeX Member

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    wow the model 32 is a nice bit of kit. I'd love to see this one done up too!
     
  12. OP
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    aokman

    aokman Member

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    Cheers :)

    i may aswell update this thread for the Model 32 as its not a big job, the next amp on the way will be the next massive job ;)

    Anyway...

    Managed to get the power supply out and found 1 cap about to fail along with 2 blistered resistors cooking the PCB. Similar results with the resistors on the amp boards aswell.

    Still have to source caps for the unit but there are only about 4 electrolytics in the whole thing, rest are films and silver mica.

    One front lamp is on the way out so im going to just replace both with a single WB series CREE LED. Will easily light up the whole face.

    Primary filter caps are:

    Sangamd Vinylclad 6800uf - 50v (35mm x 105mm) screw type

    So far:

    - I have converted the unit to 240v from 120 with the split windings on the transformer
    - Removed and stripped/cleaned power supply board
    - Replaced 1.5A 1N5393 rectifier diodes with 3A 1N5404
    - Replaced relay with new type and rerouted connectors
    - Replaced 2W 1.5k resistors with 5W 1.5k and elevated off PCB

    [​IMG][​IMG][​IMG]

    [​IMG][​IMG][​IMG]

    [​IMG][​IMG]

    I replaced the old relay and rewired to suit the old design, basically i swapped the relay coil contacts with the speaker contacts internally :) i used copper desolder braid wound up tightly to extend the coil wires :)

    The old coil looked like nice quality but i think its passed its prime now...

    also the chassis is almost done, not a perfect finish but better than before :)

    [​IMG][​IMG][​IMG][​IMG]
     
  13. TERRA Operative

    TERRA Operative Member

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    Awesome thread is awesome.

    I've been inspired. I'm starting a build of a rack mount 25W per channel Class A power-amp with external rack mount power supply. :D The pre-amp will be housed in it's own rack mount enclosure too.

    I'm building it totally overkill, just because I can. :leet:
     
  14. OP
    OP
    aokman

    aokman Member

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    nothing wrong with overkill, that is my favourite word with amps :thumbup:
     
  15. TERRA Operative

    TERRA Operative Member

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    Damn straight.

    I'll start my own thread over the weekend. :)
     
  16. Stevof1

    Stevof1 New Member

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    Marantz 2275 recap

    Many years after the start of this thread I decided to do the same thing....recap my Marantz 2275 Receiver. I figured others would be stumbling thru this processs as well as me so I will post my recap. I purchased a Recap kit from Randy at irebuildmarantz.com who it turns out lives 15 miles from here. Randy was very gracious to help me start by guiding thru the recapping of my Power board(P800) on my Marantz 2275 receiver. It is fairly easy to do this, and I wanted to add photos here to help others in the future do this on their own.
    Most importantly is to check each cap as you remove it with the cross referenced replacemant cap. Also to keep photos of what your doing for reference. It seems that for this receiver, it is unnecessary to cut wires to recap. In most cases you just need to remove screws from whatever board your working on in order to finagle it to where you have soldering iron access. In Randy's opinion it is not necessary to clean the boards when you recap. I chose to brush down the board with 91% Isopropyl alcohol and then dry off with compressed air and cotton swab for cleaning. I will post progress as I go . This should work with any analogue Marantz, but do your research!
     
    Last edited: Feb 13, 2015

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