Aquired a Marantz 8b

Discussion in 'Marantz Audio' started by RS Steve, Dec 7, 2016.

  1. RS Steve

    RS Steve Tube Junkie Subscriber

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    I originally posted about this in the tube section, and it was suggested I post here since there could be more information to be had. This link is for that post.
    http://audiokarma.org/forums/index.php?threads/marantz-8b-find.745595/

    I have only read about this amplifier and do not have any real knowledge about them other than they are considered highly desirable. I was hoping to find a replacement parts list in the manual I downloaded but it wasn't included.

    Feeling pretty lucky to own this beauty, hoping to get a nice 7C preamp someday to pair it with. :thumbsup:

    20161206_091803.jpg 20161206_091749.jpg
     
    Last edited: Dec 7, 2016
    rxonmymind, Richs_Trains and txturbo like this.

     

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  2. txturbo

    txturbo AK Subscriber Subscriber

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    Lucky you!
     
  3. bryans12v

    bryans12v Marantz Junkie

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    Hey Steve. Have you tried to power it up yet? For a significant unit like this I would only replace what is absolutely necessary.
     
  4. Djcoolray

    Djcoolray Addicted Member

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    A rocks throw from JBLM !!!!
    That's too cool.....lucky !
     
  5. RS Steve

    RS Steve Tube Junkie Subscriber

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    Yes, if you read the link for my original post, you'll see that I powered it up with great success.
     
  6. bryans12v

    bryans12v Marantz Junkie

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    If this is something you plan on keeping forever with no intentions of reselling, I would replace or restuff the multi caps, bias and hv rectifiers as well as the bridge for the power supply and all electrolytics, that's all.

    Crooner may chime in soon, he's been down this road before. I however have never even seen one in person.

    Don't let other persuade you into replacing the good all. They will out live all of us. I believe they are plastic encapsulated, not wax. Unless they test out of range or are cracked, leave them alone. Same goes for resistors.
     

     

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  7. airtime

    airtime Super Member

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    That was me that suggested moving the post over. I hope the "hard core" 8b restorers chime in. A great bunch of guys - so let's go guys!
     
  8. Pio1980

    Pio1980 AK Member Subscriber

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    I'm not necessarily hard core, but am keeping my 8 pretty much as BuzzK made it, with the Goodalls retained. I'm using it in UL with EH 6CA7s, thru a 10k pot direct into the "test" jax from the line sources, no line stage.
    Listening now to a Jon Anderson LP.
     
  9. RS Steve

    RS Steve Tube Junkie Subscriber

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    I am considering hiding a transistor radio under chassis, and creating tubes with small light bulbs in them to mimic tube glow. That would preserve the original circuits and still produce music. :beatnik: :crazy: :rolleyes:

    It is quite a battle deciding between having it for a collector value original, or restoring it for safe long term operation.
     
    Last edited: Dec 7, 2016
  10. Pio1980

    Pio1980 AK Member Subscriber

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    Or cut the difference and do an underchassis refurb and save the rejected components for a collector option later.
    Modern elyticaps are smaller and could be used where necessary without removing the gray Spragues. the smaller elyticaps should be replaces as a matter of course, the Goodalls may be just fine/ not leaky. Easy to check with all tubes pulled. The selenium bias rectifier may be ok as well, the elyticaps maybe not. Resistors should be checked against tolerance values.
     
  11. airtime

    airtime Super Member

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    Well not the response I was hoping you would get. So the basic question is are you keeping this amp until "you're done"? Or plan on selling it at some point if you don't care much for it?

    You're pretty good with this stuff - recap it and take it from there I guess. Wish more of the hard cores would have chimed in - sorry.
     

     

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  12. RS Steve

    RS Steve Tube Junkie Subscriber

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    I have sold quite a few pieces the last few years, but not tube equipment. I do not plan on selling this amp, I'd like to restore it as smartly as possible so as not to change its original sound. The value thing really isn't important to me after thinking on it, I'm leaning towards a solid restoration for a second life. :dunno:

    Maybe a couple JJ caps topside huh? :no: :D
     
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  13. airtime

    airtime Super Member

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    Do a search on this forum. I'm sure a lot of restoration stuff will pop up with this amp.

    I'm in the "take advantage of using newer parts" in the important positions when possible or indicated by being worn out by age. But no big modifications to the circuit.

    Best of luck and post some pics. That always gets these guys juices going :whip:
     
  14. RS Steve

    RS Steve Tube Junkie Subscriber

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    I would like to find out if there was ever a parts list for this amp, most service manuals have them, but not the one I found. This would help me look at the schematic, and refer back to the list to make sure I get the correct wattage and such.
     
    Last edited: Dec 8, 2016
  15. centsless

    centsless Super Member

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    Very nice and rare find. I found a 7c a couple of years ago at a garage sale of all things. Didn't know much about them until I looked up completed sales at the bay...and about fainted! Saw the price tag of six hundred and quickly bought it. Took it to my tech who simply stuck six new tubes in for another hundred....then sold it to a guy in Cali for five grand....:)

    So good luck in finding one not sky high.
     
  16. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

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    Free register and login at HiFi Engine for their copy of the 8B service manual which has the schematic and parts list.

    http://www.hifiengine.com/manual_library/marantz/8.shtml
    http://www.hifiengine.com/hfe_downloads/index.php?marantz/marantz_8b_service_partial.pdf

    Probably the Marantz forum has a lot more Solid State folks since the bulk of Marantz gear is solid state, so the Tube Audio thread may get more Marantz tube-o-philes
     

     

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  17. RS Steve

    RS Steve Tube Junkie Subscriber

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    I am signed up there, will have to double check for it, Thanks!
     
  18. RS Steve

    RS Steve Tube Junkie Subscriber

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    I downloaded everything they had on the 8B and found not parts list, not sure why it doesn't have one.
     
  19. RS Steve

    RS Steve Tube Junkie Subscriber

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    Ahhh, found it on another site, good to go now.
     
  20. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

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    It's on page 11 of the PDF of the 8B partial service manual on the linked Marantz 8 page, page 8 of the actual manual. Page 7 is the 8B schematic.
     

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