Akarakrit Uamkruea, blogger and audio gear maker who passionate in vacuum tube, audio & music.
Producing electronics projects since high school. Seriously upgrade and modify vintage audio equipment for “Real Sound” concept.
He is a co-founder of Soundaries, all audio solution provider.
Experienced and lively explore the listening rooms & audio shops in Japan as his most favorite to do.

Friday, April 22, 2016

Marantz Model 7 (Reissue Version) in upper level after modification

After success with modification of Marantz 7C original version.

http://mellowgroovy.blogspot.com/2016/01/marantz-7c-modify-Real-Sound.html

Another friend who has Marantz 7C reissue version asked me to make it better.

Almost signal capacitors using modern film type,

so many audio guys who compare with original one might not like a newer version.

 See pictures below for 7C reissue version before take modify.










Almost parts for modification like previous 7C except using Ohmite Brown Devil resistors 

in rectifier section for make more "Vintage like" sound.  

All coupling capacitors still using Arizona Capacitor that's the best one for

modify vintage audio gear in my opinion. 







Add 3 oil capacitors for decoupling all supply voltages.


Ultra fast recovery diode from ST is a great choice for upgrade to next level.



Everything that doing above, make Marantz 7C reissue has more musical and "Real" sound.

Not different with original version that I do modify before,

because all effective components are same parts.

Worth to try with yours.

Cheers !!!

Posted by at

6 comments:

  1. Victor168February 27, 2026 at 8:10 PM

    Hello Akarakrit, two more questions...
    1. in Photo #10 (the ALL PARTS Used Photo), what is the purpose of the two black 100K resistors to the LEFT of the STTH6112TV2 diode?
    2. in Photo #18 (the B+ & Filament Power Supply), there are three capacitors, two white WE's and one black Sprague's. Purpose(s)?

    Thank you and My Best,
    Victor

    ReplyDelete
    Replies
    1. Akarakrit UamkrueaFebruary 27, 2026 at 10:15 PM

      1. Replace 180k at R53A and R53B
      2. White WE resistors, one is bleeder another is use in rectifier. Sprague capacitor use to parallel with electrolytic capacitor like PIO capacitor

      Delete
    2. Victor168February 28, 2026 at 4:00 PM

      1. I assume that you used 100KΩ, in stead of 180KΩ?
      2. I assume that the one used in rectification is R105 and you've adjusted the resistance to compensate the Selenium voltage drop?
      Also, please advise where in Japan to purchase the Arizona capacitors.
      THANK YOU VERY MUCH!

      Delete
    3. Akarakrit UamkrueaFebruary 28, 2026 at 4:07 PM

      Please list what you want.
      And send me an email.
      I will go to Japan next week.

      Delete
    4. Victor168February 28, 2026 at 4:12 PM

      Just want to make sure: Did you receive my previous e-mail sent a couple days ago?

      Delete
    5. Victor168February 28, 2026 at 9:54 PM

      My current requirement list sent via email. THANK YOU!

      Delete

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