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All all interested in building or updating the Marantz 7!! Here are the info!!

Firstly, thanks to all comments!!

Secondly, I high recommended inmates who are inbterested in Marantz parts swapping. Here you go.

I go therough the line section so far, and will study about the phono section.

https://jeffsplace.positive-feedback.com/a-guest-article-from-mr-shirokazu-yazaki-my-adventure-with-my-old-marantz-model-7-part-1/

https://jeffsplace.positive-feedback.com/a-guest-article-from-mr-shirokazu-yazaki-my-adventure-with-my-old-marantz-model-7-part-2/

https://jeffsplace.positive-feedback.com/a-guest-article-from-mr-shirokazu-yazaki-my-adventure-with-my-old-marantz-model-7-part-3/

https://jeffsplace.positive-feedback.com/a-guest-article-from-mr-shirokazu-yazaki-my-adventure-with-my-old-marantz-model-7-part-4/

https://jeffsplace.positive-feedback.com/a-guest-article-from-mr-shirokazu-yazaki-my-adventure-with-my-old-marantz-model-7-part-5/

https://jeffsplace.positive-feedback.com/a-guest-article-from-mr-shirokazu-yazaki-my-adventure-with-my-old-marantz-model-7-part-6/

https://jeffsplace.positive-feedback.com/a-guest-article-from-mr-shirokazu-yazaki-my-adventure-with-my-old-marantz-model-7-part-7/

https://jeffsplace.positive-feedback.com/a-guest-article-from-mr-shirokazu-yazaki-my-adventure-with-my-old-marantz-model-7-part-8/

https://jeffsplace.positive-feedback.com/a-guest-article-from-mr-shirokazu-yazaki-my-adventure-with-my-old-marantz-model-7-part-9/

https://jeffsplace.positive-feedback.com/a-guest-article-from-mr-shirokazu-yazaki-my-adventure-with-my-old-marantz-model-7-part-10/8/


The articles give me a very good idea and direction how to deal with the Marantz 7. Even though I'm doing differently as I have read ythe following suggestions by someone posted on diyaduio.com

"Marantz 7C

The Marantz 7C and McIntosh C22 are in my opinion totally over rated preamplifiers.

Firstly their RIAA sections are both AC coupled from 1st to 2nd tubes.
Secondly their EQ is active and driven by poorly designed cathode followers.
Thirdly the choice of tubes (ECC83) is certianly not the best.
Fourth the quality of the rotary switches is not good at all.

The power supplies are wimpy and not well designed but in that era this was par for the course.

Of course in their defense the available parts in the 50's and 60's was quite poor compared to what we have today.

We have restored many of these with great results.

Replace every single passive part.
Hard wire the RIAA parts.
Add a constant current source to the cathode followers
Completely upgrade the power supply with electronic regulation and better DC on the filaments.
Modify so that all switches do not carry audio signals but only DC to control high quality relays for all audio switching.

Modify the high level stage to be DC coupledand replace the balance control with a passive type centre tap to ground and the volume control with a blue velvet type wired either conventionally or in shunt mode.

Add in a cc source for the final cathode follower (7C and C22)

Remove the output level pot on the C22 as it simply adds more colouration."






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  • All all interested in building or updating the Marantz 7!! Here are the info!! - Tube747 00:55:09 02/04/25 (0)


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