Marantz Model 7c Restoration

jpk000 · Feb 26, 2015

Hey folks, I recently acquired several pieces of Marantz equipment, which included models 7c, 7t, 8b, and 15. My grandpa used to own a drug store and kept one set at the shop. Anyway, I've been using the 7t with the 8b and it sounds amazing. I've tried the 7c too and I can hear that smooth time in there, but it clearly is in need of some new caps as that tone is patchy. Also, the rca plugs are very sensitive and getting a good connection is a struggle. Has anyone had any experience restoring the 7c? I know it highly valuable and will hold off until I get a pro to restore it if need be. Either way, I'll be keeping it as my own treasure and am not interested in its potential sale price or collector value at this point.

I'll post pics once I upload them to the computer.

Thanks!

jpk000 · Feb 26, 2015

*smooth tone

rBuckner · Feb 27, 2015

Welcome to AK and to the Marantz forum! Might I add: :jawdrop: I have not worked on a 7C but it is worth it for sure, and especially if you're keeping it.

twkted · Feb 27, 2015

Congrats on having some very nice pieces come to live with you. Welcome to AK and Marantz.

spartanmanor · Feb 27, 2015

Nice stuff!

Hull Rust · Feb 27, 2015

A Twin Cities option to service your stuff is Dave Olsen at HiFi Sound in Minneapolis. Dave's done work for me and I've been satisfied.

I have no affiliation with him other than having him do work for me in the past, just passing it along:

http://hifi-sound.com/

There are also members on AK who work on stuff. Post some pictures and ask questions and they'll chime in. Good people from my experience here on AK.

Hold on to all your Marantz pieces and enjoy them.

jstang · Feb 27, 2015

Have a 7c and worked on a few....

Do not, repeat, do not replace parts without absolutely having to on the tube units.... Every part that is not original will affect the value.. With that said, a broken unit is worth even less....

The tube units should be treated with the attention of a museum piece.

I would start testing the tubes and cleaning the sockets, then the rest of the unit.

Jk

jpk000 · Feb 27, 2015

I appreciate the welcoming and thanks for the responses!

Don't worry jstang, I've only opened up the top of the preamp to look for signs of wear. I think I may have been the first one to look inside since it left the factory. The innards look pristine save for a thin layer of old dust. No cracked caps that I can see. It still has 6 Telefunkens plugged in. I've tried swapping a few out with tubes from my guitar amp that I know to be good with little effect on the sound.

I'll post photos tonight. I've also got the original receipt and a letter from the shop in Montana written in the '60's talking about how these Marantz pieces are top of the line and sure to be the best available for at least a few more years.

goatster · Feb 27, 2015

ANY part you replace should be saved and put into a box with a label "DO NOT DISCARD"

jpk000 · Feb 28, 2015

I've uploaded some photos of the 7c. The wiring is beautifully done.

onemug · Feb 28, 2015

You have some excellent and very desirable pieces. I'm glad you appreciate them, coming from your own Grandfather is even more special.

I lusted after a 7c for a long time but they were expensive and I didn't think the sound would match the price but I was determined "one day". That "one day" happened a few years ago and to my very pleasant surprise, it sounded really good. There is some magic in that preamp!

Get yours up to spec and be prepared.

fredmarantz · Feb 28, 2015

That 7C is drop dead gorgeus - take very good care of it.!!! :beerchug:

all the best
Freddy

Sam Cogley · Feb 28, 2015

Beautiful piece.

That many molded paper caps gives me hives just looking at it...

Hull Rust · Feb 28, 2015

Very cool pictures, thank you for posting them. Restoring your 7c is a job for someone with experience with them.

A little Howard's Feed-N-Wax will help that cabinet. That's all I can help with.

Just for design comparisons sake, here's my 7t a while back.

jstang · Feb 28, 2015

In the 7c, there are some construction techniques, circuit design and components that create the magic....

jpk000 · Feb 28, 2015

Thanks Hull Rust, checking out these photos gave me a clue of just how intensive a restoration this could be. I will probably check out Hifi Sound - they are only about 2 miles from me. May be a while as I'm sure it won't be cheap.

Check out these photos - the original receipt and letter from the dealer. The 7c, 8b, and control box cost only $555.00! Although, that was in 1964 so still not cheap, but no where no where near their value today.

The best part of the letter: "We also are informed that there will not be any changes in these basic products in the current 2 years (1966). All of this, plus a new franchise structure from Marantz, seems to indicate to me that this is really going to continue as the top amplifier company for some time."

ooba tooba · Mar 1, 2015

jpk000 said:
Thanks Hull Rust, checking out these photos gave me a clue of just how intensive a restoration this could be. I will probably check out Hifi Sound - they are only about 2 miles from me. May be a while as I'm sure it won't be cheap.

Check out these photos - the original receipt and letter from the dealer. The 7c, 8b, and control box cost only $555.00! Although, that was in 1964 so still not cheap, but no where no where near their value today.

The best part of the letter: "We also are informed that there will not be any changes in these basic products in the current 2 years (1966). All of this, plus a new franchise structure from Marantz, seems to indicate to me that this is really going to continue as the top amplifier company for some time."

I love stuff like this! Please keep us updated on what is done to the Marantz's and your impression of their sound. Beautiful pieces.

Hull Rust · Mar 1, 2015

If you don't have them, manuals and other information are available online. Original manuals show up on eBay, but you can download them for free at hifiengine.com:

http://www.hifiengine.com/manual_library/marantz/7.shtml

(note the above is for the 7c, not 7t)

http://www.hifiengine.com/manual_library/marantz/8.shtml

http://www.hifiengine.com/manual_library/marantz/15.shtml

You've got some fantastic pieces, and that they are from your grandfather makes it even more special, as was said earlier on the thread. Great family history, and as you get older that stuff matters more and more, it seems.

You've got a wealth of information here on AK, many extremely knowledgeable folks here willing to help.

chinacave · Mar 1, 2015

Wonderful pre-amp - Great that they are staying in your family -

I recently partially restored three for a friend - some photos in the thread below that you may find helpful no matter which way you go. My two cents are to proactively replace the parts that go bad with age with modern components, particularly the power supply and coupling and bypass caps at a minimum, and check the resistors, I found 2-3 in each unit that were off. That is assuming you are planning to actually use the unit. I understand that completely original ones MAY be more valuable if left alone, but in use, at best they will not sound as good as they could, and at worst could cause damage. YMMV

Best luck on your system - you have an extremely fine set of gear - some of the best ever made.

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Sam Cogley · Mar 1, 2015

I have to say: when you get everything rehabbed, you'll have a killer tube setup and a pretty darned impressive solid state setup.

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