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Marantz 8B Restoration Saga

crooner

crooner

Tube Marantzed
I got this baby for only $660 on the 'Bay. Just arrived today. It will keep me busy during the long Memorial Day weekend :D

Unit is all complete, and the iron is good. I bought nice SED (former Svetlana) EL34s for it and NOS RCA and GE small signal types.

I will follow this post with detailed pics of the restoration. It's going to be one FUN project!

Regards,

crooner
 
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I looked long and hard at that 8B..... but couldn't pull the trigger.

Just have too many projects already.
 
Me too. But the money was tight (couldn't afford a mint unit) and this 8B looked like the ideal project so I went ahead. I love to bring these classics back to life.

The only concern I have is the unsoldered transformer leads. I wonder why this was done. It will be pain to ID the leads since some colors have faded with age. Any suggestions on how to bring back the color or another method to ID the leads? Richard Links suggested that I look inside the transformer case where the leads come out. Not a bad idea, but I'll have to unbolt the trannies for that.

Best regards,

crooner
 
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That's still a nice amp, even though it needs some TLC. At least you're willing to put in the time to bring it back to respectable levels, like this mint 8B (not mine...I wish)!

Good luck with your restoration project.
 
Thanks! That's one sweet 8B (lucky owner!)
Mine won't look as clean, but I am pretty confident the electrical restoration will make it sound great.

Here's an unusual photo most people have never seen (unless they have an 8B, of course). It's the amp with the trannie cover removed. All transformers are metal encased, not exactly potted, since they are not sealed in tar like McIntosh transformers.

Mine looks quite rusty under the cover. No big deal, since they are out of sight. I'll probably touch them up with something like rustoleum to prevent further corrosion.

Best regards,

crooner
 
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At least you're capable of doing your electrical repairs; not me.

Wonder if the chassis could be cleaned up to look better than it does, or if it would need a complete overhaul (hate to see how much that would cost to refinish the steel, or if there is a person or company who could even do that). Regardless, it could've been a whole lot worse!
 
Yeah, perhaps it could be done, but it would have to be stripped clean, and that's a tedious job. On a rusty chrome plated Mc it's probably worth it. This one, can be touched up to look good, not perfect or close, but decent. Good thing those transformers are covered and that the cover itself is in pretty good shape cosmetically (the nicest part of the metalwork in this unit).

Best regards,
crooner
 
Originally posted by crooner
..."On a rusty chrome plated Mc it's probably worth it."
Click to expand...

I agree. I lucked out with both the SS Macs (MC2100 and MC250); their chrome chassis' were near mint, with very little pitting only on the insides, and the stensiled lettering near perfect. I hate to see vintage pieces like these (and your venerable Marantz) abused or completely neglected. You wonder how these pieces ever get so rusty and dinged up like some do over the years...why would people do that?
 
Before I decided on this particular 8B, I was surprised to see that an earlier model 8 (with some rust) went for $901!!!

Mine was significantly cheaper and it's the 8B with better feedback circuit and output trannies.

I didn't get any tubes with mine, but look at those sadly blown KT77s!!!

MARANTZ2_0525.JPG
 
Good luck with the 8B !

Should be a super unit once you get it restored.

I see tons of Marantz stuff that makes you just shake your head. Why did someone let it go to crap.

If your not in the hobby, you don't have a clue what it might be worth, or even care.
 
Originally posted by Shain
I see tons of Marantz stuff that makes you just shake your head. Why did someone let it go to crap.
Click to expand...

I met a guy at a swap who tossed his 8B in the trash when he blew an output transformer. But I'm sure the landfills have tons of tube gear rotting away... There's a massive old house here in Toledo -- owner told me he had huge amounts of electronics. I went back the next year to see if he'd sell me some. Poor guy had had a stroke, the house had been sold, and the new owner told me it took days and days for workers to pull out all the tube gear -- to toss in the long drive-up dumpster-trailer... Rumor I heard later from a collector was that the house had a lot of Western Electric.

If I had an 8B, I wonder what I'd do about those power supply diodes...
 
The 8B Is Ready To Undergo Surgery

First thing will be hooking up all the tranny leads and installing new 1N4007 diodes and electrolytics in the bias and power supply.

I will power up with my poor man's variac (light bulb in series) and afterwards check for signs of life on both channels.

If it's positive I will finish the set by doing a recap.

Best regards,

crooner
 
Nice catch, it's too bad people carelessly just set them in a garage
but as you say, it's how you can afford one. Can always trade up later if you choose too. :) Enjoy it!

Carl
 
I'm looking forward to your continuing restoration of this 8B...what a project this will be! Keep us all posted.;)
 
Yes, indeed!
I have good news to report. I have correctly identified all 26 output transformer leads (13 for each channel). It was easier than I thought and no need to unbolt the transformer(s) from the chassis.

The faded cotton cloth can be made to reveal its original color by peeling off a small portion of it at the end, exposing the inner part of the cloth that covers the conductor. This way, I was able to see clearly the color of each cable. I am pretty much 100% confident in my ID. Testing is still needed tho, so fingers crossed!

Regards,

crooner
 
Update on the Marantz 8B restoration.

I've just finished rewiring one channel, plus the bias supply (new caps and rectifier) and the HV rectifiers (all new as well).

As soon as the other channel is wired up, the unit will be ready for the smoke test. I've decided to leave the "Good-All" original capacitors in for now. If the unit works funky or if I get red plates, I'll swap them for some Orange Drops I got from Antique Electronic Supply.

Stay tuned for the next update....
 
Unit Is Ready To Roll!!!

Finished soldering all the leads. Unfortunately, the former (incompetent) owner cut some leads too short. I had to add some terminal strips for ease of hook-up.

I hope the next service person 40 years from now, finds the unit easier to work on. I'm no electronics expert, but I always try to keep things neat.

Here's the "Before" picture:
 
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I added a protective coat of Rustoleum enamel paint to the tranformer cans. Not perfect finish but it should prevent further rusting...
 
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