Well Ive had a bit of a dilemma with my M-90.

At low volumes the speakers are scratchy.

The speakers sound nice and clear at louder volumes but the noise I am hearing indicates the coils are rubbing.

I searched out replacements and found some nice {Blue} Marantz drivers.
8 ohm 40 watters.

I fitted and tested them tonight and they sound phenomenal!!

Only problem is now getting the back cover on.
the magnet is hitting the transformer and holding the back cover out a quarter inch.

Tomorrow I am going to grind a little section out of the magnet so I could close it up.
I also have to solder the capacitors in for the tweeters and the woofer connections have to be soldered on as well.
I am also going to paint the speaker and tweeter grilles while I have it apart again.

Did anyone happen to buy any spare tuner dial trims from bredgeo?? I want to replace mine as well.
Any how here is how its progressing

check your pm

Very nice T/A! Those marantz speakers should allow you to get a lot more out of the amp onyour M90. What are the replacements rated at?

Nice upgrade!

Just curious: do you know what model those blue Marantz drivers originally came out of? Also, do they have ID#s on them?

[QUOTE]Originally posted by transamguy1977:

T/A, I just noticed that the shim is pretty thick on the Marantz replacements. You could change that out and see if it would eliminate or reduce the need to grind the magnet down.

Those speakers are gorgeous!

Looks awesome T/A, you'll have to let us know how the finished product is.

Any chance you can tell us the model number of the Marantz speakers or even let us know where you bought them?

quote:

Originally posted by oldskool69:
Very nice T/A! Those marantz speakers should allow you to get a lot more out of the amp onyour M90. What are the replacements rated at?

8 ohms 40 watts
show 7.5 ohms on the meter.
did i mention my JVC bass is as good as the Conion C-100 now?????
I cant wait to finish it up and hear it with the tweeters and all.

quote:

Originally posted by Arkay:
Nice upgrade!

Just curious: do you know what model those blue Marantz drivers originally came out of? Also, do they have ID#s on them?

Imperial 5-G cabinets are what they came from
i can post the markings tonight
These are vintage as well and I think they were probably produced in the same line of product as JVC at the time as the baskets are identical to the m-90 originals

Nice work Frank. Will you please bring your toolbox when you come out in Sept.?

Think you'd be better off selling it to me

sweet ! are you going to put the chrome caps on those woofers? those woofers look killer ,love it.

quote:

T/A, I just noticed that the shim is pretty thick on the Marantz replacements. You could change that out and see if it would eliminate or reduce the need to grind the magnet down.

with oldskool on this one... I saw that right away, too. Looks like theres at least a 1/4 inch of extra shim material on the front of those, if not more...

Those Marantz's look much more robust than the original JVC. Good find!

agree with above post. i made the mistake of sawing into the basket of a set of coaxial speakers, big 10 inch pioneer suckers, ruined them, all the metal filings got caught in the voicecoil, ruined the speakers. same thing'll happen if you grind it, the magnet'll just suck up those shavings

Nice, those new speakers just look killer ! Good luck getting it back together, I'm sure it's going to sound VICIOUS !

Got it all done and back together tonight,
Cleaned it up real good ,painted grilles ,replaced speakers ,
re-assembled.
Man this puppy can move some air now!!!!
It also weighs a metric ton
I am ordering some stainless dust caps for these woofers and also sending the originals out for repair Thanks for the info Ira!!!
I will definitely leave these woofers in though they sound so much nicer.
Here are some pics

another awesome job frank --
and yup -- though you will probably sell it NEVER --
it cant hurt to have a good set of M90 originals around

Great job man!

i am trying desperately to upload the vid to photobucket.
its killer vid.

Can't wait to see the video TA, the Marantz speakers do you have a pic. where these puppys came off originally! How did you get to fit, did you grind the magnet or reduce the shim.

Another awesome job. We need video frank!

Very nice work T/A! Did I see correctly that you did not grind the speakers down? Did you change the shims?

WOW Frank,it looks great!!!! Awesome job....

quote:

Originally posted by ford93:
Can't wait to see the video TA, the Marantz speakers do you have a pic. where these puppys came off originally! How did you get to fit, did you grind the magnet or reduce the shim.

I ended up grinding the magnet and it worked out great.
I wraped the speaker with a plastic bag and masked it so none of the filings would stick to the speaker I needed the extra shimm because of the excursion I didnt want the surrounds to sit on the frame of the opening.
Heres the video!!!!!

Very nice work! I don't care what people say, if you have a chance to improve the box when original parts are not available this is where you mke the best of your options. Outstanding job!

Nice job , how did it change the sound of your box?

I would say it definately has better bass and a fuller sound over all.
A great compliment to those screaming highs from the JVC's tweeters.
Did you see the part of the vid where I held a towel over the woofer? That demonstrates the amount of air those woofers are moving, its incredible.

Every component is a trade-off. Good but Not excelent components are expected inside. Finding a higher quality replacement isn't difficult, and the BBX is likely to improve.
Of course, impedance, power handling and high frec cut most match the original.

Reading impedance with an ohmeter would shield the resistance of the coil at 0Hz (DC). This value change as function of freq (some put a cap in parallel to compensate that variations)

quote:

Originally posted by oldskool69:
Very nice work! I don't care what people say, if you have a chance to improve the box when original parts are not available this is where you mke the best of your options. Outstanding job!

Outstanding work and another great video My son is going to freak when he sees your little guy doing the windmill

Nice job TA you even got your son being a B-Boy so cool.

So I guess the 8ohm 40 watt speakers are okay for the M-90 amp.

Dude! That is freakin' AWESOME!... I can't get over how nice that came out!!

Yap, really nice!!!!!!!!!!!!!!!!!

Nice job! I was a little concerned about your grinding off the backs of those magnets, as a LOT can go wrong with that kind of thing, but all's well that ends well.

Still curious about those speakers, though. I have the original speakers I took from an Imperial 5-G that was unmolested, and they don't look like that. Yours were almost certainly a later replacement, either because of a change during production by Marantz, or more likely else someone swapped them out later. I say that because yours also look newer than the time of the imperial 5-Gs. The basic basket shape (four pillars) looks right, though, so maybe it was an in-production upgrade by Marantz towards the later period of production(?). Anyway, sure looks great in your box there.

Thanks Arkay.
The info on the speakers were provided to me from the ebay seller I got them from and there is no way for me to verify the authenticity of his claims.
I am very happy with they way they turned out and they appear to be of a close vintage to the factory originals.
Plus the box sounds so much better with them that I am truly amazed.

If they are original Imperial 5G speakers, I'm not the least bit amazed that they sound great. Marantz was never really known for their speakers (most of them are mediocre), but they did make two series that sounded very good: the Imperial and the HD speaker lines. The top of the line speakers from these series are "audiophile" quality - really good speakers! The "lesset" ones from those lines (like the Inperial 5G) still blow away the vast majority of speakers sold today. Match the better HD or Imperial speakers with good period tube or higher-end solid state gear, and you'll find something close to audio nirvana. Fortunately, not too many people know this, and you can sometimes pick these speakers up cheaply (when you can find them at all) from people who only know about all the other, poorer speakers Marantz came out with.