I guess these may be worth refoaming ??

[SEAWOLF97]

Took a $10 gamble on a beautiful set of Marantz HD 770 's today at GW. Nice condition with decent grills. Looked them up on Fleabay and was SHOCKED ..........

http://cgi.ebay.com/Super-rare-1978-...QQcmdZViewItem

[Storm]

Wow, what a find!

Good job!

I wish our Goodwill's were that cheap. Down here, they think they are eBay and they ask stupid money for stuff.

[mech986]

Very Nice!! Those should refoam nicely, assuming you can get the correct foams. Let us know if Rick Cobb or others have it.

I always knew Portland has a lot of good vintage gear. I gotta get my brother-in-law who lives near Reed College to get on the ball and go looking. However, he's got a lot more sense than me so he probably won't be able to.

Let's see those after refoam pictures when you get them done. BTW, don't those cones look a lot like the Decade series or L40 woofers and didn't Bart Locanthi work for Marantz for awhile too?

here's some information I found on the web regarding the connection between Bart Locanthi and Marantz speaker development. Some very interesting stuff on the Flagship Marantz Imperial 9's too.

http://www.audioholics.com/techtips/...oodenough1.php

Regards,

Bart

[SEAWOLF97]

of "Rock Solids" for $5 too.

similars:
http://cgi.ebay.com/ws/eBayISAPI.dll...MakeTrack=true

[SEAWOLF97]

were designed as L100 competitors. Great sound , will be even better with new surrounds. Lable on back shows "33 to 22k +- 3 db" "crossover 750 , 2.3k , 5k"

Orion says "1977-81 , $660 pr. new"

[SEAWOLF97]

In Portland, there is a great speaker shop - Ja Mac - that does rebuilds and sells foam for about everything. They've got some awesome 30in cones on the museum wall. They mentioned that they always put the foam on the backside, no matter how the original was. Also joked that they put the glue on with a fire hose.
They took the time to walk me thru the process. Provided shims and glue, and sell quality rings. Good guys. $18 total.
Anyway, the Marantz's came out super. hooked them up and certainly worth my $28 investment.

[SEAWOLF97]

they came out OKAY. could not save the inverted dustcaps, so went with new ones.

Very Nice!! Let's see those after refoam pictures when you get them done. BTW, don't those cones look a lot like the Decade series or L40 woofers and didn't Bart Locanthi work for Marantz for awhile too?
Regards,

Bart

[mech986]

Very Nice Refoaming job. The drivers look like JBL's!! I always liked that Hexagonal Trim ring, just adds a nice touch.

Let's hear about an extended listening session.

Regards,

Bart

[SEAWOLF97]

Let's hear about an extended listening session.
Regards,
Bart

I keep reading that this model may be an Ed May design
(Unfortunately, Ed would not have the opportunity to develop his concept into a production system. He left JBL in 1976, just as detailed design was just beginning. He joined Marantz Superscope to become their head of loudspeaker design. A custom design facility was built specifically for him. He used it to turn out three complete lines of loudspeakers in very short order. However, this was the last loudspeaker work he would perform. Edmond May passed away suddenly in 1980 while still employed at Marantz.)

http://audioheritage.org/html/people/may.htm

these are VERY smooth. when first fired up, I thot they sounded like the L100s, but after extended listening , I feel the HF is a little better , the LF not quite as authoritative (but barely). The cabinets and grills are good quality.

I set them up in the spot where the L36's were. They are in almost every area, better than the L36, except they are not a cast basket.

The L36s had replaced the AR3s that had replaced the Pioneer CS77a's. Constant upgrades.

I think they are keepers.

[GordonW]

I had a pair of the DS930s, which were functionally the same as the HD770s, but in a more deluxe cabinet (inlaid parquet wood veneer on the tops and bottoms, among other things). I SHOULD NOT have sold them. Fantastic speaker. Just plain did EVERYTHING right.

Regards,
Gordon.

[GordonW]

Just looked at the after-refoam picture . Why do people INSIST on changing the dustcap orientation? They're SUPPOSED to be CONCAVE (ie, inward dish). It WILL change the sound of the speaker!

Regards,
Gordon.

[SEAWOLF97]

Just looked at the after-refoam picture . Why do people INSIST on changing the dustcap orientation? They're SUPPOSED to be CONCAVE (ie, inward dish). It WILL change the sound of the speaker!

Regards,
Gordon.

well Gordon, I didnt have a lot of choice. Have only refoamed with the shim method - didnt even know of the "faith method" until 2 days ago. concave caps wernt available, and I dont honestly see how the orientation of "A DUST COVER" can affect sound. I didnt even hear any difference with the Vari-Q plug (or sox) in the port.

Maybe you can enlighten us ??

[edgewound]

well Gordon, I didnt have a lot of choice. Have only refoamed with the shim method - didnt even know of the "faith method" until 2 days ago. concave caps wernt available, and I dont honestly see how the orientation of "A DUST COVER" can affect sound. I didnt even hear any difference with the Vari-Q plug (or sox) in the port.

Maybe you can enlighten us ??

The "concave" dust dome is just turned over.

The inverted dome has an effect on dispersion/phase characteristics near the crossover frequency, as well as adding some strength/ stiffness to the cone apex for transients.

There's no such thing as the "faith method" for those of us that are paid to do refoams....It's either a candidate or not.

Shimming is not a 100% guarantee that the voice coil will not rub, but it's a pretty good back-up strategy if it's not cooperating. If it's not cooperating, there'e a good chance the speaker just needs a recone, or possibly refoam and new spider. If the voice coil former is bubbled or otherwise damaged...fuh-gedi-bow-dit...recone/replace. Dynamic centering works nearly 100% of the time for a refoam without disturbing the original cosmetics of the driver.

Your refoam looks pretty good other than not being cosmetically/functionally correct.

The final arbiter here is....you did the work yourself and you're happy with the outcome.

Good job

[GordonW]

If you absolutely MUST remove one of those concave dustcaps, the dustcap for a Peavey Black Widow 12" or 15" (commonly known as part # 0288, stamped on the bottom side of the dustcap) can be used as a replacement. You will want to lightly spray the concave side of the cap with flat black paint before installing (if you don't want the number "0288" looking back at you), but it does have a shallow enough dome profile to work. You can either leave it at original diameter (it's 4.5" diameter, where the original Marantz cap is 4"), or you can carefully mark it and cut it with sharp scissors to the right diameter...

Regards,
Gordon.

[SEAWOLF97]

There's no such thing as the "faith method" for those of us that are paid to do refoams Good job

I was quoting ROBB3606 "Typically when you do a refoam you take a leap of faith that the foam is the only thing shot and the spider is still in reasonably good condition. If that's true the spider will keep the voice coil centered as long as the cone is not tilted in the gap."

BUT I really do appreciate your input , unfortunately don't know everything yet. Thats why I am on this forum , TO LEARN. No need to reinvent the wheel, when there are experienced, helpful co-enthusiasts who don't mind guiding you.