My 2nd GF-777Z ** PROJECT M70 SIZZLE

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Cpl-Chronic

Cpl-Chronic

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Heyya, =)

I bought a distressed GF-777Z for a project I've always wanted to try & paid more than I should have for its condition but the seller stated the decks worked perfectly fine. When I got it, it had significantly more damage than disclosed on eBay. The seller claimed shipping damage & let him know that that doesn't concern my eBay dispute. My dispute is with the seller because my ITEM did not arrive AS DESCRIBED. He gave me half refund on the entire cost & could keep the blaster. After the claims process was completed I started tinkering with it & I the last week, this is how far I got:

The picture below is showing 1 of 2 JVC M70 tweeters I got from EXCELLENT MEMBER ALBERTO, for a small but fair price.
20k6cgl.jpg

They arrived in good shape & working fine. I wanted to try these because the M70 sound is very clean & detailed for a blaster & was hoping to harness some of that prowess for the SHARP horns.
 
Cpl-Chronic

Cpl-Chronic

Member (SA)
Here's a shot of the tweeters from the magnet side:

2daaqe8.jpg


As you can see here, the center domes are an excellent fit, exactly filling the entire opening of the lens with dome area.,..
1z32rdz.jpg
 
Cpl-Chronic

Cpl-Chronic

Member (SA)
Once the tweeter is centered & shimmed properly, it is secured with strips of dead-mat to hold everything in place during mounting to each horn:

2lx7ck0.jpg
 
Cpl-Chronic

Cpl-Chronic

Member (SA)
blu_fuz said:
What's the overall plan for this 777?
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Depends on how things unfold but hopefully, I can prove that the M70 nipples will shine in those horns. The Infinity Cone tweeters I used for my last 1 did an excellent job, with lots of detail & clarity. Since the JVC's are rated 8-OHM nom. then a 3000Hz roll-off point requires a 6.8uF cap to blend better with the woofers & give a more detailed midrange sound. So I ordered ten to stock up & save, per unit. I got the good Polyester/Metal Film type that are low tol.(5%) & HI-FI quality. They cost a small fortune but well worth it.

Take a look:
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Cpl-Chronic

Cpl-Chronic

Member (SA)
I'm still sorting out resonances & rattles, but already, it sounds strong & loud as FACK for a blaster! Stay tuned.....video will follow within the hour...


Cheers,
Cpl
 
Cpl-Chronic

Cpl-Chronic

Member (SA)
Pay attention to the amount of treble coming from the JVC tweeters. The SHARP horns scream & stereo imaging is quite good. Hopefully some of that comes across in the following video...

https://www.youtube.com/watch?v=qn0l1CiCvIM

Personally, I like the sound so far & have to work out a couple of simple kinks but I think things will shape up very well & we can let the modding begin soon.....

Cheers,
Cpl
 
Vintage Man

Vintage Man

Member (SA)
Cpl-Chronic said:
I'm still sorting out resonances & rattles, but already, it sounds strong & loud as FACK for a blaster! Stay tuned.....video will follow within the hour...


Cheers,
Cpl
Click to expand...
getting along just fine without that tuner so far!!!
 
Vintage Man

Vintage Man

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without a doubt the cpl knows his ****...the lab is hard at it again with the completion of the ultimate M90..... more pics!!! more....
 
Vintage Man

Vintage Man

Member (SA)
Cpl-Chronic said:
Pay attention to the amount of treble coming from the JVC tweeters. The SHARP horns scream & stereo imaging is quite good. Hopefully some of that comes across in the following video...

https://www.youtube.com/watch?v=qn0l1CiCvIM

Personally, I like the sound so far & have to work out a couple of simple kinks but I think things will shape up very well & we can let the modding begin soon.....

Cheers,
Cpl
Click to expand...
those M70 tweets being dispursted by those new quides sound quite nicely...i will get too feel the bass in just over a a week now!!!
 
Cpl-Chronic

Cpl-Chronic

Member (SA)
Daytime pics soon....the blaster still has some blemishes but working on the sound, right now. That way, if the sound works out good & it doesn't throw me any curve balls when testing it out over the next week or 2, then I know I can invest more time into it. So far, it looks really good. Both decks work great, ALL buttons work as they should including the tape-toggle. All controls & pots are clean & smooth.

The power supply is putting out a nice stable 19.2V & there's plenty of gain on the AMP iC's :jawdrop:

so I'm just chillin', looking for a good tuenr assy to complete her.

Cheers,
Cpl
 
Cpl-Chronic

Cpl-Chronic

Member (SA)
UPDATE:

Well box-freaks, I installed my uber-rare Pioneer Cloth Woofers @ 3.2 OHM for the MId/Bass outer woofers & the BOSE subs @ 2.5 OHMS. Man it kicks butt. For me, this is the best sounding combination of dirvers so far. I still want to try Bose 2.5 Ohm MId/Bass Dirvers for the outer woofers to see what it sounds like but so far I'm very, very happy with the sound.

Check it out:

https://www.youtube.com/watch?v=GSv_XP3Vy3Q&feature=youtu.be
 
THAFUZZ

THAFUZZ

Member (SA)
Looks great Man. Looks like a lot of great planning and effort went into this, for sure. I do have a question, Just how much of that tweeter needs to be placed into an opening (such as the horn styled GF-777) for optimal tweeter sound? Just the center tweeter cap? Or, would the entire tweeter cone (exposed) give the optimal sound. Sorry, having trouble explaining My question. :dunce:
 
Cpl-Chronic

Cpl-Chronic

Member (SA)
THAFUZZ said:
Looks great Man. Looks like a lot of great planning and effort went into this, for sure. I do have a question, Just how much of that tweeter needs to be placed into an opening (such as the horn styled GF-777) for optimal tweeter sound? Just the center tweeter cap? Or, would the entire tweeter cone (exposed) give the optimal sound. Sorry, having trouble explaining My question. :dunce:
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The SHARP 777Z horn design is an exercise in trade-offs. The horns use a hybrid horn lens similar to the M70 horns that acoustically amplifies the center dome energy which creates an extended frequency range, while damping midrange & lower midrange frequencies.

It's hard to explain but horns are much more efficient than open faced tweeters & that makes up for the fact that the tweeters are partly covered & blocked out by the narrow horn neck. Only the dome is visible from the mouth of the horn & therefore the primary emitting surface that couples acoustically to the horn. It is inefficient, compared to a properly designed compression horn but the freq response curve for the entire horn is boosted in the treble range vs the same tweeter in a traditional open face mounting at the expense of mid & low mid ranges.

Most people don't realize the 777Z was designed to fill a room with sound, not hang off your shoulder or sit on your picnic table...If I stand about 5-10 feet back from it, the horns come alive but standing next to it, the horns sound subdued because of their narrow vertical axis & wide horizontal axis. They were meant to throw the high frequencies farther forward than traditional open faced tweeters...

That is the best I can explain it ....


Brace yourselves,

The long protracted 'Is this a horn?' debate is coming.....:yes:
 
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