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Post by xschop on Mar 28, 2021 13:45:44 GMT -5
Working on another set of 6502's to go into a set of custom 5Jrs. Found my notes from the 5B build that I had Cut 1.1" ID and 1.7" OD crafters felt after carefully cutting off dust cap.... photos.app.goo.gl/PA3BE9Rd5Tyvt52X8
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Post by xschop on Mar 28, 2021 13:51:05 GMT -5
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Post by xschop on Oct 28, 2021 18:25:57 GMT -5
I'm testing what adhesive to use on the factory pole-piece. More than 3/16" wide drop of either Red or Blue Loctite is too much and runs risk of sticking to inner edge of voice coil. Red is more viscous and is already set after a few hours....
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Post by xschop on Oct 28, 2021 18:40:21 GMT -5
Red doesn't run either around perimeter and stays in the interstitial areas near circumference... Wins over Eileens as it also allows the perfectly flat machined billet surface to mate completely and maintain perpendicular alignment with pole-piece axis....
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Post by xschop on Oct 29, 2021 15:40:52 GMT -5
Two perfectly functioning MW6510's. Exacto the dust cap away Smooth and make the coil edge perfectly round. I used a Sharpie pen plastic end as it is perfect and won't damage coil edge. Pre-check coil to phase plug clearance... About 1/32" all around... About 1/8" diameter drop RED Loctite in center of pole-piece Gently set phase plug and use a gently twisting motion to evenly distribute Loctite. Let set a few hours and install the thin felt ring in void left by cutaway of dust cap....
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Post by xschop on Oct 29, 2021 15:59:30 GMT -5
Use the old dust cap as template for O.D. of felt and then cut out 1.1" I.D. from felt.
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Post by xschop on Oct 29, 2021 18:23:03 GMT -5
I used a black Sharpie to color in the thin layer of VC that sticks up after the felt glue dried I'll give them a listen in the 8TL hybrids this weekend....
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Post by pitdogg2 on Oct 29, 2021 20:11:12 GMT -5
Nice Rob!
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Post by xschop on Oct 29, 2021 22:21:50 GMT -5
Thanks, these are MUCH faster to install than the ones I drilled and tapped. I sent a set out to another member here to try.
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Post by gardenstater on Oct 30, 2021 8:19:21 GMT -5
I lifted this cutaway photo of a driver from a PSB Synchrony One speaker. You are on the right track! Looking forward to the listening impressions this weekend on your modded 8tl's.
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Post by xschop on Oct 30, 2021 17:50:52 GMT -5
The Red Loctite is no joke. I picked one up by the plug and installed it in cabinet. I only got about 20 minutes to listen with machinery in shop all turned off so I could listen carefully vs. the unmodded one. A CLEAR upgrade to the 6510s. I spent rest of day doing some work and started making more plugs. I'll never own another set of vintage Polks without these installed. The midrange clarity, imaging, and cohesiveness of the Mids to tweeters is exceptional.
I'll phase plug all MW6516's next and have a listen.
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Post by xschop on Oct 31, 2021 12:41:23 GMT -5
One last tid-bit... I could not break the test plug off pole-piece by hand so I heated on stove flame for 2 minutes and knocked it off with rubber mallet so as not to score the machine finish....
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Post by xschop on Oct 31, 2021 19:36:37 GMT -5
No tricks, just treats...
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Post by afterburnt on Nov 1, 2021 9:22:08 GMT -5
Red doesn't run either around perimeter and stays in the interstitial areas near circumference... Wins over Eileens as it also allows the perfectly flat machined billet surface to mate completely and maintain perpendicular alignment with pole-piece axis.... Translation?
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Post by xschop on Nov 1, 2021 10:50:12 GMT -5
Red doesn't run either around perimeter and stays in the interstitial areas near circumference... Wins over Eileens as it also allows the perfectly flat machined billet surface to mate completely and maintain perpendicular alignment with pole-piece axis.... Translation? Translated....Let's go Brandon
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Post by pitdogg2 on Nov 1, 2021 11:30:21 GMT -5
The Red Loctite is no joke. I picked one up by the plug and installed it in cabinet. I only got about 20 minutes to listen with machinery in shop all turned off so I could listen carefully vs. the unmodded one. A CLEAR upgrade to the 6510s. I spent rest of day doing some work and started making more plugs. I'll never own another set of vintage Polks without these installed. The midrange clarity, imaging, and cohesiveness of the Mids to tweeters is exceptional. I'll phase plug all MW6516's next and have a listen. What is the MW6516 used on? RTA8t ? I'm guessing since I've never heard the speaker with those drivers installed. RTA11, 12 and 15 is all I've heard in that line of speakers.
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Post by xschop on Nov 1, 2021 12:54:34 GMT -5
They are all MW6516's in the 8TLs. When F1 sent the pair of 6510s, I swapped them into left speaker and the 6516s sounded better midrange wise and bass wise. The phase-plugged 6510s now outperform the unmodded 6516s, midrange wise IMO. This is with factory 8TL crossovers. I am not 100% convinced that the RDO198's perform their best with the factory 8TL crossover with an added 16uf capacitor in tweeter circuit. I couldn't find official info on old forum?
Ive got some more experimenting to do with the CRS+ crossovers and the phase-plugged 6502's in the SDA circuit. The IACC is definitely there, just not as pronounced unless I turn them on their sides.
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Post by xschop on Nov 4, 2021 20:02:44 GMT -5
Design note... MW6510's both at 6.7 ohm Measured two 6516's at 6.8 ohm The pleat numbers of spider are 6ea for all and look the same thin cloth weave. (6502's have a thicker cloth weave and more stiff suspension) 6516's have a tighter suspension by push-feel than the 6510's The 6510's look to have a little longer suspension travel as well...
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Post by gardenstater on Nov 5, 2021 6:51:32 GMT -5
Design note...
MW6510's both at 6.7 ohm
Measured two 6516's at 6.8 ohm
The pleat numbers of spider are 6ea for all and look the same thin cloth weave. (6502's have a thicker cloth weave and more stiff suspension)
6516's have a tighter suspension by push-feel than the 6510's The 6510's look to have a little longer suspension travel as well...Too bad we don't have specs for ALL the drivers. I looked up the compliances of 6502 vs 6510 and it is 1.470 mm/N vs 3.410 mm/N so it is quite a bit stiffer. I wouldn't doubt that the surrounds may have had thicker and thinner versions and that could effect the compliance as well.
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Post by xschop on Nov 5, 2021 9:07:01 GMT -5
Yeah, I never saw ANY info on 6516's over at the Cancel Club.
I only vaguely remember 6511's surrounds possibly being thinner butyl rubber and loosely goosey in suspension.
I believe the stiffer suspension is why I like the 6502's as opposed to 6511's in the SDA circuit, as the midrange is better IMO.
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Post by gardenstater on Nov 5, 2021 9:10:57 GMT -5
Yeah, I never saw ANY info on 6516's over at the Cancel Club. I only vaguely remember 6511's surrounds possibly being thinner butyl rubber and loosely goosey in suspension. I believe the stiffer suspension is why I like the 6502's as opposed to 6511's in the SDA circuit, as the midrange is better IMO. 6511 compliance is kind of high. 3.496 mm/N from this: Attachments:
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Post by xschop on Nov 11, 2021 17:36:20 GMT -5
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Post by afterburnt on Nov 11, 2021 18:11:23 GMT -5
Hey man, what the hell does a phase plug do? I seen em, I got em but I don't know them.
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Post by xschop on Nov 11, 2021 19:05:59 GMT -5
Whatever magic they work, it has something to do with soundwave phasing.
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Post by afterburnt on Nov 11, 2021 20:03:44 GMT -5
Whatever magic they work, it has something to do with soundwave phasing. oh
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Post by xschop on Nov 11, 2021 20:26:57 GMT -5
Also to note, a dual-layer winding is what I used and it's OD was 1.040. The ID of baseplate thru-hole was 1.080" and 0.020 shims either side of coil while glue dried and its perfectly centered.
I did a test listen and its working perfectly in the 5Bs. I cannot hear a difference between it and the other factory coil 6502.
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Post by gardenstater on Nov 11, 2021 21:17:54 GMT -5
Also to note, a dual-layer winding is what I used and it's OD was 1.040. The ID of baseplate thru-hole was 1.080" and 0.020 shims either side of coil while glue dried and its perfectly centered. I did a test listen and its working perfectly in the 5Bs. I cannot hear a difference between it and the other factory coil 6502. That's nice work as always! How do you keep the voice coil/former assy from being cocked relative to the pole piece when you glue it to the cone? I'm actually having trouble picturing how it can extend past and therefore through the front of the cone and still be centerable with shims. Is there an oversized hole in the cone and the glue just fills the gap?
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Post by xschop on Nov 11, 2021 22:15:33 GMT -5
This was one I got awhile back from a member and did some measurements on and practiced the felt addition. BTW the felt ain't going nowhere. I just ran the new leads over it and used black craft paint quick and is somewhat pliable.
I had already pulled the old coil out by simply cutting through the coil former slit line and then used fine needle nose pliers to scroll it out. It was pretty easy going slow and the outer paper wrap to the coil left a fine layer of cellulose that I scraped off and the new coil fit perfectly. The spider and cone meet exactly there and there looks to.be about 1/4" depth of glue wall abutment from factory. This may be due to spider wall but couldn't tell for sure.
I simply inserted new coil from back plate and forward 1/4" then put Eileens around perimeter, then pulled backwards. Worked out nicely.
I started a thread here asking for burnt MWs. I hate to venture over to the dark side "forum". I know there's some folks over there that have smoked a few lol.
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Post by xschop on Nov 12, 2021 12:01:04 GMT -5
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Post by xschop on Nov 12, 2021 23:11:24 GMT -5
Original tapped phase plug on left extends past basket flange @ 3/16"... The final design's apex is flat across plane of flange and it's base curve sets right where the coil flange begins....
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