Sovereign C60 S7R & LE85 Diaphragm Advice Needed

[indyaudio]

Good Afternoon
I was fortunate to purchase this pair of Sovereigns from the original owner who bought them new in 1968. A picture is attached. The woofers were reconed and foamed by JBL back in '89, and I've pulled the LE15A's to refoam again. Unfortunately I'm getting nothing from one of the LE85 tweeters. I've swapped it with the good speaker and also ran some tone sweeps, it's dead. I just cracked open the body (hated to disturb the original JBL red wax plugs) and I believe I'm seeing a damaged diaphragm. I'll post a couple pics here next and have a couple questions for the experts here, thanks!

80820

[indyaudio]

I see what appears to be small hole and some damage to the outer edge of the diaphragm, look at the pics about 1 o'clock position, agree? Everything was very clean inside when I removed the back cap, but the foam damper pad is cracking and starting to break down. I've read a couple of other great threads here about cleaning the gap and installation which I will follow religiously including running a test signal sweep. Here are my questions:

>Do I need to remove the Phase plug in the middle to clean the gap, if so, how?
>What diaphragm would you suggest using since this original is no longer available? Simply Speakers has a decent looking replacement around $40, but please let me know your thoughts
>I should replace the pad while I'm in there - haven't looked yet, but a source you recommend?
>What do you think about the LX5 crossovers? They are untouched and original since '68. These are kind of a mystery to me. I"m going to pull one and open it up. Should I recap them both or?

Thanks guys! I am excited to own these and get them back up and running again. A decade ago I had a pair of these with the bullet tweeters and extra crossover, guess that was the S8R. Loved them and can't understand why I sold them LOL. These will take front and center in my audio room powered by a pair of Mc MC30 mono block tube amps.

Thanks again for any advice or thoughts here!

808218082280823[ATTACH]

[Earl K]

With the non-existent availability of the original ( tangential ) spiral-surround diaphragm, I would recommend the Radian 1225-16 aluminum diaphragm. (https://www.parts-express.com/radian-1225-16-diaphragm-fits-most-jbl-1-16-ohm--294-722)

These are good sounding diaphragms ( & the dome is aluminum ).

It's always best to replace in pairs ( btw ).

Cleaning the drivers gap does not require removing the phase plug ( good thing, because it's not removable ).

I would replace the foam pad with cut up felt ( felt winter-boot liners are a source in the north ).

:)

[indyaudio]

With the non-existent availability of the original ( tangential ) spiral-surround diaphragm, I would recommend the Radian 1225-16 aluminum diaphragm. (https://www.parts-express.com/radian-1225-16-diaphragm-fits-most-jbl-1-16-ohm--294-722)

These are good sounding diaphragms ( & the dome is aluminum ).

It's always best to replace in pairs ( btw ).

Cleaning the drivers gap does not require removing the phase plug ( good thing, because it's not removable ).

I would replace the foam pad with cut up felt ( felt winter-boot liners are a source in the north ).

:)

Awesome Earl K - thank you sir!

[indyaudio]

Pulled one of the LX5 crossovers. Need to clean the pot as caked in white powder, but otherwise looks OK for being so old! It appears to be "potted" guts encased in what looks to be wax.

Any thoughts on what to do with these? Option 1 - clean pots only; Option 2 - replace caps; Option 3 - install a new crossover inside the cabinet and bypass these.

Anyone have experience with options #2 or #3? Thanks in advance, look forward to your input on what to do with these as part of my refresh, thanks!

80824

[Earl K]

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=57166&stc=1&d=1350574013

Here's the schematic.

I would replace the 16.5 uF cap ( in the HF section ) with a 15uF industrial type motor run cap ( not motor start ), plus another 1uF Film & Foil Polypropylene paralleled onto it ( an esoteric type of your choice ), with another .5uF cap of something really Hi-End ) preferably Polystyrene ​ ( for "air" ) .

This cap setup will give you a good ( affordable ) clean top-end ( & reasonably deep mid-range ).

I use Mallory Motor Runs ( unfortunately they are NLA ) implementing this same "cascading" formula for my 1st serial cap.

https://images-na.ssl-images-amazon.com/images/I/41W6DwNAvDL._SX466_.jpg (https://www.amazon.com/TEMCo-Motor-Run-Capacitor-RC0008/dp/B00FBQW0OW/ref=sr_1_9?s=automotive&ie=UTF8&qid=1523816387&sr=1-9&keywords=temco+capacitor)

In the woofer section I would also use similar motor runs ( of the correct value if you track them down > on eBay for instance ).

Cascading ( or simple bypassing the woofer caps is up to you > it won't hurt > that's for sure ).

:)

[indyaudio]

Earl K - thanks very much for the crossover information! I will need to study and understand this a bit more - newbie to some of what you mention. Thanks again!

Are the original caps electrolytic?

[indyaudio]

Awesome Earl K - thank you sir!

I cleaned the gap today with tape and blew out with compressed air lightly. The gap was very clean to begin with. Mine are 8 ohms and found that version of the Radian on Parts Express.

Question - can the original JVL 21956 be repaired?

[Earl K]

I cleaned the gap today with tape and blew out with compressed air lightly. The gap was very clean to begin with. Mine are 8 ohms and found that version of the Radian on Parts Express.

Question - can the original JVL 21956 be repaired?

Whatever it is, that's the dcr ( of the replacement diaphragm ) that you need to buy/match.

If the 21956 has a hole in it, it can't be fixed.

:)

[indyaudio]

Whatever it is, that's the dcr ( of the replacement diaphragm ) that you need to buy/match.

If the 21956 has a hole in it, it can't be fixed.

:)

Thanks Earl, wishful thinking LOL! I'll be purchasing the Radian tomorrow.

[Earl K]

Make sure you match dcr values ( new to old ) / I sense that you're likely going to buy the wrong diaphragm.

:)

[indyaudio]

Make sure you match dcr values ( new to old ) / I sense that you're likely going to buy the wrong diaphragm.

:)

Before disassembling any drivers - DCR on both speakers at the crossover terminals was 10.6 and 11.5 ohms.

DCR on the bad diaphragm has no reading. I have not pulled the good LE85 to test it.

The woofer pair and the bad LE85 I removed from the cabinet are all marked 8 ohms.

Is there other testing I should do before ordering the replacement? thanks!

[Mr. Widget]

I cleaned the gap today with tape and blew out with compressed air lightly. The gap was very clean to begin with. Mine are 8 ohms and found that version of the Radian on Parts Express.

Question - can the original JVL 21956 be repaired?
No LE85 was ever produced with 8 ohm diaphragms. JBL changed the way they labeled the LE85 and a few other drivers of this era. I’ve heard claims this was due to changes in rating systems, my feeling is that it was also likely due to changes in the market from mostly tube based amps to solid state amps and the fact that solid state amps in general work best with an 8 ohm load. In any event you should use 16 ohm diaphragms if you do not want to design new crossovers.


Widget

[indyaudio]

No LE85 was ever produced with 8 ohm diaphragms. JBL changed the way they labeled the LE85 and a few other drivers of this era. I’ve heard claims this was due to changes in rating systems, my feeling is that it was also likely due to changes in the market from mostly tube based amps to solid state amps and the fact that solid state amps in general work best with an 8 ohm load. In any event you should use 16 ohm diaphragms if you do not want to design new crossovers.


Widget

Thanks very much for the reply and info.

I took reading on the good LE85 that is still installed in the other cabinet - disconnected the leads from the rear of crossover and wired directly to the driver - it comes up as 6.9 ohms.

I took readings on both woofers - 10.8 and 12.3 ohms.

The bad LE85 still had all 4 red wax seals in place before I opened it up this weekend. I don't know about this one, but owner said they had never been touched and I"m assuming it's got the red seals in place with an original JBL diaphragm in place, but inconsistent with your history of LE85 noted above.

What are your thoughts? Thanks again for the help here!

[Earl K]

Thanks very much for the reply and info.

I took reading on the good LE85 that is still installed in the other cabinet - disconnected the leads from the rear of crossover and wired directly to the driver - it comes up as 6.9 ohms.

I took readings on both woofers - 10.8 and 12.3 ohms.

What are your thoughts? Thanks again for the help here!


Those readings are correct for the goofy way JBL labels their impedance.

Your 6.9ohm reading for your le85 translates into you needing to buy the Radian 1225-16 ( as mentioned at the beginning of this thread ).

Please read the Radian tech sheet (https://www.parts-express.com/pedocs/specs/manufacturer-specifications-44925.pdf)

:)

[toddalin]

The two dimples at ~1:00 O'clock are not your problem and I can tell you what they were caused by.

Someone removed the horseshoe clip from the terminal and didn't hold on to it or pull it back far enough. The clip is ferrous and was drawn in to the magnet where the two ends (bent to 90 degrees) contacted the diaphragm leaving the marks you see. In most cases, these do not cause a problem, and I have an original 2420 diaphragm where this very thing happed to me leaving similar marks (maybe not as deep), with no consequences. This is in my center channel and I later did find an original tangential diaphragm and replaced the 2420 diaphragm as my left and right speakers also have tangential diaphragms, and I prefer their warmer sound.

You either have an open coil, or are not making contact somewhere along the line. I would offer you my 2420 diaphragm, but it would not match your other tangential diaphragm.

BTW, it is hard to believe that JBL would have let this pass QC, and at some point, someone did open this up and replaced the wax seals.


http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=80821&d=1523810771

[grumpy]

I think the crack and hole a bit further toward the periphery (actually in the surround) may be a larger problem :)
It's had a long and hard life and it's time to replace... they wear out.

There appears to also be some separation at the 8 o'clock vector
between frame and surround.

[indyaudio]

Those readings are correct for the goofy way JBL labels their impedance.

Your 6.9ohm reading for your le85 translates into you needing to buy the Radian 1225-16 ( as mentioned at the beginning of this thread ).

Please read the Radian tech sheet (https://www.parts-express.com/pedocs/specs/manufacturer-specifications-44925.pdf)

:)

Earl and Widget - thank you both for your replies.

There is no way on earth I would have known that my reading would mean I needed a 16 ohm replacement! But I see it now on the Tech Sheet!

Placing the order now through Parts Express. I'm going to try one for starters, see how it sounds with the other original, some freshly foamed woofers, and go from there.

[indyaudio]

I think the crack and hole a bit further toward the periphery (actually in the surround) may be a larger problem :)
It's had a long and hard life and it's time to replace... they wear out.

Yes, that is hole all the way through the material at 1 o'clock is what I was concerned about and agree with you

There appears to also be some separation at the 8 o'clock vector
between frame and surround.

Thanks for the reply!

[indyaudio]

The two dimples at ~1:00 O'clock are not your problem and I can tell you what they were caused by.

Someone removed the horseshoe clip from the terminal and didn't hold on to it or pull it back far enough. The clip is ferrous and was drawn in to the magnet where the two ends (bent to 90 degrees) contacted the diaphragm leaving the marks you see. In most cases, these do not cause a problem, and I have an original 2420 diaphragm where this very thing happed to me leaving similar marks (maybe not as deep), with no consequences. This is in my center channel and I later did find an original tangential diaphragm and replaced the 2420 diaphragm as my left and right speakers also have tangential diaphragms, and I prefer their warmer sound.

You either have an open coil, or are not making contact somewhere along the line. I would offer you my 2420 diaphragm, but it would not match your other tangential diaphragm.

BTW, it is hard to believe that JBL would have let this pass QC, and at some point, someone did open this up and replaced the wax seals.


http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=80821&d=1523810771

Thanks for the reply and offer of your 2440. I"m going to order the Radian part.

I can see an indent at 1 o'clock, but more importantly, there is a hole clear through the material there (as Grumpy confirmed) and other damage to the diaphragm, so I'm not thinking your theory here is the root cause of failure.....

Upon further examination, there is also a small hole at 9 o'clock and I can actually see daylight from 3 o'clock to 7 o'clock all the way around the edge between the frame. It's separated. This thing is toast!

Unlikely those original wax seals I dug out had ever been touched.

Either way, moving on to the replacement phase now, thanks again for your reply!

[indyaudio]

New Radian diaphragm installed. Fit perfectly, lined up exactly as it should on the pegs and snugged down just right. Ran tone and sweep test, all good.

Scraped off the old foam residue in the back of the rear cap cover. There is a solid fabric pad below it that I left in tact. Glued some new open cell foam on the face and good to go.

Now on to the clean up of the woofers old foam and installing the new pair809678096880969.

Thanks again guys!

[grumpy]

Gotta love a good happy ending!