Another new KLH Five owner with questions

[jessiAV]

Earlier this week I added a pair of KLH Fives to my collection and I have a few questions for you all, if I may ask? These are the later Fives with the PCB xo board, and with visible wood screws securing the midrange chamber to the front baffle.

    First, it's clear the fabric surrounds desperately need treating with Roy's/Vintage-AR's sealant. Currently, a search turns up no way to purchase a bottle however. Any suggestions on how to obtain some?

     Also, I believe the two midranges share a common chamber that should be well sealed from the larger woofer chamber? Is that correct?

 And finally, there appears to be extra brown sealant between the cone and dust cap on one midrange. It looks much like the factory sealant; could it be original?

    my sincere thanks

[JKent]

24 minutes ago, jessiAV said:

the fabric surrounds desperately need treating with Roy's/Vintage-AR's sealant. Currently, a search turns up no way to purchase a bottle however. Any suggestions on how to obtain some?

Send RoyC a PM through the forum, He'll sell it to you directly.

25 minutes ago, jessiAV said:

the two midranges share a common chamber that should be well sealed from the larger woofer chamber?

I forget whether it's 1 or 2 chambers but yes--they are sealed from the larger chamber. I wouldn't be concerned unless there is obvious damage.

26 minutes ago, jessiAV said:

there appears to be extra brown sealant between the cone and dust cap on one midrange. It looks much like the factory sealant; could it be original?

I've never seen that but I suppose it could be a very sloppy original. Have you listened to the mids to see how they sound?

And, not that you asked, but these speakers will really benefit from new caps and resistors.

Kent

[jessiAV]

  Thank you Kent.

      My suspicion is that the midrange chamber is open somewhat as pushing on one mid cone does not move it's neighbor. Maybe sealing here is not critical to the overall performance though?

      The midranges seem to play similarly, but it is difficult to acoustically isolate them by listening while they are in the cabinet of course. I will listen more soon and report back.

     Also, are the iron core XO coils only used as bypass components, and not in the signal path?

   And also, what are the best sounding caps you have found for renewing the Fives?

 

[JKent]

Jessi,

I regret (for many reasons) I no longer have my Fives so I can't check whether that's a single chamber for the mids or 2 separate chambers. I don't suspect it's a problem. I will refer you to the KLH Service Bulletin in our Library that says both the woofers AND the "Twelve point five" drivers (i.e. the mids) should be re-doped. http://www.classicspeakerpages.net/library/klh/other/klh_schematicsservice/klh_service_bulletin_60.pdf

I'm afraid I don't know the answer to your coil question. As for the caps, that's very controversial but I'll say a couple of things:

1. The PCB xo is tighter than the point-to-point so the physical size of the caps becomes an issue. In the photos below, the first xo has all yellow mylar caps--a mix of Carli (no longer available) and Erse. These fit pretty well. https://www.erseaudio.com/Products/PEx
2. The second shot shows all poly--Dayton in this case but Erse has similar caps. https://www.erseaudio.com/Products/PulseX  You can see fitting the 25uF is quite a challenge so I pulled that out and went with stacked parallel mylars as shown in the third shot.
3. Mylars tend to be closer to the original NPEs in ESR
4. You could use all NPEs or a combination of film for the smaller values and NPE for the larger. A couple of members here have praised Mundorf E-Caps, available from Parts Conexxion https://www.partsconnexion.com/capacitors-ele-mundorf-e-cap-ac-series.html
5. I have long been a proponent of replacing the resistors. Originals are 5w and I've seen burned ones. Standard sand cast wirewound 10w resistors work fine and they're dirt cheap from Erse. A little bit of a challenge to shoehorn them in though https://www.erseaudio.com/Products/WireWoundResistors10w
6. You "could" use Mills resistors. I seriously doubt they "sound" any better but they are smaller and easy to work with. Last I checked they were about $7 each from Parts Express but less from Parts Cpnexxion https://www.partsconnexion.com/mills-mra-12-resistors.html

Kent

 

[RoyC]

9 hours ago, jessiAV said:

     My suspicion is that the midrange chamber is open somewhat as pushing on one mid cone does not move it's neighbor. Maybe sealing here is not critical to the overall performance though?

      The midranges seem to play similarly, but it is difficult to acoustically isolate them by listening while they are in the cabinet of course. I will listen more soon and report back.

     Also, are the iron core XO coils only used as bypass components, and not in the signal path?

   And also, what are the best sounding caps you have found for renewing the Fives?

 

Hi Jessi,

The mids share a common chamber isolated from the rest of the cabinet, and it is not unusual for there to be a compromised seal where the crossover leads enter it. I've seen caulk, cork, and rubber used as sealing materials. It should be checked out.

It is not unusual for KLH speakers to have iron core inductors in the signal path, though I haven't looked at that aspect of the KLH 5 board. There are schematics in the forum Library.

That brown material on the mid is typical KLH adhesive.

I agree with Kent's capacitor recommendations. I also have no problem using Parts Express NPE caps for the larger values, especially when dealing with the smaller xover board.

I've responded to your inquiry regarding surround sealant.

Roy

 

[jessiAV]

Thank you Kent and Roy for your insights into the Fives and your recommendations. Very helpful !!

   Roy, the seal for the wires into the midrange box is a soft caulk and one had pulled away from it's hole, causing a leak. Good call. Something to re-check when it all goes back together.

   Kent, yes I've read through most of your expert write-ups on the Five's crossover here on CSP. Thanks!  After I get everything back to stock and the drivers re-sealed, I will look into upgrading the caps, probably with the Mundorf caps. Ten watt resistors also sounds like a very good idea (the pic of the cracked resistor was very convincing), but I keep my volume levels low so I may not upgrade those unless I sell these (which I doubt I will do).

     BTW, somewhere here I thought I saw a photo here showing the foil side of the Five's PCB. Does anyone know where it is?

[JKent]

Good tip from Roy about that chamber. I now realize I've worked on about a dozen sets of Five xo's but only one pair of cabinets!

Here are the only backside pics I could find

[jessiAV]

Wow!!  Thank you Kent 😃 those are great pictures and they now reside in my Five's file.

      Forgot to post my PCB Five's serial numbers for everybody.  They are 034947 and 0349xx (label is torn). Maybe that will further help with your thoughts regarding when the PCB was introduced?

   And I've ordered some of Roy C.'s magic sealant 😀

[JKent]

The pics above, the first had no SN but its mate was SN 12470.  The 2nd pic is SN 06845. Do they resemble the 1st or 2nd?

[Brad1234]

23 hours ago, jessiAV said:

  Thank you Kent.

      My suspicion is that the midrange chamber is open somewhat as pushing on one mid cone does not move it's neighbor. Maybe sealing here is not critical to the overall performance though?

      The midranges seem to play similarly, but it is difficult to acoustically isolate them by listening while they are in the cabinet of course. I will listen more soon and report back.

     Also, are the iron core XO coils only used as bypass components, and not in the signal path?

   And also, what are the best sounding caps you have found for renewing the Fives?

 

Hi Jessi, the mids may be leaking thru the surrounds and thats why u arent seeing the other move when pushing on one. Once you get them doped u may see a huge difference. Now I am worried about my fives because I completely forgot to add sealant to where the 2 wires go into the mid enclosure!  The wires were in there pretty tight and were hard to pull thru a little when removing the mids, so it's likely not leaking a lot. My mids are a little loud though compared to other speakers after my recap, thinking I should go back in and seal those 2 holes and see if it makes a difference?

[jessiAV]

Kent:  Darn, my Fives are temporarily back together, so I cant accurately answer your question yet, but I will look when I apply Roy's seal (within a week or so?). Still, my memory is the color of the board is identical to your 06845 pic, which kinda makes little sense as mine show a higher number than both of your boards (and maybe were made at a later date?). There is no date stamped on the magnet of the one woofer I've removed so far.

  Brad:  Maybe your Fives are typical (?) as my midranges play louder than the tweeters and woofers, this before re-capping of course. Or alternatively, mine currently have an edgy-ness in their upper response that may make them be perceived as louder? Also, one of my speaker's output seems slightly lower than the other, and I suspect this may be due to the original caps failing differently even though all their ESR's read quite good (less than 1/2 ohm) .  When the woofers are out again, I will also measure their capacitance (I was in a hurry to reassemble & audition them today, and didn't pause to check).

    BTW, here is the seller's picture of my speakers:

[jessiAV]

  Here is a photo of one of my Five's crossover PCB boards -

 

[Brad1234]

10 hours ago, jessiAV said:

Kent:  Darn, my Fives are temporarily back together, so I cant accurately answer your question yet, but I will look when I apply Roy's seal (within a week or so?). Still, my memory is the color of the board is identical to your 06845 pic, which kinda makes little sense as mine show a higher number than both of your boards (and maybe were made at a later date?). There is no date stamped on the magnet of the one woofer I've removed so far.

  Brad:  Maybe your Fives are typical (?) as my midranges play louder than the tweeters and woofers, this before re-capping of course. Or alternatively, mine currently have an edgy-ness in their upper response that may make them be perceived as louder? Also, one of my speaker's output seems slightly lower than the other, and I suspect this may be due to the original caps failing differently even though all their ESR's read quite good (less than 1/2 ohm) .  When the woofers are out again, I will also measure their capacitance (I was in a hurry to reassemble & audition them today, and didn't pause to check).

    BTW, here is the seller's picture of my speakers:

Nice looking Model 5s!  I have the older model with the black mesh tweeters and aluminum frame crossover board. Out of curiosity and a little OCD, I took my woofers back out and sealed the speaker wire holes to the mid cabinets and resealed the woofers back in, and I think the mids do actually sound better now, not as loud and more balanced. I cant believe enough air was passing thru those tiny speaker wire holes but I think it was just enough to make a difference!  But I also may be crazy, not sure anymore. 

[Brad1234]

1 minute ago, Brad1234 said:

Nice looking Model 5s!  I have the older model with the black mesh tweeters and aluminum frame crossover board. Out of curiosity and a little OCD, I took my woofers back out and sealed the speaker wire holes to the mid cabinets and resealed the woofers back in, and I think the mids do actually sound better now, not as loud and more balanced. I cant believe enough air was passing thru those tiny speaker wire holes but I think it was just enough to make a difference!  But I also may be crazy, not sure anymore. 

Here is a pic if the little wire holes I sealed up. 

[RoyC]

3 hours ago, Brad1234 said:

I took my woofers back out and sealed the speaker wire holes to the mid cabinets and resealed the woofers back in, and I think the mids do actually sound better now, not as loud and more balanced. I cant believe enough air was passing thru those tiny speaker wire holes but I think it was just enough to make a difference!  But I also may be crazy, not sure anymore.

Internally sealing the mids' enclosure prevents them from acting somewhat like passive radiators due to the woofer's back pressure. Of course the mids are not passive, but it could result in some phase anomalies.

Roy

[Brad1234]

I definitely think that was what was happening thru that very small air leak where the wires go into the mid cabinet. It's amazing how sensitive the mids are to air pressure in these acoustic suspension cabinets. I'm glad I took the time to seal those holes up because they do sound better now. 

[RoyC]

59 minutes ago, Brad1234 said:

I definitely think that was what was happening thru that very small air leak where the wires go into the mid cabinet. It's amazing how sensitive the mids are to air pressure in these acoustic suspension cabinets. I'm glad I took the time to seal those holes up because they do sound better now. 

Interestingly, the issue will become more pronounced when the woofers are properly sealed.

Roy

[1rebmem]

For the record, the midrange driver enclosure does not separate the two mids.

If you remove one mid, you can reach in and feel the magnet on the other. 

EDIT: Sorry....my bad.......

 

[RoyC]

1 hour ago, 1rebmem said:

For the record, the midrange driver enclosure does not separate the two mids.

If you remove one mid, you can reach in and feel the magnet on the other. 

For the record, that was established a number of posts ago. 😉

"The mids share a common chamber isolated from the rest of the cabinet, and it is not unusual for there to be a compromised seal where the crossover leads enter it. I've seen caulk, cork, and rubber used as sealing materials. It should be checked out."

Roy

 

[Brad1234]

It makes sense they would share an enclosure since both mids are wired in series. They are producing identical sounds. Roy, while I have ur attention, I need help finding the black scrim cloth for the liner for my model 5 grill cover replacement. I cant seem to find it anywhere, I am close to dying some cheesecloth I have black to make it myself. Everything I find at fabric stores is too thick and/or tightly weaved. The original scrim bled a ton of black when I washed it and basically disintegrated  when I touched it. That explains the staining on the original cloth on 5's. 

[RoyC]

7 hours ago, Brad1234 said:

 Roy, while I have ur attention, I need help finding the black scrim cloth for the liner for my model 5 grill cover replacement. I cant seem to find it anywhere, I am close to dying some cheesecloth I have black to make it myself. Everything I find at fabric stores is too thick and/or tightly weaved. The original scrim bled a ton of black when I washed it and basically disintegrated  when I touched it. That explains the staining on the original cloth on 5's. 

Hi Brad,

I don't use the black cloth. It wasn't used for sonic reasons, so I paint the frame black like AR did.

Roy

[1rebmem]

23 hours ago, RoyC said:

For the record, that was established a number of posts ago.

I bet you a dollar you can't find it?🤑

[JKent]

On 3/11/2022 at 12:44 AM, RoyC said:

The mids share a common chamber isolated from the rest of the cabinet,

Pay up

[Brad1234]

I will just spray paint the cover frame black and check that the baffle and speaker frames don't show thru. Don't need to waste more time searching for the black scrim. Thanks Roy!  I have my KLH 5's up against my AR 3a's now, let the east coast battle begin. I have to say the AR's are kicking ass, but 5's have more mid volume, which can be good or bad. You can see how the 5's need new cloth, those stains didn't really come out. 

[JKent]

That will be an interesting comparison. The Fives were KLH's answer to the 3a. I really liked the Five's AFTER sealing the surrounds but sold them before getting the 3a's so never had a chance to compare them myself. btw, I totally agree re the scrim.