Renovation of my KLH 17's is complete (long)

[alteclipsch]

I think the bulletin said the dust caps, not the cones. I don't have it in front of me but I've not seen anything about doping the cones.

 

[ace218]

First of all great forum. Very informative. I just picked up a pair of Klh 17 waiting for caps and resistors to replace originals and also ordered some speaker sealant described as Roy C's to me it looks like there isn't any on them. With all that said I was wondering if anybody has ever made new speaker grill covers? The cloth was pretty bad and the boards are warped and was wondering what to use to make new ones. Thanks.

 

[Phillip007]

Hi guys,

I just wanted to post a few upgrades/modifications I made to my KLH Model 17s thanks to the inspiration of this thread and everyone’s contributions.

I replaced the existing Dayton 8.0 uf capacitor (2 x 4 uf) and two 2.0 uf Dayton capacitors with Jantzen Superior Z-Caps with similar values.

I bypassed the 8.2 uf Jantzen Superior Z-Cap with a 0.1 uf SSG-2 Silver Mica Capacitor.

I replaced the three sand cast resistors with three Mills 5 watt resistors.

I have around 50+ hours on the speakers with the new internal components and can confidently say the speaker is a superior version in all aspects to when using all Dayton Capacitors and the original sand cast resistors.

The low and mid frequencies improved for the better with better definition, punchiness, and musicality.

The higher frequencies sound much more clear, dynamic, and full of life for lack of better descriptive words. There is less smearing of percussion instruments and less sibilance heard in vocals. Also, I am noticing more "air" surrounding the vocals which give a more holographic sound presentation. I am guessing these are the 0.1 uf SSG-2 Silver Mica Capacitors at work.

I believe the Mills resistors helped to lower the noise floor of the speakers thus making micro and lower-level details of the music easier to hear with an additional benefit of making the sound more "refined".

The speakers were awesome before and the modifications/upgrades just made everything the KLH does well, sound that much better.

Cheers,
Phillip

 

[TroutBear]

Very pleased with the sonic and visual results from renovation of the model 20s that I picked up at an estate auction. The veneer and trim were in good shape so I did a 3 step sanding 150 / 220 / 320 followed by application of Sutherland Welles 50% thinned tung oil with a small bit of their cherry stain [all materials on hand], with a top coat or Tried & True licensed oil with beeswax to buff out for warmth to the finish. I rebuilt the first crossover keeping the switch path and compared settings for a couple of days - in the end, I liked the Normal best, so I deleted the 7.5 ohm resistor and switch in both crossovers. Not authentic I know, but I like them and the switch is out of the signal path. A nice heavy duty terminal strip installed below the recessed panel - forgot to get a pic there - from Mouser replaced the RCA input. Neotech 18 g copper wire that was also on hand. I'd like to find 8 ohm woofers from a 17 sometime and [heresy to dedicated KLH fans I'm sure, but...] might try Seas tweeters that are good to 1500 Hz seas-excel-t35c-002-35mm-mid-tweeter so I used the grounding lugs for connection as seen in a Positive Feedback article of an external crossover for some Tannoys to reduce the unsoldering thing

 

[alteclipsch]

Very nice work there! I've had Twentys, now have their kissin' cousins, the 8 ohm Seventeens. Both are wonderful sounding speakers and still reasonably plentiful. I've always liked the front solid walnut trim, it really sets them apart.

 

[The Hornet]

Specialidiot says to "Make sure you put a 10MF cap in series with the positive lead of the tweeter to block the lower frequencies"
Then he said this?

Ron[/QUOTE]

These caps are solely for testing the tweeters while outside of the cabinet and crossover circuit to prevent low frequencies from reaching the tweeter. It does not go into the circuit when you put the tweeters back in.

Good luck with your project!!!

Rock6x, I didn't change the circuit at all, I simply replaced the aging capacitors.

So I'm unclear what these statements mean? Do you need to add the 10MF cap in series with the positive lead or not?

 

[KJ244]

I think what specialidiot is referring to is to use a 10uF capacitor in series with the tweeter positive when testing a tweeter outside of the cabinet. This is common bench test technique for checking tweeters. You should replace the caps in your crossover with equivalent capacitor values. For example, in a Model 17, the 8uF capacitor should be replaced with an 8uF or an equivalent - e.g., 4.7uF and 3.3uF in parallel.

 

[The Hornet]

I think what specialidiot is referring to is to use a 10uF capacitor in series with the tweeter positive when testing a tweeter outside of the cabinet. This is common bench test technique for checking tweeters. You should replace the caps in your crossover with equivalent capacitor values. For example, in a Model 17, the 8uF capacitor should be replaced with an 8uF or an equivalent - e.g., 4.7uF and 3.3uF in parallel.

Thanks KJ244 for your reply.
Currently the 17's I just purchased had apparently been previously modified as I discovered when I opened them up.
There's a 10uf on the positive side of the tweeter. Should I just remove that and follow the rest of specialidiots cap replacements?

FYI: Currently the only caps in these speakers are the 10Uf on the tweeter and (1) 2UF 50v on the circuit board. They play but sound muffled.
The drivers all test good. ( as I mentioned, someone did some mods )

 

[KJ244]

I would return the crossover to the original specs if you can.

 

[KJ244]

The Model 17's are wonderful speakers. I've restored four pairs in accordance with the original specs. I have not found a reason yet to deviate.

 

[The Hornet]

The Model 17's are wonderful speakers. I've restored four pairs in accordance with the original specs. I have not found a reason yet to deviate.

Got it. So that 10 Uf was not part of the original specs and not necessary?

 

[RTally]

FYI: Currently the only caps in these speakers are the 10Uf on the tweeter and (1) 2UF 50v on the circuit board. They play but sound muffled.
The drivers all test good. ( as I mentioned, someone did some mods )

Got it. So that 10 Uf was not part of the original specs and not necessary?

It sounds like a previous owner decided he could do better than the factory and modified the crossover. That is generally a bad idea.

When a vintage speaker sounds muffled, the likely culprit is an old, out-of-spec capacitor.

The crossover should have three caps (2 each 2 uF and one 8 uF), three resistors, and one 3-position switch. I suggest tracing out the crossover and drawing a schematic. At the very least, take pictures and post them here (resize to around 100 to 300 kb first).

Below is the factory crossover schematic for the Model 17. I suggest making your speakers look like the factory intended.

 

[The Hornet]

It sounds like a previous owner decided he could do better than the factory and modified the crossover. That is generally a bad idea.

When a vintage speaker sounds muffled, the likely culprit is an old, out-of-spec capacitor.

The crossover should have three caps (2 each 2 uF and one 8 uF), three resistors, and one 3-position switch. I suggest tracing out the crossover and drawing a schematic. At the very least, take pictures and post them here (resize to around 100 to 300 kb first).

Below is the factory crossover schematic for the Model 17. I suggest making your speakers look like the factory intended.
View attachment 2869599

Thank you for the schematic.

 

[Bbyaka]

Thank you for to the original poster!!! This is very useful... Just picked up my first pair of Model 17 ($130) in great shape cosmetically and I cannot wait to get it recapped and re-doped. Could have gotten the Model 23 for $250 but decided against it for the moment.I will bite if I can get the price down to $200.

 

[Jrogers13]

Thanks KJ244 for your reply.
Currently the 17's I just purchased had apparently been previously modified as I discovered when I opened them up.
There's a 10uf on the positive side of the tweeter. Should I just remove that and follow the rest of specialidiots cap replacements?

FYI: Currently the only caps in these speakers are the 10Uf on the tweeter and (1) 2UF 50v on the circuit board. They play but sound muffled.
The drivers all test good. ( as I mentioned, someone did some mods )

amazing, this string has gone on 10+ years! I found a pair of KLH 17s at the thrift store, $12 each. Grills were spotless, the cabinet pretty bad. I lightly sanded the veneer and what a pleasant surprise! Danish oil plus General Finish’s satin topcoat. Recapped with Dayton 1% caps (used the 8.2 mF). Treated the speaker surrounds, sealed the cabinet. Old 8 mF caps tested at ~9.5, double 2 mFs about 3.5 each.
theysound and look great!

 

[alteclipsch]

Welcome to AK! Nice work there. My KLH fetish has been lifelong, I've had more Seventeens than I can remember, they're great, no nonsense speakers. None now, but if a pair comes up, I'll do it again.

 

[jcamero]

I'm restoring my 20's. I followed this thread to the letter. I had 1 woofer screw with a stripped hole. I'm going to try the toothpick method before changing the woofer position, and drilling holes. After that, I'll reseal the surrounds and dust cap, and will be finished. This was a terrific thread, thanks to all.

 

[Bbyaka]

The toothpick method is the way to go. It has never failed me. A toothpick (or a few toothpicks) set in glue in an oversized hole provides enough wood for the screw to bite into.

 

[Airjmax]

I totally agree with @Bbyaka. I've also used wooden golf tees. Don't be in a hurry, and let the glue dry completely. It wouldn't hurt to drill a tiny pilot hole, so the glue and toothpicks don't blow out. I'd hand-tighten the screws as well. They only need to be snug. Be sure to put your hand in-between the screwdriver and the woofer. I slipped once and put the screwdriver right through a woofer cone. Please post pictures!

 

[NCislander]

New to the forum,
Awaiting delivery of KLH Model 17's from a recent eBay purchase. Great thread on recap job.

-Thanks OP.