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Klh 17

WoW​
To think I've been living with my KLH-17's for 20-something years and thought I was hearing it all. It's like getting a whole stack of new CD's & LP's. No, it's like my ears were plugged. The music just rolls out now. It sounds effortless. My kids may be about to inherit my unconverted pair of KLH's.

Report later - with pix - I'm just listenin' now. This is too good. Oh yeah, the porting worked!!
 
Just amazed at all the time I went without thinking to question the quality of my sound equipment. I wuz snoozin'. :boring: I had it good, but I could have had it a lot better.

I'll pull together a separate thread with all the details. I've been making notes and photos. This is just today's highlights.

Really, really helps to have all the drilling and sawing done first! Lots neater.
3427s.jpg


Sunny, head of QA, checks out the new ports. Those ports gave me another octave I hadn't been hearing.
3432s.jpg


In they go, beside the massive deadly weapon coil and up past the Selenium. Crowded in there.
3434s.jpg


On the stand, next to the other KLH-17's they're about to replace.
3435s.jpg

That's it for today. I'm whupped.
Thanks, Zilch and all the E-Wavers for bearing with me. I'm learnin'.
Here's to y'all! When you're in Florida, drop by & claim your beer. :beerchug:
 
Paratima said:
Just amazed at all the time I went without thinking to question the quality of my sound equipment. I wuz snoozin'. :boring: I had it good, but I could have had it a lot better.
Click to expand...
Jackgiff listened contentedly to Valencias for forty years. I believe he'd be the first to tell everyone that this work has been a revelation to him.

Does that diminish the pleasure he enjoyed for all of those years? Not so much, I shouldn't imagine; there are now new and even greater pleasures to be explored and enjoyed, is all, and like many of the rest of us, he's having great good fun doing just that.... :thmbsp:


********

I trust you put some fiberglass back in your 17s.... :yes:
 
Finished the first ZLH-20 today (same cabinet size as a 17). It ain't a 4 ohm speaker anymore. And, doesn't connect the speaker wires via a single RCA plug anymore either. New five-way binding posts installed on back. The second speaker will have to wait until a 10 uF capacitor comes. I had one, but absentmindedly used it on another project. Here's a picture.
 
Last edited:
Zilch said:
It's a design concept with which you are well familiar from your earlier Heath AS-10 upgrade project, this time full passive:

http://audiokarma.org/forums/showthread.php?t=160792

Do the original grilles fit reasonably well? With two pair of KLH-17s here, alas, I have no grilles.... :dunno:
Click to expand...

Haven't tried to fit the grills yet. They need to be recovered. Am certain the mounting points for the velcro will have to be raised to clear the wave guide and woofer that in no longer recessed in the cabinet.

The ZLH-20 sounds good :D, was using a Dynaco A25 on the other channel. Adjusted the tweeter pot by ear. Will take some REQW measurements to compare frequency response on refurbished KLH-17 to the new ZLH-20.

I don't care what some say.....old wood sounds good with new drivers!! :thmbsp:
 
Had an eye (maybe ear) opening experience today. Was completing the build of the second ZLH-20. Got it all buttoned up, plugged it in and no woofer output. Pulled the woofer, checked it, good resistance reading. Pulled the crossover board. Started doing point to point continuity checks. Found out the lead from the 3.5 uH coil to the woofer positive junction point was an open circuit. Long story short, the red coating on the coil lead is an insulator and prevented a good solder joint. Scraped the red coating off with a razor knife and resoldered. WaLa, woofer music.
 
ZLH-17 Impedance:

attachment.php

Polar Response:

attachment.php

Attenuation:

attachment.php


Comments:

1) Bottom impedance curve is with 82 Ohms across the input. These speakers are relatively inefficient, but bottleheads may want to do similar for a more tube-friendly impedance curve, if it's an issue. Minimum impedance with this parallel resistor is ~7 Ohms just above 100 Hz; the system tuning is ~30 Hz.

2) The polar response of this small PE waveguide is surprisingly good; they'll do the Geddes "extreme toe-in" sweet-spot expansion trick nicely. Measurements with L-pad at 12:00 setting. Compare to the stock response and polars here:

http://www.audiokarma.org/forums/attachment.php?attachmentid=116408&d=1225962400

3) I had to build up a new crossover and use a different Selenium D220Ti driver for these tests. Comparing with earlier results, the design is solid.

4) It's now been a while since I heard these. I was asked earlier in this thread how these sounded, and I begged off 'til others had built and heard them. We're all in agreement to date -- damn good. :yes:

5) I'll confirm driver polarity when I disassemble, but it appears both drivers should be connected in-phase, whereas standard E'Wave is inverse.
 

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Ayup! That there's what my impedance readings looked like - see previous page. ...and, sounds great! :thmbsp:

The dispersion is outstanding. Toe-in works as predicted. Doesn't much matter where I am in my smallish living room.

Confirming "noon" setting. Also, I've noticed the inefficiency. Got to run my receiver volume up one notch, sometimes two notches on quieter program. Got plenty of headroom from my Pioneer SX-7 (1981 or thereabouts), 65 WPC, I believe.
 
Paratima said:
Ayup! That there's what my impedance readings looked like - see previous page. ...and, sounds great! :thmbsp:

The dispersion is outstanding. Toe-in works as predicted. Doesn't much matter where I am in my smallish living room.

Confirming "noon" setting. Also, I've noticed the inefficiency. Got to run my receiver volume up one notch, sometimes two notches on quieter program. Got plenty of headroom from my Pioneer SX-7 (1981 or thereabouts), 65 WPC, I believe.
Click to expand...
Lower efficienty is the price we pay to achieve the bass response these are delivering; it's a classic trade-off. These can be made biampable, of course, for tube enthusiasts.

BmWr75 has posted measurements of his KLH-20s upgraded per this design in comparison to stock KLH-17s:

http://audiokarma.org/forums/showthread.php?p=2418663#post2418663

Clearly, we have achieved substantial improvement in response at both ends of the spectrum, as well as in dispersion characteristics and power response.

He also compared them both to Dynaco A-25XL several posts further down, largely confirming my own and Jackgiff's findings regarding Dynacos earlier posted in this forum. :yes:

Edit: Our impedance curves are virtually identical: minimum impedance, tuning, flat 8 Ohms above 4 kHz, right down to the micro-notch at 900 Hz. No BS here, either, looks like.... :thmbsp:
 
Paratima said:
...Need a pink noise generator, I suppose. Will Pink Floyd DSOTM work? ....
Click to expand...

Pink Anderson (1900-74) and
Floyd Council (1911-76), bluesmen they admired.

Band originally called "The Tea Cups"... but since that was already taken, Syd Barret suggested renaming it "The Pink Floyd Sound" (or "The Pink/Floyd Sound"?). Later they became Sound-less.


You seem to have a Pink Floyd Sound generator there. A Pink generator should use Pink Anderson,

414N1v6QpSL._SL288_BO1,0,0,0_.jpg


but P!nk is debatably more photogenic in an ironically enlightened post-punk tatooed, pierced, danger-dyke kind of way. She will, in her own words, get this party started:

pink_mis.jpg


I did try to find a pic of her hanging upside down from a Circ-De-Soliel ribbon and spinning madly. Nice concert stunt.
 
Don't encourage ported speakers with fiberglass. You want to breathe that? "You race towards an early grave".

Breathe, breathe in the air
Don't be afraid to care
Leave, but don't leave me
Look around
Choose your own ground

Long you live and high you fly
And smiles you'll give and tears you'll cry
And all you touch and all you see
Is all your life will ever be

Run, rabbit run
Dig that hole, forget the sun
And when at last the work is done
Don't sit down
It's time to dig another one

For long you live and high you fly
But only if you ride the tide
And balanced on the biggest wave
You race towards an early grave
 
:lmao: That's almost more Pink information than I can absorb! Interesting, though.

I did try to find a pic of her hanging upside down from a Circ-De-Soliel ribbon and spinning madly. Nice concert stunt.
Click to expand...

Now that would be worth seeing!

Don't encourage ported speakers with fiberglass. You want to breathe that? "You race towards an early grave".
Click to expand...

Nope. Zilch quotes Dickason at me about how FG is better than Acousta-Stuf, but I like stuffing I don't have to put on gloves and a mask to handle, thanks so much. I've read Dickason's notes on the subject and A-S isn't that far behind FG and is a lot "friendlier". :yes:

No one told me when to run; I missed the starting gun.
 
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