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KLH-1 Score

Great work! Getting ready to recap mine, have all the parts. May rewire them while I am at it based on what Roger said. Also installing proper binding posts as opposed to the infuriating "connect the wires to a knurled nut on a post that's just asking to slip off and short out" situation on the originals. They definitely have the "the capacitors were once in spec long ago" sound at the moment. May recap the ABCs as well.
 
I recently noticed some hiss when my ABC is on. I noticed it when I put on my headphones. If I switch the ABC off, hiss goes away. I am wondering if this might be a noisy component….chip, etc.?
 
Speakers continue to sound fantastic especially now through my restored Yamaha CA-1000 and modified AR XA turntable. One "issue" is that I can periodically get a "pop" when I turn the ABC on and/or when another piece of gear gets turned on or off when the ABC is on. Is there a way to modify the power input to reduce any pops?
 
Back to working on my ABC again...I think the hiss and noise is due to the op amps. There are three...2-14 pin and 1-8 pin. I am pretty certain that the noise is coming from one or both of the 14 pin.

1) MC14007UB
2) RC4136J

There are quite a few replacements for the 4007 but not really any for the RC4136. The RC4136 evidently has an odd pin out. I did come across this adapter than one can solder a couple SME Op amps. My question then is which op amps are good for the ABC or will any be better than the RC4136?

https://www.cimarrontechnology.com/product/browndog-060601-rc4136-upgrade-adapter
 
I am thinking about how to build a better board for the crossover. I have had a Couple of instances where the component leads have come out of their soldered locations. I think this is mainly due to size of the new caps and the age of the board.

I am thinking of a more point to point set up rather than traces on a board.

thoughts? Anyone having similar issues?
 
Roger Gorke said:
I am thinking about how to build a better board for the crossover. I have had a Couple of instances where the component leads have come out of their soldered locations. I think this is mainly due to size of the new caps and the age of the board.

I am thinking of a more point to point set up rather than traces on a board.

thoughts? Anyone having similar issues?
Click to expand...

I did notice that when I redid the crossover, getting some of the components to fit properly was a pain in the butt. In addition, I had a drop of solder jump between circuits and it was bypassing the tweeter cap, senting the full range to the tweeter. Those are robust little tweeters... Doing it point to point would make sense.
 
bakes said:
I did notice that when I redid the crossover, getting some of the components to fit properly was a pain in the butt. In addition, I had a drop of solder jump between circuits and it was bypassing the tweeter cap, senting the full range to the tweeter. Those are robust little tweeters... Doing it point to point would make sense.
Click to expand...

thanks, Danny Ritchie over at GR research has a video on how he does it, makes
Sense to me. Just gotta make sure I connect
Everything the right way…
 
I finally got a KLH1 ABC! I have been using a KLH2 ABC. I can definitely hear a difference between the two...the KLH2 seems to put out much more bass that the KLH1 computer.

It just came today, so I can report back after I have some additional time with it.
 
Roger Gorke said:
I finally got a KLH1 ABC! I have been using a KLH2 ABC. I can definitely hear a difference between the two...the KLH2 seems to put out much more bass that the KLH1 computer.

It just came today, so I can report back after I have some additional time with it.
Click to expand...

Nice one! I once did some measurements of my KLH-1 with and without the KLH-1 ABC and it was a pretty flat response in the bass with the ABC. So perhaps your KLH-2 was over boosting the bass? Glad you got it and keen to hear your thoughts. The KLH-1 is an amazing speaker.
 
So after a day of listening, using the correct ABC makes a difference. I think you were correct that with the KLH2 ABC, the bass was over boosted. Which makes sense since the KLH2 has only 1 woofer.

To confirm that there is a difference, here are two pictures of the boards. Look at the differences in resistor values.

On the KLH2 board, I had recapped it with those red WIMA caps.

The best word I can think of now is that the tone is much more homogeneous rather than the bass popping out. The mids seem more pronounced and glorious!

Maybe pronounced is the wrong word…they aren’t over shadowed by the bass.

I’ve also been futzing with the foam material around the tweeter and mid driver. The foam I have might be a bit too dense.
 

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Hi KLH 1,2,3 fans I am a fan as well since the first time I heard the 3s with my dad in I think 80s but I swear it was '79. I have had 3 pairs of 3s over time (which my friend I lent them to sold damn drugee arghh).. . I have pair of 1s and I just last week found another pair of 1s that I intend to dig into and fully upgrade. Now in my 60s, I am realizing how special these speakers are! I thought I'd share the KLH bass computer patent.
 

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littlelabs said:
Hi KLH 1,2,3 fans I am a fan as well since the first time I heard the 3s with my dad in I think 80s but I swear it was '79. I have had 3 pairs of 3s over time (which my friend I lent them to sold damn drugee arghh).. . I have pair of 1s and I just last week found another pair of 1s that I intend to dig into and fully upgrade. Now in my 60s, I am realizing how special these speakers are! I thought I'd share the KLH bass computer patent.
Click to expand...

Thanks! I printed this out yesterday and read through it. I was thinking of trying to compare the schematic to my KLH1 and KLH2 ABCs. As I mentioned previously, the KLH2 ABC definitely boosts the bass more than the KLH1 ABC with my KLH1 speakers, which makes sense since the KLH1s have two woofers and need less of a boost.

I need to do some investigation of my KLH1 ABC, when I push the "Position" button I get a pop in my speakers which didn't happen with the KLH2 ABC. It's a button I don't push often at all but there is a voltage leak somewhere and I need to figure that out.
 
I'm sure just a leaky cap for the pop. I'm planning on upgrading the 4136 quad op amp in the ABC to an OPA 1656 or OPA 1692 using one of these https://www.cimarrontechnology.com/product/browndog-060601-rc4136-upgrade-adapter . Question for you fans, what are the crossover frequencies and slopes on the Model 1? I thought of having this company that makes these slick crossovers make some https://www.humblehomemadehifi.com/crossover.html I have two pairs so I'd have 4 made, maybe we could get a few more of us in on it to bring the price down?
J
 
So nobody knows the X-over frequencies and slopes for KLH model 1? That X-over schematic posted earlier in this thread is it accurate? Trying to save time here. If there is no response, I will post my findings to help 8-)...
 
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