KLH-1 Score

[Remek70]

Guys, you know what’s amazing? That even after 50 years, besides upgrading the crossovers, you can still tweak the sound of these speakers by swapping out the op-amps in the ABC. My NE5534AN hasn’t arrived from Taiwan yet—it’s a NOS from 1986.

But this Analog Devices AD797AN is also awesome. And there are plenty of alternatives: OPA627, OPA637, AD797, AD8610, AD711, OPA134, OPA604, AD811, AD829, AD844, LT1028, LT1115, LME49990, LME49710, NE5534, JRC5534, LT1122, TL071, Burson V5i Single, Burson V6 Vivid Single, Burson V6 Classic Single, Burson V7 Vivid Air Single, Burson V7 Pro Vivid Single, Burson V7 Pro Classic Single, and I don’t think that’s all of them.



The Bursons are also awesome, but a bit pricey.

If anyone’s interested, have fun and let us know your impressions and how they compare.

 

[Remek70]

Hello.
Perhaps someone might be interested:

KLH 1 Bass Computer

Verkaufe einen KLH 1 Bass computer, leider ist kein Netzteil dabei, aber es sollte kein Problem...,KLH 1 Bass Computer in Köln - Ehrenfeld

www.kleinanzeigen.de

 

[Remek70]

I think I now have the final version of the ABC build. I’ve fitted a NOS Signetics EN5534AN op-amp on the main board and used 2 x AD797AN from Analog Devices Inc. on the side board. The system is very quiet. The speakers have absolutely no inherent noise. They sound very coherent and musical. The bass end has gained speed and definition. The colouration in the bass has disappeared – the bass has become linear, tight and nuanced. There is a ‘black background’ effect. Microdynamics and detail have improved. At the same time, they sound warm, rich in colour and very musical. Although ‘never say never’, for the time being I consider the restoration of these magnificent speakers to be complete.

The photograph was taken before the op-amps were replaced.

 

[Roger Gorke]

Great to hear that the changes were worth the effort! And, never say never!!!

I switched out the RC4136 chip for a "new" one and immediately heard a difference in clarity. The 4136 is just 4-741 chips slapped together.

So...it might be worth getting one of the adapters with upgraded chips from here. I scanned through the specs on the alternatives they have and the OPA1612, OPA2604, NJM5532C, and LM4562 seem to be the best match based on voltage. The 1612 has the best overall specs.

And finally, I really need to rebuild my crossover. I have ginormous caps hanging off that measly board and periodically a solder joint will come loose.

 

[Remek70]

Well, you see, Roger—you planted a seed

Tomorrow I’ll look into substitutes.

As for the crossover, it’s worth building it on a new circuit board with new components. Scraps of plywood or flooring panels work great for this.

Just as a reminder, here’s my modification.

 

[Roger Gorke]

Yeah, your new crossover inspired me! You can tell by looking at mine why things keep coming apart!!!

There are things I am noticing about the KLH-1s that have me scratching my head. If you look at pictures early in this thread, specifically the back of Goldjazz's set, his (+) and (-) posts are opposite of mine, and possibly yours Remek70. So, the early schematics aren't correct for my speakers, but yours is.

Also, on the mid circuit, why does the (+) input end up on the (-) speaker terminal? Is that for phase alignment with the tweeter?



Goldjazz KLH1s



My KLH1s



And finally, here is what my crossover looked like when I got the speakers. Yikes!!!

 

[Remek70]

The terminal configurations on my units are the same as yours.

I think so—it’s about phase alignment.

You can tell from your photo of the crossover that “it hasn’t had an easy life.”

 

[Remek70]

Order sent.
I’ve ordered the RC4136 Upgrade Adapter – BrownDog 060601 – Add two OPA1612 op-amps.

Thanks, Roger, for the suggestions. We’ll see how it improves what’s already almost perfect
The ABC still has a Motorola MC14049 chip, but it doesn’t affect the sound.
So it’s very likely that this is the final upgrade for the ABC

I’ve also got 3 pairs of KLH-3 speakers, along with 3 x ABC units that have already been upgraded with new capacitors, resistors, solder joints and crossovers in the speakers themselves. Now I can get round to replacing the op-amps in those too

 

[plenumpete]

FWIW I fed the ABC patent circuit diagrams and other reference info into AI to get an overview on how the ABC functions. There are a few errors but the essentials are there.

 

[Roger Gorke]

FWIW I fed the ABC patent circuit diagrams and other reference info into AI to get an overview on how the ABC functions. There are a few errors but the essentials are there.

So it appears the 4136 chip does play a significant role in how the ABC sounds!

 

[Roger Gorke]

Order sent.
I’ve ordered the RC4136 Upgrade Adapter – BrownDog 060601 – Add two OPA1612 op-amps.

Thanks, Roger, for the suggestions. We’ll see how it improves what’s already almost perfect
The ABC still has a Motorola MC14049 chip, but it doesn’t affect the sound.
So it’s very likely that this is the final upgrade for the ABC

I’ve also got 3 pairs of KLH-3 speakers, along with 3 x ABC units that have already been upgraded with new capacitors, resistors, solder joints and crossovers in the speakers themselves. Now I can get round to replacing the op-amps in those too

Did your BrownDog's come in yet? I am eager to hear about how they sound?

 

[Remek70]

Hello.
They haven't left the United States yet.
I hope they'll arrive by the end of September.

 

[Roger Gorke]

Hello.
They haven't left the United States yet.
I hope they'll arrive by the end of September.

Ugh...the USPS appears to more interested in running our elections that delivering packages.

 

[Roger Gorke]

Other KLH1 Stuff...

If I switch (push the button) the "Position" button, I always get a loud pop in my speakers. I usually don't do it very often and have begun switching the speakers off prior to pushing the button to avoid the pop. This tells me there maybe/is DC current on the output. Has anyone else had this issue?

I did rebuild my cross over using the same parts I had. They original PCB had become somewhat flimsy and the solder points would come detached with the weight of the massive caps. I picked up a piece of 2'x4' white peg board and used the holes for zip ties. Seems to be working well!

Here's what I am using:

All resistors are Kiwame.
Treble circuit: 4.7uf Jantzen Superior-Z, with 0.33uf Miflex KPCU-03 in parallel.
Mid circuit: 10uf Jantzen Superior-Z, 82uf Jantzen Cross Cap with 18uf Jantzen Superior - Z.
Bass circuit: 2-25uf Dayton DMPC with a 0.01uf Cornell Dubilier 940C as a bypass cap.

Now I need to get my set up dialed in better!!!

 

[Roger Gorke]

I am going to build some new stands for my KLH1s. Are the stands built to keep the speakers completely level or do they have a slight tilt upwards?

 

[Remek70]

The originals are horizontal.
Mine are tilted slightly upward.

 

[Remek70]

BrownDog has already arrived in Warsaw, Poland.
I hope it will arrive at my house any minute now.

 

[Remek70]

But it sounds lovely.

 

[plenumpete]

Nice setup Remek, good to see cassette tape in use!
Quick question: how do you connect the ABC unit into the system given you're using an integrated amplifier? And, have you done the adaptor quad opamp upgrade?

 

[Remek70]

Hi.
I’ve connected it between the pre-amp and the power amp. It’s marked in yellow in the diagram.
I’ve also included instructions on how to connect the ABC KLH.

My BrownDog hasn’t arrived yet, but it’s very close now.