Klipschguy

I am not necessarily in disagreement with JRH. Most of the old, oil-filled caps have an ESR value which is creeping up and should be replaced, but an exception I have seen is the 13uf caps in Khorns; many of those test good as new. One thing for certain, the old caps are not getting any better with time.

I have experimented with a bunch of different capacitors, both in listening tests and on the bench. I like the way the GE oil filled capacitors sound (others will disagree, which is fine). The quality control is always tight in my findings as well. Their caps are rated at +/- 6%, but I usually find them closer to 1%. ESR numbers look good too. Also, in my mind, I like to think the oil damps microphonics (but I may be reaching a bit here). I have replaced a bunch of old Klipsch oil filled caps (for others and myself); the ESR creeps up on those old caps causing the highs to sound rolled off. The new GEs have ALWAYS made an improvement to my ear that was not subtle. After decades of experience with Klipsch Heritage speakers coupled with a good ear: replace your caps.

Hi Mike. Thank you for running the curves. From the graph, it appears the .34 mH inductor shifts the crossover frequency from about 5800 Hz to about 4800 Hz relative to the .245 mH inductor. I might add the iron core inductor would have a lower resistance versus the air core which would shift the .34 mH curve up a bit. Again, I appreciate you taking the time to run the simulation. Andy

DizRotus, same path, different result. Maybe a little test is in order? Henry, like you, I have been around music/audio/electronics a long time and I often leave “well enough alone.” As a 21 year member of this forum, I rarely post anymore, but I felt this moment of serendipity was worth sharing. I may stand corrected. Thank you again for your thoughtful replies.

It sounds like the steel screw may have been a production oversight. I am generally a “tweak skeptic”, but a little more energy to the the lower range of the K77 is a good thing to my ear. With a cost of about 50 cents, it is certainly one of the cheaper tweaks in audio! Thank you all for taking time to reply.

I rebuilt a pair of crossovers for a pair of 1950s Khorns (not mine); they had brass machine screws in the 500-5000 from way back, so the engineers are/were aware. 1976 Khorns have steel from the factory (which is when I noticed the sound difference upon replacement with stainless).

I am too lazy to calculate the change in the crossover frequency with .24mh versus .34mh. Anyone have a calculator handy?

Recently, I was a bit surprised to discover the AA Network in the Klipschorn sounds perceptibly better to my ear with a steel screw (not stainless or brass) securing the .245mh inductor. It seems to give a little more energy to the lower treble that to my ear is necessary to that “magic Khorn sound”; with the brass screw it sounds a just a tad “too polite” (again, to my ear). My inductance meter shows .24mh (brass screw) versus .34mh (steel screw). I realize this post is going against the grain, so I was a little hesitant to post. If anyone is interested, the screw is a #8 1.5” steel Phillips pan-head.

Hi Brian, If possible get them in the corners angled towards the listener; it will make a huge difference in the way they sound. Paul Klipsch had plenty to say about the advantages of corner placement, including considerable bass reinforcement. Secondly, Paul Klipsch liked the sound of 1st order crossovers, but went to steeper slopes mostly to help protect the tweeters from abuse. Keep the Type B networks and replace the caps. I personally like the General Electric motor run capacitors (inevitability, disagreement always erupts over “which caps”, but the GE caps test remarkably well on the bench with spot on capacitance and very low ESR - plus they sound good). You will need 2 2uf and 2 4uf caps for the job. Use 2 sided clear Gorilla tape to stick them to the board. You can put the old screws back in the holes for safekeeping. If you keep the power clean, you should be able to turn the Cornwalls up very loud without damage. Abuse would be clipping the amp with the treble control turned all the way up; that is a great way to fry your tweeters. For home use, even at impressive levels, you should be just fine; just keep it clean and “sub-ridiculous.” Your cabinets are raw birch that look to be stained, not painted (although it is hard to tell from the pictures). If they are stained, you could mix boiled linseed oil and minwax stain and go over the cabinets with the mixture and a green superfine scotchbrite pad. Buff lightly with the grain and then wipe off any excess with the best bath towel you can find. Just my opinion. Let us know how it turns out. Andy

I found a little piece of history inside the top hat. The paper had become quite brittle over time; it was repaired and preserved with clear packing tape and then back into the top hat.

Thank you, JRH! We enjoy the Khorn sound with its “wild grain” gracing our living space.

Hmmm….having trouble with uploading pictures because they are bigger than the 2 meg restriction of the Klipsch website.

Thanks Budman. Yes, 1981 with solder terminal K55. Maybe Klipsch knows when and where it was shipped. No idea how the pair got separated. Maybe it was always a single??

Greetings, I have in my possession a single Klipschorn. (In case anyone is wondering, I am using it and it is not for sale.) The serial # is 17W758. The finish is walnut lacquer. Any historical info would be appreciated. Andy

Thanks, Edgar. I appreciate your time and insight. Andy

Hmmm…3db more attenuation for the 8 ohm versus the 16 ohm. So, the high frequencies from the 8 ohm driver will effectively have 6dB more SPL relative to the 16 ohm driver (3dB more mid attenuation relative to the highs plus 3dB more sensitivity from the lower 8 ohm driver impedance)? It seems like the curves would intersect of that were the case. Interesting. Please know your input is very much appreciated!

Yes exactly! Are these circuits impedance dependent? By the way, I skimmed over the article and I see it has good information; when I have more time I am planning to read it more carefully. Thank you for posting!

Kornukopia, I am definitely asking. The “Altec 3904” is supposed to attenuate the mid frequencies leaving the highs in tact. In the schematic, the high frequency driver has an attenuation filter, the low frequency driver has a zoebel network to equalize the impedance. The “Altec 30923” only has the midrange attenuation circuit - no zoebel. My question is will this attenuation unit have to modified to work with a 16 ohm driver? I would ask this question on the Altec heritage forum, but as a lifelong Klipsch listener and owner and member of this forum for over 20 years, I have really come to respect the knowledge and opinions found on this board. Andy P.S. Edgar, thank you most kindly for taking time to run the curves; I am not sure what think yet. Please know I am not doubting, it just doesn’t seem to make sense Altec would design an attenuation circuit that doesn’t attenuate. It’s kinda like having a machine that goes “ping” but nothing else.

BD, when I look at notch filter equations, they do not have impedance in the equation. Online notch filter calculators do not ask for driver impedance either. BTW, I am a student science and engineering as well. Andy

Thanks, BillyBob. See the picture for what I have in mind. This picture/schematic is the Altec factory designed midrange compensation network to reduce/notch the mids to allow less relative roll-off of the highs in 2-way system when utilizing an 802D driver. So, the circuit will operate the same whether the driver is 8 or 16 ohms? Andy P.S. I miss Gil; this question would be right up his alley.

Greetings, Does a notch filter (for instance, to tame the midband frequencies of an Altec 802D driver) depend on the impedance of the driver? In other words, will the notch filter designed for an 8 ohm diaphragm also work for for a 16 ohm diaphragm? Thanks, Andy

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