JohnA

Klipsch, maybe. An Atlas dealer, definitely. https://www.fullcompass.com/prod/027035-atlas-ied-d-20gb-diaphragm-for-pd-5vh-and-pd-5vt If your drivers work, leave well enough alone. Don't have audio nervosa. I had a pro replace a bad diaphragm in a spare K-55-V and it buzzes on piano.

I think I remember seeing the old dome rear cover in old literature for the -5VH. It will be essentially the same as the current production and should use the same diaphragm, should you ever need one. I'm sure Atlas will sell you all you can carry, too.

As new as they are, I'd expect you would ruin the sound. Ask again in 30 years.

Heresy or Forte. I'm partial to the H IVs. You will not need the sub, but it won't hurt.

You may, or may not need new capacitors. If the sound is not out in the room with you, consider it. I had a '67 H700 that did not and a '68 that did. I have an unproven theory that speakers used regularly will not need new caps as soon. At any rate, install high quality film and foil caps. They don't need to cost $250 each, but spend some coin. One very good update, was the K-77-F version of the tweeter with a recessed flange that placed the mouth of the tweeter flush with the front of the motorboard (no more playing through a hole). Not only does that eliminate the diffraction of the hole, but the tweeter itself responds to higher frequencies than the old AlNiCo tweeters you have. That new tweeter is a modification of the ceramic K-77-M the factory went to in 1980. The -F may be hard to find, but worth it. The factory added "Z" brackets the the -M to do the same thing for a while, but that would require enlarging the tweeter hole in your top section.

The square magnet K-77-M Is the better tweeter, responding to higher frequencies. Being newer than 1979, yours should have had the -Ms.

You're in like company here! Your '78s are likely made by Eminence in KY and they will have proper recone kits to restore them to OEM performance. Eminence probably will not sell to you directly. Look for a gray ink stamp number in the back side of the cones, 15162?. Also look for the EIA build code. It will be 67-xxxx; 67 for Eminence and xxxx for build week and year. The '69s may not have Eminence woofers, you you will need to start with the EIA code and determine who made them. However, early K-33-Es might well be a good match for the cabinet. compare the dimensions of your cabinets to that of mid '70s Cornwalls. If your woofers have failed, I'd recommend ebay for vintage replacements. If you want new, consult Klipsch to see if the current K-33-E is a good match to your cabinet. There is enough precision required that I would not DIY a recone. I say this after reconing a pair of Peavey 1504-4 woofers built for quick, easy cone replacement in the field, requiring no gluing.

DCR for the tweeter should be 7.2 to 7.5 ohms. If they are REALLY old and rated at 16 ohms, you might see 12 to 14 ohms. If you can hear scratching while rubbing the leads with the meter, it is most likely good. A 1.5V battery is good for this test, too, but be sure to rub, don't hold the leads against the battery terminals. Tweeters don't like DC.

Yes, H IVs run circles around H 1s (I had 7 at one time and still have 3 in my HT system). H IVs are much more natural sounding and better on vocals, especially. H IVs do not need a subwoofer, though open E on a double/electric bass is down a little compared to G, but not so much you might not think the song is recorded that way.

Since they are ported, you will not damage the sound, but surely there is a better way than damaging the finish, even if on the bottom.

I'm still looking for that 50 to 60 watts/channel. I'm driving my La Scalas with 125 wpc. While certainly more than enough, I wouldn't want less than half for the trip through "Sweet Jane", "I Don't Need No Doctor" and "Layla". 😆

It appears an 811A tube, often used in RF power amps, could be used in an audio power amp and may produce a 160 watt audio amp. True? If not, how much power could it produce? I had a pair of 8 watt monoblocks once. They were fine for most listening, but I'd really want 50 to 60 watts/channel. Could the 811A do that? How well would it sound?

You've got a very good start. If you do not want to buy another pair of H IVs for the rear channels, consider a pair of KG2s. I hope you can find some original Quad programming/LPs. It was quite good, but ahead of it's time.

LOL! My first exposure to Klipschorns like yours was in Nashville in the later 70's. While looking at stuff I might one day afford, I heard a thunderstorm (Alan Parsons Project). It was a blue sky, severe clear day. Sneaking into the high end room, the next record up was Santa Esmerelda (disco). I noticed my bell bottoms were tickling my ankles. They were visibly moving to the bass drum!!! and yet, it was not so loud you couldn't talk. I was bit that day. In my whole house I have 2 proper corners for K-horns, ... in different rooms. 😐 You have a wonderful gift.

Those are what the Forum has dubbed Heresy 1.5s. H1 woofer/tweeter and H2 squawker.

Dang it Roy! You're costing me money!!

Sounds like you're going to cost me money!

Sounds like you have a hard, bright room. Carpet and furniture help and should be done first. Very heavy stage curtains could work, but I never found where I could buy them. Look at A/C duct board. For your place, I'd say use 2" thick duct board. The absorption will be similar to the chart above (1.0 is like an open window, 100%). Build panel frames from 2"x2" in various sizes, fill with duct board, cover with a thin, fine mesh, neutral colored cloth, say like a bed sheet, cover that with a coarse, burlap-like cloth in a festive color and mount to the walls where you want to reduce reflections. You can build bass traps in a similar fashion. Build a 2 x 2 box out of 2" x 2" lumber, say 4' to 6' tall, cover with chicken wire, or similar, fill sorta loosely with unfaced fiberglass batts and cover as above to make it attractive. Put those mostly in the corners. I'd start with 2 in the rear and make more as needed. I am sure you could buy something premade. I got my inspiration from the cubicle walls I lived in for 25 years.

1 - the room 2 - speakers 3 - power amplifier

I was quite pleased with an A-T OC9 on a Decca London arm in a Thorens TD-125. I used an Aragon outboard phono preamp. I think you might like an OC9 in it's current editions. It brought out much delicate detail, good or bad. I still have it, but is is not in service.

Having gone from 1 to 2 to 4 subwoofers, I'll recommend at least 2, placed near mid wall on opposing walls. Second choice would be near the corners, but the 3rd wall may disturb the frequency response too much. I also will recommend getting subs with 15" drivers (or larger) to minimize excursion and thus harmonic distortion. I have not heard the 2 you listed, but there are several available with excellent performance. Also, remember, if you can "hear" a subwoofer and tell it's there, it is 10 dB too loud. You might like that, but it is not accurate.

Too much $$$ for butt-ugly.

In my experience, cables matter, some, but their differences are subtle. One reason is your speaker cables will normally pass very little power, 1/2 watt or less, so losses are miniscule. This is due to the Chorus' sensitivity. However, since the cost is low (discounting my sore fingers), I use thick speaker cables, about 11 gauge. Mine are hand made braided CAT-5E, but low resistance from 10 or 12 ga wire is most important. My interconnects are moderately priced, but the preamp to power amp cables for the front 3 are silver-clad copper with tight fitting, heavy phono plugs. I use those because I could hear a change in sound I liked. I used those on my turntable, too. They were about $40/meter 25 years ago. The other line level cables and digital cables are similar, but unclad copper and 1/2 the price. The brand is Vampire Wire, but only their connectors are available, now. The cables are unique because the shield does not carry the signal and is only bonded at the preamp end. I recommend you find similar, moderately priced cables because there is some improvement in sound and quality lasts, but beyond a point, improvement costs exponentially more money for another tiny improvement.

Yes, and Yes. Baltic Birch is neither light, nor cheap, over here, but it can be had in a void free "plywood", a layered, glued construct that is surely what you called multiplex. Other plywoods can be and have been used in Klipschorns and other Klipsch speakers. My La Scalas are made from plywood with a birch veneer on the top and bottom. I do not know what is in the other layers. I have read it was a void-free product made for Klipsch that is similar to home cabinet birch veneered plywood, like what I have in my kitchen (la cucina).