boom3

This is a perennial topic in audio. The vast majority agree that not all amps sound the same, yet there is great disagreement why that is so. I would stay with analog amps right now. Digital amp technology is not quite mature enough for high-resolution audio. Leave it to the boom car/"home theater in a box" crowd for the moment. I have no experience with the Quad amps, however, you need to be cautious about buying any product 34 years old, and a niche product at that. At least the Klipsch Heritage line has a solid foundation of factory and after-market parts support. Many folks on this forum drive Cornwalls and other Heritage models with tube amps. I will reserve judgement on that. However, tube amps do, and this has been proven many times, exhibit considerable variations of frequency response when driving real world loudspeaker loads. Some have pronounced all tube amps as high-priced tone controls. Again, I want to try tube amps with my Cornwall IIs, someday and make up my own mind. I am driving my 1986 Cornwall IIs with a Sumo Polaris power amp. It is rated at 120 w/ch RMS into 8 Ohms. It's an FET design, which was popular in the 70s but seems to have fallen out of favor. My experience-from 32 years of building many speakers- has been that bass-reflex speakers, like the Corns, need a solid-state amp to help control the low end. The Corns-as much as I love 'em-do have a bit of tubbiness in the bass, and I think a tube amp might exacerbate that. The Klipschorn is another animal altogether, so I can't (and wouldn't) make a generalization about how they interact with tube amps. Again, many K-horn owners are happy with tubes.

If you want to read some remarkably honest articles about audio, you need to read Voice Coil and Multi-Media Manufacturer, both by Audio Amatuer (the Audio Express folks, formerly publishers of the late lamented Speaker Builder). These are as close to 'peer-reviewed' articles as you will find, even better, in some ways, than those in JAES, where some well-documented and interesting nonsense has been published over the years. The articles covering manufacturing will open the eyes of audiophiles to the realities of the business. Which is more sickening-Mr. Joe Sixpack "getting" Home Theater In a Box for $100 or 'audiophiles' paying $10,000 for $1,000 of Chinese labor and materials? The patent watch sections are the best parts, as audio and speaker patents are analyzed and critiqued. Many of those presented should never have been granted patents at all.

I'm chiming in kinda late on this...but here's an article worth pondering if you live in a city with a pro sports franchise: http://www.nola.com/newslogs/middaytp/index.ssf?/mtlogs/nola_tp-midday/archives/2004_12.html#043156 Having watched Jack Kent Cooke, late owner of the Washington Redskins, play the politicians of DC, MD and VA like violins as he extracted commitments from them, this article is important to me as a New Orleans ex-pat and frequent visitor. It isn't just that the Saints have an abysmal record. Even if they were the Superbowl champs, they have still fastened themselves, leech-like, to a poor state and a desperatly poor city. Louisiana nearly had some parishes secede to Texas over the building of the Superdome and now the Superdome is not good enough, not enough luxury skyboxes to be 'competetive'. Our resident contrarian, James Gill, also adds: http://www.nola.com/news/t-p/gill/index.ssf?/base/news-0/1102231415244800.xml Change the names of the teams and the cities, and the story can fit most, if not all, pro sports markets. Hopefully, the team's owner will make good his threat and decamp for Los Angeles. Louisiana may lose its only NFL team, but it will also 'lose' a massive drain on its meager resources.

Such a bargain!!! http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=12&item=2292076216&rd=1 and get a load of that feedback score! contrast this with: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=132&item=2291471836&rd=1 as somebody on the antique radio newsgroup said, "This guy must have bought the Brooklyn Bridge and now he wants his tolls'

---------------- On 11/29/2004 11:40:29 AM fini wrote: As a general rule, what's the minimum amount of time a piece of tube gear has been out of service (i.e. not used) that one would want to power it up slowly with a variac? One month? Several months? One year? Also, what's the general proceedure for powering up? Oh, one more: If someone has plugged-in a piece of gear (you know, "It lights up"), does that make the variac power-up a moot point? ---------------- The point of bringing it up on the variac is to reform the electrolytic caps AND to see if there are any other problems, like shorts, loss of bias etc. An AC ammeter must always be in series with the unit under test (UUT) and the variac so that current may be monitored as the voltage is increased on the variac. Once the unit is brought up to line voltage, and if no problems are found, it does not need the ammeter or variac again unless caps are replaced or a problem is suspected. Phil Nelson is The Man of old audio gear. See his site, http://www.antiqueradio.org/checkout.htm for the proper variac procedure. You should know the current draw of your gear before you power it up so you can watch the ammeter. If a unit is already in service with no apparent problems, then the variac procedure is moot. It does NOT mean that the equipment is completly safe, but that's another discussion.

Bob, Thanks for doing this test. I'm sure you appreciate that what is remarkable here is not the difference but that there is so little variation. Even between new woofers, fresh off the line, these would be considered normal production tolerences. Says a lot for stability of pulp cones and fabric accordian edges. Makes me wonder what kind of woofer-to-woofer tolerence Klipsch uses and what kind of system-to-system matching was/is done between consecutively numbered systems. I'd be surprised if the slight difference in magnet mass would have any impact on amplitude response. Normally, a larger magnet equals greater efficiency (up to a point) and control where the voice coil is reaching its limits of excursion. Since the Heritage line didn't use trick field geometries or shorting rings on woofers, it's hard to believe that a round vs. square magnet was anything more than the result of one vendor's tooling versus the other.

Here Here to what Eric said. Mass market stuff of that vintage is best preserved intact, there is nothing special about the phono stage of that genre. If you want to see Da Man of old audio-video gear, go to: http://antiqueradio.org/ Phil is very generous with his advice as well.

Iron cores are prone to what is called 'saturation' which causes a degree of disortion. However, well-designed iron core inductors will not saturate with inputs under 500 watts. For Klipsch heritage products, this is a non-issue. Air cores do not saturate, but their DC resistance is higher. The DC resistance of the inductors is, in a properly designed crossover network, figured in to the design to achieve the target response. Most designers realize that, since the inductors required for woofers will be 1 millihenry (1mH) or greater, air-core design may have so much DC resistance that it will affect the woofer's tuning. Specifically, a high DC resistance in series with the woofer causes a loss of damping which makes the bass tend to boom. So many designers will use an iron-core inductor for the woofer rated for the expected power input (plus some above that for 'peaks') and keep the DC resistance contributed by the woofer inductor low. How low is low enough? Well, my rule of thumb is that the series inductor should have a DC resistance no higher than 1/10 of the DC resistance of the speaker (typically, 3.2 Ohms for a 4 Ohm "nominal", 6.5 Ohms for an 8 Ohm "nominal")that, i.e. 0.3 Ohms. Well-designed iron-core inductors meet this easily. For midrange and tweeter work I always use air-core inductors, unless I need a large inductor in shunt of the midrange, in which case a good iron-core is perfectly acceptable.

Well, I did search thru the archives here and found a great deal of info, but not the exact answer I am seeking. I am piqued by my continued rediscovery of my music via my CW IIs. As a long time (30+ yr) speaker builder I am wondering, what are the K57 and K79? I.e., who made them, are there commercial equivalents, are they still made and were/are they used in other systems, etc. Thanks in advance!

Very nice Dean, and thanks for the info. I probably would use SEAS H143 for the mid bass. They are about the flattest (amplitude response) midrange cone I've ever seen.

I have some experience cleaning fabric of various types. The question is, what are you trying to clean? If your fabric has simply faded from age, then there is nothing to clean. If you are trying to remove tobacco smoke residue (very common with products that age) then Fantastic or 409 sprayed on a lint free cloth and gently rubbed on the fabric will help. Try on an obscure part of the grill first. The worst problem with this kind of cleaning is streaking, so it's important to do a uniform job. I cleaned the grilles (not same material as the cane grilles) of my 86 Corns recently with Turtle Wax spray auto upholstery cleaner, spraying just enough to see foam form on the fabric, and then wiping off and blotting with dry paper towels. Should go without saying I removed the grilles and stood them in a dry bathtub first! I sprayed Fantastic on paper towels and gently wiped the baffles to get the smoke off them. As far as 'preserving' fabric grilles, I'd be cautious about applying anything. Preservatives tend to fall in three classes: barrier (wax, silicone, varnish etc, ScotchGuard), lubricant (oils) and formaldhyde (ArmorAll and certain clones). Anything you apply will have to be removed later. ScotchGuard may be appropriate for some fabrics, but I would not try it on anything irreplacable. Barriers and lubricants can cause fabrics to break down or may darken them. Formaldehyde is not something I would use on fabrics, particularly those with old plastic in them. In sum, if the appearence of the grilles is unacceptable, I'd simply find new material and replace them.

Thanks Gil. The Cornwall is an interesting story in its own right.

---------------- On 11/18/2004 7:47:10 AM DeanG wrote: Nope, don't have them anymore. I bought 'em, built 'em up -- then sold 'em. As great as they sounded -- once you get your ears dialed in to the horn sound, everything else just sounds a bit dry. I wouldn't mind taking another stab at them and loading them up with different drivers. The show stopper was the midwoofer, but I think I've finally found a replacement that will work -- which ends a three year search. So, I'm ready for a new summer project with these, but need to find a good pair to work with. I want a set that are in decent shape to begin with because I really don't feel like spending a month sanding and painting. ---------------- Dean, thanks for the pix. Beautiful job. Two questions: 1. What is the material you put over the back of the midbass? 2. What did you replace the midbasses with? I am told these are the hardest to replace of the DQ-10 drivers. Boom

My S/Ns are very low (around 1000). The original woofers were replaced with factory units some time ago. The only tweaking I have done is to replace the series cap on the midrange with a Solen. I found a small but noticable improvement. Mine are not mirror-imaged. Just not a priority right now. I put fast-acting fuses in line, I think they are 1.5 amp but maybe 2 amp (same as on my Cornwalls). I built sold stands for them which elevate the systems 7 and 1/2 inches above the floor and connect the woofer solidly with the ground plane. The factory feet/stands all hurt the bass by not maintaining a solid connection to the floor. (Ah done learned that from Pawl)

Gerry, I have the "wrong" reply e-mail ion my profile, so I am not surprised you don't recognize my e-mail. I will respond to you from home tonight. Boom

Thanks for all the inputs. I have a web article on the DQ-10s but the page is being repaired right now, I will post it when it's ready for prime time. I have not done a side-by-sde comparison between my CW IIs and the DQ-10s. I don't intend to, but I will note a few points: Both speakers have clarity of what PWK called the 'inner voices' of the music. I am hearing things I have not heard before, and they are all part of the inner texture of the music, not just interesting effects and colorations. With many speakers, it takes a lot of critical listening to parse out the colorations, strengths and weakneses. With the CW IIs and the DQ-10s, it does not take much time at all, because both can give the credible illusion of actual, un-reproduced music. With the CW IIs, "They are here". With the DQ-10s "You are there". The DQ-10s are voiced to give a middle-row concert hall presentation; the Cornwalls, fifth row center. The most obvious difference is that the DQ-10s just do not have the dynamic range of the Cornwalls. The piezo tweeter and the Advent woofer are the main culprits. Like I said, I use the DQ-10s in my study where volume level is never very high and my listening is while I am multitasking i.e. creative writing. The Cornwalls are the main channel of my HT set-up and are played loud to enjoy their dynamic range.

I like my Scott 333. It was a gift; I spent $200 having it repaired and realigned by a pro. Unfortuantly, I am not using it now since I am using an old integrated amp for my study system and we rarely if ever listen to FM on the primary HT system.

Besides my 86 CW IIs, I also have a pair of Dahlquist DQ-10s that I use in my study, mainly for low-level listening while I write. If anyone is interested in discussing these, (Dman is also a fan/authority, I believe!) please e-mail me.

I have some 86 CW II's with the later version (I think) of the copper foil logo. I have the Jubilee pie slices arriving next week. I'd like to remove the stock logos and place the pie slices on the grilles. How easy is it to remove the stock logos? Can I gently pull them off without harming the grille or leaving a residue? The corollary of that question is, what should I use to attach the pie slices with? TIA!

Today the S.O. was telling a co-worker that he had the pleasure of just sitting and listening to music over the new speakers last night. "What kind ya got?" "Klipsch Cornwalls" "Never heard of 'em" "What kind do you have" "There're pretty good-they're Bossy brand" "Bossy?" "Yeah, ya know, B-O-S-E!"

Here are some pointers: For a given RPM, a larger fan will be quieter than a small one, since the blade tips are turning at a lower radial velocity. The back of the cabinet should be open, but if not, it should have a large vent at the top of the back, and a smaller one on the front near the base (perhaps hidden by a lip of molding). In this manner, the difference between the two vent sizes will cause a modest 'venturi' effect to enhance airflow. Most pro cooling setups also include a filter. These are usually washable metal mesh. Depending on your home (smoking, pets, and other airborne particle contributions) you may want to include this. If you filter the air, then the cabinet has to be airtight with openings only at the intake (fan/filter) and exhaust. How are you going to mount your components? In the olden days (before the 90s) receivers etc were mounted by their front panels to the AV cabinet panel, and the receiver enclosure was removed for better cooling. I'm not sure today's components have the structural integrity, or adequate front panel overhang, to be mounted 'nude'. Whatever you do, buy a cheap remote thermometer. These are available from Radio Shack and other outlets for very little. Put the sensor at the top of the cabinet and keeping an eye on the temp when all components are energized. I can't give you an absolute max temp, since there are too many variables. The traditional rule of thumb (literally) for home audio is that if the heatsink of a solid-state amp/receiver is too hot to touch, you are probably overheating. Get a heavy-duty powerstrip with a breaker (unless you are using a power line conditioner with a breaker/master switch). Put the power strip where you can get to the breaker easily. Hope this helps!

Hey Gil, Do you have PWK's original paper on the Cornwall? I have it, but it's deeply buried in my paper archives right now. Thanks!

We have a Mac based music/video server. Currently, we're looking for an old (but not too beat-up) radio console to house the minitower and monitor. Our CRT based TV just doesn't have the resolution to allow it to be used as a computer monitor. We normally launch iTunes from the master Mac in the computer room (linked by ethernet to the living room server) and play music as background for household chores. We didn't rip any classical to the Mac format (.aac?) so we still haul out our CDs (or DVD-As) for that genre.

Thanks!

I read somewhere-maybe it was Bruce Edgar's article in Speaker Builder-that after Thiele-Small analysis became known to K&A, the Cornwall was analyzed and found to be a 6th order Butterworth alignment. I'm wondering if anyone has this analysis. I'm thinking it wouldn't change with the CW IIs?