JohnA
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Posts posted by JohnA
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Most of a movie's sound comes fom the center channel. I'd recommend up grading to the best match for your mains.
John
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Boa,
"john, but you seem to be discounting the idea that 2 different amps at the same rated
output driving the same set of speakers will exhibit different characteristics at different
loads like you already agreed above speakers do have on various material."
Not rated output, but *actual* output. While all speakers vary in impedance with frequency, in this discussions we need to hold some things constant so that true statements may be made. At this point, we're discussing conceptual amplifiers driving any speaker. If we confine the discussion to conceptual amps driving one speaker, say a Cornwall, then we can make accurate statements about amp design and behavior as they comply with Ohm's Law. In addition, we also have to stipulate that neither amp is to be driven beyond its capability.
A good comparison might be the old B&K M-200 Sonata I used to have. It was rated at 200 watts into 8 ohms, 385 watts into 4 ohms and stable down to .75 ohms and rated to produce at least 200 watts at .75 ohms. Compare that to the H-K, rated at 75 watts into 8. When driving the Cornwall at the same power level (within the H-K's capability), the 2 amps will produce the same voltage and current. That fact that the M-200 *could* flow 16.3 amps at .75 ohms and the H-K can't doesn't matter, the Cornwall doesn't dip that low. Its impedance is high enough that it will prevent the M-200 from delivering that much current and the drive voltage that results in less than 75 watts cannot push more current than that that results in 75 watts, or 20 or whatever level we decide to test at.
Ray,
That Linn does look like a bear!
John
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john, why not say volts are also exactly the same across all amps at any given wattage
output? - volts would have to be constant for that to be true.
are you saying the proportion of current and volts is always the same for all amps at any
given wattage output & a given load?
As a matter of fact I am. Power = Volts x current, also. So, for 75 watts every amp must apply the same voltage and current to the same impedance, what ever it is.
I chose to focus on current because that was the subject of the question. I also focused on a constant impedance load since we are discussing the performance of 2 receivers connected to the same set of speakers. What ever the capability of an amp into another impedance, the 2 hooked to the same speakers will put out the same voltage and current at the same wattage, up to the limits of the amps power supply or protection circuits, if it has any.
I've also focused on the operating envelope we will typically see with Klipsch rather than discussing what an amp might see with another brand, say Magnepan. If we throw in too many variables, too soon, understanding will excape all of us. There WILL be speakers that tax the entire amp and show weaknesses that Klipsch will not.
IF I were made King, I'd require an amp to double its 8 ohm power output at clipping into 4 ohms at clipping in order to use the label "high current".
Ray, a La Scala is undoubtedly a tough load. The min. should be about 3.5 ohms at 50 and the max. hits 40 or so at 2200. I'll bet there is not a wider range anywhere. I'll also bet the autoformer causes a substantial phase shift between voltage and current. That's gotta be strange for the amp.
None of this precludes an amp from sounding good in your setup. Tube amps rarely, if ever increase power output into 4 ohms.
John
This message has been edited by John Albright on 04-26-2002 at 11:52 AM
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I have a Dish 4700 that has a digital audio out. It will pass DD IF the program is broadcast in DD.
John
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Fitting the 3 wedges in the rear would be a good idea. I wish I could remember if mine are fitted that way.
The K-33-E is only $100 or so from Klipsch. There's no better woofer at a cheaper price. You could contact CTS or Eminence to see if they have something else that's close enough. Used drivers could save you something, too.
One squawker was/is made by Atlas. They still sell the PD5-VH to the public. It is either the same, or very close to the K-55-V. I think you'll pay about $160 each new. Look for used ones.
Nobody makes a similar horn to the K-400/-401. If I was building a La Scala, I'd add corner reflectors and make it a 2-way system using an Altec 511B and a 802/902 or 806 driver. You'll HAVE to get the Altec stuff used, but you'll have a cheaper crossover (I think a 511B/806 is 104 dB/m) and fewer parts. If it's not cheaper, it won't be more. Getting E-V T-35/T-35A tweeters, the K-77/K-77-M is getting tougher and more expensive.
John
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We wouldn't be engineers if you didn't have to prove everything!
john
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I've met Hunter, I've got to hear that!
John
This message has been edited by John Albright on 04-25-2002 at 09:18 PM
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The zero setting would be full output at some reference input level. If your input level is below reference, what ever that might be, you could need to boost the signal with more pre-amp gain to get the loudness you need.
John
This message has been edited by John Albright on 05-01-2002 at 10:20 AM
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I can't stand it ANY MORE! "HIGH CURRENT AMP" IS NOTHING MORE THAN ADVERTISING!
Of COURSE H-K is blowing smoke and BAD! If both receivers are putting 75 watts into any load, speaker or not, the current output from each one is *exactly* the same! It doesn't matter that the H-K could produce more current than it takes to put 75 watts into your speaker. The Denon would be capable of putting even more current into that same speaker because it is designed to put out 47% more power!
Ray is right. Speakers are not constant impedance loads. So, an amp that has the power supply reserves to maintain constant voltage into a varying impedance will operate without audible strain (distortions and/or non-linear frequency response) and will probably sound better WHEN PUSHED NEAR ITS MAX OUTPUT. However, if a 75 watt amp is averaging 0.05 watts and hitting microsecond peaks of 20 watts (typical Klipsch operating range), its power supply will never be challenged even if it were to be a "low current" amp.
Power=current x current x impedance.
So, for any 2 amps producing the same power into the same impedance, regardless where you measure it or what it is, the current must be the same.
Looking at the AVR 520's specs, it is not a "high current amp. It cannot drive all channels to the same output as it can just 2. Its power supply is not large enough. The hallmark of so called high current amps is at least 1.5 times the 8 ohm rating into 4 ohms (2 times is theoretically perfect). H-K doesn't even spec 4 ohm performance.
Rant off.
From looking at each receiver, I'd bet on the Denon sounding better. Neither will be pushed driving Klipsch.
John
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Something loose?
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Hiss at high or full volume setting is normal to almost EVERY preamp; every one I've ever seen. It will do that with any input. It will be easier to hear when there is no signal on that input (set to CD with the player off). You have no cause to complain about that. It comes from the very large gain the preamp section can generate at full volume setting and is made more easily heard by Klipsch's high efficiency.
The bleed over from the tuner section is sometimes called crosstalk. While expected and somewhat typical in cheap gear it is ultimately from a poor quality component. I'm not familiar with your Denon, but all of my cheap receivers from my college days do it.
Audible hiss at very low volume settings (the minimum or first click or 2 of the volume control) should not be normal, but it very often is these days due to the digital processing sections in HT gear. I think that should be cause for a return of the piece for repair.
John
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It is virtually impossible for speakers to produce hiss. The only way is for the crossover to be near a VERY strong magnetic field. The problem is your Denon. If you had speakers of normal efficiency you would not hear the inherent noise floor of the digital processing section. I've seen $4000 HT preamp/processors do the same thing. It seems the digital section in all HT gear is inherently noisy. It is NOT caused by your house wiring and expensive filter systems will not reduce the hiss (they would remove clicks and pops caused by switches and appliances). You MAY have to replace the Denon to get rid of the hiss.
Talk to your Denon dealer.
John
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I'm with Tom on this one. I'm not familiar with modern Crown amps, but their amps from 30 years ago were well respected. Be careful which ones you buy, though. Some of the modern designs are intended for very high power sound reinforcement and do not seem to be aimed at high quality home systems. With limited experience, I've found SS amps to be more satisfying with my La Scalas.
BTW, Mr. Paul uses all SS gear to run his system and one of the amps is a Crown D-60. I'm not sure whether it's hooked to the K-horns or the Belle.
John
This message has been edited by John Albright on 04-22-2002 at 09:18 PM
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All of the talk of builder codes got me to look. I'd never noticed them before. My '81 La Scala, 28W186 had the code MB beside the squawker and F in the plywood edge. My '82 LS, 26X610 has an F in the plys, but I couldn't find a builder code. Both '87s have the code BC on the "shelf" for the xover, but no sander code I could find.
HDBR, any idea who these maight be?
John
This message has been edited by John Albright on 04-20-2002 at 09:21 PM
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Great story! And well told!
John
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Great story!
John
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Technically, a La Scala would be the best match for the K-horn. It used the same Squawker horn.
John
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About half of new price.
John
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I used Netflix ALOT before they required a membership. We would get our money's worth in the fall and winter, but not during good weather. I quit using them when menberships began.
John
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Klipsch.
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Ray,
I know you didn't generate any of these, but why should there be any difference betweet the K-horn, La Scala, and Belle above 500 Hz? They used the same drivers and crossover for most of their lives. Even after the crossovers began to diverge, they only had minor differences.
John
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The Heritage series crossovers underwent several iterations with the "modern" set of drivers. The original Type A was used in the K-horn. Type AA was used in KH/B/LS. Then Type AB/AL/AK was used in the corresponding speaker. Next, there was a Type AK-2 and AB-2, but maybe not an AL-2. Next, was the AK/AL-3; I've never heard of an AB-3. Now the new ones likely have an AB/AL/AK-4 network. Al's network has been nicknamed Type ALK; it can replace anything from Type A to Type Ax-3, or the entire A-series of networks except perhaps the Ax-4 network. I'm sure he's working on that.
John
This message has been edited by John Albright on 04-17-2002 at 05:49 PM
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I'll bet you won't hear much difference at all. Bi-amping first started when amps were small and speakers were generally inefficient (the 70's). It gave you more power/channel. It was then discovered that a good electronic crossover could improve the sound quality by removing the reactive elements in the passive crossover.
Crossover parts are a lot better, now. And, your KLF-30s are so efficient that you will be hurting at 10 watts out of the 140 the Parasound produces. You will never tax the power amps in your receiver, so I doubt the Parasound will do you any good at all. If the receiver's power amps are so poor you hear a big difference with the Parasound, then your preamp section is also suspect. The better use of the Parasound is to hook it to a HT Pre/Pro.
John
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Tom,
Be patient with ebay, a pair will show up after a while. Altec 511Bs could also be used and some say they sound better. I haven't bought any adapters to try them, yet.
Builder,
This LB-76 you mention; is it a narrow (about 18" wide), tall "J" bass horn or "scoop" with a Belle squawker horn and K-77 tweeter? Did it have optional wings to improve bass performance? The patent date for that was 1979. That's why the -76 confuses me. The '79 patent bass horn is the subject of an inquiry of mine. I toying with having a pair made for rear surrounds. I'm guessing it is taller that a La Scala and would be able to "see" over my furniture.
John
Denon poa5200 vs. 4802 power supply
in Technical/Restorations
Posted
It's pretty tough to look at amp specs and tell anything about how it sounds. The damping factor is one that you can look at; the higher the better. I've been told that anything above about 450 is not helping much. I've been able to hear the difference between an amp with a damping factor of 100 vs. one with 800. Large differences like that may be required for it to be audible. I also look for an amp that doesn't have too low a distortion rating. You get that by using lots of feedback. Since feedback comes from the end of the circuit and is reinjected at the beginning of the circuit, there MAY be some time smearing that occurs. Some think any feedback is a bad thing. I believe in moderation.
All that said, you just have to listen to the combination to see how it works.
I have a low opinion of adding good amps to poor reciever preamps. If you want more power, buy a bigger receiver. Don't add a good amp to a cheap receiver preamp section and expect good sound. It'll never sound better than the cheap preamp section. Buy a better receiver. If you want better sound than you think you can get with a receiver, you've got to go with a good amp and a seperate pre/pro.
John
This message has been edited by John Albright on 04-28-2002 at 03:16 PM