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Amplifier Power test


captainbeefheart
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I realized I didn't even participate ūüôÉ

 

I just did my 1982 La Scala's

 

Average level- 850mV

 

Loudest level- 2.8v

 

For an 8 ohm load this works out to 722mW for my average and 8 watts for maximum. I couldn't stand in the room for long on maximum.

 

If you want to be prudent and go by the lowest impedance for the La Scala it dips down to maybe 4 ohms we'll say to error on the side of caution. That tells me to be absolutely safe to drive my speakers to that level at the lowest load impedance seen for the speaker I need a 16 watt amplifier. That's a bulletproof value that you I can safely assume my amp won't run out of steam on tough loads at that extreme volume level.

 

I'll do my RB 81 ii's and Heresy's when I have time.

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CB - Just a guess into the vacuum, here, but I think it's the nature of a lot of the regular community here that those interested in the numbers did so long-ago and, through continued and deeper review of PWK's writings (and the refs he cited), have a good-enough handle on this stuff.

If it's to better specifically target your amp projects for the community it's clear you have the chops to find a nominal sensitivity target, tack-on increases for distance & headroom, and have what you need.  

My guess is you've hit the "hrmmph of silence" (aka have you heard of the Symposium on Auditory Perspective...).  I might be wrong, but that's how I read it. 

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Did not do the test knowing already 5 watts is the sweet spot for me with tubes. Done similar test many year ago.This is not to say I would not be happy with the couple of flea watt amplifiers I own averaging 2 watts or less. There is some sacrifice of bass with the flea watt ones but if I had to I could be satisfied with them.

 

 

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11 minutes ago, grindstone said:

CB - Just a guess into the vacuum, here, but I think it's the nature of a lot of the regular community here that those interested in the numbers did so long-ago and, through continued and deeper review of PWK's writings (and the refs he cited), have a good-enough handle on this stuff.

If it's to better specifically target your amp projects for the community it's clear you have the chops to find a nominal sensitivity target, tack-on increases for distance & headroom, and have what you need.  

My guess is you've hit the "hrmmph of silence" (aka have you heard of the Symposium on Auditory Perspective...).  I might be wrong, but that's how I read it. 

 

I am not motivated by only self interest. I do things to help the hobby community, I was raised so that when I give and help I get a reward out of it by making a positive impact on someones life, it makes me feel good. I guess that can be a considered self motivation but I wouldn't think it's a bad thing to enjoy helping other people.

 

The point of the thread as I mentioned is to have an informational resource to help anyone get an idea of power they may need for a specific set of speakers. I said at the beginning of the thread, most likely the first post that I have seen many posts/threads of people asking about how much power they need for their speakers. That or they are interested in an amplifier and it's somewhat low powered and they want to know if it will work for them. I get that there are some experienced members here that have a good grasp on what they need for power, to be honest I think some of them think they have a good grasp on how much power they need but they really don't. Well that was the case from doing this on another site where I read many times something like "wow I really thought I needed more power but this shows I can get away with a lot less."  Regardless that isn't the point, it's that people participate not only for their own agenda and knowledge but also to contribute to a thread that may be a great resource for the community. So even if you have a great idea of what your needs are do the test anyway to contribute data to the community for the greater good. Next time someone starts a thread or asks about how much power they may need (remember there will always be noobs jumping into the hobby) they can be guided to the thread where the resources are. I don't expect it to be this exact thread, I already went through the other thread from "Maynard" and wrote down the results of who did the test and will do the same for anyone doing the test in this thread. Eventually if I can gather enough data to have say have 4-5 people for every speaker in the heritage line and other popular models I will make a spreadsheet and start a new thread where it could possibly be sticky'd. Sort of like how there is a thread on frequency vs impedance plots.

 

You are most likely correct, this doesn't seem like it will ever come to fruition. There just isn't going to be enough people willing to contribute to get a decent spreadsheet going.

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41 minutes ago, geezin' said:

I tried tonight with a small Radio Shack autoranging meter but it bounced all over the place. I'll bring home my good meter from work tomorrow.

Had a couple of those trying to get rid of the analog hand-down meter, neither lasted very long and weren't the cheapies.

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On 2/23/2022 at 10:13 PM, captainbeefheart said:

 

I really hope this thread doesn't turn out the same as the other thread. I am several pages through and "Maynard" who started the thread has stated only 3 people so far has done the test out of 72 posts. Most of the posts are just people trying to over complicate the test because they do not understand it. The reason it works so well is because digital sources can only go to 0db so it accounts for headroom.

I appreciate what you are trying to do as a Newcomer to this forum. I did all this even before I got Khorns right after high school. I built my own Stereo LED Voltage meter (using a Resistor Ladder Network) that bounced to the music, later adapted to a light show for my DJ stuff, so not need to do it at all since then.

 

Been there, done that, 45 years ago after reading all the Klipsch Papers and joining the Audio Engineering Society. Upgraded to a Radio Shack version when I got Khorns, which showed 2 Watt PEAKS at really loud levels. End of testing and no need 45 years later since All of my speakers are 100-106 db sensitive as soon as they are plugged in!

 

 

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4 hours ago, captainbeefheart said:

 

Yes exactly I copied Pano's test from there. The results from there show most people really don't need a lot of power but I figured since this is a Klipsch forum and one great thing about most of Klipsch's speaker line especially the Heritage models is their amazing efficiency so I would love to see a lot of people participate here and see the data for a group of mainly high efficient speaker users. Ultimately it would be great if enough people participated and we got enough data that we could sticky the thread. That way there anyone interested in Klipsch speakers can see real world power levels for specific speakers. It would help a lot of people take the guess work out of purchasing speakers and amps and what their power requirements are. I can update the thread with a spreadsheet showing users test results for each speaker used, they can quickly see the number of tests done and the results divided into each speaker model.  So say you own a 300b SET amplifier good for 8 watts and your looking to get new speakers, click on the sticky thread pull up the latest spreadsheet and look through the speaker models to get an idea of what power people use with them on average and maximum levels.

 

 

AHH Very cool... It would be nice to have a good sample from the high efficiency crowd. My results showed 90-95db I need less than half a watt. When I was around 110db it was about 10 watts. That is of course in my room which isn't big. I love big horns nearfield listening. PWK had a great chart.

 

image.thumb.png.0ecf3a1e6e2936fcd3da88c43951d55e.png

 

 

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11 hours ago, babadono said:

Curious what is the damping on those meters? I had a Mac 2105 back in the day, it got stolen long ago (bastards). The meters were S-L-O-W.

 
A google search found the following claim from McIntosh.


"..There are two circuits that give these meters the indicating capability of the short interval power in a sound wave. The first circuit is an accelerating circuit that compensates for the inertia characteristics of the meter movement. Because the short interval power fluctuation is so rapid, the eye might not perceive the instantaneous power reading so a time stretching circuit is employed to delay the meter needle at peak reading for a few milliseconds."

Whether their description is completely accurate or embellished marketing hype, I have no idea.

 

But can tell you with certainty that when the meters show 5 watts the volume is insanely loud. You’d have to be beyond stupid to listen at that level for more than 10 seconds.  

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A quote from Nelson Pass on the other forum regarding power this week. This is with a full range speaker that I assume is pretty efficient but probably not as much as our speakers. 

 

" I haven't seen any mention of the loudspeaker's sensitivity. I have some full rangers that can break your lease with an ACA Mini."

 

The ACA Mini is a few watt diy project. The myth of needing gobs of power with horn speakers is just that, a myth propagated by manufacturers promoting their products. Old timers like myself can remember the power wars in the 70's and from all accounts it worked selling many monster amplifiers. More has to be better, right. 

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8 hours ago, seti said:

 

AHH Very cool... It would be nice to have a good sample from the high efficiency crowd. My results showed 90-95db I need less than half a watt. When I was around 110db it was about 10 watts. That is of course in my room which isn't big. I love big horns nearfield listening. PWK had a great chart.

 

image.thumb.png.0ecf3a1e6e2936fcd3da88c43951d55e.png

 

 

If you are listening over 95db, 100db you can be sure you are going to have hearing problems as you age. Horns are so clean you do have a tendency to increase the volume. If you cannot carry on a conversation while listening you can be sure you are listening too loud. 

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4 hours ago, ODS123 said:

Whether their description is completely accurate or embellished marketing hype, I have no idea.

It's a lay person's description of a peak-sample-and-hold circuit. No hype. Just better words than those understood only by electronic circuit chasers.

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1 hour ago, henry4841 said:

If you are listening over 95db, 100db you can be sure you are going to have hearing problems as you age. Horns are so clean you do have a tendency to increase the volume. If you cannot carry on a conversation while listening you can be sure you are listening too loud. 

OSHA recommendations have dropped from 90 db for 8 hours being save, down to 85 at some point in the last 40- years. My HT is calibrated for 83 db average level, which is the modern standard. I just bough a Montreux 2011 Blue Ray Recording of Santana with DTS-HD on my full Atmos System. Excellent mastering and video quality. It's the same band I heard live outdoors in the summer of that same year in Michigan where I had not control of the volume.

 

This is much cheaper, better sound, and Safer on the Ears. Plus a drink doesn't cost $10 and I can pause for the bathroom run.

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2 hours ago, henry4841 said:

If you are listening over 95db, 100db you can be sure you are going to have hearing problems as you age. Horns are so clean you do have a tendency to increase the volume. If you cannot carry on a conversation while listening you can be sure you are listening too loud. 

 

That was an example senior. No comment for the person that listens at 110db? lol.....  I am usually in the upper 80's with peaks into the 90's. However if a party is involved it does get a bit out of control... I've been thinking of building a mW amplifier to see how little I can get away with... Maybe use some ancient triodes...

 

 

 

 

 

 

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3 hours ago, henry4841 said:

The myth of needing gobs of power with horn speakers is just that, a myth propagated by manufacturers promoting their products

 

15 years ago or so I use to throw regular house parties with my Chorus II's usually cranked so loud in the living room that the bulk of the party would migrate to the kitchen / dining room to mingle and even there would have to talk kind of loud over the music. At that time I cycled through many solid state amplifiers and determined that 200wpc would only get me to about 80% volume without hearing distortion, they would simply run out of gas. It took 300 watts minimum to be able to crank them up as loud as I wanted and still sound clear. 

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1 hour ago, jjptkd said:

 

15 years ago or so I use to throw regular house parties with my Chorus II's usually cranked so loud in the living room that the bulk of the party would migrate to the kitchen / dining room to mingle and even there would have to talk kind of loud over the music. At that time I cycled through many solid state amplifiers and determined that 200wpc would only get me to about 80% volume without hearing distortion, they would simply run out of gas. It took 300 watts minimum to be able to crank them up as loud as I wanted and still sound clear. 

What you say!

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