‘HEAD-ROOM” In response to: 'Another amp for AR-3's

[samberger0357]

18 minutes ago, frankmarsi said:

Oh, early morning riser in the glorious digs of Oakland, CA. huh?

I don't buy your understanding of what "Kimmo" is saying, although it reads well. Not that I know any better but, look at "owlspalce" link here https://en.wikipedia.org/wiki/Damping_factor

Not that I'm a numbers wiz but, from what I've learned 'damping-factor' does matter and it's obvious when hearing the iron-fisted control my woofers enjoy with PL amps high damping factor. I base this on my history of intense listening since I was a little kid listener. Actually, I still do listen with a very critical ear and monitor what my system's bass response is offering up to me everytime I listen.

P.S. watch out for owlsplace because it's apparent my fearful suspicions of his behaving like 'Rama, King of the Jungle' are clearly evident. I mean who else is so fearless to be able to handle what appears to be a baby Diamond Back rattler as he is doing.

No doubt I imagine for a very brief moment he pondered using its skin as a modified woofer surround. Go on owlsplace you know you did.

And good morning to you Prof. Marsi...Yeah, I  like the early mornings. All the quiet I need before I start creating a racket of me own.

Not sure what you "don't buy" re my lack of  understanding of the DF thesis? Are you assuming I know more, or less, then I'm claiming? Because as a wiser man with the last name of Schultz was famous for saying "I know nothing, I see nothing..."

Anyway, still trying to get my arms around this big power vs. low power thing. Over the last 24 hours I've read a lof of different opinions. "You need lots of power"..."Nonsense, I drive my 3's with 25 watts no problem"..."It all depends on ..." Yada yada yada.

So, here I am again, still looking, so questioning, and maybe still being annoying. Sorry 'bout that. A bad habit of mine going on nearly 60 years. Maybe one day I'll fix it. 

Hope things are well in your world this morning. 

[iso]

Frank´s wiki-link is good reading.

" Therefore, damping factor values above 50 or so are not meaningfully different from 50. For higher values of speaker damping than about 50, actual speaker damping no longer increases in any way that can be confirmed by a double-blind A/B listening test, or measure."-quote is something one might call scientific fact. 

Large amount of NFB is the most practical way to make amplifier with so low source impedance that DF can reach figures like 1000 with 8-ohm load.  It seems that large amount of NFB is not good or easy way to make amplifier to reproduce other than test signals. This is one reason why we hear quite often positive comments about tube amplifiers... output transformer make it very difficult to use more than 20-30 dB global feedback due phase shift. Therefore DF of 30 (from 16 ohm tap) is about maximum you could expect to archive with transformer coupled tube amp.  

My point was not to show that global feedback is no-no-no, as there are good and bad amps with high or low amounts of feedback... but to say that DF figure over 20 is very unlikely to be reason for improved sound quality. Instead you should ask yourself how this figure is archived. 

Kimmo

PS    "Perhaps you can dumb it down and let me know if this means that in the real world there shouldn't be much difference between using a solid state amp with a high damping factor(my Adcom has a 500 DF) and a smaller watt tube amp like my Fisher 400."  maybe you should trust in your ears?

[samberger0357]

Got it. Thanks. 

[owlsplace]

12 hours ago, iso said:

PS    "Perhaps you can dumb it down and let me know if this means that in the real world there shouldn't be much difference between using a solid state amp with a high damping factor(my Adcom has a 500 DF) and a smaller watt tube amp like my Fisher 400."  maybe you should trust in your ears?

Yes, excellent idea ... my ears are suspect these days so I occasionally enlist some help ...

Today I was doing some long overdue spring cleaning upstairs and after removing some dbx speakers bought back in the 80s when I was going to college that were serving as fronts in my bedroom HT setup -- I moved the old glass-topped Infinity Column II speakers from the rear to the front just for the heck of it. I really don't need the super-duper home theatre stuff some people like. I mean I bi-amped the dbx's using a Denon Audissey system and played a WWII movie -- PTSD from watching movies in bed is not my idea of a fun time.

Anyway, I flat-lined the EQ on the Denon (pain to work with this unit) and put it in stereo mode. Quick summary was it plays very loud in that small environment and with sub-optimal speaker placement the bass was boomy. Sort of felt like I was in an Irish pub when I went downstairs to make dinner. Long story short is I am not used to hearing music like this -- sort of like wearing clothes that don't fit. These speakers have two woofers, one mid, and two tweets, one of which is back firing. It is an acoustic suspension design. To the point, I don't think the Denon has what it takes to make these speakers sound good. Is it damping factor? Is it headroom? Maybe tomorrow I'll take a few minutes and wire up the QSC ISA280 and see how that sounds with its 200DF@8ohms. TomT likes this amp but I don't have any time on it except to make sure it was working when it came in. It has class AB output with anywhere from 185 to 830W depending on configuration.

This will be the prequel to the "tri-5" project -- three tri-amped AR-5's. Hey, who needs a sub anyway

Roger

[samberger0357]

13 hours ago, iso said:

maybe you should trust in your ears?

I'm trying my friend, I'm trying. 

[frankmarsi]

Just some swipes/clips/culled from the web.

http://thehub.musiciansfriend.com/tech-tips/tech-tip-wattage-speaker-efficiency-amplifier-loudness

""Wattage, power, and SPL

So how many watts does it take to get twice as loud? Let's imagine two amps—one 10 watts, and a second 20 watts. The 20-watt amp is double the power of the 10-watt amp, but doubling the power only translates to an increase of 3dB SPL. Remember, in order to sound "twice as loud," you need an increase of 10dB, so while a 20W amplifier will sound noticeably louder than a 10W amp, it will not sound twice as loud. The same thing holds true at higher wattages—a 100W amp is not going to sound twice as loud as a 50W amp; assuming identical 

speakers, it will only be 3dB louder, which is noticeable, but definitely not a doubling of perceived loudness.

 

http://www.gcaudio.com/resources/howtos/voltageloudness.html

 

""The implications of this comparison in a typical hi-fi system is significant. Let us assume that you are listening to your stereo at a comfortable volume of 8OdB. We will further assume that this level requires 25 peak watts from your amplifier. To just barely increase the volume, we might increase loudness by 3dB. As we can see from the chart, this will require a doubling of power from the amplifier, which will now be churning out 50 peak watts to produce a loudness of 83dB. If we want to double the apparent volume from our original level we will need to create 9OdB of sound pressure, requiring 250 peak watts.

It is obvious from the example above that adequate amplifier power is necessary to provide an accurate portrayal of music. This is especially true when attempting to reproduce realistic levels, or when driving inefficient speakers. However, even small efficient speakers may require copious amounts of power to cleanly reproduce transient peaks. In the final analysis, it is difficult to have too much power. While a small amplifier of only a few watts output can produce surprising average loudness, the dynamic peaks will usually suffer unless the sensitivity of the speaker is very high.

Many individuals I have spoken with are concerned with having "too much" power. The perception is that an amplifier with an output greater than that recommended by the speaker manufacturer would be likely to damage the speaker. This is not necessarily so. Interestingly, an under powered amplifier is more likely to cause speaker damage! During my training at the JBL factory for transducer servicing, I saw more speakers (tweeters/midranges) damaged from use with under powered amplifiers than ones that succumbed to being overdriven. Sound strange? Not really, once you understand what is happening.

When an amplifier is over-driven, it "clips" the wave-form. What was a clean sine wave becomes a distorted, almost square, wave. A square wave is extremely difficult for a speaker to reproduce, as it requires virtually instantaneous starting and stopping of the diaphragm. At sufficient power levels, the tweeter will simply die trying to reproduce this wave-form. A given tweeter rated to handle 50 watts of clean undistorted sine-wave power, will be capable of handling only a fraction of that amount in square-wave input.

As you can see, clean, undistorted power is the key. A 25 watt amplifier, constantly driven to clipping, is more dangerous than a 250 watt amplifier that is never taxed. Of course, let reason prevail. I am not saying that speakers can handle endless input, they cannot. However, extra power does not mean that speaker damage is bound to occur. If common sense is used, any size amplifier can be employed.""

 

 

 

 

And from another site:

 

""Power output and speaker volume is not a linear relationship! Doubling the amplifier/receiver power won't double how loud the music sounds (hint: it's logarithmic). For example, an amplifier/receiver with 100 W per channel will not play twice as loud as an amplifier/receiver with 50 W per channel using the same speakers. In such a situation, the actual difference in maximum loudness would be just slightly louder – the change is only 3 dB. It takes an increase of 10 dB in order to make speakers play twice as loud as before (a 1 dB increase would barely be discernable). Rather, having more amplifier power allows the system to handle musical peaks with greater ease and less strain, which results in better overall sound clarity. There is little point to audio enjoyment if too much power causes the speakers to distort and sound terrible.""

 

I rest my case, I'm done.

FM

 

 

 

And, I bet you didn't know that years ago, one of the ingredients in Coca Cola was cocaine.

[iso]

This is exactly what I did mean when I said few days ago  " Power seems to be such a thing that usually 2-15 wpc is enough for listening, but if this is not enough most likely 100 wpc will not solve "more power"-issue." .

Kimmo

[samberger0357]

1 hour ago, frankmarsi said:

And, I bet you didn't know that years ago, one of the main ingredients in Coca Cola was cocaine.

Heh heh heh...who do you think you're talking to?

[frankmarsi]

3 hours ago, samberger0357 said:

Heh heh heh...who do you think you're talking to?

Ah....... a person who drinks sarsaparilla?

[frankmarsi]

Ciao, sonnar, come sta?

These 'new' amps and according to my limited knowledge may offer more efficient and easier operation but, may be somewhat 'hissy' compared to the 'normal' use intended for such use. Many have been designed for commercial and large 'PA' use.

My own PL amps and pre-amps are a bit 'hissy' but, make up for it in many other glorious ways.

 'A' or 'A/B' design of amps are and have been the accepted as the 'norm' for 'Hi-Fi' use throughout all these years of amp design and were some of the earliest designs. And all of those out there who may be-

perfectionists, class 'A' has always seemed to be their choice. Cost is up there as this design involves different parameters.

They do tend to run hotter than a normal 'A/B' design of amp and even offer a higher degree of power for a low wattage rating but, may actually prove to be more powerful than their wattage ratings indicate.

If I were you, I'd try to learn as much about these designs as possible before I would decide. Keep in mind that their costs are higher than a normal class 'A/B' amp. 

Case in point, the early "Crown" amps were basically designed as strong, brutish amps that in the early 'Golden-Era' were used for heavy usage and not necessarily used for 'Hi-Fi' although at that time were some of the highest power ones available and many folks bought because at the time, there were no others that compared. In 1970-72 Phase Linear adopted many of the Crown and Marantz designs along with many of Bob Carver's own designs and made it possible for at the time for young men like myself to purchase and profitability on a bigger scale was his reward. And although the Crown amps were pretty much rock-solid, they lacked power compared to the first iteration PL-700 Phase Linear amps. With in the same era "BGW" and a few other names followed suit, like "S.A.E" and few others were the accepted entries in that wonderful era that I myself found myself in and I struggled to decide which one I was going to buy with my limited funds.

This BS about Phase Linear being 'sub-par' was brought about because these amps although not intend for PA use were thrust into that world because of their high power ratings. Many a 'roadie' and sound reinforcement folks mis-used these amps profusely and horribly so. 

Companies like "Clair Bros." and a couple of others modified Phase Linear amps to eventually become the standards of large venue usage. Unfortunately, the abusive, unknowledgeable and incorrect usage by 'un-washed' masses forcible garnered the bad reputations of these amps by 'over-fusing' and other sorted abuse unfortunately brought the names of many of these great amps down and scared them even into the present.

Here's a starting point; http://www.audioholics.com/audio-amplifier/amplifier-classes

Keep in mind that the other and newer designs, aka last 25 years or more were produced for specific purposes and although designs have been improved with time, some draw backs may still exist. And/or not be the best one can do for hi-fi/ personal, serious listening.

I'd consult on this with those of which have more qualified information than I.  And some of us know who they are!

Keep me posted of your fact finding.

FM

Ciao, soonar, come sta?

These 'new' amps and according to my limited knowledge may offer more efficient and easier operation but, may be somewhat 'hissy' compared to the 'normal' use intended for such use. Many have been designed for commercial and large 'PA' use.

My own PL amps and pre-amps are a bit 'hissy' but, make up for it in many other glorious ways.

 'A' or 'A/B' design of amps are and have been the accepted 'norm' for 'Hi-Fi' use throughout all these years of amp design and were some of the earliest designs. And all of those out there who may be-

perfectionists, class 'A' has always seemed to be their choice. Cost is up there as this design involves different parameters.

They do tend to run hotter than a normal 'A/B' design of amp and even offer a higher degree of power for a low wattage rating but, may actually prove to be more powerful than their wattage ratings indicate.

If I were you, I'd try to learn as much about these designs as possible before I would decide. Keep in mind that their costs are higher than a normal class 'A/B' amp. 

Case in point, the early "Crown" amps were basically designed as strong, brutish amps that in the early 'Golden-Era' were used for heavy usage and not necessarily used for 'Hi-Fi' although at that time were some of the highest power ones available and many folks bought because at the time, there were no others that compared. In 1970-72 Phase Linear adopted many of the Crown and Marantz designs along with many of Bob Carver's own designs and made it possible for at the time young men like myself were able to purchase such greatness. These amp's popularity and profitability on a big scale was Bob Carver's reward. And although the Crown amps were pretty much rock-solid, they lacked power compared to the first iteration PL-700 Phase Linear amps. With in the same era "BGW" and a few other names followed suit, like "S.A.E" and few others were the accepted entries in that wonderful era that I myself found myself in and I struggled to decide which one I was going to buy with my limited funds. At the time being a fashion photographer's assistant didn't bring me more than $67. a week on 19th Street and Broadway.

This negative BS about Phase Linear was brought about because these amps although not intend for PA use were thrust into that world because of their high power ratings. Many sound reinforcement firms like "Clair Bros." and a couple of others modified Phase Linear amps to eventually become the standards of large venue usage. Unfortunately, the abusive, unknowledgeable and incorrect usage by the 'un-washed' masses forcible garnered the bad reputations of these amps by 'over-fusing' and other sorted abuse had unfortunately brought the names of many of these great amps down and scared them even to the present. It's called the blind leading the blind, and these company's great amps went down with unfounded bad reputations that linger to this day.

Groups like Pink Floyd, Aerosmith, The Who and many others used Phase Linear PL-700 and PL-400 amps exclusively.

Here's a starting point; http://www.audioholics.com/audio-amplifier/amplifier-classes

Keep in mind that the other and newer designs, aka last 25 years or more were produced for specific purposes and although designs have been improved with time, some draw backs may still exist. And/or not be the best one can do for hi-fi/ personal, serious listening.

I'd consult on this with those of which have more qualified information than I.  And some of us know who they are!

Keep me posted of your fact finding.

P.S. My big amps with my AR-LST haven't only made a big different in volume but, more but, the main point is they have afford me a 'BIGGER' sound, much like a real performance, along with more detail, depth, dimension, and realistic portrayal. Turning up the volume control simply makes the sound larger in scope.

The musicians along with their instruments are with me in my room.

A bigger sound, not just loud.  'Bigger', 'Bigger'  I said 'Bigger' as if the performers are in the very same room as you are or that you're in a larger hall!

FM

[genek]

More detailed charts of comparative dB levels:

https://www.chem.purdue.edu/chemsafety/Training/PPETrain/dblevels.htm

Speaker efficiency charts generally use 80-85db as an SPL. As you can see from the chart, that's pretty damned loud.