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Lascala amp requirements?


Allhartfidelity

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On 2/13/2017 at 11:22 AM, scalawag said:

I'm in agreement with previous posters on the very low watts needed to power a set of Klipschs.  Every now and then I will run my Yam CA-2010 in class "A" just to give it some exercise, and the 30wpc is way more than enough to drive my 'Scalas to very painful levels.  Wish you luck on your search!

 

IMG_0146_zpsalyymyiu.jpg

 

Now, that is a beauty!!!  Now back to the topic at hand.

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On 2/15/2017 at 2:26 PM, mr.pee1 said:

Gosh, I like my Dynaco st 70 so much with the LaScalas that I have bought a VPI classic 1 turntable . So I can play LPs . I am getting rid of the  Adcom 5500 I have been using for 21 years. I do listen "loud"

What preamp do you use if i may ask?

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On 2/16/2017 at 4:20 PM, TubeHiFiNut said:

The Quicksilver Horn Mono and Mid Mono amps are both very synergistic matches for your La Scalas.

 

In my opinion, you will have to spend considerably more money to get anything better.

Thank you for the input, amd thats what im hoping. plan to sell the vtl mb450 and buy a pair of the Horn Mono

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On 2/13/2017 at 0:45 PM, Allhartfidelity said:

   Thank you for the math you provide there. I will need to research and try and understand what a db essentially does in my room, andhow  variouse voltages obtain these levels. perhaps a db or sound meter of some sort? Measure voltage out at some comfortable level and see exactly how many watts i produce and at what db the room is? use this to calculate amp power requirements ? 

  does this sound logical? Seems doable actually. I have indeed measured the output of many, perhaps i will find a decent sound meter of sorts... great idea, thank you! (Did i run away with that a little? ););)

 

You can measure average voltage* from the output of the amp and use W=V^2/R to figure average power.

Average power in watts is average voltage squared, divided by the load impedance.

So for example, 15 volts average...

 

(* Since the voltage is AC, the long term average is zero if you use a simple volt meter. You need a modern meter that is designed to measure AC voltage, or an old VTVM (vacuum tube voltage meter) with an AC probe.)

 

W = (15 x 15) / 8

W = 225 / 8

W = 28 watts (28.125)

 

You can specify watts and figure the voltage

W=V^2/R

so

W * R = V^2

V = SQRT( W * R)

 

So you might ask how much voltage is one watt (into 8 ohms)?

 

V = SQRT( 1 * 8)

V = SQRT(8)

V = 2.83 volts (2.828)

 

Sensitivity of speakers is measured with 2.82 volts (so 8 ohm speakers will be getting 1 watt)

 

+20dB is a convenient figure for dynamic headroom over average level because it is a linear factor of 100.

That means figuring the clean average level of power from an amp is easy - divide the rated power by 100.

A 30W amp will have clean +20 peaks when its average output power is limited to 0.3W (or 300mw milliwatts).

 

The conversion of output power to speaker sound level depends on its sensitivity, distance, and room gain. The distance and room gain often balance each other out.

An average output level of 300mw in typical large rooms with La Scalas is going to be very loud. My loudest average listening level is about 10mw... that is only 1/100 of a watt. That seem a little crazy, but La Scalas are about 20dB more sensitive than average speakers. That is a linear factor of 100, that is like using a regular speaker with a sensitivity of 85dB/2.83V with a 100W rated amp played at its maximum clean average output of 1W - the result is about 85dB sound level in the room, same as the La Scalas with 10mw.

 

85dB is about the standard level agreed around the world for monitoring during engineering of recordings in studios throughout the decades of record production. This is the level at which the engineer established the tonal balance and many other things.

 

With La Scalas, you should focus on the quality of sound at very low powers. All amps will have more than enough power for La Scalas; the question is how good do the amps sound running at low power. The specifications for amps don't show below 100mw because it takes much more expensive instrumentation to measure down there... and there are some very expensive amps that show high distortion levels down there.

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1 hour ago, pauln said:

An average output level of 300mw in typical large rooms with La Scalas is going to be very loud. My loudest average listening level is about 10mw... that is only 1/100 of a watt. That seem a little crazy, but La Scalas are about 20dB more sensitive than average speakers. That is a linear factor of 100, that is like using a regular speaker with a sensitivity of 85dB/2.83V with a 100W rated amp played at its maximum clean average output of 1W - the result is about 85dB sound level in the room, same as the La Scalas with 10mw.

 

85dB is about the standard level agreed around the world for monitoring during engineering of recordings in studios throughout the decades of record production. This is the level at which the engineer established the tonal balance and many other things.

 

With La Scalas, you should focus on the quality of sound at very low powers. All amps will have more than enough power for La Scalas; the question is how good do the amps sound running at low power. The specifications for amps don't show below 100mw because it takes much more expensive instrumentation to measure down there... and there are some very expensive amps that show high distortion levels down there.

Thanks for re-stating this.  There have been a number of similar discussions in the tubes section.  At 6 feet from LSs, 1/2 wpc will provide around a 100 db level.  So, a 5 wpc amp will provide 10 db of headroom which I can't possibly imagine would not be enough at that level.  Going to a 50 wpc amp to get things up to 120 db seems totally insane to me (I know that the high power SS guys disagree with this).  Single ended amps are wonderful in that their distortion is directly proportional to output power.  An amp which has, say, 2% thd at 5 watts out will have distortion in the range of the best SS amps when delivering 1/2 watt.  One needs to tailor the amp to the individual system needs as opposed to going for a blanket recommendation.  And, in the case of low power amps, the monetary savings can be substantial.

 

Maynard

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7 hours ago, tube fanatic said:

Thanks for re-stating this.  There have been a number of similar discussions in the tubes section.  At 6 feet from LSs, 1/2 wpc will provide around a 100 db level.  So, a 5 wpc amp will provide 10 db of headroom which I can't possibly imagine would not be enough at that level.  Going to a 50 wpc amp to get things up to 120 db seems totally insane to me (I know that the high power SS guys disagree with this).  Single ended amps are wonderful in that their distortion is directly proportional to output power.  An amp which has, say, 2% thd at 5 watts out will have distortion in the range of the best SS amps when delivering 1/2 watt.  One needs to tailor the amp to the individual system needs as opposed to going for a blanket recommendation.  And, in the case of low power amps, the monetary savings can be substantial.

 

Maynard

Very informative, thank you to you both. In particular, the mention of distortion levels at low output. Though my xovers are not designed to sound thier best at low power, my understanding is that horns themselves can be susceptible to this distortion. That said, while i have not done a listening test to see if i can even detect such things  that show on paper (measurments gauged by instruments and written on paper) i am none the less inclined to believ and follow this line of reason. This same logic also interested me in the Quicksilver Horn Mono, as he mentions the same distortion there in his writup, and as the builder also listens to horns. 

  While uncertain as the 85db and its effect, i look forward to hearing some differences. My lowest sensative speaker is currently the Chapman T-7 Tall Boy. Specs aside, somewhere between 85 and 87 db. 

     As far as the Lascala, my xovers are biampable. I did have great success in biamp of my ADS 2030 speakers, as well as the 1590, and 980. (All ADS) My only concluson is therefore to use the 25watt Horn mono on mid/high region ,  and a SS amp on the cone woofers. If, i can get xover/slopes correct, this seems to allow me best woofer control on a 15" cone that is less sensative than the rest. 

  currently augmenting the bass with dual JL audio Fathom f112 subs, and not entirely pleased.

   thank you all so much for your inputs .  i do realize there is subjectivity  here, and do my best to consider most importantly sound level, and room variance . 

  soon will also put an EV T-350 on the tops, and move them back to the mid horn location  as also suggested elsewhere . Though i do hear that the 2 way design may be ideal, i am currently unable to comprehend how to do this so will learn in short steps. 

Many thanks to all! Very enjoyable journey indeed.

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18 hours ago, Allhartfidelity said:

Thank you for the input, amd thats what im hoping. plan to sell the vtl mb450 and buy a pair of the Horn Mono

 

The Quicksilver Horn Mono amps are very special on the La Scalas.

 

Not trying to confuse the issue but you should also, as others have stated, listen to some nice SET amps on the La Scalas. :D

 

 

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On 2/13/2017 at 11:22 AM, scalawag said:

I'm in agreement with previous posters on the very low watts needed to power a set of Klipschs.  Every now and then I will run my Yam CA-2010 in class "A" just to give it some exercise, and the 30wpc is way more than enough to drive my 'Scalas to very painful levels.  Wish you luck on your search!

 

IMG_0146_zpsalyymyiu.jpg

 

That is really nice!  I like the darker cabinet... was that original?  Mine and matching mint CT-1010 are the lighter finish.

Not to divert from the topic too much I vote for VRD's.  That is what I use with my La Scalas.

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4 hours ago, muel said:

That is really nice!  I like the darker cabinet... was that original?  Mine and matching mint CT-1010 are the lighter finish....

With apologies to the OP for getting "off track," thanks for the compliment!  And you've guessed correctly, the CA-2010 is not wearing the original tint - I refinished it some time ago with Varathane Premium Wood Stain in "Cabernet."  Three coats with very light sanding in between, no top clear.  Here are my two Yam CA's side-by-side for comparison - the 2010 drives the 'Scalas in front and the 1000 (original finish) drives the RP250s in back.  Both CA's normally reside in the console below the Carver Pre, Onkyo CD player, and a Technics TT.  Happy listening!

 

2%20Yam%20Ca%20Amps_zpspw67kggb.jpg

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21 hours ago, TubeHiFiNut said:

 

The Quicksilver Horn Mono amps are very special on the La Scalas.

 

Not trying to confuse the issue but you should also, as others have stated, listen to some nice SET amps on the La Scalas. :D

 

 

Is not the Horn Mono a SET amp?

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  • 6 months later...

I have two la scala and I just bought a center speaker and two book shelf speakers. What channel should I put the la scala on? I also have a subwoofer as well the book shelf and center speaker are klipsch. I have a dennon reciever that has 120rmswatts by 7 at 8 ohms. Any help will be appreciated.

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Probably the CHEAPEST route you can take would be an old early to mid 1970's H/K 430 or 730 model twin-powered receiver.  Their twin powering belies their 25 and 35 WPC RMS rating which was very conservatively rated to begin with.  They sound marvelous with LaScalas, and have the OOMPF to rock the joint both inside and outside the house. 

 

Those who know will back this up, and a number of forum members KNOW!  I had people over a mile away from me sitting out back on their patio enjoying some LaScalas back in the day with an H/K receiver that only pushed 32 WPC from  that same era pushing a pair of Skalawags backed up to the rear of the house...it was a H/K 900+ model.  The next Mondazy morning, when I got to work at Klipsch, the homeowner who lived over a mile away asked me: "Was that you and some outside Skalawags the other day?"...I said "yes"...he replied:  "Not really MY KIND of MUSIC, but the wife and I sat out back on the patio with a pitcher of iced tea and enjoyed them for a couple of hours!  How many watts was pushing them?"...I told him that the receiver was rated at 32 WPC, but the volume control never went past 9 o'clock or so"...and he laughed and said..."It sure doesn't take much to get those big horns busy does it?"...'nuff said!

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My favorite amps for my LaScalas are my 2A3 SET amps, at about 3.5 watts each. Awesome detail and will still rock the house as much as I need. Unfortunately, one of the amps is down for repair and needs some work.

 

Bruce

 

 

Welborn Labs 2A3 Moondogs_sm.jpg

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  • 3 years later...

Hi Tom...wlcome to the forums. As much as I hate to use it  the word 'synergy' also plays a part. Some amps don't sound good with some speakers. Some speakers don't sound as good until the volume is up a bit. Some crossovers need to be pushed before sounding good, such as the aftermarket  ALK extreme slope models.

 

Most all klipsch are very efficient, and will work well with lower powered amps (tube or ss).  For me, a 20-50 wpc amp is plenty.

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  Depends on what you want. Many like a “sound” that adds warmth and richer overtones. Others prefer a neutral sound, Straight Wire with Gain. 

  There are many great performing amps out there. Look for a THD + N versus output power plot. The power range of 20 mW to 200 mW is what you are looking for.

  The Purifi based amps have incredible specs in this output range. So does the Orchard Audio Starkcrimson Mono amps. The Benchmark AHB2 is another. 

  I doubt you could tell these three options apart if blind listening. Once the distortion plus noise is 0.000x% the other parts of the playback chain dominate nonlinearities. 

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