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Low Wattage Tube Amps - 6 Watts enough for La Scalas?


CharlieFromVB

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I have a new set of La Scalas and run them with a 50 WPC Black Ice Audio tube amp.  They sound fantastic.  I am, however, considering swapping the amp out for a different look that I'm wanting to achieve for my den (yes, I know a bit shallow, but work with me here).  I am considering a setup from Decware.  The styling on these amps are unbeatable and I've yet to read a bad word about them or the company.  So, I'm strongly considering a pair of their small amps that run at 6 watts in a monoblock configuration, fronted by their Ultra Preamp.  My question to the broader community: Do you believe 6 watts is enough for the La Scalas?  

 

The listening room is fairly large with high, cathedral type ceilings.  I do like to crank them up from time-to-time, but can only take so much.  I also use the La Scalas as fronts to a home theater system.

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11 hours ago, CharlieFromVB said:

I have a new set of La Scalas and run them with a 50 WPC Black Ice Audio tube amp.  They sound fantastic.  I am, however, considering swapping the amp out for a different look that I'm wanting to achieve for my den (yes, I know a bit shallow, but work with me here).  I am considering a setup from Decware.  The styling on these amps are unbeatable and I've yet to read a bad word about them or the company.  So, I'm strongly considering a pair of their small amps that run at 6 watts in a monoblock configuration, fronted by their Ultra Preamp.  My question to the broader community: Do you believe 6 watts is enough for the La Scalas?  

 

The listening room is fairly large with high, cathedral type ceilings.  I do like to crank them up from time-to-time, but can only take so much.  I also use the La Scalas as fronts to a home theater system.

Some use 2A3 amps which are only a few watts , and they are satisfied ,   but given you have a large and cathedral ceiling , and you like to play them loud ,  you have to factor in the distortion levels as well

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Well, if 6 watts is enough for any speaker, it should be enough with a La Scala.

 

In my fairly big room with a high ceiling, I figure 6 watts into a Klipschorn (same sensitivity as a La Scala) will produce about 102 dB, with instantaneous peaks higher.  But, there would be only a small safety factor.  THX, in a large home theater, wants ~~~ 102 dB above about 80 Hz, and the capacity for 112 dB below 80 Hz.  This takes into account the multiple early reflections in the typical large home room.  In a large cinema, reference level peaks are 105 db above 80 Hz, and 115 dB below.

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10 hours ago, dwilawyer said:

Welcome to the Forum, you will get a lot of responses on this, looking forward to reading them myself. If may get more attention in the "Talking Tubes" section, so if you would like me to move it there let me know and I would be happy to do so.

 

Travis

Hi Travis.  Yes, you are probably right.  I didn't even notice the "Talking Tubes" section.  It seems it would get more traction there.  So, yes, go ahead and move to that forum.  Thank you. 

/ck

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I’m using a 12 w a side Class A Unison Research Simply Italy integrated tube amp with La Scala’s in a 12 x 24 room with 8 foot ceilings. I can reach nose bleed sound levels if I wanted to. I rarely need to turn my volume knob more then 8 o’clock to reach a pleasant listening level. (Clock face on my volume starts at 7 o’clock and goes to 5 o’clock) Hope that made sense lol


Couple of  things That could be issues are the height of the ceilings and the lack of bass when watching movies as your room is large.

 

Hopefully you can try or borrow a low watt amp to try before buying.

 

Good luck.

 

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On 7/27/2020 at 12:49 AM, garyrc said:

Well, if 6 watts is enough for any speaker, it should be enough with a La Scala.

 

In my fairly big room with a high ceiling, I figure 6 watts into a Klipschorn (same sensitivity as a La Scala) will produce about 102 dB, with instantaneous peaks higher.  But, there would be only a small safety factor.  THX, in a large home theater, wants ~~~ 102 dB above about 80 Hz, and the capacity for 112 dB below 80 Hz.  This takes into account the multiple early reflections in the typical large home room.  In a large cinema, reference level peaks are 105 db above 80 Hz, and 115 dB below.

This is good information.  Thank you so much.  And yes, if 6 watts isn't good enough for the La Scalas, what's the point in making the amp.

 

So, I've found some amplifier calculators; one from Crown that I used.  If I'm understanding this correctly, and I've plugged the right values in, it's calculating that I need 3 watts for the La Scalas to hit the peaks of 115 db.  So, running a 6 watt monoblock to each speaker s/b enough.  Am I looking at this correctly?

 

image.thumb.png.48f44512ecc66b49d85cf9b0c5a9742b.png

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1 hour ago, CharlieFromVB said:

So, I've found some amplifier calculators; one from Crown that I used.  If I'm understanding this correctly, and I've plugged the right values in, it's calculating that I need 3 watts for the La Scalas to hit the peaks of 115 db.  So, running a 6 watt monoblock to each speaker s/b enough.  Am I looking at this correctly?

YES. I used to run a 6 Watt amplifier on my LaScala center channel about 12 years ago. The calculator is correct.

 

In my small basement room about 10 years ago, I measured about 50 Milliwatts per speaker to get 85 db at my sweet spot. You gotta love HORNS!!

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I once ran a pair of Transcendent SE-OTL amps.  1 1/2 watts in stereo mode or 4 watts per mono block if bridged.

 

I ran them bridged.

 

Though they were arguably the nicest SOUNDING amps I've ever had in my system (Khorns at the time), every time I'd turn them up beyond what I'd call "toe tapping" levels, they pooped out, frustrating me that I couldn't get more of that glorious sound out of them.

 

I finally sold them.

 

I think it really depends on how you like to listen.  If you sit there and focus on what you're hearing, I'd suppose these are enough.  If you leave the room to do something like make dinner and want to turn them up louder so you can hear while in the kitchen....  well, for me, it was a fail.

 

 

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Though I am using more power now for other reasons, I used a 4 watt SEP to power my La Scalas for years.  With a powered sub taking the low-bass load away from the little amp, I had no problem reaching hearing-damage levels of loudness.  6 watts is absolutely plenty for La Scalas in an indoor setting.  Only reason you would ever need more is if you were playing outdoors to a crowd.

 

 

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I've used three different amps on my La Scalas...

 

2A3 monoblocks at 3.5 watts each

Modified Crown D45 at 35 WPC

Crown XLi 800 at 300 WPC

 

The 2A3 work for me most of the time, as I don't play much rock, the D45 is the sweetest, rivaling the sound I get from the tube amps, but more solid bass. The XLi is good for taking the LS out to parties...  😆, and still sounds good.

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It may depend on what you play on them and how you listen. I expect you will note undue congestion or loss of clarity in loud, complicated passages, especially in the bass, if your wattage isn't adequate.  I think it wouldn't be adequate for me.  Your sound quality may influence what music you play.   --Larry

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12 hours ago, CharlieFromVB said:

This is good information.  Thank you so much.  And yes, if 6 watts isn't good enough for the La Scalas, what's the point in making the amp.

 

So, I've found some amplifier calculators; one from Crown that I used.  If I'm understanding this correctly, and I've plugged the right values in, it's calculating that I need 3 watts for the La Scalas to hit the peaks of 115 db.  So, running a 6 watt monoblock to each speaker s/b enough.  Am I looking at this correctly?

 

image.thumb.png.48f44512ecc66b49d85cf9b0c5a9742b.png

 

Well, I don't know.

 

First, I need to say that my gut says that 6 watts would be enough for the La Scalas, for most people, but not for me, as Gershwin might say.

  1.  85 dB desired (continuous?) power is 30 dB below the 115 db (presumably peak) you got ("it's calculating that I need 3 watts for the La Scalas to hit the peaks of 115 db.").  The usual peak margin for the THX folk (and others) is 20 dB, and many amps have a hard time putting out 3 dB above the continuous rating -- the $85,000, 2,000 watt McIntosh puts out 6 dB on peaks, and it is a "just" a, monoblock, so one would need to buy two (three boxes each) for stereo.    In 1977, Paul Klipsch and Don B. Keele, Jr. put out a paper* indicating that a La Scala in a typical 3,000 cu. ft. room being fed 6.3 watts would put out 105 dB (no listening distance given).  They also indicated that there could be peaks 10 dB higher (from an excellent amp ?), which would give you extremely brief (truly instantaneous ?😕) peaks of 115 dB.  I wonder if these peaks would be just a few milliseconds long -- the leading edge only, of a peak.  To produce a 115 dB peak, I would presume that just for that moment, just for that handful of ms, would need a surge of 63 watts.  In their paper, they characterized your 85 dB as "medium level," which  seems about right to me.  When I have measured a live full orchestra from about row 10, "C weighting," "fast" I usually got about 85 dB for a normal, loud-ish passage (f ?),but at the end of a Beethoven or Mahler symphony, or The Great Gate of Kiev or The Firebird, or Fanfare for the Common Man (ff or fff?), I would typically get about 105 - 110 dB, and my meter was not one of the peak reading types.  In a room in a home, unless it's very absorptive, loud sounds will sound a few dB louder than the SPL, reads because of those usual, sometimes noxious, early reflections.  If you are ever tempted to turn up the bass (likely with the La Scala, because it starts rolling off below the high 50s Hz), you will use more, "soak up" more, watts.  This does not apply, of course, if you have a subwoofer ... but if you get one, I hope it  is a horn type, to keep the bass as clean as it is with the La Scala.  I didn't do that when setting up my Khorn room, and regret it.
  2. Where did you get 11 dB as "amplifier headroom?"  Does Decware claim that, or did a "bench test" from a magazine find that, or did you measure them yourself?  That seems awfully high.
  3. Here's what I get, plugging in the 105 dB sensitivity of a modern La Scala (in a "typical" room, about 101 dB in an anechoic chamber), and looking at an SPL of 98 dB (PWK "Loud level"): To produce 98 dB at 4 meters takes 6 watts.  With the usual 3 dB headroom, that would provide a conceivable peak of 101 dB, but depending on it makes me nervous.  If your amp really has 11 dB headroom, about 109db ... I would think, if I'm doing this right!

* Dope from Hope Vo. 16, No1, January 1977 available online.

image.png6

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When a fellow member came to pickup his new Khorns I already had Jubes in place and at the time had 2a3 monos running them. They pushed the Jubes just fine until his wife asked for a little louder, then a little little louder. At this point they were pretty damn loud but you could tell they reaching their limits. Two and half to three watts is, well after all, 2-3 watts. 

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10 minutes ago, richieb said:

When a fellow member came to pickup his new Khorns I already had Jubes in place and at the time had 2a3 monos running them. They pushed the Jubes just fine until his wife asked for a little louder, then a little little louder. At this point they were pretty damn loud but you could tell they reaching their limits. Two and half to three watts is, well after all, 2-3 watts. 

That's odd! She seemed like the nice one. Her husband was the annoying one.

 

 

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12 hours ago, tube fanatic said:

Instead of debating how much power is needed, why not measure it?  
 

https://community.klipsch.com/index.php?/topic/170414-who-wants-to-measure-how-much-power-voltage-is-really-needed/

 

That said, I have powered LS systems with as little as 300 milliwatts per channel and it was far more than needed.  
 

 

Maynard

WWPWKD? He would calculate/measure it, but he could probably do that in his head, and he could also tell you the derivation. After that he would make you a handmade slide rule type thing  specifically for your speakers that you could calculate this on the fly (I'm not kidding about that, he did exactly that for performance criteria for his specific airplanes he made himself).

 

He is often quoted as saying "what America needs a a really good one watt amplifier" but I have heard that has been taken a bit out of context, I don't know for sure.

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