Sorry about the standard answer... it depends. A very high quality high current design, 50wpc definitely could be fine. Tubes, easily. 30 wpc... tubes probably, maybe solid state... Pass XA30.8 would work. I have had three sets of Sonus Faber. They were all 89db. I am driving mine currently with an Audio Research Ref 160s in triode mode, so 70wpc.
Solid state amps are much more prone to underpowered a set of speakers. I would not go looking for a solid state amp less than 100 wpc unless I was in love with an amp of less power, then I would try it first. The Pass XA series is probably and exception.
I’m not one prone to "get by" with something in high end audio. There are typically compromises before they become obvious and it would take a long time to know... or a comparison to find out. I might play this game in a second system. If I was looking, I would be looking for tubes over 70 wpc and very high quality solid state over 100 wpc.
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It depends on how loud you listen & how big your room is..If you listen at levels around 80db.in a small-medium size room 15 watts of Class A power will,IMO,be plenty..If your listening at levels above 80db.in a big room then you’ll need at least 50 watts Class A..
Another factor to think about is the impedance characteristics..Your speakers may be 8 ohm nominal but they could drop far down into the 3 ohm region & have dramatic phase swings,which are highly stressing on an amp...
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It is a combination of the voltage ease which 91dB @2.83V/1m is very easy load voltage wise but what is the electrical phase shift like? That can mean you'd need a high current amp. But yes plugging these parameters into this calculator -
Even if you sit 12ft away, you'd be getting to 96.7dB SPL peak at your seated position with the 50W maximum tube amp.
But why do you want the tube amp? You already have a competent power amplifier why cripple yourself? @curiousjim
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I think that evaluating specs is an exercise in futility. I had an integrated specced at 300w @8ohm and then moved up to separates with an identically specced amp. The separate amp must be making twice the actual power of the identically specced integrated. Get some gear into your room and trust your ears. I don't trust the measured specs. |
My room is X feet long and Y feet wide and Z feet high. What color should I paint it for best sound? Pretty absurd question right? Please try to think before you post. Ask yourself what is it you really seek to learn.
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You get 91dB @ 1m from 2W. It will drop by 6dB at double distance resulting in 79dB @ 4m. Presence of the second speaker and room reflections add 3dB each resulting in 85dB. 20W of power will produce sufficient 95dB loudness (85dB+10dB).
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@kofibaffour
Opting for a tube amp is hardly “crippling” oneself.
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I regularly drive a pair of JBL 4349s (91dB) with either a Sugden A21 SE Signature (30W class-A solid state) an an AR i/50 (50W push-pull tube, class AB). No issues with either having plenty of power.
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To the OP, I have several pairs of SF speakers. You may want to look at the impedance curve. Many SF speakers have a very low dip in impedance at the low frequencies. The current output may be more important then the power output in watts.
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Sonus Faber speakers are a wolf in sheep's clothing. Starting with the mid-level models and up are very watts and current hungry but just as sensitive with electronics and cables. SF work very well with MAC gear and sounded sublime with Burmester.
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Congratulations on owning such fine speakers.
I have a pair of Kef Reference 3-2.
91dB efficiency at 4 ohms.
I drive them with a Conrad Johnson LP66S tube amp using 6550 tubes.
It delivers about 70 watts per channel in push pull mode.
My CJ preamps volume control goes up to 100.
If I push past 50, I most likely will blow the windows out of the house.
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My speakers have about the same sensitivity as yours and when I am playing at 75 dB I rarely use more than one watt.
Forty to 50 watts is ample power to drive those speakers unless you listen very loud or they are for some reason unable to provide the expected current with the 4 ohms nominal load (which probably can go down to 2 1/2 to 3 ohms at its lowest point).
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I drive a pair of ZU Audio, Omen Def Supremes with a Pass Labs XA 25 class A amp. The speakers are listed as 98 db sensitive and I am using my PS Audio Direct Stream DAC as a volume control (probable not optimal), the room is 24x21x8 and I do have 2 Rythmic 15” down firing sealed subs, my listening position is 12’ from speakers. I can reach 100 db sound levels at my listening position. As someone mentioned above Pass labs may be an outlier when it comes to power rating their equipment. Conclusion I listen to mostly rock and the wife will crank up the Techno(feels like I’m in a German Discotech) while working out and I have never wanted for more power.
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As others have said not all watts are equal- I was dumbfounded by an ARC VT-80 that was rated at 70 watts. It was more dynamic, finessed and detailed than several amps rated at 400 watts or more.
Ideally try and get a demo with your equipment - ideally at your house.
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@billstevenson
"Ask yourself what is it you really seek to learn."
I'm curious. Did you watch a lot of "Kung Fu" when you were younger?
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As others have mentioned, power requirements also depend on the size of your room & volumes you enjoy. In addition, the type of music is a consideration. Quieter acoustic music generally uses little watts but music w/ big dynamics and / or big bass can use 10 times the average power on peaks which is the primary reason for truly needing hundreds of watts/ channel.
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The answer is in your room size and how loudly you listen along with the impedance curve of the speakers. In a 14 x 20 room with a 90dB SPL monitor I use 55w of class a tube power and they are driven well. 25w from a SET mono I have is adequate in the same space. In my 20 x 40 main basement, neither is adequate at reference levels.
My speakers also have a nominal 6ohm impedance. Usually speakers measures at 4ohms are less sensitive than the measured spec due strictly to the way it is calculated. See any review for Tekton in Stereophile. It is in how the math is done.
so the answer is maybe, possibly probably but need to know more.
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- My input on the output required.
Simple logic….. l am not an engineer but time has taught me a few things which l put on offer and share here.
1. Just make sure your amplifier is not having to work flat out to drive your speakers.
2. Some people may think their amplifiers are matched just because their speakers go loud.
3. Remember 4 ohm and 6 ohm speakers draw more watts per channel power than 8 ohm
Amplifiers must have a reservoir of extra power to draw on for when the music demands. Underpowered and there will be clipping, distortion and in extreme circumstance’s the amplifier unable to control the drivers. Sometimes the cones can get torn or distorted and written off when an amplifier looses control.
In simple terms a mismatched amplifier will overheat and possibly fail, (if no protection circuits) and could ruin your speakers.
A comparison would be equivalent to putting an English Mini engine into a racing car. It would work fine at first but inevitably burn itself out.
Simple facts but as true today as when l started with hi-fi back in the 1960s.
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@kofibaffour
I said class A watts. I never mentioned Tubes. But now that you mention it, there’s an ARC 80S amplifier listed elsewhere that peaked my curiosity.😁 It uses 4KT 150’s and can put out 70 watts.
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ARC Ref 80S + Sonus Faber is an excellent match.
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@curiousjim like I said you don't need a new amp but if you wanna dabble regardless that's your decision. Have fun :)
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@ghdprentice
George, I knew when I mentioned the Ref 80s that you’d chime in.😁
Do you have an older Amati model? The G5 ( which I have) is 91 db, so that makes me agree with you even more about 70 watts being more than enough.
Now to start working on the wife.
Wish me luck.🤞🏻🤞🏻
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Older ones.
Buy your wife a really extravagant, heart felt gift before casually mentioning it. Mention in the afterglow.
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Agree with @ghdprentice . My Pass XA25 pure class A can drive my 91 db Dynaudio at 4 ohms. Room size will be a factor to consider however. Mine is 10x 19 .
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@curiousjim ,I have a small Chinese made Pure Class A integrated amplifier that is based on the original Sugden A21..Puts out 15wpc.@8 ohms & can drive a 4 ohm speaker...
I would be willing to let you borrow it any time as it's just sitting in it's box..You pay round trip shipping...Cheaper than buying & trying...
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@freediver
Thank you!
That is incredible generous of you and I will definitely keep it in mind.
curiousjim ,I have a small Chinese made Pure Class A integrated amplifier that is based on the original Sugden A21..Puts out 15wpc.@8 ohms & can drive a 4 ohm speaker...
I would be willing to let you borrow it any time as it’s just sitting in it’s box..You pay round trip shipping...Cheaper than buying & trying
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No one did any math....91 db sensitivity would give you 101 db at 10 watts or 111 db at 100 watts. That is for the peaks in the music...if the peak levels you experience when you listen are less than 111 db, which they probably are, 100 watts is a healthy choice. That means the amp won't struggle to keep up with the demand. Chances are, at most real world and sane levels, 30-50 watts of high current amplification would be perfectly adequate.
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Actually, no..., the difference between 1 watt and 100 watts would be less than 20 dB because the speakers will undergo power/thermal compression at higher power levels (especially sustained) and this reduces their dB output. The reduction could be substantial.
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What you are saying is true but as a rough estimate my approach gets you in the ballpark of what you are looking for. Speakers that are rated for much higher power than 100 watts won’t suffer significant power compression or at least they shouldn’t. How much there is is going to be depends on the dynamics of the music...if its heavy metal head banging stuff then this is a real possibility due to the lack of dynamic range in the music. Classical guitar would be a whole different ball of wax. I would expect a speaker rated for 400 watts to be able to handle 100 watts with little to no compression. After all that is 6 db less than rated power.
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No experience with Coda. An under the radar company that produces high current amplifiers you might find interesting. https://coda.cc/amplifiers
This is not a suggestion, just my experience.
According to Audio Science Review (I have no knowledge or reason not to trust his methods) my Carver 180 watt KT120 tube monos measured the most distortion he’s ever measured yet they sound absolutely stunning driving my very revealing Avalon Acoustics Eidolon speakers. Better presentation than my legendary sanctified Marantz 8B.
As tube amps go the Carvers run cool and are easy on the power tubes.
Good luck with your search.
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Two things for me when thinking about this. 1. Headroom, going from the PS Audio amp that has tons of headroom to something much much smaller that may not have that extra in the gas tank.
2. Damping factor, going to small tube class A amp you might be lacking there compared to the PS Audio amp probably has DF in spades.
But I think overall you should be fine. Your ears will tell you if the SF speakers will get enough to sing.
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"I would expect a speaker rated for 400 watts to be able to handle 100 watts with little to no compression. After all that is 6 db less than rated power."
You would be surprised!
I use JBL 2241H 18" woofers rated at 600 watts continuous. These were redeveloped from the 2240 specifically to overcome the effects of power compression.
At 600 watts, they loose 4.3 dB.
At 300 watts, (i.e., -3 dB), they loose 2.6 dB.
At 60 watts (i.e., -10 dB), they loose 0.8 dB.
As I noted, these are 18" woofers with 4" vented voice coils specifically designed to mitigate power compression and I can imagine that a "lesser" woofer would undergo more compression that this.
https://jblpro.com/products/2241H
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I have speakers that are 89spl efficient. My 30wpc primaluna with EL34 power tubes has no problem with sound level in a 20ftx 15ft room. I have drapes covering an 8x6 window, fabric furniture and carpet. The room size and what you have in it is a determing factor. With the power your system has you should be able to blow off your roof. 😆
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I have an Elekit 8900 I use with 93db speakers NX Otica with the OB subs. I started out with 300b tubes and had plenty of volume and recently decided to try 3.5 watt 2a3 tubes. Surprisingly, it sounds better to my ear even with what most would consider an under powered amp. I don’t listen loud anymore, but it easily plays loud enough for my normal listening levels. I listen sometimes in the mid 70DBA range with measured peaks in the mid 90db range and it sounds unrestrained and enjoyable to me.
I am using a high pass filter so the signal to the amp starts rolling off at 80hz, I have plenty of punchy and defined bass and even watch movies with this setup and it never sounds strained, keeping in mind I don’t listen real loud anymore. I’m not sure how much head room I save from this setup, but I think letting subs handle some of the bass helps when using low powered amps that otherwise could sound more strained or run out of juice before reaching satisfying listening levels.
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I used to drive a pair of B&W 805s (sensitivity of 87) with my Cary V-12 switched to 50 wpc triode most of the time, and I always thought it did fine. It has been so long ago since I have listened at ear bleed levels that I cannot remember if I (always) went 100 wpc ultralinear or not. I know that some of thee times I did.
About a year ago I put a pair of Revel M126BE's (rated at 86) in my system and I was liking it in 50 wpc triode, but a while ago I decided to try 100 wpc ultralinear and I found that I actually preferred that effect. But it may have just been the 'something different effect.'
I would THINK that 50 wpc of good power should work well with speakers rated at 91, but the more I read the less I feel I know. I am now almost thinking that maybe the speakers lowest impedance may be more important than the sensitivity rating.
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I happen to have focal Sopra 2 speakers 91db efficient at 8 ohms
I have a 45wpc Pathos inpole integrated amp 45wpv 8 ohms and 75 wpc into 4 ohms my room is big 30x 16x8 but I only sit 11 feet from them .itcan playinto 95db peaks it weighs 86 lbs and a dual mono design .the question is how often do you need to play a tear damaging level ? In class A it does get warm over 100 degrees sonically superior to class AB and the Patented Inpol technology it uses the 4 vacuum tubes for again stage to power the speakers as well as to the resistor ladder preamp section , and has dual linear power suppliesforthepreampsectiin to big inductor transformers ,Mosfets, then potted torroidal transformers to the output section . For me it’s plenty loud and very tunefull and detailed Pathos makes a great hand built product from Italy.
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I was at a dealership yesterday chatting with two other customers who own very expensive 12 watt amps. We were listening to custom built horn systems and I assumed that is what we all ran. I was surprised that one ran a pair of 89 db/w tower speakers. It wasn’t surprising to me that these amps can handle such speakers, it was just that he had $70k or more of amps and linestage powering so comparatively modest speakers.
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Had a pair 4367. Woofer sensitivity is 94db with the mid/tweeter resisted to match. A seventy-WPC VAC amp and a 150-watt Hegel amp could not properly control the woofers. I had a sense of it at the time, but it was obvious after replacing them with a 300 watt ML amp. The issue wasn't room size or volume level but of bass dynamics and articulation. I now have 85db speakers which are much less sensitive between the Hegel and ML amps. I use this is an example of how I have never related volume, room size and sensitivity to amplifier power requirements. Before that may come in to play, I already hear bass problems. That's my experience, though. curiousjim already has a good reference point.
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I would like to thank everyone except @billstevenson for giving me intelligent and helpful answers. I’m going to borrow a friend’s DVR that even though it class D, it’s rated at @75 watts per channel, so I should be able to get an idea.
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If your going to check out a class D amplifer, you may wish to consider the Hypex Nilai 500.... Great reviews :-)
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An amplifier power in Watts is not an absolute measure of power. A standard example, 50 watts in a tube amp can be equivalent to double of Watts in a solid state amplifier. My 5 Watts SET amplifier drives surprisingly good my 87 DB speakers, my normal listening level is less than 20 % of max volume. If you want a guaranteed outcome with a 50 Watts amplifier with your speakers choose a tube amplifier.
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@quincy
Sorry. Somehow I missed your post. Before the Sonus Farbers, I had a pair of KEF Reference 5’s and they were very dynamic. Normally I don’t play loud, but the other day I played Tricycle by Flim & The BB’s for my wife. Don’t know if you’re familiar with the tune, but it starts off with a piano playing and then it gets LOUD for a second and then goes back to the piano. My amps are class A/B. The first 10 are A and Class B up to supposedly 600 at 4ohms. Other than having to scrape my wife off the ceiling everything sounded great.
Do you think your amps could handle the dynamic range when played loud?
Thanks.
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@curiousjim I believe so. I also have a pair of very nice SVS unported sub woofers working in the system as well. They have their own Class D power amps rated at (If I recall properly) 600 Watts x 2. I have a tendency to play my music louder than normal since my hearing is less than stellar.
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@niodari
See the post above I sent to @quincy . My amps are Class A for the first 10 watts and I rarely use all 10, but I’m sure I went wayyy above the 10 when I was playing tunes for my wife.😁 I might have hit 50 watts or I may have hit 300. I didn’t check the dbs. Maybe I should have.
Out of curiosity, have you ever played Tricycle on your system? If you do, keep the volume way down the first go round.
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@curiousjim Take care of your ears. Above sone threshold, the louder you listen the more is the distortion, you can note this even in live performances, more in home audio. I didn't put that track on my system but I can try if you are interested in some particular performance issue. At this moment I'm listening to Mozart's symphony 41 on LP and would like to continue. This morning I listened to Ozzy Osbourne's late (2001) solo album. It is recorded too loud, I listened it also quite loud (my wife was not at home!) on my SS class d amplifier. The distortion during the recording session is quite notable. But it is somehow unavoidable in this kind of music. Surprisingly, some tracks on "Master of Reality" are better recorded.
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