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I recently bought (but have not yet received) a used Raven Nighthawk MK2. The amp is rated at 20wpc, but all the reviews seem to say that it punches above its weight.
I was reading a thread about pairing "low power" tube amps with inefficient speakers, and was a little worried that the Raven would fall a bit short on power for my speakers (Wharfdale 240s, specs below).
Any thoughts while I wait for my new amp? thanks
General description: 3-way floorstanding speaker
Enclosure type: bass reflex
Transducer complement: 3-way
Bass driver: 165mm Woven Kevlar Cone x 2
Midrange driver: 130mm Woven Kevlar Cone
Treble driver: 25mm Soft Dome
AV shield: No
Sensitivity(2.83V @ 1m): 89dB
Recommended amplifier power: 25-150W
Peak SPL: 102dB
Nominal impedance: 4Ω
Minimum impedance: 3.0Ω
Frequency response (+/-3dB): 40Hz - 20kHz
Bass extension (-6dB): 35Hz
Crossover frequency: 470Hz & 2.7kHz
Years ago I was in the market for a good Tube Int.
I purchased a nice Int. with good reviews, by users and the press, from a very good company who's products I actually liked from previous listening sessions. In the end, I didn't like the Int.. Afterwards I purchased a cheap Chinese Tube Int. from a well known company to tide me over. Years later I have no urge or desire what so ever to change. I spent about 1/4th and to my ears received a product that sounds twice as good.
You have not tried it yet. Tube amps don't hard clip which is oneof the reasons that "perceptually" tube amps are often said to equal SS amps at three times the power. i have not heard Raven so I don't know how much above their watt rating they can hit. Many good tube amps can give you 50% to double their output into peaks.
Now I agree with the others in general that if you are going to go with tubes or SET amps you should be designing the entire system to go that route. So a higher efficiency speaker with the low power amp. Indeed some speakers are tailored for a tube or SET amps damping factor level and power so as to play to the strengths.
But your Raven is close to the same power as my Line Magnetic 219IA which is a 24 watt SET amplifier that has two massive transformers each weighing more than an entire 160 watt per channel Bryston.
And when you compare the two - same speakers and same room you wonder what the hell happened to the bass in the Bryston. All the watts but none of the sound.
It happened back in 2004 when I was going to buy one and then the dealer puts on the Audio Note OTO a 10 watt SEP (4.2 watts undistorted) and again it was a lights out drubbing. So there I was going to spend on Bryston separates and the integrated at 1/16th the power blew it away. Yjhe interesting thing is resolution - with the OTO/Speaker combo I could play it at a relatively modest level and get into the music - it was all there. With the SS thin tin can nature I had to keep turning UP the dial to try and get back the missing gestalt of the presentation - up and up and up until the speakers compressed badly. Meh.
I am constantly surprised by what tubes deliver when on paper they shouldn't deliver it and also amazed that SS with hugely impressive figures often sound totally banal.
You don't need to be tied to those speakers - HE speakers usually sound a LOT better dollar for dollar than LE speakers.
I'd look for a good single driver or 2 way speaker - Speakers like the Tekton Lore, Zu Audio line, Audio Note AZ or AX Series or preferably the AN K if budget is $2k (I reviewed the AX Two for dagogo), Omega loudspeakers, certain Tannoy, JBL.
If you want a BIG powerful speaker that is fairly easy to drive and has eviction notice bass - try the Cerwin Vega CLS215. But big. Good review - CV is under new ownership - soundstage did a review of them some time back.
But definitely see what happens with what you got. If you love the sound and your only complaint is volume level - then just get an easier to drive speaker. The great thing with HE speakers is that you can run any amplifier.
As a reviewer I can run a 5 watt amp or a 10,000 watt amp. I can choose amplifiers based on sound quality and not watts ability. And in 25 years of listening i have yet to hear a single 100+ watt amplifier that I can say I would want to live with. I'd rather buy based on sound not be forced by bad speaker design to "have to" buy a giant boat anchor to power them.
Thanks so much for all the good info and guidance.
Since my speakers are relatively new Im going to stick with them for a bit. So in the mean time I decided to go with a SS amp. Im leaning towards the Peachtree 150 since I found a really good deal on one, and I plan on upgrading to a more efficient speaker down the line. Unless Id really be missing out by not going with the 300? the price difference is about $800.
In a few years Ill probably get new speakers (have my eye on some Focal Arias) and run them with the SS amp for a while until I make the change to tubes when my setup budget is more tailored that option.
I like the fact that the Blackhawk appears to have a full preamplifier built into it considering the tube complement it has, though don't know if that really makes a difference.
Looked at the Wharfdale loudspeakers and with so many cones, you must have a good size room to listen to them, otherwise they would not integrate so well.
Yeah, I'm wondering why you are considering low power tube amps at all?
The speaker **sensitivity** is 89 db. The impedance is 4 ohms.
The amp OTOH makes 20 watts whether its 4 or 8 ohms.
Now here's the tricky bit:
The sensitivity spec is 2.83 volts at 1 meter. 2.83 volts into 4 ohms works out to 2 watts.
So your efficiency of the speaker is only 86 db 1 watt/1 meter.
In my room which is 17' by 21' I would need about 800 watts to really make that fly. I used to have speakers that were 89 db and I found that 200watts was not really enough power if I was pushing it. 400 watts might have been enough in my situation; now imagine that the speaker needs 3 db more power and now you see why I would need 800 watts(!) with a speaker like that.
That is very very inefficient, bordering on criminal as the amplifier power requirements become profound; there really aren't any amplifiers made that sound like music and make that kind of power.
This is not to say that the amp won't play- it will and might sound pretty nice, but you won't be able to turn it up much in an average room.
The fact of the matter is that tube power is expensive; back in the old days when tubes were the only game in town that is why there were so many high efficiency loudspeakers. If you are really sold on tubes, do yourself a major favor and get a speaker that is higher efficiency **and** higher impedance!
Tubes in general will perform better on higher impedance speakers- going from 8 ohms to 4 can cost you an octave worth of bandwidth on the bottom end due to the output transformer. Plus the transformer will be less efficient so it will run warmer. OTOH with an 8 or 16 ohm speaker the tube amp will not only have more bandwidth, but its distortion will be lower and you might have a slight amount of more power.
Fantastic post, Ralph. Thanks for taking the time.
Yes, thanks for the info.
I think you are better off with a good tube amp and easier to drive speakers than you are with speakers that are harder to drive and solid state amp that can do the job.
All amps (tube, solid state, class D) make distortion. Not only that but in all cases distortion is higher when driving lower impedance loads. You would think that distortion is inaudible but that is not the case at all!!
The distortion is audible and measurable too.
The human ear converts distortion into tonality! This is why tube amps generally sound richer and smoother (more lower ordered harmonics, less higher ordered harmonics) and transistors tend to sound leaner, brighter and harder (less lower ordered harmonics but more higher orders than tubes usually make).
In fact that's the tubes/transistor debate in a nutshell.
So when you are increasing the distortion by driving a lower impedance, in just about all cases the amp is making more of the higher ordered harmonics. This means it will be less detailed (more distortion masks low level detail due to the ear's masking rule) and harsher (due to the fact of higher ordered harmonics being added).
So any loudspeaker company and make their speaker sound smoother and more detailed at the same time simply by designing it to be higher impedance. Of course if the amp is solid state it will not make as much power, but if sound quality is your goal this is less of a concern.
So its something to think about:
If sound quality is your goal go with a speaker that is easier to drive and especially higher impedance.
If sound pressure is your goal there is a 3db argument for 4 ohms over 8 ohms if your solid state amp can double its power into half the load impedance. IMO/IME 3 db is not much of an argument.
But if you have a tube amp and sound pressure is your goal a higher impedance will serve you better.
So before getting an amp or speaker, first figure out where your preference lies- if you prefer tube amps, try to find a speaker that works with it rather than the other way around. Don't try to make it work hard to drive a difficult speaker, because even a powerful transistor amp driving a hard to drive speaker will never sound like real music, it will at best sound like a hifi. Instead, have the amp drive something easy, so it won't have to make distortion and then you will find the music there as well.
Back to the drawing board I guess. Maybe I should stick with SS amps for now. I previously had my eye on a Peachtree Nova 150.
If you've got the Nighthawk coming, give it a try. If your room is on the small side, you don't listen at higher volumes and your speakers don't dip below 4ohms you might like it. I do believe you're on the right track in regards to the Peachtree Audio Nova 150 but I would actually go for the Nova 300. Ultimate volume is one thing but actually driving the speakers correctly is the bigger issue IMHO.
John Darko @DAR has good write-ups on both the PT 150 and 300. It will give you some insight on what the 300 will give you over the 150.
Computer Audiophile also has good write-ups of the PT 150 and 300. Good luck with your search.
You also might want to check out the Wyred 4 Sound STI500 MKll
It depends on how far away you sit, how large the space, how well your amp handles the impedance of the speaker and the dynamic range of the music. Classical is usually a bigger problem than rock which is loud but with small dynamic range. Well done piano classical will probably strain your amp since the peaks while very short can be huge. I worry about 20 watts even in a good amp but I think you may just be on the edge, so try it.
I have some low power tube amplifiers that I liked the sound. I have had good luck with crossing the main speakers up at the preamp, depending on speakers, 100 to 250 Hz and using powered sub.
I'm curious if others have had similar positive results.
On paper.... not a perfect match. For a tube amp like the 20 watt Raven, you'd ideally want a speaker with a friendlier impedance curve.....something that is rated at 8 ohms and stays above 4 ohms. 89 db in efficiency is certainly doable if the impedance were a bit friendlier. It's worth a try, but I think you'll be somewhat limited to simpler music at moderate levels. FWIW, a friend recently mentioned how much he's enjoying his Wharfedale Denton's with a tube amp in the same power range as the Raven. So basically, you might not get a true picture of the Raven amp's potential with the more complex load presented by the 240. As always, YMMV.
I agree with Mik Wolfe here. People drive Harbeth all the time with tube amps, harbeth are around 85 dB efficient. It's the impedance, low impedance speakers take some current which to my knowledge, if their is a high current tube amp, it's scarce. If the Wharfedale are fairly stable and don't dip below that given minimum you could still be alright.
I had a pair of Revel F52's that sounded alright with 100 watt Conrad Johnson monoblocks but they really came to life with a solid state high current amp. The 52's were 6 ohm with multiple drivers.
I've listened through speakers with under powered amps and the setup may sound fine initially, until you replace it with a more powerful amp that is better suited for the speakers.
The experience that sticks out in my mind was when I brought my 100wpc Rogue Stereo 90 Super Magnum amp (KT120 tubes) to a friend's house to power his Maggie 1.7s. It seemed OK initially but after comparing against a more powerful amp, the sound was a little compressed and veiled on the Rogue. This same Rogue amp drove my Thiel CS2.4 with no issues at all but didn't have enough oomph for even the smaller Maggie 1.7 speakers.
My friend put his 400wpc monoblocks back on the Maggies and they came to life with effortless dynamics and transparency that clearly showed that 100wpc from the Rogue was not enough.
Also, if a speaker manufacturer says the recommended power is 25-150W, I would lean more toward the middle of that range (or more) for best results. That's just based on personal experience with the speakers that I have owned.
For example, Tannoy recommends 30-175W for my Tannoy Definition D500s (91dB 6 Ohm nom.) but with most amps they need about 75W or more to really 'come alive'. The one exception was with my 50wpc Krell KSA-50S, but I think (like BMW cars) Krell was ultra-conservative on their power rating.
And BTW, this is regardless of listening room size or volume level. An under powered amp is going to sound under powered even at lower volume levels in a smaller room. It's still going to sound a bit compressed. I had a similar experience with the Pass Aleph 3 and Aleph 30 (30wpc Class A) amps in another system. Some folks will say "so long as you listen at modest levels you'll be fine". That has not been my experience.
You'll have to judge for yourself. Try your speakers with that modest 20wpc, then try with a quality higher power amp. Enjoy!
I tried running a pair of Maggie 1.7's with a HK Citation-II tube amp at 60 wpc and was not all that impressed. I sold the Maggies because I wasn't going to sell the Citation-II, and I'm not going to have multiple Amps or Speakers lying around that I don't use.
I liked the way those Maggies sound with my friend's high powered monoblocks but even then, they didn't have a lot of bass. He uses a powered subwoofer with the Maggies and the whole setup sounds great.
But I tend to prefer speakers that are more versatile as I like trying different amps and usually not very large ones.
As long as you don't have a huge room and/or listen at lease breaking levels, you should be fine.
Don't worry about avoiding temptation. As you grow older, it will avoid you.
- Winston Churchill
I don't think 89db is considered inefficient.I don't think you should worry about it until you try it out!
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