AudioNervosa
Systemic Development => Amplification and Preamplification => Topic started by: dflee on July 25, 2016, 10:42:03 AM
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Am in a dilemma and would like some advice.
Things I think I've learned through reading:
1. Although a speaker has a high efficiency, if there are multiple drivers it can be pretty power hungry. Question here is does it have to be continuous or just plenty of reserve power. Can I get by with 25 or 30 watts as long as I have a K reserve (is there even such a thing)?
2. Clean, efficient low power is better than higher power crud.
Q- Is there a way to determine if a good lower power amp has enough oomph to power a multi driver speaker without clipping? An example would be the Luxman M200. It states 35 watts into 4 ohm but doesn't tell reserve or peak power. Is that enough for a multi driver speaker. The speaker manufacturer states the speaker will work with as little as 15 watts but recommends 200. Here again it isn't put in terms of peak or continuous. How does one interpret or put it together with any sense?
Any input would be appreciated even if it's just to tell me I'm fubar (cause even that is helpful to know).
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What does the mfgr. claim the speaker's 1watt/1meter sensitivity to be.
If it was a 4 ohm speaker for example and had a sensitivity of 95dBwith 1 watt of power input, then even with a 4 ohm load presented to the amplifier, it won't take much power to play loudly. 10 watts in would yield 105dB at 1 meter.
In most cases when the speaker is played in an actual room it is even louder.
Scotty
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Speaker rating states: Sensitivity (room, dB@2.83V) is 92.
What's that mean?
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The spec means that if you drive the speaker with a 2.83V rms signal for a sinewave, the output at 1 meter will be 92dB SPL.
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What he said. :)
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Legacy specs "in room" sensitivity, which is different than most companies quote anechoic sensitivity. In-room sensitivity adds in the room's reflections, to make about 1-2dB louder than anechoic sensitivity depending on type of room construction and materials and decor. Theoretical maximum room contribution is 3dB, that's probably what they add for their spec, so when comparing Legacy sensitivity to other speakers measured anechoically, subtract the 3dB. We listen in a room, so in room is real world sensitivity, but we all have different rooms, so it's impossible to compare in room sensitivity, while anechoic sensitivity is more comparable, if nominal impedance rating is also considered.
No problem on the 35w Luxman. James Edwards has similar luxman on his Focus, works great. All big Legacys have low impedance dips with negative phase angle in the bass, and it draws a lot of power but it's is part of their successful recipe. But for moderately loud levels a very strong 35W like luxman should be enough. If you have loud dance parties or listen to loud rap with long low bass synth tones right in the highest current freqs, or if you play loud uncompressed music like symphonies then I'd go for 100W+ SS amp. But for normal loudish music listening <95dB it should be enough.
I listened to my Focus 2020 for a long time with 50w tube amp, which had less current than the 35W solid state Luxman. I loved it, very satisfying. But it did distort and damage tweeters when I played loud dance music. Solid state can source current much better than tubes, so less of an issue, to a point.
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So is that what they are referring to with the term reserve or peak power. Th Coda refers to itself as a high current amp. What does that mean. I always thought it meant it had a lot of reserve power. How does one determine if there is enough reserve power to properly run a speaker?
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You shouldn't count on "reserve or peak power" meet the speaker systems power requirements. There's really no standard for specifying what these terms actually mean.
At the end of the day they are marketing terms that may have nothing to do with the amplifiers behavior into real world speaker loads.
The RMS measurement into a specific load resistance; 4ohms, 8ohms and perhaps 2ohms, are directly comparable between different amplifiers.
Depending upon the speakers stated impedance, and a 92dB at 2.83volts the amplifier you mentioned may be more than adequate to drive the loudspeaker.
Scotty
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Does the amp have a spec for headroom? Most SS amps have a 1-3dB headroom that is above the spec for rms power.
Also short term transient power is what some folks call peak power. That can be considerably higher if the signal is less than 10mSec.
All depends on the amp and the specs.
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Reserve is potential energy stored in the power supply. It is stored in two ways, as magnetic flux in the transformer and as static electricity in the PS filter caps. In the case of Coda 4.3.2 amp, there is ample headroom/reserve with 1.4kVA tranny and 80mF filter bank, serving 4 channels rated 100W>8R. 4 channels can be bridged to two channels rated 400W>8R. There is no explicit 4 ohm rating, but it has handled the Legacys biamped for many years.
The problem is the amplifier output transistors are not as robust as the PS. Usually it's the other way around, and the PS sag protects the amplifier from overload. We see that sag in the Luxman with 4 ohm rating not doubling the 8 ohm rating. It will sag more into <4 ohms like legacy, or it may protect.
I'm pretty sure the Focus SE has impedance dip of 2.9 ohms on the chart I saw 5 years ago. The bass drivers and alignment hasn't changed since then, but the crossover might have changed a little. But Luxman is working fine on that, I don't know how loud or what kind of music James plays, you could ask him. It might be the same amplifier circuit used in both Luxman amps.
The Luxman M200 is rated 25W>8R stereo, 35W>4R stereo and 70W>8R bridged channels. So it has 1/4 the power rating of the Coda. It really depends on how you're going to use the speakers. You might only have 95dB SPL available at the bass impedance dip, that's pretty darn loud, but it's capable of more, so you'd be leaving some speaker performance on the table. But might be worth if you love the luxman's sound.
http://www.luxman.com/product.php?pid=16
Can you get the impedance and FR/phase charts from Legacy? I couldn't find them online.
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Hey Rich: Wasn't able to get the charts either (guess it's due to age) but was told that there is a dip at 30 hz to 3.8 ohm. Other than that it's flat at 4 nominal. Bent the techs ear with my situation and asked where would he go given the same. This led to an interesting discussion concerning amplification of today and yesteryear. The terminology of High Current was to have plenty of reserve power to not get dips or losses when energy is needed. The non-transformer type of amplifier doesn't have the staying power and so the newer types (digital I'm assuming) while may have a good deal of power is only for instantaneous or short burst and can not maintain it causing the sound to in effect chop off. It was recommended to have 200 to 250 watts for my speakers and over that could create problems for one with my age (speakers not mine). With less power, I just wouldn't be getting what the speaker was capable of delivering even if they weren't turned up to ear splitting levels. This has been an interesting journey so far and I hope to come out of it better informed. So to put it into terms I could understand the tech said as in any speaker there is a range of power that works best, try to get to the high side of that wattage and get what sounds best for what I can afford.
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That sounds like pretty good advice.
3.8ohms not bad at all! I bet the Lux would work OK for everyday listening. If you still want the ability to shake the walls when you are home alone, then you might want more. You have the Coda for that. :thumb:
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As far as switching power supplies are concerned, if the bean counters don't decide a 200watt amp should only have a 200watt rated supply to limit the production cost, you shouldn't see a problem with sustained power demands.
You could easily spec a 600watt supply for a 200 watt amp much the same way you spec a 750 toroidal transformer for the same application.
Another aspect of better performance relates to the impedance of switching supply. The bigger supplies have bigger switching mosfets rated for higher current throughput and they have a much lower RDS on spec, as result the amp just sounds a lot better with the bigger supply even if you can get away with running a smaller one.
Scotty
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Was kinda thinkin the same thing. If the amp has enough power for peaks why would it need the reserve? But then you pay for the additional wattage and can lose some quality. Am I correct in stating not all watts are equal or are we getting into the aspect where most argue they are?
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All watts are definitely not equal. You can have an amp that will measure X amount watts at X amount of distortion on a test bench under static conditions into into a resistor. Under dynamic conditions the driver stage may suffer beta collapse and the amp falls down on the amount of power it can actually produce under real world conditions. This applies to solid state Class A as well as Class A/B designs. RMS power at a specific load is a place to start comparing apples to apples but is no indication of performance under dynamic conditions. Class D is whole different kettle of fish.
Scotty
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More is better. I've yet to have that not be the case.
I bought a fairly neutral/leaning to warm sounding 400 wpc amp so I wouldn't have to buy another, ever.
That's been the case for the last 8 or 9 years.
It took away the question I kept having: "will there be synergy between this particular amp and these speakers?" (Because, yes) :lol:
If you like the Luxman's sound, the Legacy's will probably reveal it well.
If it's not enough power, it'll sound a little too thin or have flabby bass. At that point you'll have to decide about the amp. Unfortunately you won't know till you hear it.
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More is better.
https://www.youtube.com/watch?v=YQwYNca4iog
:rofl:
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More is better. I've yet to have that not be the case.
I bought a fairly neutral/leaning to warm sounding 400 wpc amp so I wouldn't have to buy another, ever.
That's been the case for the last 8 or 9 years.
I'm inclined to agree and I've been there and done that twice, once with beefy tube monoblocks and now with NCores. With the likely exceptions of running extremely efficient speakers (98 db or better) or efficient single driver full range speakers or trying to tailor your speakers with a certain tube sound, e.g. SET, more power is better in most cases. And, as Carlman wrote, it removes the variable of wondering if you have enough power--"Am I really hearing what these speakers can do?"
As someone who grew to appreciate tubes and lived with them for years, I must say that the clarity, neutrality, dynamics and sheer oomph of the NCores is great.
Good luck in the journey.
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It seems as though this topic has been decided, but in my case, I had also thought that more is better, and I usually like my music on the louder side of 90db.
I've had the Moscode 402- 200wpc, NAD Masters M3- 180wpc, Bryston 4BSST2- 300wpc, CJ don't remember model/power, etc., etc.
I was about to pull the trigger on some 1000wpc Red Dragon amps, figuring I'd up the power ante significantly. For reasons still murky in my mind, I went the other way- the class A 30wpc Luxman L-590AX Mk.2.
Every type of music sounds better. It does classical, rock, jazz, new wave, and folk more convincingly than I've ever heard in my room. And if the meters are correct, I've not yet gone into the red; not even close.
Different speakers, amps, preamps, and cd players have come and gone, but the current setup is by far my favorite. I keep expecting I'll come upon a compromise, but it hasn't happened 2 months in.
All I'm saying is you might want to give a class A amp a go in your system. You might be surprised.
As we all say, your mileage may vary.
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I have been using a re-engineered class AB Superphon DM 220 for about the last seven years. Stan Warren revisited his old design using 20/20 hindsight and it now has vintage copper cased TO-3 Motorola bi-polar output transistors among other things changed or upgraded.
About 108w/8ohms and 180w/4 ohms. With 95dB sensitivity loudspeakers, I haven't run out of power yet. Ironically I probably listen at about 75dB to 80dB average, peaks are another matter.
Watching block buster movies is where the system usually gets asked to do stupid things, explosions, gunfire and bass effects gratuitously added to soundtracks are hair raising. Fun but scary, you are always wondering, crap is something going to break.
Even though power is cheap now a days, if you can get higher sensitivity speakers this seems to be the way to go to me. Way less dynamic compression and lower THD and IM contributed by the speaker.
Scotty
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Yes but then again high sensitivity speakers also magnify any kind of noise that may be in your system so the electronics that you use to push them as well as all of your connections and cables need to be that much quieter. As with everything else in this hobby, nothing for nothing. Each time you do something to improve one thing it tends to open you up for issues in other areas. Hence the whole issue of synergy. Every type of equipment has its advantages and drawbacks and the trick is to find combinations that accentuate the pluses while minimizing the effects of the minuses. And not the least of the variables is the acoustic properties of the space we need to work with. Many different ways optimize things, which is why we all end up with such diverse systems
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You certainly have to have your ducks in a row to use speakers with higher sensitivity.
If you have legacy equipment with less than a 90dB S/N ratio A weighted, then you may have a problem. Likewise if your TT doesn't have very good rumble figures and resistance to structure borne as well as acoustic feedback then high sensitivity speakers which also plumb the depths in the bass region may cause you big headaches.
You have to approach system building in an organized fashion while being full cognizant of potential problems. Using a ill-considered haphazard approach and trusting to dumb luck to beat Murphy seldom works.
Scotty
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Like everything else what you are looking at here is yet another compromise. Good watts are expensive. Big watts are expensive and goo big watts are really expensive. So what it boils down to is an asset allocation exercise. For a given budget you can have better power, larger power or choose to dedicate a bigger piece of your budget tot he power amp and have bigger and better power, but less money to spend on other things, stereo or otherwise.
And while I agree with Carl that for the most part more watts is better than less. And lets face it, we can always get bigger and better by throwing money at the problem, but the reality of the situation is that most of us here have a finite amount of money to dedicate to this hobby and the trick is to figure out, given our musical tastes, our equipment preferences and the acoustic properties of our listening spaces, how much quality can we get (or maybe better stated how much money can we spend) before an increase in the cost of one component will lead to an overall decrease in the SQ of the system because we will need to dial back what we can spend on other components. And ultimately what is the balance of quality and spending across all of the components that will maximize the overall musical enjoyment of the system.
This of course is a complex multi-variable analysis with many different possibilities, which one of the reason why this hobby can get so consuming and why we end up with such widely varying yet all good sounding systems.
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I wish this forum had a thumbs-up button.
Thanks for the thoughtful thoughts on the amp subject. :)
👍
:thumb:
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Thought I'd throw this in with all the great things put in this subject. Long story short the Coda came back with problems (money not really well spent) and for what I had I got an Odyssey Khartago with more and better caps, connections and wiring. I do like it except the issue of oomph has reared it's ugly little head. I have tried everything I can to get the bass to increase, it''s there and does sound like it can get it right but it is anemic. Had to push the (heaven forbid) loudness button and bam, it's there (maybe more than I want it to be) but not near as tight as I had in the past. Don't get me wrong the Khart is a good sounding amp, very clean and really inner sound on plucked instruments but can't create the earth shattering bottom end on the Legacy Classics I'm used to. So in the words of sir Elton "where to now Saint Peter".
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Too bad about the Coda. :( Sounds like they changed the output transistors if the sound changed that much. Original parts maybe obsolete.
Class D is good for bass control, and detail, slam, due to very low output impedance. Always liked them on my Legacys, NuForce, Spectron, etc. Maybe Khart not so great impedance, maybe the mods messed up the output impedance? Audiophile brands tend toward detail anyway. OK if the bass still good. McIntosh autoformer amps have great balls and neutral tone, slightly less incisive than audiophile hotrod amps but much more musical like Coda. Look for MC250-MC450 and similar. They aren't cheap, but good bass.
Nord NC500 amp is a Hypex N-Core 500W at a good price. Pair came to my house last G2G, they really kicked ass. I didn't get a chance to listen to refinement, it was a loud rock song, but I didn't notice any problem. Bass was excellent.
http://www.iqspeakers.co.uk/hypex-amps
DAC Cherry stereo amp seemed a bit bottom-heavy when I auditioned it, and very smooth, musical, wonderful sound! Not typical old style edgy class D sound. I couldn't judge the slam on those horn speakers, but it was definitely bass heavy, which the speakers really needed. People really seem to like the new DAC amps.
If you use computer for playback you could add some bass EQ with effect plugin. But it won't help the softness.
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If it were me I would go for more power. Do you have a budget for a new amp ?
For SS Parasound comes to mind. Most high powered tube Amps cost big money so maybe a stretch. CJ, VTL, AR all can be good but cost. Then there is Hybrid Class "D".
If you are using a tubed preamp I would suggest either Class"D" hybrid or SS.
charles
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You should look at the systemgain including the source gain. This will get you volume. What is the VA size of the transformer in that amp? If it is small then system gain won't mean much if its low bass performance you want. You have to have a big VA rating for that.
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Just saw these announced on Legacy email newsletter:
http://legacyaudio.com/products/view/powerbloc4/
4x325wpc, class D
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Just saw these announced on Legacy email newsletter:
http://legacyaudio.com/products/view/powerbloc4/
4x325wpc, class D
That makes sense good recco.
charles
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Spoke with Bill Dudleson yesterday. Had a great conversation concerning the amp. He recommended getting the stereo version cause it uses the same tranny and costs less and I wouldn't get that much difference with the Classics. Told him I would love to someday have the Signature SE and he stated he would still go with the stereo version. It's an ICE class D and one of he best out there right now. He uses it to run the bottom end on his top line speakers but said for sigs down is great all around. My object now is to try and get what I can for the Odyssey and go towards the Legacy. I really do like the detail and upper sound of the Odyssey but it just can't quite get four 10 inch woofers going.