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Post by desmoface on Mar 13, 2017 11:55:39 GMT -5
Hello everyone, I'm planning my desktop audio system and was seriously considering the A-300. My question is will this amp play well if the impedance drops below 4 ohms? The reason I ask is I'm considering the Elac ub5's and it looks like it's quite a demanding speaker "Nominal impedance: 4 ohms; minimum 3.4 ohms," according to Absolute Sound. Do you think this would present any problems with the mighty A-300? Thanks in advance. Steve |
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Post by copperpipe on Mar 13, 2017 12:15:58 GMT -5
The A-300 is rated 300 watts/channel at 4 ohms. Another good sign, it's double the wattage of the 8 ohm spec. I wouldn't worry about the Elac's at all, with any emotiva amp, even the little a-100.
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Post by desmoface on Mar 13, 2017 12:18:29 GMT -5
The A-300 is rated 300 watts/channel at 4 ohms. Another good sign, it's double the wattage of the 8 ohm spec. I wouldn't worry about the Elac's at all, with any emotiva amp, even the little a-100. Hi Copperpipe - awesome..thanks for the reply. Steve |
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Post by rvsixer on Mar 13, 2017 21:38:56 GMT -5
Caveat emptor. Though the spec doubles the wattage from 8 ohms to 4 ohms, the spec frequency range goes from 20-20KHz to only 1 Khz, and the THD goes from <0.1% to < 1.0%.
Not in the same league as true muscle amps that have the same freq and THD specs at either load (now THOSE are amps with some great power supplies). Personally I would guess the A-300 would perform equally at the 8 ohm freq/THD specs at either load, and beyond that power rating with a 4 ohm load those specs become diminished. Just a guess, YMMV.
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Post by Axis on Mar 13, 2017 22:00:38 GMT -5
The A-300 will have the same sound quality and drive the Elac ub5's as good as any $4000 150 watt per channel amp out there.
There is plenty of power to drive the Elac speakers and if they need a special amp, Emotiva's amps are and have always been special. Sound quality is what you should be concerned with when you are dealing with a 150 watt per channel amp and some speakers like the Elac speakers. Turns out from all the profession reviews and lounge member reviews that the A-300 has excellent sound quality.
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Post by leonski on Mar 18, 2017 19:39:46 GMT -5
The one review of ELAC speakers I read which actually had measurments showed them to be a pretty easy load of lower than advertised sensitivity. You should be fine with the A-300 except at the most extreme loudness. At that point, the limits of the amp will become apparent. Don't let the 'doubling' of power fool you. At the 4 ohm rating, you are right against the distortion limit. 1% at some frequencies is too much. www.stereophile.com/content/elac-debut-b6-loudspeaker#apIH8BjYbyIjqmXH.97I heard ELAC at a big show but do not remember which model. Sound was good. |
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Post by Dan Laufman on Mar 18, 2017 20:10:59 GMT -5
The A300 will drive the pants off of the Elac's.
Nuff said...
Seriously, this is a good combo. Try it, you'll like it.
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Post by vneal on Mar 18, 2017 20:21:01 GMT -5
I too think you should be good to go. Let us know how they sound
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Post by gzubeck on Mar 20, 2017 22:50:04 GMT -5
What people are failing to understand is that for a reasonably sensitive speaker 86 db and above the speaker will be cruising between 10-20 watts with momentary peaks with high frequencies and low dips when lower frequencies are played. So most most of the time (80-90%) you really have a low distortion amp because of the overbuilt nature of it. Unless your driving a speaker with low sensitivity and big woofers I cant see there being a problem driving speakers cleanly. As a matter of fact my a300 sounds even better after its been warmed up a bit after heavy explosions and such. It sounds almost class a-ish...cheers...
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Post by leonski on Mar 22, 2017 0:25:16 GMT -5
Normal 'crest factor' is anywhere from 10db= 20 watts rms / 200 PEAK on up. 20db crest factor would turn that 20 watts into well over the 1% limit of the A300.
20 watts is pretty darn loud, even with 86db sensitive speakers. I doubt I play my even LESS sensitive panels with this much power except on 'break the lease' day.
This is just my Opinion, but 86db sensitive? That's on the low / normal side. Double that to 89db and things begin to get interesting.
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Post by gzubeck on Mar 22, 2017 21:32:03 GMT -5
Normal 'crest factor' is anywhere from 10db= 20 watts rms / 200 PEAK on up. 20db crest factor would turn that 20 watts into well over the 1% limit of the A300. 20 watts is pretty darn loud, even with 86db sensitive speakers. I doubt I play my even LESS sensitive panels with this much power except on 'break the lease' day. This is just my Opinion, but 86db sensitive? That's on the low / normal side. Double that to 89db and things begin to get interesting. By the time your crossover on your speaker is done the speakers lose sensitivity to make them blend more evenly...so your 91db tweeter and your 89 db woofer will average between 86-88db on average...on the power usage im just WAGing-it...  The red and blue are raw drivers in the box and the black is the total drivers with crossover. |
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Post by leonski on Mar 22, 2017 23:39:40 GMT -5
Speaker reviews, at least the kind with 'measured' data will not 'exclude' the crossover. The only speaker I can think of without some kind of crossover that I actually listen to is the 2 1/2" driver in my clock radio.
Come to think of it, I doubt my earbuds or even my Grado headphones have crossovers.
Sensitivity can be measured near-field in a room with boundaries far enough away to take them out of the time window. 10 feet in all directions should do it for a 10milisecond tone burst at 1 watt. The microphone will
be fairly close so it measures only direct sound and NO reflected.
Disconnecting one driver and doing a freqquency sweep than repeating for each other driver in turn will generate response curves Per Driver. Putting them on a single graph should give you 'system' response.
Bare driver sensitivity is useful during the design phase, For Certain.
Sure, crossovers cost sensitivity against a bare driver. Sometimes they are used to 'shelve' the response for a given driver Down to make a better match with a less sensitive driver.
As kind of an aside, direct connection of a driver TO the amp and handling the crossover at the line level is a fine way to 'gain' amplifier power. Various sensitivities, crossover frequencies and amp gain all gets put in the blender, but Best Case,
you might gain as much as 3db additional amp power 'apparent'.
I always give my gear 20 or 30 minutes 'on' time before doing any critical listening.
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Post by gzubeck on Mar 23, 2017 0:31:41 GMT -5
Speaker reviews, at least the kind with 'measured' data will not 'exclude' the crossover. The only speaker I can think of without some kind of crossover that I actually listen to is the 2 1/2" driver in my clock radio. Come to think of it, I doubt my earbuds or even my Grado headphones have crossovers. Sensitivity can be measured near-field in a room with boundaries far enough away to take them out of the time window. 10 feet in all directions should do it for a 10milisecond tone burst at 1 watt. The microphone will be fairly close so it measures only direct sound and NO reflected. Disconnecting one driver and doing a freqquency sweep than repeating for each other driver in turn will generate response curves Per Driver. Putting them on a single graph should give you 'system' response. Bare driver sensitivity is useful during the design phase, For Certain. Sure, crossovers cost sensitivity against a bare driver. Sometimes they are used to 'shelve' the response for a given driver Down to make a better match with a less sensitive driver. As kind of an aside, direct connection of a driver TO the amp and handling the crossover at the line level is a fine way to 'gain' amplifier power. Various sensitivities, crossover frequencies and amp gain all gets put in the blender, but Best Case, you might gain as much as 3db additional amp power 'apparent'. I always give my gear 20 or 30 minutes 'on' time before doing any critical listening. I don't know what your arguing about as I'm just making a point about frequency ranges for a particular set of speakers. there are so many variables that go into voicing a speaker that if you have a slight tilt in your curve downward that can change things up a bit. No I dont have a setup with a mike and boom for sound measuring as its almost an art form even for stereophile reviewer John Atkinson out in his back yard.... |
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Post by leonski on Mar 23, 2017 14:17:54 GMT -5
Never said a word about voicing. My remarks were aimed at mostly electrical considerations. However, it IS the designers choice about sensitivity matching when using drivers of differeing sensitvity in any given design.
And I'll agree with measuring speakers in the back yard. Any place you can get away from reflective surfaces helps. 'semi anachoic', maybe?
I'm a big fan of active line level crossovers, these days. Very flexible and some even include the possiblity of FIR filters which unlike all other types, have NO phase shift thru the passband.
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Post by digdugger on Mar 31, 2017 11:52:16 GMT -5
The A300 will drive the pants off of the Elac's. Nuff said... Seriously, this is a good combo. Try it, you'll like it. Would the a500 drive say two pairs of ub5 front and back and a unifi center channel? |
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Post by gzubeck on Apr 1, 2017 13:37:15 GMT -5
The A300 will drive the pants off of the Elac's. Nuff said... Seriously, this is a good combo. Try it, you'll like it. Would the a500 drive say two pairs of ub5 front and back and a unifi center channel? I would say most of the time...if your above 80 watts with all channels driven then I would guess that if the three fronts were in use most of the time it would be over 100 watts which should be sufficient power...for a reasonably sized room...not a 20 x 40 foot room etc... |
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Post by leonski on Apr 9, 2017 1:33:43 GMT -5
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tbase1
Seeker Of Truth
Posts: 3 
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Post by tbase1 on May 3, 2017 15:12:09 GMT -5
I just started using a A-300 to drive my Boston Acoustic Lynfield 500L series 2 speakers. My A-300 shuts down multiple times a high levels. I have it connected to the pre-outs of a Anthem MRX-510 receiver. My speaker wire is 10gauge solid silver twisted. my RCA's are a little on the low end, but that being the weak link I don't see there being a major issue there. Movies sound great, but music in 2 channel is where it shuts down. What should I do?
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KeithL
Administrator 
Posts: 10,261
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Post by KeithL on May 3, 2017 16:13:22 GMT -5
According to several reviews, the Lynnfield 500's drop to just below 2 Ohms at 112 Hz, and have an efficiency of 86 dB. At least one review also mentioned that they offer a reactive load, with "a very difficult phase angle", at that low impedance point of 112 Hz. They also have a reputation of being a very difficult speaker to drive. Therefore, I'm not surprised that the A-300 might go into protect if asked to play them "at high levels". Compared to them, the Elacs look downright friendly.... I just started using a A-300 to drive my Boston Acoustic Lynfield 500L series 2 speakers. My A-300 shuts down multiple times a high levels. I have it connected to the pre-outs of a Anthem MRX-510 receiver. My speaker wire is 10gauge solid silver twisted. my RCA's are a little on the low end, but that being the weak link I don't see there being a major issue there. Movies sound great, but music in 2 channel is where it shuts down. What should I do? |
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Post by leonski on May 3, 2017 19:08:13 GMT -5
The published data (Stereophile) is for the 'original' Lynnfield 500. I'd hope the 'mark II' version was a little easier on the partnering amp. But I somehow doubt it.
The 'reputation' appears well grounded in fact. Huge phase angles suck power like no tomorrow and many amps simply FAIL when confronted with such loads.
Another good reason (I'm repeating myself, here) for amps to be tested with some kind of REAL speaker load and not simply with a resistor.
I'm sure the A-300 is capable when driving the appropriate speaker, of moderate sensitivity and reasonable phase.
For tbase1? :: Buy a more capable amp. THAT'S the real 'weak link' in your setup, not your RCA I/Cs...
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