KeithL
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Post by KeithL on Apr 21, 2017 11:55:15 GMT -5
I really wouldn't worry about it. 3.2 Ohms is a bit low for a "nominal 8 Ohm speaker"..... (which might lead you to question their rating the speaker as 8 Ohms instead of 4 Ohms). However, 3.2 Ohms isn't at all low for a 4 Ohm speaker..... and the BasX amps work just great with them too. IMHO - A BASX compatible speaker has relatively high-efficiency and reasonably high impedance. Beyond that all speakers are BASX compatible. Having heard your speakers, I would stick with the A-300. Thanks for the input. The LS50 specs indicate: Amplifier requirements: 25–100W. Nominal impedance: 8 ohms. Minimum impedance: 3.2 ohms. So clearly the A-300 has enough powers at 150W a channel. But I just wonder about how it will do with the impedance needs.
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Post by garbulky on Apr 21, 2017 11:59:45 GMT -5
IMHO - A BASX compatible speaker has relatively high-efficiency and reasonably high impedance. Beyond that all speakers are BASX compatible. Having heard your speakers, I would stick with the A-300. Thanks for the input. The LS50 specs indicate: Amplifier requirements: 25–100W. Nominal impedance: 8 ohms. Minimum impedance: 3.2 ohms. So clearly the A-300 has enough powers at 150W a channel. But I just wonder about how it will do with the impedance needs. I heard it with the A-300. It'll do fine I think it's a decent match. No need to spend more with it.
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KeithL
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Post by KeithL on Apr 21, 2017 12:57:01 GMT -5
The fans are thermostatically controlled and rarely run.... and they're also pretty quiet when they do. I think the BasX amps would be off my short list for a secondary system. Why? Those damn fans that collect dust, make noise and fail way too often. I would rather have a larger "fool proof" heat sink.
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klinemj
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Post by klinemj on Apr 21, 2017 13:09:35 GMT -5
I saw the CES2017 announcements for new BasX gear YouTube with Dan Laufman. But, so far, they are merely teasing me. Products announced at earlier CES events are still in la la land. Does Emotiva only announce new products and then not release them, and never admit they will not be released? Does anyone know about the upcoming soundbar? I was interested in the 125 watt per channel 5 channel BasX amp I saw on YouTube. But, so far that is merely a tease. Outlaw Audio has the same product with similar specs for $100 less than the "announced" price. I'm new to Emotiva and am still trying to figure out if they are trustworthy or not. Having the president announce and then nothing happens is not a confidence builder. If you change your mind after announcing, please do me and others the courtesy and have a press release where you state plainly the product is withdrawn and will not be released. If I recall correctly, they shared approximate timing for that product on their most recent podcast. And guess what, it is on the websote right now, along with the BasX cd player and the multizone amp they showed. Mark
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KeithL
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Post by KeithL on Apr 21, 2017 13:55:41 GMT -5
All true.... But the overall "cost/benefit" ratio can be a little bit more complicated. For example, it's absolutely true that there is no specific benefit in making a speaker less efficient. In other words, all else being equal, there's no reason why you would specifically want a speaker to be less efficient. However, there ARE tradeoffs if you set "high efficiency" as one of your design parameters. (Think of it like cars. There's no possible reason why, given the choice, you would specifically design a car to get low gas mileage. However, specifying that a car must have very high gas mileage will limit your options, some of which may cost you performance in other areas. And it's going to be much easier to design a very high performance car if you can ignore gas mileage as a consideration.) In the case of speakers, it means that you limit your design options - because you become unable to make lots of design decisions that might get you better sound at the cost of lower efficiency. Most modern speakers are designed with the presumption that, because amplifier power is relatively cheap, extremely high efficiency isn't especially important. One thing you're slightly wrong about, however, is the relationship between efficiency and cone movement. For a given type of speaker, the sound output at a specific frequency is directly related to the diameter of the cone and the distance it moves - and not much else. A more efficient driver will move the same distance with less power driving it, but, for that same distance moved, it will NOT produce more sound. The correlation you're seeing is between efficiency and different TYPES of speakers. For example, when compared to a normal speaker, a horn speaker produces more output for the same amount of cone movement - and this happens because the horn acts as a sort of transformer for air pressure. The driver is actually moving less distance, but working HARDER over that distance, and the transformer effect of the horn then converts that short movement at higher acoustic pressure to a larger movement of air at lower pressure. (For that same horn enclosure, substituting a driver with a weaker motor mechanism would reduce the efficiency, but would still produce the same amount of output per mm of cone movement..... ). It's a fine distinction, but it is worth noting that two speakers OF THE SAME TYPE OF DESIGN will in fact require the same amount of cone movement to produce the same sound level REGARDLESS of how efficient each is. The difference in efficiency, for example between a horn enclosure and a sealed box, is because the horn design itself is more efficient than a sealed speaker - even using the same driver for each. The usual "catch" is simply that, within normal design limitations, producing a speaker with very high efficiency usually requires that you make significant tradeoffs in other areas. In general, very high efficiency speakers tend to have very good dynamics, and have relatively low distortion... but the usual tradeoffs are that they tend to have frequency response limitations, be larger in size, and cost significantly more. By sacrificing efficiency, it's relatively easy to "buy" improvements in other areas, like getting a flat frequency response which extends reasonably low in a more compact enclosure. Likewise, there are speakers that utilize a single driver, and so avoid the power losses and complications of a crossover, but the "payback" is that they also eschew the minor frequency response corrections that a good designer can accomplish in the crossover, and never make high treble that sounds quite as clean as what a purpose-built tweeter can deliver. You may consider the compromises to be worthwhile, but they are there, and are relatively obvious if you look - and listen. (Some of that will also depend on the type of music you listen to and your personal priorities. For example, if you listen to mostly jazz with vocals, you may be happy to sacrifice some high frequency extension for an especially coherent midrange.) (Incidentally, if a lot of cone movement at one frequency ends up modulating the audio at other frequencies, that would be plain old intermodulation distortion. The term " transient intermodulation distortion" is really specific to distortion in an amplifier or preamp caused by the interaction of too much negative feedback with an insufficient slew rate... and it's sort of an outdated term since it shouldn't ever occur in an otherwise well executed modern amplifier design.) Hi foggy1956 - In fact, less-efficient do not bring known benefits. To the contrary, less efficient speakers require more amplifier power for the same volume. The extra power required generates more heat in the voice-coils. As the voice-coils heat, their resistance increases. As their resistance increases, their interactions with the crossover components change AND their power demands on the amplifier increase even more. In general, less-efficient speakers' cones also have to move further to generate the same volume. This increases transient intermodulation distortion. So in general, the more sensitive the speaker, the less distortion and the less demand on the amplifier.
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stiehl11
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Post by stiehl11 on Apr 21, 2017 19:10:52 GMT -5
But (and this qualifier is the killer) your speakers must be "BASX compatible" to get that quality. Hook up my modest A-300 amp to Gar's speakers, and I (strongly) suspect that the performance would nosedive. I haven't tried, so this IS speculation on my part. So, is there a list of speakers that are BasX approved? Is there special labeling if it is (like THX Certified)? The BasX A-300 handled my Phase Tech PC-3 speakers without a sweat, with bass-heavy music, at both low and high volumes, for a few hours. Phase Tech PC series speakers are power hungry with wild resistance swings below 80Hz; even worse than the Axiom speakers. I have yet to hook up an AVR (including Sony's ES series) that can power them correctly. I've thought about selling my UPA-2, considering what owners were wanting for their outdated, out of warranty, sale priced around $200, used amps when I wanted to buy one for my daughter, and getting an A-300. I think your "speculation" is pretty much bunk on this one.
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Post by Boomzilla on Apr 21, 2017 21:56:10 GMT -5
...The BasX A-300 handled my Phase Tech PC-3 speakers without a sweat, with bass-heavy music, at both low and high volumes, for a few hours. Phase Tech PC series speakers are power hungry with wild resistance swings below 80Hz; even worse than the Axiom speakers...I think your "speculation" is pretty much bunk on this one. I admitted as much when I made the speculation.
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Post by brutiarti on Apr 21, 2017 22:51:09 GMT -5
Can the a-300 drive the T1's with no problem?
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stiehl11
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Post by stiehl11 on Apr 22, 2017 9:05:33 GMT -5
...The BasX A-300 handled my Phase Tech PC-3 speakers without a sweat, with bass-heavy music, at both low and high volumes, for a few hours. Phase Tech PC series speakers are power hungry with wild resistance swings below 80Hz; even worse than the Axiom speakers...I think your "speculation" is pretty much bunk on this one. I admitted as much when I made the speculation. And I'm confirming it. So, all good.
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stiehl11
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Post by stiehl11 on Apr 22, 2017 9:06:55 GMT -5
Can the a-300 drive the T1's with no problem? They should. Again, the A-300 drove my PC-3 speakers without issue. From what I know of Emotiva speakers, I can't imagine the T1 being more difficult.
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Post by brutiarti on Apr 22, 2017 11:23:16 GMT -5
Can the a-300 drive the T1's with no problem? They should. Again, the A-300 drove my PC-3 speakers without issue. From what I know of Emotiva speakers, I can't imagine the T1 being more difficult. Do you have the specs of your speakers handy?
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stiehl11
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Post by stiehl11 on Apr 22, 2017 11:55:55 GMT -5
They should. Again, the A-300 drove my PC-3 speakers without issue. From what I know of Emotiva speakers, I can't imagine the T1 being more difficult. Do you have the specs of your speakers handy? I don't, but they should be on the phase tech website.
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Post by rbk123 on Apr 22, 2017 14:43:37 GMT -5
Makes me wonder since the XPA Gen 3 line uses XPR tech, if the BasX line uses updated XPA-G2 technology but with smaller power supplies.
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Post by garbulky on Apr 23, 2017 17:29:21 GMT -5
Makes me wonder since the XPA Gen 3 line uses XPR tech, if the BasX line uses updated XPA-G2 technology but with smaller power supplies. I don't know for sure but I don't think so. The BasX is similar in look to the UPA-200 and UPA-500. Namely that all their channels are on one blade. Now I was sternly told that there are differences, which may be, but if you look at the comparison pictures, they look very similar. The older XPA gen 2 amps use one blade per channel...at least the XPA-3 and 5 do. The old UPA-1, UPA-2 and UPA-5 use XPA blades, one per channel. So they would share similar XPA technology. Now the new XPA gen 3 uses XPR tech. From what I gather from one post I think I read, it's a modification of the XPA blades in some way though I might be wrong here.
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Post by rbk123 on Apr 24, 2017 8:50:44 GMT -5
I don't know for sure but I don't think so. The BasX is similar in look to the UPA-200 and UPA-500. Namely that all their channels are on one blade. Now I was sternly told that there are differences, which may be, but if you look at the comparison pictures, they look very similar. The older XPA gen 2 amps use one blade per channel...at least the XPA-3 and 5 do. The old UPA-1, UPA-2 and UPA-5 use XPA blades, one per channel. So they would share similar XPA technology. Now the new XPA gen 3 uses XPR tech. From what I gather from one post I think I read, it's a modification of the XPA blades in some way though I might be wrong here. While true, that is a manufacturing difference not a circuit design difference. I recall somewhere the BasX boards are double-sided, so perhaps that allows them to put the increased XPA circuitry on one blade. That being said, you're probably right and all things considered, BasX is more likely refined UPA tech not refined XPA G2 tech.
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Post by drysdale on Apr 26, 2017 13:52:12 GMT -5
Does anyone have a 5 or 7 channel power amp and only use of the 3 channels with their AVR to power the LCR channels and then use two other channels with a separate pre-amp to do 2.1 stereo? Is this breaking some rule or would it hurt the power amp to connect it to two pre-amps?
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Post by repeetavx on Apr 26, 2017 15:48:26 GMT -5
Breaking the rules, no. But it certainly is an opportunity for ground loops. You may be able to get away with it.
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berg
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Post by berg on Jul 23, 2017 7:51:12 GMT -5
I originally were looking for a couple of smaller single channel amps, like the upa-1, xpa-100 or xpa-1l, to power my rf82's. Since that's no longer an option, how about bi-amping two a-300, or is the gain so small that I should just stick with one a-300?
When bi-amping, would one usually have one amp powering the tops, and the other powering the lows of each speaker, or could one have one amp powering top and low of one speaker?
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Post by Boomzilla on Jul 23, 2017 8:17:33 GMT -5
In general, I think that my A-300's output is just fine. It's flat, images well, and has driven all the speakers I've hooked up to it with ease. My only complaint has to do with the A-300's (low) input impedance. At 27K-ohms, that impedance is low enough that lots of equipment has trouble driving it. Now admittedly, 27K isn't as bad as some amps' 10K, but it's still a far cry from the 47K-ohm input impedance of a line-level preamp.
Some volume-controlled DACs, my Oppo UDP-205, and other equipment without robust output buffer amps sound bright and screechy on this amp due to the low input impedance. Now, I hear you say, let's not blame the power amp for the wimpy construction of upstream equipment. And it's a legit argument. But at the same time, a higher input impedance on the A-300 would have potentially cured a whole host of ailments.
This issue alone turns the A-300 from a component that can be driven by anything into a component that virtually demands a preamp.
Oh well...
Boomzilla
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Post by alucard on Jul 23, 2017 11:50:07 GMT -5
In general, I think that my A-300's output is just fine. It's flat, images well, and has driven all the speakers I've hooked up to it with ease. My only complaint has to do with the A-300's (low) input impedance. At 27K-ohms, that impedance is low enough that lots of equipment has trouble driving it. Now admittedly, 27K isn't as bad as some amps' 10K, but it's still a far cry from the 47K-ohm input impedance of a line-level preamp. Some volume-controlled DACs, my Oppo UDP-205, and other equipment without robust output buffer amps sound bright and screechy on this amp due to the low input impedance. Now, I hear you say, let's not blame the power amp for the wimpy construction of upstream equipment. And it's a legit argument. But at the same time, a higher input impedance on the A-300 would have potentially cured a whole host of ailments. This issue alone turns the A-300 from a component that can be driven by anything into a component that virtually demands a preamp. Oh well... Boomzilla Hi Boomzilla, One of your posts regarding input impedance had me look closer at that spec while I decide on an amp replacement. I read that it's good to have an amp input impedance of at least 20x the output impedance of source device (i.e. preamp). My XMC-1 has an output impedance of 100ohm so times 20 is 2k ohms. The BasX being at 27k ohm should be fine and the XPA series are about the same at 33k ohm (unbalanced).
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