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Post by ryanmh1 on Sept 19, 2017 12:50:31 GMT -5
How has there been no rebuttal or explanation of this review yet? I was tentatively considering one of these amplifiers (although what I really want is a PA7-350...), but NO WAY after seeing those measurements. The amplifier under review failed to deliver even 50 watts without severe distortion into frequencies over 15kHz. On music, of course, this would mean that if the amplifier is working reasonably hard, each time there is content over 15kHz the amplifier is spewing out all sort of intermodulation distortion. I came here hoping to find Emotiva's response, since they made no manufacturer comment to Stereophile. Nothing here, either. Then I checked for their own measurements for their 20Hz to 20kHz sweep. There was one published for the Gen1. For the Gen3? Nothing. Hmm...
Is this actually accurate performance for this amplifier? If so, some engineer or supplier needs to be dragged out back and fired. It is the worst measured performance I have seen in Stereophile in two decades for a solid state product. The amplifier had to be broken, right? Has Emotiva conducted its own internal review and conducted a post-mortem on the review sample to determine what went wrong?
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Post by audiosyndrome on Sept 19, 2017 13:16:28 GMT -5
Just read the review. I've heard a few different Zu Audio speakers at shows and I think they can be sub-optimal unless paired with the right amp. At two shows, the sound from the Zu room drove us out of the room with it's hardness; I'm talking headache. The third time I heard a Zu setup, I didn't want to leave. It was gorgeously smooth but had substantial upper frequency extension. Here's a video hosted by Herb interviewing the owner of High Water Sound in Brooklyn. Eccentric, esoteric and entertaining in my mind and it might give you an idea what he loves in terms of sound. High Water Sound is in Manhatten not Brooklyn. Well worth a visit but you'll need lots of cash to buy anything there. 😉 Russ |
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Post by teaman on Sept 19, 2017 14:14:07 GMT -5
How has there been no rebuttal or explanation of this review yet? I was tentatively considering one of these amplifiers (although what I really want is a PA7-350...), but NO WAY after seeing those measurements. The amplifier under review failed to deliver even 50 watts without severe distortion into frequencies over 15kHz. On music, of course, this would mean that if the amplifier is working reasonably hard, each time there is content over 15kHz the amplifier is spewing out all sort of intermodulation distortion. I came here hoping to find Emotiva's response, since they made no manufacturer comment to Stereophile. Nothing here, either. Then I checked for their own measurements for their 20Hz to 20kHz sweep. There was one published for the Gen1. For the Gen3? Nothing. Hmm... Is this actually accurate performance for this amplifier? If so, some engineer or supplier needs to be dragged out back and fired. It is the worst measured performance I have seen in Stereophile in two decades for a solid state product. The amplifier had to be broken, right? Has Emotiva conducted its own internal review and conducted a post-mortem on the review sample to determine what went wrong? Ryan, Dan Laufman CEO of Emotiva did in fact reply to Stereophile's review of the XPA Gen 3 amp. Basically he thanked them for their review...I too was wondering why Dan would not challenge their out of whack distortion findings. For the fact that Stereophile posted the amp as a referred model, even with the bad measurements is even more confusing. Tim |
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Post by Dan Laufman on Sept 19, 2017 14:21:47 GMT -5
Hi all, Regarding Stereophile's review of the XPA-2 G3 amplifier... We don't see this anomaly in amplifiers on the production floor. I haven't put my hands on this particular review unit and I had not commented back to Stereophile because I did not have all of my facts right. Frankly, it's been a non-issue up until now because we're not seeing this behavior on the line. I'll post results from a production XPA-2 tomorrow and then you'll be able to see what's really going on. If it seems necessary, we'll post a manufacturers comment. Cheers, Big Dan P.S. We haven't made a strong reputation over the last dozen years or so by making the "worst measuring solid state amplifiers" ever reviewed. By the way, if you've been a long-term Stereophile reader, you've seen some real crap get a "passing" grade. Just saying...  |
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Post by ryanmh1 on Sept 19, 2017 15:49:01 GMT -5
Well that was fast... Glad to hear this is not normal. I assumed as much. It is still not the XPR or PA7-350 replacement I have been hoping for (a now abandoned market niche ... if anyone does that again for a reasonable price, they will have my money), but hopefully still a competent amp. Still holding out for something off those product lines in the secondary market, but the supply has been pretty dry of late. Eventually, I might have to settle for one of these things. We'll see. SMPS amps raise a whole new set of reliability/repair issues. Hopefully the review sample can be conducted and a post mortem conducted to figure out went wrong and fix it.
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cawgijoe
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Post by cawgijoe on Sept 19, 2017 15:52:21 GMT -5
I just wanted to make a comment here that there must have been something wrong with that review sample. A good friend of mine bought the XPA-5 Gen 3 at Emofest to replace a Gen 1 XPA-3 and he has had nothing but praise for the new amp. he is a EE with a masters degree and has been an audiophile his entire life. I can guarantee you that if there was something wrong with the design or implementation he would not have bought it or praised it as he has.
I still need to go over to listen, but he says it sounds better than the Gen 1 design and has very quickly sold his Gen 1.
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Post by wilburthegoose on Sept 19, 2017 19:54:54 GMT -5
I'd still love to understand the audible difference between Gen 2 and Gen 3  |
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Post by teaman on Sept 19, 2017 19:56:38 GMT -5
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Post by leonski on Sept 19, 2017 20:04:19 GMT -5
The Crestron has 2x15amp AC inputs.
And is ALL balanced inputs, which accounts for the 4v sensitivity to get 400 watts out. 2v per leg.
This amp is NOT for the casual HT guy or someone unwilling to drop a pair of 15 amp lines for the amp.
And NO, you can't plug it into a duplex outlet which is all from a single circuit.
The Mondo 7x amps ALL require some serious input power.
TANSTAAFL (google it)
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hemster
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Post by hemster on Sept 19, 2017 20:05:40 GMT -5
I'd still love to understand the audible difference between Gen 2 and Gen 3 ... if you can hear it! |
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Post by teaman on Sept 19, 2017 20:08:35 GMT -5
The Crestron has 2x15amp AC inputs. And is ALL balanced inputs, which accounts for the 4v sensitivity to get 400 watts out. 2v per leg. This amp is NOT for the casual HT guy or someone unwilling to drop a pair of 15 amp lines for the amp. And NO, you can't plug it into a duplex outlet which is all from a single circuit. The Mondo 7x amps ALL require some serious input power. TANSTAAFL (google it) Yeah, that was a blast of sarcasm when I posted that Crestron Pro gear. The new 7 channel amps weighing in at 108 lbs and 105 lbs respectively, 7.3 processors and even their new HD 4K 7.1 receiver look pretty amazing. Cha-ching! |
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Post by leonski on Sept 19, 2017 21:27:12 GMT -5
I'd still love to understand the audible difference between Gen 2 and Gen 3 ... if you can hear it! I suspect that EMO was tired of shipping heavy amps and having Gorilla Monsoon (famous wrestler) shot put the new amp from the curb to the porch. Heavier stuff gets less respect, maybe? And the REALLY heavy stuff should be shipped on a pallet which really adds up. From the audible side? Probably no change except under some very specific conditions of load and drive level where one amp is slightly more or less capable than the other. If EMO just repackaged an output stage from a previous amp (maybe adding output devices for more output?) than look to the parent amp for cues. As for the stereophile test? i'd have to see exact conditions of the test. Some test equipment and SMPS don't get along due to the switching frequency which 'rides along' and can mess up measurments without necessarily being audible. Over My Pay Grade. What did the TEXT portion of the sterophile test reveal? Any notes there which could be associated with the measured data? If not, I'm not certain I'd worry about it. |
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hemster
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Post by hemster on Sept 19, 2017 21:28:59 GMT -5
... if you can hear it! I suspect that EMO was tired of shipping heavy amps and having Gorilla Monsoon (famous wrestler) shot put the new amp from the curb to the porch. Heavier stuff gets less respect, maybe? And the REALLY heavy stuff should be shipped on a pallet which really adds up. From the audible side? Probably no change except under some very specific conditions of load and drive level where one amp is slightly more or less capable than the other. If EMO just repackaged an output stage from a previous amp (maybe adding output devices for more output?) than look to the parent amp for cues. As for the stereophile test? i'd have to see exact conditions of the test. Some test equipment and SMPS don't get along due to the switching frequency which 'rides along' and can mess up measurments without necessarily being audible. Over My Pay Grade. What did the TEXT portion of the sterophile test reveal? Any notes there which could be associated with the measured data? If not, I'm not certain I'd worry about it. All good questions.. to which we do not have answers as yet. |
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Post by rbk123 on Sept 19, 2017 22:13:40 GMT -5
Someone asked Lonnie about the Stereophile review of the Gen 3 amp and Mark captured Lonnie's response in his Emofest write-up:
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Post by teaman on Sept 19, 2017 23:51:40 GMT -5
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cawgijoe
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Post by cawgijoe on Sept 20, 2017 7:35:24 GMT -5
... if you can hear it! I suspect that EMO was tired of shipping heavy amps and having Gorilla Monsoon (famous wrestler) shot put the new amp from the curb to the porch. Heavier stuff gets less respect, maybe? And the REALLY heavy stuff should be shipped on a pallet which really adds up. From the audible side? Probably no change except under some very specific conditions of load and drive level where one amp is slightly more or less capable than the other. If EMO just repackaged an output stage from a previous amp (maybe adding output devices for more output?) than look to the parent amp for cues. As for the stereophile test? i'd have to see exact conditions of the test. Some test equipment and SMPS don't get along due to the switching frequency which 'rides along' and can mess up measurments without necessarily being audible. Over My Pay Grade. What did the TEXT portion of the sterophile test reveal? Any notes there which could be associated with the measured data? If not, I'm not certain I'd worry about it. I suspect that the current line of amps with switching power supplies are also more powerful which may contribute to a sound difference versus the older toroidal amps plus the instant response from the high voltage at the rail. I will get a more technical response from my EE friend as to why he thinks they sound better. He is also driving Thiel speakers which points to your load point above. IMO, whether they sound better or not, this design is very cool. Being able to configure these amps from one channel to seven makes it easier for the company to quickly configure an amp to your specs, they are lighter for shipping and you can add blades later on as you wish to meet your needs. |
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Post by Deleted on Sept 20, 2017 8:28:45 GMT -5
Most Thiel speakers aren't ridiculous loads. I have a pair of CS1.7 speakers which are a simple two-way affair, and they have a well-controlled 4-ohm impedance. However, there have been some that were simply amp-eaters, like the CS5 which had three 4-ohm woofers in the bass section and presented a 1.8 ohm impedance below 200 Hz. And Emotiva amps aren't shrinking violets into low impedances, but the self-protect function often wants to kick in below about 2 ohms so if the speaker has wicked impedance dips then there could be sporadic or frequent occurrences where the amp goes into protection, even though it isn't overheating. The protection function tends to err on the side of caution.
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Post by leonski on Sept 20, 2017 11:24:12 GMT -5
How well do EMO amps do when confronted with highly reactive loads? Say 45 degrees or better?
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Post by ryanmh1 on Sept 20, 2017 12:06:59 GMT -5
i'd have to see exact conditions of the test. Some test equipment and SMPS don't get along due to the switching frequency which 'rides along' and can mess up measurments without necessarily being audible. Over My Pay Grade. What did the TEXT portion of the sterophile test reveal? Any notes there which could be associated with the measured data? If not, I'm not certain I'd worry about it. They control for the hash on the output. Stereophile has the proper filter, and has used it for well over a decade. The rise in distortion was abrupt and sudden, which suggests to me that it was clipping on high frequencies tones. Also note that both channels exhibit the same behavior. Thus, it seems unlikely that the something went wrong in an output module. Assuming a failure, it is a common component which is the power supply. If not a failure, it is (or was) a design flaw. The note someone posted above about one of the Emo techs saying production models don't measure this way at least suggests it was a design issue that was subsequently remedied. Still, it would be most interesting to see how the 20kHz THD actually measures on this. Most amps with a SMPS still have not mastered the art of keeping the distortion reasonably low. If the production version actually manages to keep it below .03%, it's a pretty good achievement. It still does not take the long term reliability issues of the equation, but only time will tell how that goes. The nice thing about linear supplies is they rarely break. With a SMPS, anything breaks ... good luck. |
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Post by leonski on Sept 20, 2017 12:30:54 GMT -5
The reason I asked, is I saw no mention of the filter which goes between amp and measuring equipment. That mention was all over d-amp reviews not too long ago.
I'll go with what ryanmh1 says. Makes perfect sense.
And in reading the review? Some speakers sounded wonderful (the Maggies) and others, not so good, which the tester ascribed to the poor measurements in the high frequencies.
They mentioned the original 'dis' against solid state which was 'transistor sound'. An etched or brittle HF is the usual note.
And yes, again, agreeing with ryanmh1, SMPS are a lot more complicated to both maintain AND design. I can cookbook up a reaonable Linear. No frills, but it's gonna work. I stand No Chance in getting
a switcher up and running.
I'd like to know what was changed and WHERE in the G3 to 'fix' what could have been an issue. And see a RETEST under stereophile conditions.
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