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Emotiva BasX A-100 Review (stereo amplifier)

infinitesymphony

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#41
I had been holding out hope that the Emotiva BasX would be a sleeper class AB integrated amp. Looks like the AIYIMA A07 remains the budget king for integrated amps, otherwise might as well buy a used NAD C320BEE or stick to other similar vintage integrated amps and simple AVRs.
 
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#42
Is there any chance if you could test some professional high output pure analoge poweramp (like QSC rmx4050 or plx3602, Mc2 T2000 or s1400)?
 

escape2

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#43
Thanks @amirm for the review. I think your measurements correlate closely with this measured test:
https://translate.google.com/transl...sty/stereo/wzmacniacze-stereo/3307-basx-a-100

I've had mine for about 3 months now and like it quite a bit. I listen at my desk at fairly low volume usually, so the amp never gets warm.

I'm quite surprised about much higher distortion while cold. Do other Emotiva amps exhibit similar behavior?

Regarding earlier question about connecting a subwoofer, I have an old Velodyne VX-11 sub that has speaker level inputs/outputs, so that's what I'm using - speaker wire from A-100 to the sub, and then more speaker wire from the sub to my bookshelf speakers. Sounds great to my ears.

And yes, it looks good.

 
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ta240

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#44
stupid question: is the PS noise created by the power supply or just mains noise making it through the power supply?
 
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#45
I have an A-100 and THX-789 for my desk, with the A-100 powering my Revel M16s (and JBL 530s before that) in near field. Source is an LG V30 Quad DAC sending Spotify HQ files. Through the speakers it sounds fantastic, with no perceptible hum or distortion and I've noticed no channel imbalance.

The headphone section really is a major reason people buy these, and I initially bought it for that as well as its speaker amping (and it's unique shape that fits better on my desk). The headphone output is definitely rounder and less clean than the THX-789 but that works well with brighter, high-impedance phones like the Beyerdynamic DT-1990. With the jumpers in it powers my Hifiman HE6SEs more effortlessly than the THX-789 but the noise floor/less-clean sound is more apparent. At this point I really only use the 789 for headphone listening (Hifiman HE6SE, HE-500, Focal Elegia).

Looks good on the desk too, with the 789 stacking nicely on top (I notice no heat issues in my application). Interestingly, the 789 will also pick up some hum from a nearby wireless phone charger if they're too close together but if the A-100 is picking it up it's inaudible.
 
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respice finem

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#46
This is true for a lot of things ....but cars are probably the worst possible example, right? At least in recent decades. Also, hasn't ASR shown that price != performance for amps and other audio gear as well, hundreds of times over!??
All this being true, the chances with any "more expensive than cheap" gear to last longer are better, at least it is my life's experience so far. As far as cars go, yes, the days of "forever running" simple to fix cars are definitely over, they are nowadays computers with an added car functionality :)
 

mrmoizy

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#47
stupid but serious question, coming from headphones and now exploring loudspeakers.

with this kind of amplifier, how do I connect a sub. both passive and active?
I don't own this amp, but just looking at the back panel, I'm guessing you could leverage the Output RCA connectors to send your input source out to an active subwoofer. This amp wouldn't power a passive subwoofer along with speakers, you would either need another standalone subwoofer amp feeding a passive subwoofer, or an active subwoofer.

Some active subwoofers only have one RCA connection for their input. You can find Y cables, where the one end has Red and White male RCA ends, and the other end combines them into one RCA male end. That should feed an active subwoofer just fine I'm guessing, unless I'm misunderstanding what those Output jacks are.
 

ta240

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#48
I don't own this amp, but just looking at the back panel, I'm guessing you could leverage the Output RCA connectors to send your input source out to an active subwoofer. This amp wouldn't power a passive subwoofer along with speakers, you would either need another standalone subwoofer amp feeding a passive subwoofer, or an active subwoofer.

Some active subwoofers only have one RCA connection for their input. You can find Y cables, where the one end has Red and White male RCA ends, and the other end combines them into one RCA male end. That should feed an active subwoofer just fine I'm guessing, unless I'm misunderstanding what those Output jacks are.
The signal on the output is the same as the input signal so it doesn't have any connection to the volume control. It isn't a preamp out type; it is just so you could daisy chain amps off the same signal.
https://cdn.shopify.com/s/files/1/2572/6926/files/BASX_A-100_User_Manual_v10.pdf?9161570434650216536
 

escape2

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#49
Some active subwoofers only have one RCA connection for their input. You can find Y cables, where the one end has Red and White male RCA ends, and the other end combines them into one RCA male end. That should feed an active subwoofer just fine I'm guessing, unless I'm misunderstanding what those Output jacks are.
Wouldn't such summing up of signals from two channels result in too strong of a signal going into the sub? I suppose you could just lower the sub's gain though to account for this.
 

escape2

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#50
The signal on the output is the same as the input signal so it doesn't have any connection to the volume control. It isn't a preamp out type; it is just so you could daisy chain amps off the same signal.
https://cdn.shopify.com/s/files/1/2572/6926/files/BASX_A-100_User_Manual_v10.pdf?9161570434650216536
It would still work if you control the volume upstream (like with a pre-amp), and just leave the A-100's volume knob in one spot.

FYI, A-100 uses an analog pot, which results in some noticeable channel imbalance at very low volume levels, like 8 o'clock and lower. I keep mine at 12 o'clock and adjust volume with the pre-amp in my DAC. Based on amir's testing results, it looks like a little bit of that channel imbalance carried into higher volumes as well - curious how high the volume knob was turned during his testing?

Speaking of volume knob on the A-100, it has no markings of any kind, so it's impossible to tell where it's at. Adding some kind of a sticker to it is a must.

Lastly, there is the inconveniently located power switch on the back - depending on how you have it placed, you may find it awkward to have to reach around to the back to power it on/off. I've added a piece of extension cord with an inline on/off switch to mine so that I can have it up front.
 
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amirm

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Thread Starter #51
On testing the headphone out, I can do it as is. With the jumpers, it can damage my precision dummy load for headphones. And at any rate, it is the same performance I already measured for the speaker terminal. What else would it be?
 

JohnBooty

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#52
One thing puzzles me though, it seems for passives, even similar ported design with similar woofer size, it seems bass extension is usually worse than actives? any reason behind that?
Sure. It's the whole Hoffman's Iron Law thing.

With EQ/DSP you can always trade bass for efficiency. Smash down everything except the bass by 6dB and voila, a 6dB bass boost and usable output down to 40hz or so.

It's generally a smart and easy tradeoff to make. Sacrificing efficiency is not such a big loss when power is cheap thanks to cool and efficient Class D, and massive max SPLs are not a requirement. This is the playbook of the JBL 3 Series and any number of other actives.
 

Billy Budapest

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#53
With its small size, I was thinking it would employ some sort of Class D solution, or an IC amplifier solution. So we have a small, inexpensive, mediocre performing Class AB amp. I’d rather go for the cheapest NAD amplifier, personally.
 

Newman

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#58
Plenty of harmonics from the rectifier, plenty of intermodulation with the 1 kHz carrier. Some of this may be radiated due to the close proximity of components in that case. Maybe they also economized the current source of the input LTP, resulting in poor PSRR?
When I have in the past asked Amir to measure PSRR, he has dismissed the idea as pointless.
 
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amirm

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Thread Starter #59
Does it cost big money to make the crosstalk good?
Kind of. You need space between the two amps and that makes the case more expensive. And shipping costs.
 
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