Showing 1 of 1264 conversations about:
DenonFanboy
687
Feb 27, 2018
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I’m sorry, don’t get me wrong I do love Massdrop but all specs measured at 1% THD isn’t great.
Feb 27, 2018
Motorrad
2368
Feb 27, 2018
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at full power to load? I disagree.
Feb 27, 2018
DenonFanboy
687
Feb 27, 2018
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I’m just used to measurements that all other companies do and quite frankly don’t understand this standard :S
Feb 27, 2018
Motorrad
2368
Feb 27, 2018
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"THD: -140 dB, 300 ohms, 100 mW" I'd call this impressive.
Feb 27, 2018
Bobthedespot
82
Feb 27, 2018
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'"THD: -140 dB, 300 ohms, 100 mW" I'd call this impressive.'
More likely B.S...
Never seen a credible spec taking with a useful standard that can place THD+N that low, largely due to a total lack of equipment capable of that kind of measurement.
Feb 27, 2018
Motorrad
2368
Feb 27, 2018
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haha. I've seen -140...the -143 is suspect, but from prototypes I have heard, I'd say it was possible. The architecture is not new and such low THD/N has been theorized for some time.
Feb 27, 2018
Bobthedespot
82
Feb 27, 2018
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But never measured. Seriously, just name a single company that makes a signal analyzer that works that well.
And regarding the topology, unless higher-order distortions are controlled just as much as lower-order distortions, the THD spec will not be even remotely useful.
The topology that THX claims to use here is a high-efficiency dedicated low frequency design. If the website is factually accurate (doubtful in light of other incorrect statements on the site), then the current feedback will not manage higher order harmonics well at all, and the general sound will be similar to a saturated class-D amp.
Feb 27, 2018
Motorrad
2368
Feb 27, 2018
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Naming manufacturers of signal analyzers is really not my forte...maybe 20yrs ago. I would doubt you could count how many that measure that on one...finger. I doubt it will be long before someone chimes in with the answer how they measured that... "...and the general sound will be similar to a saturated class-D amp..." ...I was thinking that about a year ago when I heard the design discussed; it does not sound like that. I'm very familiar -intimately even- with how similar topologies were implemented on sub amps, but this is not that. BTW, which THX spec are you referring to?
Feb 27, 2018
Bobthedespot
82
Feb 27, 2018
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I'm only 3 years out of the industry, and I worked with totl Audio Precision, B&K, and Rhode/Schwartz equipment.
None of it even approached 140 dB, and the best I have ever seen was the LX800 prototype which could manage 138dB. Chris Straum is dead now, and there is a 0% chance he would ever work with THX.
Here is the spec with the reference design: https://www.triadsemi.com/wp-content/uploads/dlm_uploads/2016/12/triadsemi_tsthx88_productbrief.2016-12-19.pdf
Feb 27, 2018
Cokeman
1956
Feb 27, 2018
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It's Razer, what do you expect.
Feb 27, 2018
Bob: The APx555 is new on the scene, and is a wonderful instrument. And yes, AAA completely avoids generating the higher-order harmonics at all listening levels, without resorting to a space-heater Class A architecture. Quiescent consumption on the unit is ~3 Watts.
APx555 Loopback @ 5.5 Vrms, 1 kHz
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Massdrop THX AAA 789 @ 5.5 Vrms, 1 kHz, 300 Ω (100 mW per Ch):
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Massdrop THX AAA 789 @ 0.55 Vrms, 1 kHz, 300 Ω (1 mW per Ch):
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(Remember Nelson Pass' assertion that the first watt is the most important? When it comes to headphones, one could argue the first mW is probably the most important!)
Feb 27, 2018
Bobthedespot
82
Feb 27, 2018
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Holy crap
Edit: This is really interesting, can you run this with a set of 10-20 ohm cans or iems?
Feb 27, 2018
Motorrad
2368
Feb 27, 2018
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Holy Crap.
Feb 27, 2018
CEE_TEE
3385
Feb 27, 2018
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THD: -143 dB 300 Ω@ 1 mW = 0.000007% -140 dB 300 Ω @ 100 mW = 0.000010% -125 dB 32 Ω @ 1 mW = 0.000056% -123 dB 32 Ω @ 100 mW = 0.000071% -120 dB 16 Ω @ 1 mW = 0.000100% -118 dB 16 Ω @ 100 mW = 0.000126% IMD: -123 dBSMPTE 70 Hz + 70 kHz, 300 Ω = 0.000071% -124 dBDFD 18 kHz + 19 kHz, 300 Ω = 0.000063% Crosstalk: -127 dB, 300 Ω = 0.000045%
Feb 27, 2018
DenonFanboy
687
Feb 27, 2018
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Ok that’s dead quiet, I think u will hear a ghost b4 u hear distortion on this amp.
Feb 27, 2018
Bobthedespot
82
Feb 27, 2018
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Depends if Earl Geddes was correct in his theories of psychoacoustics...
I think I'll buy one just to put on my analyzer, to see if the hype is real.
The crazy good specs for this headphone amp are @ zero gain... it remains to be seen what happens in different scenarios.
Feb 27, 2018
sheaSTL
21
Feb 27, 2018
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Don’t scare me!!!
Feb 27, 2018
Rajb
2
Dec 30, 2018
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Hi Andrew. Just wondering if you know when the THX AAA 789 will drop again? Thanks.
Dec 30, 2018
Hi, sorry I don't know about the next one. Maybe ask @CEE_TEE
Dec 31, 2018
Rajb
2
Dec 31, 2018
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Dec 31, 2018
rastus
816
Sep 28, 2019
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Andrew, Is the drop Airist R-2R DAC well matched to the THX789? A statement that it was “too hot”; is 2.5V on the high side for the THX?
(Edited)
Sep 28, 2019
Lisasonictower
463
Oct 3, 2019
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No it’s perfectly fine.
Oct 3, 2019
rastus
816
Oct 3, 2019
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Thanks, knew, but hoping for a response also from the maker, to counter a “hot” accusation in another thread.
Oct 3, 2019
Lisasonictower
463
Oct 3, 2019
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If we were to go by the tech specs then you would say do not use gain 3 with a input signal above 2.1v
Oct 3, 2019
rastus
816
Oct 4, 2019
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Thanks, used that.
Oct 4, 2019
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