Nov 13, 2018549 views
Let the burn-in commence! Happy to have received my Massdrop x THX AAA 789 amp today (originally scheduled for Feb 2019). The first thing I noticed is in Gain setting I (lowest) I have to turn the dial to 2-3pm to hit the sweet spot on the Focal Elegia -- which are very easy to drive. On Gain setting II (medium) I only need to hit about 11am to hit that same level of output. Have not tested gain setting III (highest) as I've seen in reviews and charts which doubles the THD (although still incredibly low). In comparison with exact same setup but with Feliks-Audio Echo (only has one gain mode) the Elegia hits their sweet spot at around 8-9am. Can't make any comments yet to its fidelity or sonic performance as I haven't had yet the chance to do quiet and critical listening. But I have it going with some music in the background for burn-in purposes.
haha2339, Megazine, and 7 others

Alright, I've listened to this amp enough to actually give an informed opinion: It's aggressively transparent and ruthlessly free of distortion. I cannot over emphasize how clean and clinical the THX AAA 789 is. If you like color, or character in your amps, you will not enjoy the 789 to its fullest. If you appreciate preposterously low noise floor and absolutely faithful reproduction and rendition, this amp should be at the top of your shopping list.
Just to comment on Gain, since I doubt a lot of people actually know what it does: Gain is the factor that the input is multiplied by before it hits the output and should be selected based on your source. You're tweaking the input sensitivity when you adjust gain. Ideally, you set the gain to exactly what is needed to take the output of your source to the max swing of your amp. That would result in a maxed volume control for full output. Higher gain doesn't result in more output power at that max level. By going beyond what is needed to take the peaks of your source to the max of your amp, all you do is clip and distort. It can still get louder that way, but that's probably not what you're after. Most people run waaay more gain than they really need. You won't see much issue in running more than needed if you set things to levels that are actually sensible and aren't hitting the limits of your gear, but you're only wasting power somewhere along the way by running higher than needed. Side note, THX is actually one of the reasons everything has too much gain for the average person these days!
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Ok so as a novice maybe I'm doing Gain wrong. Where can I learn "the right way" to do Gain? Or do I need a PhD to really answer that question?
Not sure where to point you for it, so here's some info. Formatting is going to be awful here, but bear with me. To calculate necessary gain, you can use this equation: Gain = Output (Vrms) / Input Sensitivity (Vrms) Assume input sensitivity is equal to your source device's rated output voltage. Let's say 2V for simplicity's sake here, but it can be all over the place depending on what you're using. Now most things don't give you output voltage, so use this to find that for your amp. E = sqrt( P * R ) [Voltage = sqrt( Power in Watts * Resistance in Ohms)] ^ This is just Ohm's Law if anyone doesn't know where this comes from. Magni 3 for example, because it's easy to find these numbers for it: E = sqrt(2 Wrms * 32 ohms) E = 8 V You get 8 Vrms out of a Magni 3. Gain = 8 V / 2 V Gain = 4 You need a gain of 4 to get full output from a Magni 3 with a 2 Vrms source. Now, you can skip over all of this if you have a rated input sensitivity. Just compare your output to the required input. Realistically, you want more source voltage available than the minimum required by the input sensitivity if you're aiming for that full output. This is because you probably don't listen to nothing but full scale sine waves. Real music sits below that full output, some significantly more than others. Obviously, you can swap different known elements in to figure out different things. If you have a known gain, you can find input sensitivity, for example. We know the Magni 3 has a gain option of 2 or 7. 2 is going to net us 4V of the 8V available at full output. That's fine... but you're not going to make use of the full 2W output. At 7, you'd swing 14V if it was capable of it. Instead, you're chopping off 6V (sort of... all of these numbers are RMS, and it'll swing more to the peaks, but ignore that and just assume you're clipping signals here anyway) if you run full 2V into it with no attenuation. But like I said, music isn't full scale all the time, and you're probably using that volume knob. Of course, my original comment on full output and gain not being load dependent doesn't mean everything else isn't. Do you actually need full output is the next question. You have a super sensitive Grado or just about any in ear, and an amp that will dump 2W into that impedance. 2W is well in excess of SPLs capable of deafening you for both options. I mean, it's probably going to kill those drivers too, but whether you actually need full output is important too, and a lot of things are getting so powerful that you probably don't a lot of times. If you don't need 2W, that low gain of 2 and the 4V swing is potentially very useful now. If you actually needed more than 2W, then you want a bigger amp, not more gain. That's just distortion and compression, not real power. So it all depends... Sometimes less than full is great, others you're great at that ideal number, and sometimes you still need just a little more. But let's say the Magni had 3 gain settings, 2, 6, and 12. You have no need for that 12 in any scenario with that 2 V source. The 6 already does more than it's capable of. 12 is just additional distortion over the 6. All I'm really saying in all of this is if you have enough to hit your max at a lower setting, that higher one is only going to do negative things. You really need to know how much power you actually need if you want to calculate every little detail about what is enough for you, but don't worry about it too much. It's only really worth thinking about if you're curious which gain setting to use on something with options, or you're trying to minimize any excess gain in a chain or something.
Question, why didn't you buy the Liquid Carbon X + SDAC over the THX 789? Love the pic!
At least for me, the THX is cleaner (lower distortion) and more powerful. It also has better gain options and the inclusion of more outputs (3.5mm, 6.35mm, and 4-pin XLR). Also, the new balanced SDAC has more inputs and I believe is truly balanced where the LCX is using a phase-splitter so the new implementation as well as other updates are substantial for the slight tick in cost ($80 to $150). Overall, it made more sense to get the more powerful and flexible system for $120 more over the LCX. If the THX 789 and Balanced SDAC didn't exist, the LCX would be the top dog. Otherwise, it's a very solid #2 but may also be better to some folks that prefer a bit more warmth over the seriously uncolored THX.
By far the most peculiar aspect is that it runs remarkably cold! It has been playing continuously for hours and it still is cold to the touch both the top and bottom of the unit. Truly impressive. Shows great thought was put into its efficiency and cleanliness.
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Electro comes with the science once again
I am bit of a research nut and been at this for two decades. I still have only scratched the surface of all the factors at play in audio reproduction. I did a significant amount of research around 2007 when I bought I my first separate amp for my HT. I also have several friends making their jump to separates over the last couple years so feel free to hit me up with amp questions as needed.
Focal elex: worth the price and if so, why?
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The Elex or Elegia? I have both. And I have the Ebony Fostex cans. But, against those, the Focal's are superior in pretty much every regard except bass impact (but that should be a given). However, they have much more realistic bass texture equivalent to an actual woofer, not than boom-boom-pow bass that makes the Fostex sound more "fun."
They are worth the price to me because they are VERY good. I have two pair for two locations. I have absolutely no desire to try and find anything better. Who doesn't want to end the search and just be happy?
Glad to see you got your pair back. Did Focal ever deny/confirm the issue you were experiencing? Also if you can, run the Elegia balanced. They become just absolutely wonderful and can really highlight the acoustics of the room/chamber/venue quite well. It's an interesting effect I've been enjoying in a lot of tracks that I know up and down. Plus, their bass tightens up and really helps round out the sound that much more with some added weight.
I have a balanced cable on the way, really looking forward to trying that. As for the defect of my first pair, I never got word. peeps are amazing. I sent them back and as soon as they got new stock, they shipped one to me all at no-shipping-cost to me. They're def good folks I plan to buy cans from next time.
That's good to know. I can vouch for Moon Audio myself as well as they expedited mine on shipping and answered all my annoying questions via email very promptly. Nice to be able to add another vendor to the "trusted" list, haha.
What are your thoughts on the Elegia?
I wrote some first impressions here: TL;DR: they're fantastic. They have my previous fav pair, AQ NightOwl, hanging from their perch getting little use.