FluxLab FA-10 powerful headphone amplifier

I've got the 22 and 12, had the 10 for a month or so. Similar voicing in the line, oversimplifying:

FA-10: I believe this was the first, and plays no particular favorites between bass\mid\treble in it's voicing. "Special skill" in the line is it puts out a lot of power....this is a good juice-hungry cans choice.

FA-12: Highlights the bass, slightly warms and thickens the FA-10 sound. "Special skill" is fully balanced.

FA-12S: Single-ended out only version of FA-12...cheaper.

FA-22: Highlight mid's\dynamics.....takes the house sound a bit faster\more detailed, but also a little thinner in tone.

All above is of course "to my ears"..... more experienced ears mileage may vary. The " line tone" to me shades neutral with a bit of warmth. I've been comparing this week to the Liquid GX I got last Saturday. It's like the LauX and the Jot 2 had a baby, while the Lyr 3 with a JJ tube watched from the closet. The LauX has a bit deeper soundstage with a real impressive rich delivery......the FA-22 rocks a bit harder\faster....doesn't have the hint o' roll-off that I get with LauX. I think the FA-22 plays nice with the Bifrost 2 and the LauX is more a DAC 2541 partner (for me). At the under $1k level, I think the Flux amps are very solid.

 

Yah, I’m a newbie user and you don’t know me, but it sucks that this board doesn’t have any experience with this Flux series of amps so here’s my datapoint. Take it with a grain of salt as there is a bunch of amps I’ve never heard.

I’ve owned the Flux FA-12 for about 9 months and I can compare it to the THX 789 for reference.

Chain is pi2aes->Denafrips Ares 2 balanced ->THX 789/Flux Fa-12->Anandas

First off, the thx 789 does not play well with Ares 2. Something about it oversharpens the treble to fatiguing levels. THX 789 is a way better match with my old Modi 3. If I were to guess it’s a high frequency noise that is fatiguing but cannot be heard. Going single ended from ares 2->thx amp alleviates it slightly.

The Flux FA-12 is warmer while still having good treble presence. The presentation is far more nuanced and dynamic with more micro detail, but it doesn’t try to shove that detail at you. Sound stage actually exists on it in comparison to the thx amp which IMO doesn’t have any.

Mids/bass are again more nuanced/detailed, but it’s not a night and day difference like the treble. The two regions are warmer in comparison to the 789, but I think still closely neutral sounding. Micro dynamics are better on the flux amp, but big sub bass slam is pretty similar.

If I were to give an edge to the thx it’s probably it’s black background and ability to reveal poorly recorded tracks. The Flux amp just makes all my crap pop, K-pop and J-pop sound more pleasing and less grating. The background just seems less black on the Flux amp though.

The flux amp relays emotion much, much better. My benchmark for this is Cat Steven’s Father and Son. You can hear and feel the emotion from him particularly around 1:00-1:30 minute Mark with the FA-12. The THX amp makes the song feel lifeless in comparison.

For IEM’s I still prefer the Flux amp, but since it has no summing circuit it’s a pain to use single ended and have to switch cables.

 

I really enjoy my Flux Fa-12 with my planars, but I'm probably going to start modding this amp soon. If anyone is interested on the mods on it I'll post some updates There is a slight graininess in the treble on the amp, and I've heard that this is an issue with the series of caps in this amp. I won't know what I'm going to do until I open it up and look at the circuit, but I'm certain I'm going to blow some money

 

Did you end up doing the mods?

 

Not yet, but it turns out Flux themselves made a modded out “limited version” you can google. I’ll probably re-cap what they did in mine when I find the time.

 

Well, your post got me to actually order parts and install them. Here it is below:



After talking with Flux and a year of reading capacitor reviews in the deepest audiophile holes on the internet, I decided to stick to Nichicon capacitors. I replaced the Nichicon Fine Gold caps to Nichicon's highest end UKZ audio caps. The no name Hitano filter caps have been replaced with quality Rubycon capacitors. The remaining Samwha power caps were replaced with Nichicon UPW caps. Every power cap was bypassed with 2.2uf or 1uf Wima film caps. The UKZ's were left alone without bypass film caps. SMD caps on the bottom of the PCB were left alone.

You can see the bypass below:



Note that the FA-10 Limited Edition that I mention previously uses Mundorf filtering caps for the big 10000 uF filters, but that won't work here as those have 4 pins and would need a new PCB. That led me to just adding film bypass caps and saving about $300 CAD.

Total cost for parts was around $130 CAD or for you Americans, just shy of $100 USD.

So... how does it sound? Well I have some balanced modded KSC75 installed for burn in duty just in case it blows up, but I'll report back after a week or so. So far it appears positive. Kinda tubey.

 

Over 100 hours of burn in, and the changes are pretty dramatic over stock. Resolution is through the roof. I can now hear that the HD6xx are more resolving than my Anandas. Dynamics have improved. Microdynamics are pretty similar to stock, but way more resolving. Blackness of background has improved a bit too. I get sub bass on the ear with my modded out CQC 6xx's now without using a tube amp. The sound stage is more filled in left to right, but still not deep. Might be a limitation of the rest of my gear, I'm not really sure. Separation of instruments is on another level and the layering is very tube like.

When I used to read reviews about hearing the whole lip smacking in to the microphone thing I thought it was nonsense audiophile exaggeration. I think most of you know what I'm talking about, but f**k if this level of resolution doesn't make you think, "Wait wtf was that lip smacking?"

When I was reading capacitor reviews, I wasn't really sure what to expect after a re-cap. I predominantly wanted the crappy samwha and hitano caps out asap and I would change the rest for fun since it would only cost an extra $20 CAD. I read that the UKZ series of caps had a bit more bass oomph, but I certainly wasn't expecting this boost in resolution. Very recommended upgrade! Hurry before all the UKZ are gone as they're out of production!

 

I just noticed that there are two OP amps on the back of the PCB, they are AD8620. It also looks like you could replace them with Burson V6 vivid op amps or something from Sparkos to make this fully discrete as there are Via's that could be potentially used. Something interesting IMO.


I was under the impression that this amp was fully discrete. Very odd. It would be interesting ask Flux if OP amp rolling is possible here.

 

Without much else to go on... I'm gonna guess they are opamps that do DC servo duty. So technically not part of the amplifying circuit per se if they claim everything else is discrete.

 

I would tend to agree, but it seems like a very fast and high bandwidth OPAMP to use for that sort of duty. Most DC servos use very slow low bandwidth products for the utmost stability.

In any case, I doubt that changing it for something 'better' is a good idea.

 

Thanks for your input as always Beefy. I am so satisfied with the performance of this amp now, that I believe I will leave it well enough alone, especially if it is not in the signal path. I have too many other mods in the works anyways.

I know rolling capacitors isn't a popular topic around here, but subjectively there seems to be quite large differences. Pretty unbelievable.

 

That's what I thought too. At first I was trying to think of some sort of fancy reason why they would do that... maybe because there's two dual channels so they are paralleling each on the outputs for some magical reason blah blah... but then I realize the more likely reason is that fancy spec opamps look better for bragging rights. Basically it comes down to this:

 

I doubt this as the op amp was hidden on the bottom of the pcb with plenty of room on top. When this amp was new, being fully discrete was a major selling point. If anything, I think Flux wanted to hide the op amp.

 

Straight from Flux:

Shoot was this a chip amp after all Ah well, it sounds fantastic after mods. Putting nice caps as close to op amps as much as possible seem to do magical things.