Why would a powerful amp behave like a less powerful amp?

Context: I just received the new dx3 pro+. I was excited because I needed a small desktop solution that would have more power than my Qudelix.

I am not a topping fan. But, the price and power were hard to beat for a background listening desktop amp.

This thing performs like it has less power than my qudelix. I can literally max my source (macbook pro) and the amp on high gain on my lsa hp-2 ultra. I will DIE if I do that on the Qudelix. (I almost did).

The dx3 pro has low and high gain of +6 and +19. Unfortunately, the +19 creates noise on my IEMs (not even my sensitive ones)

So, um, what gives? this thing has measurements of 1.5 watts into 32ohms. But my little 240mw Qudelix is wiping the floor with it.

as in Qudelix-5K Reference DAC AMP?
with 3.5mm Unbalanced 2.0V RMS (80mWatt/Ch) and 2.5mm Balanced 4.0V RMS (240mWatt/Ch).

That’s the one. These two amps feel comparable in power. While things like the idsd micro signature (which I think is comparable to the dx3 pro+ but need to check) simply obliterates the qudelix on power.

From what I know it’s based on gain, you can have 2 amps with equal power but have one with higher gain and one with lower, the higher gain amp will be able to produce higher volumes assuming efficient enough loads. So you could have an amp with more power but less gain reach lower volume with an efficient iem compared vs a higher gain and lower power amp. But if you change the load to something more difficult, the higher gain lower power amp may struggle more and the lower gain higher power may not. So if you are talking a purely volume perspective, it’s just the gain of the system in this case (since you are comparing dac/amps) that’s doing this. But gain technically isn’t power so keep that in mind. But this whole thing doesn’t take into account sound quality at all here so eh

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I agree, not a sound quality consideration. But what you just said implies that the Qudelix has gain above +19db of the dx3 pro+ High gain setting. Enough so that 240mw becomes competitive with 1500mw.

The Qudelix (on it’s high power mode) is definitely able to drive things louder than the dx3 on low gain. And seems quite comparable on dx3 high gain. Probably still louder on the IEMs.

I also just read that dx3 may struggle with low impedance loads. All my headphones are low impedance.

Going to see if I can find gain specs for Qudelix.


Not exactly, if you put something with higher power demands on both, you’d likely hear the qudelix wimp out. Just because it has higher gain doesn’t mean it will drive harder to drive loads well, it just means it can push louder volumes, but that doesn’t mean it will actually sound good at those louder volumes when given a more challenging load compared to lower gain higher power. But all depends ofc, but the whole comparing power thing doesn’t quite make sense in this context since it’s gain, not power output

Sure, this is only volume not sound quality or anything else like that

Not tried the pro+ myself so can’t comment there. I have tried the regular pro and didn’t exactly observe any issues but I hadn’t tried any iems or headphones below 32 ohms. In the past the high output impedance of topping gear did cause problems, but I’m pretty sure that was fixed on the pro unless they for some reason reverted with the pro+

Correct. Dx3 pro+ sounds pretty good from the brief listening sessions. By that I mean good for a topping which I expect to be competitive with Qudelix. The goal here was a higher powered small desktop dac/amp that matched the Qudelix but with more power.

Correct, it’s roughly 3X the power and < 1 ohm output impedance compared to previous model. That’s why I bought it. It is Brand new so it was a blind buy. No reviews.

I was expecting something that would drive my hp-2 and IEMs with more authority.

I think all my headphones are sub 16Ohms. Need to check. None are over 32.

Seems like this just isn’t the right amp.

I should probably bite the bullet and re-buy the ifi idsd micro signature again. sigh

One aspect of it is that not all power is created equally. Say you have an amplifier that can do 2W peak output. The following graph for this theoretical amp shows Power (as a function of V and A) aswell as Voltage (limited to 10V) and Current (limited to 0.5A).
The X-axis is resistance from 1 to 1000 Ohm.

Depending on what resistance your headphone presents to the amp, it will find itself somewhere on the yellow curve.


That’s probably just the topping being lackluster in that regard rather than anything power or gain related

I would mention an Asgard given it’s a similar enough price point but those are pretty backlogged so it’s likely not an option, shame since they work quite well with both headphones and iems for the money

Yep power is on a curve, and that curve is decided by voltage and current limitations

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I am familiar with ohms law. What I don’t know are the current and volt limits of this unit.

I only use sub 32Ohm headphones. And I wasn’t expecting this to struggle.

I don’t have anything “harder to drive” currently. But I was looking for something that could drive my easy stuff and some future harder stuff.

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I had the jot 2. It did everything fine and I probably should have kept it.

I have a long history of trying lots of stuff and unable to find the balance of price/performance for my headphones. I think it’s a combination of having headphones that drive really well off most things and having too high expectations for the more expensive stuff. :frowning:

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Could be, the expensive stuff can be really worthwhile with really picky things, but for less picky headphones/iems they might not scale enough to warrant dropping more money into source gear

That’s close to what I feel about it as well, nothing remarkable at the price point but didn’t really have much to nitpick either


Bingo. And I want to be wowed for the price. The Qudelix is obscenely good for the price.

Have any dac and amp recommendations for LSA HP-2 Ultra as well as dusk, timeless, teas and zen for IEMs?

I am not a collector of sources to match headphones. So I need some generalist capabilities.

Hmm, so I’ve only heard the zen, teas, and kennerton horn/gh50 so that’s somewhat close to how the lsa might drive. I’ve heard the b2 but not the dusk version, not heard timeless. Generally what signature you are going for, what aspects of sound would you want to prioritize, and what do you enjoy about the 5k and what would you change?

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Not really targeting anything. I will state a few amps I have heard that I liked most and why: idsd micro signature had this smoother sound (compared to prickly sp200/m200). The dx300 and xduoo ta-30 both had a similar quality to me. But then I got the hp-2 which brings that liquid bliss in spades and doesn’t need help from the amp/dac. And I think that’s why the jot 2 and playmate 2 didn’t impress me. (Playmate 2 edged out the jot for me. Liquid smooth while bringing some subtle magic that worked for me)

Since I am looking for generalist I kind of assumed relatively neutral but not boring (a90/d90 boring. M11 plus dap, boring)

On the hp-2 I hear very little difference between amps. The qudelix is a touch brighter than the jot or the playmate 2. The playmate seemed to have that environmental magic. The Qudelix simply wasn’t that far behind. Now, on the Zen, I felt it responded to changes much better and it definitely seemed to like playmate 2. But the idsd micro signature was a stand out for it. If it weren’t $750 I would probably have kept it.

I did not hear all of this back to back or with the same headphones. Sooooo, can’t really rule any of it out.

Gotcha gotcha

Would agree there lol. Although the m11 makes a great transport to connect to a nicer portable dac/amp since 2 sd cards at that price is real nice lol


Now this might be a bit of an odd pick, but perhaps try a rupert neve rnhp + a bifrost 2. So the neve seems somewhat unimpressive on paper, but has some very nice characteristics, although is dependent on the dac it’s being fed with. You would likely want to use an iematch with it for the iems since it has some hiss, but it’s really quite nice after that. It’s a more forward neutral/natural signature with lots of depth, lots of dynamics, and impressive resolution but well presented without being harsh, solid tonal density while still being well balanced, impressive speed and separation, great timbre as well, also great overall control throughout the range besides subbass. Impact/slam is it’s weaker point but not lacking enough to really detract from the experience unless that’s your main goal, it does have a more intimate stage but it has lots of depth to make up for that. Also does start to run out of juice for harder to drive planar from my experience. Overall just very impressive for the price point with the right headphones imo. The reason I’d suggest a bifrost to pair with it is to give more impact/slam, improve width without messing with depth, and also to relax the treble slightly, overall ends up being a pretty organic and well balanced sound. If you wanted to go lower on the dac front you can but you’d be trading away a bit of performance, but the allo revolution dac does a great job for the price and can also be tweaked signature wise which is helpful for dialing things in. But I do really think the bf2 is important for getting that next level experience in combination so I think it’s worth the extra cost in this case

If you wanted something portable, I’d honestly look for a chord mojo, they still hold up very well, and is pretty energetic and engaging overall. Great impact and great control, a bit brighter leaning but not harsh or anything, lots of resolution, a more microdynamic focus overall, solid timbre, great extension. Overall hard to complain about imo, and also works well with both iems and headphones without an iematch from my experience

For another desktop solution, it’s a bit hard since most desktop stuff isn’t really designed with iems in mind, another one that comes to mind is the lake people g111, but I slightly worry about it’s lower impedance performance since it’s really designed for more around mid to higher impedance cans, although still drives a lot of planar and lower impedance pretty well, although can’t speak to iem performance. It’s a more studio neutral signature with a bit of a smoother top end. It’s pretty wide with decent depth although a bit hazy stage, great overall control and command, nice impact, good resolution that’s well presented, a more macrodynamic focus imo, great speed and separation, nice body, also a bit more forgiving than the neve in pairing which is nice. I’d personally pair it with something like a denafrips ares ii if I wanted to lean it more warm and fun but still great technical ability, or something like a soekris dac1421, 1321, or 2541 if you wanted to lean it more toward pretty dead neutral clean and very technical without reaching analytical yet.

But if you already had liked the ifi, that’s a safe and easy known pick so perhaps that might be the best option if you wanted something without much hassle if you enjoyed it alot, since that’s going to be in or under the price range of some of the aforementioned anyways (but I’d personally say a neve or g111 do outperform it with a decent dac, and offer a next step up with some of the nicer dacs. The mojo trades blows with the ifi but with a different signature and it would come down to preference there)

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I would second this pairing…had it here for awhile…was really exceptional.


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I just recently got the G111, so far I am happy with it, yeah, for iems it has too much power but since my DAC has a volume output I just turn down the volume on the DAC and that makes the iems usable with the G111.


Yes a dac with adjustable volume can work pretty well. If you don’t have that then the iematch is handy too


The thing that kept me away from rnhp was future headphone drivability. Drop ether cx is a favorite of mine. But hp-2 beat it and there was only budget for one.

This one has been on the long list for a while.

When I had the Jot I also had the bifrost (but for a very short time). And, again, for the money on my hp-2 I was not particularly impressed. I even a/b the jot 2 + bifrost and jot 2 with akm dac by connecting jot through RCA, and flipped the input switch, which seemed to automagically volume match them. I could not tell a difference between them on the hp-2. On the Zen, again, there was some differences but I was never going to use the Zen on that stack.

I know, I am like one of three people in the entire world who has had that schiit stack and went “meh”.

I think the real answer here is I should let my mobile stuff be driven by mobile stuff (in this case, my hp-2 is included in mobile) and get a desktop setup geared more toward the next few over ears.

I always had this feeling if I still had the drop ether cx, I would have liked some of these stacks more. They sounded like exactly what that headphone could use. And that headphone could highlight everything for me. Basically the dead opposite of the hp-2. (but I like both!)