DX3 Pro+ with 50 ohm headphones? Is this okay?

[Moscato359]

I previously had a fiio q1 dac/amp, which died, and then a topping nx4 dsd, which also died last week.

I have Sennheiser 558 headphones, not the best, but they are what I have. They're comfortable, but are getting worn down after I've had them for 6 years.

I recently ordered, but not have yet received a topping dx3 pro from amazon.

After I ordered it I told my friend, and he said that they aren't right for my headphones, requiring atleast 80ohm headphones per what he said, while the sennheisers I have are 50 ohm

Should I return it, and buy something else?

What is an appropriate dac/amp for my uses? I just listen to medium quality music, and play videogames. I use a desk mic, so no mic required.

Should I get new headphones? If so, what? I don't want anything heavier, or less comfortable

He was telling me jds atom dac+amp would be better

This graph is from this forum

Should I be concerned about this? What should I do?

 

[solderdude]

After I ordered it I told my friend, and he said that they aren't right for my headphones,

He is talking nonsense and doesn't really seem to know what he is talking about.
It can drive the HD558 beyond its max power rating.

Slap some new pads on the HD558 and it'll keep going or look for something better if you want.
The DX3Pro+ can drive a lot of headphones without any problems.

 

[Moscato359]

He is talking nonsense and doesn't really seem to know what he is talking about.
It can drive the HD558 beyond its max power rating.

Slap some new pads on the HD558 and it'll keep going or look for something better if you want.
The DX3Pro+ can drive a lot of headphones without any problems.

The question wasn't can these headphones power high ohm headphones. The question was are they fine with low ohm headphones, without distortion.

The above graph indicates maybe not?

Something about a 1/8 rule for output impedance, where it's 10 ohms of impedance (compared to many amps which are close to 1 ohm)

 

[DVDdoug]

After I ordered it I told my friend, and he said that they aren't right for my headphones, requiring at least 80ohm headphones per what he said, while the sennheisers I have are 50 ohm

50 Ohms seems pretty "normal" so almost any headphone amplifier should be able to drive them.

At 80 Ohms and the same voltage you get less current* so less power (Watts or milliwatts) so you higher impedance headphones tend to me less sensitive and that could be a different problem if you can't get enough volume, but 80 Ohms is also in the "normal range"... This is a more common issue with 600 Ohm headphones.

...If the headphone impedance is too low (relative to the amplifier's source impedance) that's a problem because headphone impedance "interacts" with the source impedance making a voltage divider. Since headphone resistance varies over the frequency range that results in frequency response variations. Most headphone amps are fine with a 40-Ohm load and I'd expect the Topping to be virtually immune to this.



* Resistance and impedance are "the resistance to current".

 

[Jimbob54]

The question wasn't can these headphones power high ohm headphones. The question was are they fine with low ohm headphones, without distortion.

The above graph indicates maybe not?

Something about a 1/8 rule for output impedance, where it's 10 ohms of impedance (compared to many amps which are close to 1 ohm)

No- the question, per the title was "DX3 Pro+ with 50 ohm headphones? Is this okay?"

The specific headphones in question were the Sennheiser 558

The unit can put roughly 7v into the (nominally) 50ohm Senn 558 before clipping.

So yes, there is no problem for the OP with this device.

 

[solderdude]

The question wasn't can these headphones power high ohm headphones. The question was are they fine with low ohm headphones, without distortion

Powers low ohm headphones fine. Distortion is low. 1.5W in 32 ohm is excellent. It is just current limited to 130mA.

Where does it state the 3+ has 10ohm out ?
Data sheet says less than 0.1ohm.
The 1/8th rule does not apply to all headphones b.t.w.

 

[Moscato359]

Powers low ohm headphones fine. Distortion is low. 1.5W in 32 ohm is excellent.

Where does it state the 3+ has 10ohm out ?
Data sheet says less than 0.1ohm.
The 1/8th rule does not apply to all headphones b.t.w.

Sorry, the 3 and not 3+ had 10 ohm out.
I got that mixed up.

Still the above chart concerned me, mostly because I wasn't sure how to read it.

 

[Moscato359]

No- the question, per the title was "DX3 Pro+ with 50 ohm headphones? Is this okay?"

The specific headphones in question were the Sennheiser 558

The unit can put roughly 7v into the (nominally) 50ohm Senn 558 before clipping.

So yes, there is no problem for the OP with this device.

Okay, so there are no issues, and this is overblown. Okay

 

[solderdude]

As said, I see no reason for any alarm bells.

During the 20ohm test it went in protection (that's the weird fold-back you see). It did not in 12, 16 an above 32ohm
A reason for this could be that it started to overheat from the 12 and 16 ohm test and when it got to 20 ohm the thermal protection kicked in.
Could also be that it clipped asymmetrically in 20 ohm and DC protection kicked in. We'll never know.
Will never happen in practice with headphones and music. Its a testbench issue at most. It worked fine even in 12ohm with low distortion.

 

[Moscato359]

As said, I see no reason for any alarm bells.

During the 20ohm test it went in protection (that's the weird fold-back you see). It did not in 12, 16 an above 32ohm
A reason for this could be that it started to overheat from the 12 and 16 ohm test and when it got to 20 ohm the thermal protection kicked in.
Could also be that it clipped asymmetrically in 20 ohm and DC protection kicked in. We'll never know.
Will never happen in practice with headphones and music. Its a testbench issue at most. It worked fine even in 12ohm with low distortion.

Thank you for the clarification and comfort

I'm an over anxious person

 

[Jimbob54]

Okay, so there are no issues, and this is overblown. Okay

OK. But I would be interested to hear if anyone with roughly 20ohm insensitive planars that needed a lot of EQ had any issues using this device.

 

[Moscato359]

OK. But I would be interested to hear if anyone with roughly 20ohm insensitive planars that needed a lot of EQ had any issues using this device.

That does sound interesting

 

[Moscato359]

Alright, when it comes in saturday, this will be my test

I will test it with cheapo sansa clip headphones. If it doesn't explode, I think I'll call it a winner.

 

[Jimbob54]

Alright, when it comes in saturday, this will be my test

I will test it with cheapo sansa clip headphones. If it doesn't explode, I think I'll call it a winner.

I'm pretty sure it wont explode because of that test. Dont have them in your ears when you put the hammer down though.

 

[solderdude]

Alright, when it comes in saturday, this will be my test

I will test it with cheapo sansa clip headphones. If it doesn't explode, I think I'll call it a winner.

I would ONLY do that test when you want to blow up those earphones in the process.
My Sansa earbuds are 16ohm (just measured them) and they would be getting 0.3W which I am sure (when sweeping a sine, same test as Amir) they won't survive and the amp will not even go in protection unless you do that several times in a row... but the earbuds will already have let out the magic smoke.
Besides, with music I doubt you can get this amp to go in protection.
If it were people would have started complaining here about this model driving DCA headphones and cutting out every time.
12 ohm is a much more severe load than 20ohm and obviously the 12 and 16 ohm sweep were fine.

 

[Fraxo]

OK. But I would be interested to hear if anyone with roughly 20ohm insensitive planars that needed a lot of EQ had any issues using this device.

I'm using the DX Pro+ with a 16ohm Planar IEMs (S12) constantly, with extreme EQ to shape their sound, obviously always on low gain, all works great for months now...
I'm a mixing & mastering engineer so not a noob, yet I have no idea how to understand the measurements of the DX3 Pro+ (and other measurements in general) in regards to distortion, glad I found this thread though perhaps you'd be kind enough to explain or link me.

I don't want to constantly bother with "is this combo ok..?" I'd appreciate understanding for myself, so I could make better purchase decisions that would suit my mostly IEM + Speakers needs. Am I dumb for thinking the 1/8 rule for output impedance is what made the DX3 Pro+ a good purchase? What's up with all of this distortion talk?

I'm highly perceptive just struggle to find good educational sources to make sense of technical measurements of hardware playback devices, so thank you all.

@solderdude @Jimbob54

 

[solderdude]

Am I dumb for thinking the 1/8 rule for output impedance is what made the DX3 Pro+ a good purchase? What's up with all of this distortion talk?

DX3Pro+ has < 0.1Ω output resistance. IF the '1/8th rule' applies (an if because it is not valid for all head/ear-phones) then you would need an earphone with a substantially varying impedance that is nominally around 1Ω.
These don't exist. Wellll... there is the RAAL SR1A when used without the specialized amp/speaker amp box but... there would not be much sound coming from the SR1A powered directly by the DXPro3+, at least it would be very low level.

When you do not hear any self noise of the amp section then you can't hear any distortion products either as the signal is then so far below the maximum output distortion is lower than the noise floor.

 

[Fraxo]

When you do not hear any self noise of the amp section then you can't hear any distortion products either as the signal is then so far below the maximum output distortion is lower than the noise floor.

That point right there...
That's fantastic, simplifies a whole lot and makes sense (assuming I got it right haha).

So can I deduce that if I crank up the volume\gain without playing any sound and hear no noise from the amp - there's no risk of distortion?
I mean, I can take it to the extreme and really crank the DAC+AMP up to levels WAY beyond real use, and if it passes that in complete silence than I can rest assured there will be no audible distortion in any level below that... Right?

 

[solderdude]

So can I deduce that if I crank up the volume\gain without playing any sound and hear no noise from the amp - there's no risk of distortion?

Unless you clip the output (high gain at max volume) and/or use a headphone with a very low impedance and sensitivity or have music files with distortion or intersample overs in it this can be valid for this particular device...

There are always stipulations....

 

[Fraxo]

Unless you clip the output (high gain at max volume) and/or use a headphone with a very low impedance and sensitivity or have music files with distortion or intersample overs in it this can be valid for this particular device...

There are always stipulations....

Hahaha I see I see... I won't attempt to over simplify it.
Glad I was able to understand a term from my Mixing world with some of this slowly progressing hardware knowledge lol , I call it intersample peaks but yea that makes sense, all scenarios which I'd gladly never deal with. DX3 Pro+ going strong!

Any reason I'm missing to want to upgrade from it in the future - in your opinion?