Topping L30 Headphone Amplifier Review

[v5cvbb]

Thinking of pulling the trigger on a L30,E30 stack, but should I be worried about broken pogo pins and whatnot?

I think mine was one of the hand soldered 2012 replacement models. I wouldn't be concerned buying a new one.

 

[avatar]

Finally got one (s/n 21xxx)

I have some pretty dumb questions though, regarding gain levels.

How do the 3 gain levels work ?
What is the voltage fed to the headphone at -9db, 0db and +9db ?
Can I use the +9db gain on a 32ohm load or is there a risk to damage the HP's drivers because of voltage is too high ?
Is there any way to know what is the voltage limit of an headphone ?
And ultimately, which gain sounds better ?
I tought the -9db would have been the one with the best thd+n, but that clearly isn' t the case judging by Armirn's review ... how's that possible ?

Please educate me

 

[solderdude]

It happens every time I go from pre to hpa or hpa to pre. It doesn’t change with volume on the amp, usual listen level vs full attenuation it’s the same. With the dac powered off it behaves the exact same

Could be the speakers (the amp connected to them)
Do you also here a plop/tick in the headphone when you switch between these modes ?
When the headphone also does this there is a DC component on the output of the amp.
When switching is silent in the headphones it is the amp before the speakers.
An extra resistor to ground when the input of the amp is 'open' could prevent this.

 

[solderdude]

Finally got one (s/n 21xxx)
How do the 3 gain levels work ?

Set it to a position so that you get a usable volume adjusting range. It really is that simple.

What is the voltage fed to the headphone at -9db, 0db and +9db ?

Depends on the DAC and what you put into the DAC.

Can I use the +9db gain on a 32ohm load or is there a risk to damage the HP's drivers because of voltage is too high ?

Yes, you can use it in any position. As long as you don't play ear shattering loud or hear distortion its all fine.

Is there any way to know what is the voltage limit of an headphone ?

Yes, my list will tell you.

And ultimately, which gain sounds better ?

They sound the same, they just differ in loudness.

I tought the -9db would have been the one with the best thd+n, but that clearly isn' t the case judging by Armirn's review ... how's that possible ?

Gain between L and M is the same, the input in L is attenuated so M is 'technically' the best but even L and H are already exceeding every humans hearing limit.

 

[Atanasi]

Yes, my list will tell you.

What happens at the maximum voltage, does it clip?

 

[solderdude]

All amplifiers clip at some point, be it voltage- or current-limit being reached.

At full volume control settings the L30 clips (slghtly above 9V) at the following input voltages in the listed gain settings.
H= 3V (3x gain)
M= 9V (1x gain)
L= 25V (0.36x gain)

At 16 ohm load it clips at 7.5V (470mA current limit)

 

[Atanasi]

All amplifiers clip at some point, be it voltage- or current-limit being reached.

I meant the maximum voltage of headphones listed in your table.

 

[solderdude]

The maximum voltage in the table is based on the continuous power rating.
That is very different from peak power rating.
Also in most cases the power rating is determined by the manufacturer. Not all of them do this in the same way.
Some seek the point where, after a certain time, the voicecoil burns, others list the value where it can handle it without burning with some warning.

In general using music one can apply +6dB without the chance of frying it. This means double the listed voltage in short peaks can be allowed.
This also means that when max. SPL is listed as say 116dB that you can apply a voltage (very shortly) that could make it produce 122dB.

BUT.... most headphones start to distort or 'softclip' (compress) so that expected 122dB in the example above may well be 120dB as the driver gets non-linear (thus distorts in the form of soft-clipping)

When you apply +10dB music for a longer time period you can expect it to burn the voice coil.
If you have a 20mW rated voice coil (say the HP50) you can blow it up playing average levels of say 30mW (so peaks in music of 0.3W)
But.. by then it distorts and is very loud and you would turn it down.

 

[Benaudio]

Yes, my list will tell you.

Oh, so this is your list!
Been using it without knowing, and I am immensely grateful for your work good sir!

 

[Jose Hidalgo]

They sound the same, they just differ in loudness.

That is true (because few people will hear the difference), but AFAIK it's not entirely accurate.

Like said by John Yang (designer of the L30) somewhere in this topic, the L30 offers its best performance at the 0 dB gain position, with the volume knob close to the max. Then the listener can play with digital volume control in the DAC and/or in the audio player.

 

[Benaudio]

It is true and accurate because it will sound the same regardless of performance being slightly different (no audible difference).
don’t believe me? Do an ABX. I did and couldn’t hear a difference.
of course your ears could be better than mine

 

[solderdude]

That is true (because few people will hear the difference), but AFAIK it's not entirely accurate.

Like said by John Yang (designer of the L30) somewhere in this topic, the L30 offers its best performance at the 0 dB gain position, with the volume knob close to the max. Then the listener can play with digital volume control in the DAC and/or in the audio player.

Right below the part you quoted I wrote this:

Gain between L and M is the same, the input in L is attenuated so M is 'technically' the best but even L and H are already exceeding every humans hearing limit.

So yes, the M position will offer best performance. The 'poorer' performance still is better than any audible thresholds so for all intends and purposes the sound quality is the same. Technically slightly less but not audible.

 

[Jose Hidalgo]

It is true and accurate because it will sound the same regardless of performance being slightly different (no audible difference).
don’t believe me? Do an ABX. I did and couldn’t hear a difference.
of course your ears could be better than mine

Oh boy, please don't fight here You asked a question on ASR and we are trying to answer you as accurately as possible, according to the only thing that matters here : measurements. Not ABX : measurements.

The designer of the amp confirmed this, hence there is no discussion possible, sorry. Like I said, few people will hear the difference. But your question wasn't if you could hear it or not. The 0 dB position with vol knob close to the max objectively sounds better. Whether you or anybody else can hear it or not is irrelevant. Again, we are on ASR here, not on "superaudiophilelove".

PS : Thanks to @solderdude for confirming it BTW. Of course we are saying exactly the same thing. So @Benaudio , please don't discuss this anymore. Thank you.

 

[Benaudio]

Oh boy, please don't fight here You asked a question on ASR and we are trying to answer you as accurately as possible, according to the only thing that matters here : measurements. Not ABX : measurements.

The designer of the amp confirmed this, hence there is no discussion possible, sorry. Like I said, few people will hear the difference. But your question wasn't if you could hear it or not. The 0 dB position with vol knob close to the max objectively sounds better. Whether you or anybody else can hear it or not is irrelevant. Again, we are on ASR here, not on "superaudiophilelove".

PS : Thanks to @solderdude for confirming it BTW. Of course we are saying exactly the same thing. So @Benaudio , please don't discuss this anymore. Thank you.

Chill bro, I think you got me mixed up with somebody else. First I’m not the one who asked the question and also I’m not fighting at all, just confirming solderdude assertion that you said was not accurate.
not sure who’s fighting, but you said his comment was not accurate, and I think this is demonstrably false.
Measurements show a difference, nobody disputes that, but all below threshold of hearing which was the point you apparently overlooked. So although it measures better, it does not “sound objectively better”.

Also, you inferring "a few people" can hear below audibility levels is the kind of things that could pertain on "superaudiophilelove".

Also, since when blind ABX tests are a taboo on ASR?
Also you don't get to tell me what I can discuss or not anymore after wrongfully attacking me in an aggressive tone. Tu t'es pris pour qui?

 

[companyja]

Here's a question to L30 owners, do you notice that the amp has a rather large volume pot deadzone from around 3:30 o'clock to the end? To me, even with pure sines, the volume sounds equally loud past 3'oclock or so. Is this the effect of running the L30 from the E30 which can't provide enough voltage to max out the volume, or is the amp designed with this large deadzone? Is my unit's volume knob just monumentally shit?

Not that I'd be running it past 3 o'clock on any gain anyway, just found it rather curious; my old K5 Pro didn't have this deadzone, it instead only activated at 9 o'clock

 

[Bsdzilla]

Still no photo of the new board? Unfortunately my replacement hasn't arrived after 5.5 weeks and according to 4px tracking it looks like it hasn't even been shipped yet, despite Shenzen Audio saying it has. :-(

 

[life.exeMPLAR]

Yes you should. Actually your whole life should be governed by fear.
Or maybe just take a leap of faith and remember that on the Internet, people who complain on forums are usually the 1% with problems. The 99% others just enjoy life!

Seriously now, there's no reason to worry. Worst case scenario you'll get a refund or an exchange.
I personally have a 3rd amp to buy, and guess what it will be ?... Yes, another L30.

just out of curiosity, why would you need third l30

 

[life.exeMPLAR]

Here's a question to L30 owners, do you notice that the amp has a rather large volume pot deadzone from around 3:30 o'clock to the end? To me, even with pure sines, the volume sounds equally loud past 3'oclock or so. Is this the effect of running the L30 from the E30 which can't provide enough voltage to max out the volume, or is the amp designed with this large deadzone? Is my unit's volume knob just monumentally shit?

Not that I'd be running it past 3 o'clock on any gain anyway, just found it rather curious; my old K5 Pro didn't have this deadzone, it instead only activated at 9 o'clock

It looks like it's normal

 

[GoMrPickles]

Thanks to whoever posted the Facebook screenshot. I requested a replacement for my 2007* unit from Shenzhen Audio.

I haven't had any failures with it, but I've noticed a bit of crackling in the 6XXs. Bummer that I sold my THX 789...

 

[jbfilho]

Regarding the L30 recall, the seller Linsoul has just drop me an email saying that I should make a video "destroying" the amp before they send me a replacement. Anyone got it from them as well? How do you guys managed to "destroy" it? I'm really not confortable on doing that before receiving my replacement unit...