Topping L30 Headphone Amplifier Review

[Jave]

I am pretty sure that someone posted 2 images of the inside of L30 and I went through the entire thread and can't find it. Anybody recalls the page number or can upload the images, please?

 

[bahamot]

Just from the google cached though...

 

[mnemonix]

I know that. And because i´m a guy who belive in science my first hifi dac+amp will be L30+E30. My surprise was on is inicial review.. we all ear things different and DMS is no exception...

Given half a chance we all hear different things that simply aren't there too.

DMS employs no AB testing, let alone blind or level matched and then relies on auditory memory from who knows how long ago, to pronounce on "soft highs", "mid focus" and "lack of bass presentation" (whatever that means) compared to other amps. The measurements, and specifically the linearity of the frequency response as well as the amp's very low output impedance show this simply cannot be the case.

DMS's review is literally worthless, thank you for bringing him to my attention so I can ignore him in future.

 

[liu]

 

[dpippel]

View attachment 79796

 

[w1000i]

Yes for low impedance load. And for high impedance if you can supply enough input voltage.

I have a question, does the current value change based on gain value ?

For example with 16 ohm headphone like Mr.Speaker Aeon, is it going to with draw a same amount of current for all Low, Mid, High gain ? Also does increasing the volume nope will increase the current value or only the voltages?

last question , for 16 Ohm headphone with it the max current value from L30 ?

 

[JohnYang1997]

I have a question, does the current value change based on gain value ?

For example with 16 ohm headphone like Mr.Speaker Aeon, is it going to with draw a same amount of current for all Low, Mid, High gain ? Also does increasing the volume nope will increase the current value or only the voltages?

last question , for 16 Ohm headphone with it the max current value from L30 ?

No difference in current. Gain is basically a volume control.

 

[damian612]

As there's some pcb changes going on with E30

If you do not mind, how significant are the changes?

 

[liu]

For people wish to have higher gains:

just change the resistor values on the bottom of this photo. Those 3 100ohms (smd code 1000) each side forms the 3x gain (200/100+1 = 3x). if you change the inner side to 100ohm to 50ohm you get 200/50+1=5x gain.

 

[JohnYang1997]

For people wish to have higher gains:

just change the resistor values on the bottom of this photo. Those 3 100ohms (smd code 1000) each side forms the 3x gain (200/100+1 = 3x). if you change the inner side to 100ohm to 50ohm you get 200/50+1=5x gain.

View attachment 79968

Don't.

 

[JohnYang1997]

To change the gain 4 resistors in total needs to be changed. Four 100R 1206 0.1% (two per channel) should be changed to 374R 1206 0.1%. The ones from output to feedback not the ones to the ground.

 

[dmac6419]

To change the gain 4 resistors in total needs to be changed. Four 100R 1206 0.1% (two per channel) should be changed to 374R 1206 0.1%. The ones from output to feedback not the ones to the ground.

I ain't messing with mine,sounding good just the way it is.

 

[JohnYang1997]

I ain't messing with mine,sounding good just the way it is.

Someone's posting modification that's potentially dangerous sacrificing stability without fully understanding the circuit. I have to post this.

 

[liu]

Someone's posting modification that's potentially dangerous sacrificing stability without fully understanding the circuit. I have to post this.

well, as an alternative to providing mod instructions, the best way to educate forum members is to teach them the basics. I can see there're several places you made to make the circuit stable, such as the zobel network on the final output. let people know how the feedback resistor contributes to the circuit stability then. a gain mod usually incorporate changing the grounding resistor. why in your case it's the feedback resistor?

 

[JohnYang1997]

well, as an alternative to providing mod instructions, the best way to educate forum members is to teach them the basics. I can see there're several places you made to make the circuit stable, such as the zobel network on the final output. let people know how the feedback resistor contributes to the circuit stability then. a gain mod usually incorporate changing the grounding resistor. why in your case it's the feedback resistor?

Because you didn't get the full circuit. At unity gain the Rg will be disconnected from ground and fold up to the output reducing noise.

 

[liu]

Because you didn't get the full circuit. At unity gain the Rg will be disconnected from ground and fold up to the output reducing noise.

I knew that would be folded and thought reducing the grounding resistor would make it the noise even lower in 0x gain. Didn't run the stability simulation though.

 

[JohnYang1997]

I knew that would be folded and thought reducing the grounding resistor would make it the noise even lower in 0x gain. Didn't run the stability simulation though.

View attachment 79990

There are two half 6120s in parallel. Sharing current and capacitive loads.

 

[liu]

To change the gain 4 resistors in total needs to be changed. Four 100R 1206 0.1% (two per channel) should be changed to 374R 1206 0.1%. The ones from output to feedback not the ones to the ground.

do you mean 174R? 374*2/100+1 would give 8.5x instead of 4.5x

 

[Racheski]

I received my L30 a few days ago and did an AB comparison volume matched by ear with my JDS Labs Atom set to low gain and L30 at 0dB gain setting. My comparison was done with the DX3 Pro (1st Gen) running in DAC mode and HifiMan Sundara headphone. After a few days of comparison, I've found that the Atom is slightly more powerful with a slightly wider soundstage. The L30 seems to add a little more decay on the upper lows or lower mids area which gives a little more body to that frequency range whereas the Atom has less decay and gives a tighter response in that region with nice low frequency extension.

As for the high frequencies, it's the direct opposite with the L30 producing shorter decay whereas the Atom produces a little more decay making it sound more airy in high frequency region. The Atom also reproduce instrument separation much more clearly though it's not night and day's difference, you can definitely tell the difference especially with the Sundara headphone. Fast percussive transients are reproduced equally well on both amps and mid frequency region is about on par with both amps too.

@JohnYang1997 Can you please widen the soundstage and separate the instruments as much as possible on the upcoming A30 pro? And a RGB version too. Thx!

 

[JohnYang1997]

do you mean 174R? 374*2/100+1 would give 8.5x instead of 4.5x

Or you can use 200Ohm. 374 was from an earlier post where I was aiming about 18dB. I thought people want gain so let them.