Topping L70 Headphone Amp Review

[Nordling]

2k ohm input impedance on all inputs? this is really really bad design, mismatch will reduce tons of performances, many got 50k or 100k input impedance

oh boy

I totally agree. In the thread of the Topping Pre90 Review this low impedance topic is already extensively discussed .
I would say the Topping L70 is only suitable for DAC with output impedance lower than say 200 ohms.

 

[rocksteady]

this is really bad and overpriced

should make the L30II as flagship and and price at $500

and this mumbo? $119 to rival schiit (xmas $99)

You have got a really weird notion of Bad. The L70 is state of the art in every parameter. So, according to your criteria, the A90, A90D, A30 Pro all "Suck Bad", right?

 

[MRC01]

... The L70 is state of the art in every parameter. ...

I agree, except for input impedance. It should be higher, industry standard convention is 10 - 20 kOhm. The reasons why have been discussed at length elsewhere, no need to reproduce that here.

 

[Gregorey]

Sorry if it's a dumb question or the wrong place for this, but i am somewhat new to this passion and would like to improve my setup. Would a pairing of focusrite Scarlett solo and a L70 work and how does the L70 compare to a dx5 for example, since both are at a similar price point and i do own a scarlett already. Or should I even think about going the full e70/L70 stack. I intend to upgrade my headphone collection in the near future. Currently owning sundara, dt880, dt700 pro x. I'd like to have more power and even more details and clarity.

 

[Adaboy4z]

Sorry if it's a dumb question or the wrong place for this, but i am somewhat new to this passion and would like to improve my setup. Would a pairing of focusrite Scarlett solo and a L70 work and how does the L70 compare to a dx5 for example, since both are at a similar price point and i do own a scarlett already. Or should I even think about going the full e70/L70 stack. I intend to upgrade my headphone collection in the near future. Currently owning sundara, dt880, dt700 pro x. I'd like to have more power and even more details and clarity.

I don't know about the Scarlett, but the E70 stack is great many good useful options. Plenty of power.

 

[Lukino]

 

[don'ttrustauthority]

And where did this part come from?

Laws in California for one.

 

[Ziroz]

Laws in California for one.

There are laws in California that dictate Topping must have worse benefits for employees than Schiit?
I wonder have you worked for either of the companies, or talked to their employees about their benefits, or are you just assuming that a Chinese company must treat their workers worse than a California company?

 

[renaudrenaud]

I am living in China and was surprised by the first comment. May I suggest the creation of a thread elsewhere to discuss about the employees from SMSL, Topping and Gustard?

 

[Tovarich007]

Except for the fact the L70 was designed to be paired with E70, where it is stellar.

Maybe, but why did Topping chose by design a much lesser impedance value than the usual one ? Just to be sure that customers will buy the full combo ? Thats's commercialy smart, but not fair, what about compatibility issues with other products from other brands ?
By comparison, new RME ADI 2-4 Pro SE 's input impedance is specified at 9 KOhm for balanced inputs and 4,5 KOhm for unbalanced ones, see designer page below :

ADI-2/4 Pro | High-end USB Audio Converter & Headphone Amp - RME Audio Interfaces | Format Converters | Preamps | Network Audio & MADI Solutions

RME Audio Professional Live, Studio, Recording and Broadcast Solutions. Unrivalled Quality, Performance & Stability MADI Interfaces, Converters & Preamps.

rme-audio.com

Of course, the RME being an ADDAC/Headamp/preamp will be used mainly as a DAC/heaphone amp/preamp by most amateurs. But for people using it as a preamp as well on its analog inputs, that's quite higher than the Topping impedance !

What can be the effect of such a difference on performance and sound ?

I would appreciate that Amir will measure this in his upcoming reviews and give us his technical point of view on what is the minimum input impedance required for best performance.
I mean, this is probably more important than a slight difference in excellent SINAD, the absurd race towards best figure in distorsion and SINAD isn't the whole story for technical measurements and sound quality !

 

[DRuszaT]

Maybe, but why did Topping chose by design a much lesser impedance value than the usual one ? Just to be sure that customers will buy the full combo ? Thats's commercialy smart, but not fair, what about compatibility issues with other products from other brands ?
By comparison, new RME ADI 2-4 Pro SE 's input impedance is specified at 9 KOhm for balanced inputs and 4,5 KOhm for unbalanced ones, see designer page below :

ADI-2/4 Pro | High-end USB Audio Converter & Headphone Amp - RME Audio Interfaces | Format Converters | Preamps | Network Audio & MADI Solutions

RME Audio Professional Live, Studio, Recording and Broadcast Solutions. Unrivalled Quality, Performance & Stability MADI Interfaces, Converters & Preamps.

rme-audio.com

Of course, the RME being an ADDAC/Headamp/preamp will be used mainly as a DAC/heaphone amp/preamp by most amateurs. But for people using it as a preamp as well on its analog inputs, that's quite higher than the Topping impedance !

What can be the effect of such a difference on performance and sound ?

I would appreciate that Amir will measure this in his upcoming reviews and give us his technical point of view on what is the minimum input impedance required for best performance.
I mean, this is probably more important than a slight difference in excellent SINAD, the absurd race towards best figure in distorsion and SINAD isn't the whole story for technical measurements and sound quality !

Input impedance @ 1 kHz, balanced: 90 kOhm, unbalanced: 45 kOhm


"The input of the ADI-2/4 Pro SE has an impedance of 45 kOhm, which is
high enough to not overstrain even older Hi-Fi units with higher impedance outputs (up to 10 kOhm).
That is even more true with newer units having outputs significantly below 10 kOhm.
Additionally the input of the ADI-2/4 Pro SE has been designed to have the exact same technical
specifications, no matter if a balanced (XLR) or unbalanced (mono 6.35 mm) signal is applied.
RME's servo-balanced input also provides an automatic level correction - so that even the reference levels are identical.
With the outputs such an adapter causes no change at all - technical specifications and operation
stay unchanged. The outputs of the ADI-2/4 Pro SE serve RCA inputs without any problem."

User's guide page 105

 

[Tovarich007]

Thanks DruszaT, but this doesn't answer my question. I know the input impedance of the RME and I don't doubt this impedance is quite sufficient.

But my issue is on the input impedance of the Topping L70, and, more generally, which is the minimum impedance which can be considered as sufficient with any electronic source.

 

[DRuszaT]

Thanks DruszaT, but this doesn't answer my question. I know the input impedance of the RME and I don't doubt this impedance is quite sufficient.

But my issue is on the input impedance of the Topping L70, and, more generally, which is the minimum impedance which can be considered as sufficient with any electronic source.

I quoted page 105 of the ADI-2/4 user's guide because I think it answers your question about what is sufficient.

 

[Tovarich007]

One again, I am sure that the specified input impedance of the RME is sufficient, but I would prefer a more general and technical answer that doesn't emanate from an audio designer about this question of input impedance.

What is the generally estimated threshold under which an impedance can be considered as too low, that's my fundamental and general question ?

And what about the 2 KOhm input impedance of the Topping L70 ? It seems low, but is this eventually problematic ? By the way, I haven't seen any spec of the input impedance on the Topping website, only the output impedance, is it certain that the input impedance of the Topping is 2KOhm ).

 

[rarewolf]

I took the plunge, and I’ll be connecting the L70’s RCA inputs to my DX3Pro+ RCA outputs. Next year, hopefully by March, I’ll be able to afford and match it with the Velvet…

… any thoughts on how to best configure the DX3P+?

 

[Bleib]

I took the plunge, and I’ll be connecting the L70’s RCA inputs to my DX3Pro+ RCA outputs. Next year, hopefully by March, I’ll be able to afford and match it with the Velvet…

… any thoughts on how to best configure the DX3P+?

Well.. DAC mode

 

[rarewolf]

Well.. DAC mode

Thanx Bleib! Just for clarification… “DAC” mode will provide a constant voltage at the output, correct? That is, I believe it appropriate to eliminate the DX3P’s volume control…

 

[rarewolf]

I’ll need audio I/O cables for connecting the DX3Pro+ to the L70. Most obvious would be to use ‘RCA to RCA’, but I see that ‘RCA to male XLR’ cables are also available. Would there be advantage/disadvantage to either?

The post below would imply a possible significant difference if the implementation of “balanced” was differential for the L70(?)

RCA output to XLR input

Hi guys, can I easily make or buy already finished reduction? I have describe my situation. I have amplifier Kinki EX-M1 which has three analog RCA inputs and one XLR female balanced input. I don't have equipment with XLR outputs and need another RCA. The question is if I make/buy some...

www.audiosciencereview.com

 

[Veri]

I’ll need audio I/O cables for connecting the DX3Pro+ to the L70. Most obvious would be to use ‘RCA to RCA’, but I see that ‘RCA to male XLR’ cables are also available. Would there be advantage/disadvantage to either?

There can be a tiny tiny noise cancellation advantage but unlikely one that you would notice in real-world usage, just connect RCA in to out and see if it all works fine.

 

[rarewolf]

If you have hard to drive headphones, like HiFiMAN HE6se, the extra voltage using XLR to XLR, from DAC to amp, can help to drive them better. In your case, the DX3 Pro+ only has RCA out and there will be no benefit to using any kind of XLR cables at all. Just skip the RCA to XLR and make the connection RCA to RCA which will be excellent with nearly all but the hardest to drive phones.

I’m not sure what happened, but the link I had pointed to regarding “differential implementation of balanced” actually pointed to the post just before the one intended…

In an case, the specs for the L70 imply that the power nearly doubles for “SE in/Bal out”, and that implies to me that the L70 implementation for balanced output is traditional and not differential. I suppose my question is if that’s true in spite of which input is used, ‘RCA to XLR’ or ‘RCA to RCA’. I’ll assume you and @Veri are correct