Confused with Topping L50 Amp SE/Balanced Toggle switch

[Kfire85]

I am confused how this headphone amplifier work. It has 6.35mm sized port, and there is a toggle switch at the left - from Off to Balanced then to Single Ended. I presume it changes the headphone output of this headphone amplifier.

Topping L50 specs
The toggle switch (in orange) is as follows (it goes vertically, from up to down):

• SE (Single Ended)
• BAL (Balanced)
• Off (Powered off)

So this means right away that to go from Off to SE, you have to cross or go through BAL (Balanced) mode. I think this presents a safety issue?
It also comes with this 6.35mm to 3.5mm TRS adapter, so from that alone we can say for sure the headphone output is of size: 6.35mm

The problem is, if I plug in 6.35mm to 3.5mm adapter and then plug a headphone with 3.5mm (unbalanced/single ended), then accidentally swap the mode from single ended to balance (i.e. some object pressed on the toggle) then, would it not damage or fry the amp? Because the amp is now a balanced source but your headphone is unbalanced.

Another scenario is you want to turn the amp off from single ended (SE) mode with an unbalanced headphone. You have to cross BAL (balanced) mode to get to power off state, so you damage it each time you turn it off?

Please correct my understanding since I watched this video on why you can connect balanced headphones to unbalanced amps but not the other way around (i.e. unbalanced headphones to balanced amps)

So from my understanding, it is best to just connect your headphones as balanced. So this way, even if you go from BAL to SE accidentally, you will not damage the amplifier?

Also from my understanding - TRS is usually unbalanced because the assignment is:
T - Left Channel
R - Right Channel
S - Ground (Shared ground for both ear cups)

TRRS on balanced headphones, signal assignment looks like this:
T - R-
R - R+
R - L-
S - L+

So to prevent a short on the amplifier, it is always best to use a 6.35mm TRS adapter onto this amplifier?

Also one more question - does the plug itself (i.e. the TRS or the TRRS plug) determine the signal assignments (i.e. R-, R+, L-, L+) so TRS plugs can be different from one another/Each TRRS plug is unique or is it determined by the headphone? or by the amplifier?

I have not yet bought this amplifier yet but I am considering to. I am choosing between this (Topping L50 Amp + Topping E50 DAC) stack or just go with DX3 Pro+ for my ATH-R70x headphone which is 99 db/mW, 470 ohm. I know at 470 ohm, both alternatives can power this headphone.

 

[unpluggged]

So this means right away that to go from Off to SE, you have to cross or go through BAL (Balanced) mode. I think this presents a safety issue?

This is the input selector All the outputs are active simultaneously.

The problem is <...>

The following statements mostly are either wrong or not relevant. There is no problem beside the rule that you must not connect unbalanced headphones to balanced output, thus shorting the amp.

 

[Kfire85]

This is the input selector All the outputs are active simultaneously.

Ahh...i thought it changes the output type of the headphone amp from Single ended to Balance and off lol
So with the input selector, you can select what is activated at the back, one at a time.
Nothing about it is described in the specs guide by Topping.

So I guess that input selector selects between this part of the L50 at the back - between 2x TRS Bal or 2x RCA SE.

So the headphone output of the Topping L50 is 6.35mm:

• balanced or unbalanced?
• Should I plug-in TRS or TRRS?

 

[unpluggged]

Nothing about it is described in the specs guide by Topping

That says something about this manufacturer.

So I guess that input selector selects between this part of the L50 at the back - between 2x TRS Bal or 2x RCA SE

You guess right.

So the headphone output of the Topping L50 is 6.35mm:

• balanced or unbalanced?
• Should I plug-in TRS or TRRS?

It's the industry-standard single-ended output that provides left, right, and a common ground. Hence TRS.

 

[Kfire85]

Would you recommend me to go for Topping L50 + E50 stack or just go with DX3 Pro+ DAC-AMP?
I think the most power hungry headphones I will run are around the level of ATH-R70x. I am not going to go for something crazy like Dianne Abyss V2.
I am looking to possibly use a Loki Mini+ in the future, it is hardware EQ - but I am not sure how it connects. I think unbalanced RCA (Red & White) to input, but to standalone DAC or to standalone amp?. Not sure if I go with DX3 Pro+ DAC-AMP, I may not be able to.
Sorry I am new to this.

 

[kchap]

The output of the L50 is SE. On the TRRS jack L- and R- are connected together. This not an issue and was discussed in relation to the Sabaj A10d

Would you recommend me to go for Topping L50 + E50 stack or just go with DX3 Pro+ DAC-AMP?

I have the L50 + E50 stack. I'm happy with the pair. I have no experience with the DX3, but you could also consider the newer A50 III + D50 III stack.

 

[Kfire85]

The output of the L50 is SE. On the TRRS jack L- and R- are connected together. This not an issue and was discussed in relation to the Sabaj A10d

I have the L50 + E50 stack. I'm happy with the pair. I have no experience with the DX3, but you could also consider the newer A50 III + D50 III stack.

I have another question
If you will use balanced headphones with a balanced jack on the A50 III amplifier (because this amp has both 6.35mm Se and 4.4mm balanced):
Do you have to use TRS balanced connection to connect the A50 III + D50 III stack?
Or can you use RCA unbalanced to connect the A50 III + D50 III stack?

About the DX3 Pro +, after listening to iiWi reviews - it actually sounds "thinner" than the DX5, but then again the DX5 stays hot even on standby unlike the DX3 Pro+. DX7 might be better than either two, or rather just go with stack.
E and L series stacks of Topping afaik are entry level
A and D series stacks of Topping are the more professional one.
But there are some products in those lines that can be just as good as the tier above it. A lot of nuanced caveats. I think iiWi got the differences right.

 

[Jimbob54]

I have another question
If you will use balanced headphones with a balanced jack on the A50 III amplifier (because this amp has both 6.35mm Se and 4.4mm balanced):
Do you have to use TRS balanced connection to connect the A50 III + D50 III stack? No
Or can you use RCA unbalanced to connect the A50 III + D50 III stack? Yes

About the DX3 Pro +, after listening to iiWi reviews - it actually sounds "thinner" than the DX5, but then again the DX5 stays hot even on standby unlike the DX3 Pro+. DX7 might be better than either two, or rather just go with stack.
E and L series stacks of Topping afaik are entry level
A and D series stacks of Topping are the more professional one.
But there are some products in those lines that can be just as good as the tier above it. A lot of nuanced caveats. I think iiWi got the differences right. Most if not all of these devices have been measured and reviewed on here- far better to go with that than what is said on youtube channels without reference to measurements IMO

My comments in red

 

[JOCoin]

That says something about this manufacturer.


You guess right.


It's the industry-standard single-ended output that provides left, right, and a common ground. Hence TRS.

I would just like to point out that switch is literally the first label in that picture. Labeled as "input switch" Top left of the picture Kfire85 posted. Topping is top of the line when you consider price vs performance. I don't get why people love to hate Topping. *edit* added photo for reference.

 

[davmol]

I have another question
If you will use balanced headphones with a balanced jack on the A50 III amplifier (because this amp has both 6.35mm Se and 4.4mm balanced):
Do you have to use TRS balanced connection to connect the A50 III + D50 III stack?
Or can you use RCA unbalanced to connect the A50 III + D50 III stack?

About the DX3 Pro +, after listening to iiWi reviews - it actually sounds "thinner" than the DX5, but then again the DX5 stays hot even on standby unlike the DX3 Pro+. DX7 might be better than either two, or rather just go with stack.
E and L series stacks of Topping afaik are entry level
A and D series stacks of Topping are the more professional one.
But there are some products in those lines that can be just as good as the tier above it. A lot of nuanced caveats. I think iiWi got the differences right.

I haven't been able to hear a difference on any of these DACs, so just go for the features and power that you need at the best price point. I have the A50III / D50III stack and it does everything I need, including 10 band PEQ when listening on USB source (which for me is almost all of the time), so I can tweak headphone response to preference. I also have a WiiM mini for streaming and listening when the laptop is off. I run TRS balanced out on D50III to TRS in on A50III, and I do prefer the L/M/H gains of -6/+6/+17.9dB using the balanced inputs, vs -12 / 0 /+11.9dB using the SE inputs. It also means the RCA jacks are free on the D50III, so I could also use it as a pre-amp for some active desktop speakers or power amp, which is very handy.

Overall, it's a great stack but if I didn't want the PEQ / dual outputs / 4.4mm jack then I'd probably go for the DX3Pro+, as it's practically half the price and does everything else this stack does, plus to me it looks neater on a desktop (fewer cables etc). It all depends on what features / aesthetics you want, so don't listen to the reviews saying they sound different, because they really don't sound different at all in my experience (and in the objective measurements).

Happy shopping!

 

[Kfire85]

Many thanks guys, I actually went for the A50III and D50 III stack a week ago with ATH-R70x headphones and it is great.
My only gripe about it is that if you press the D50III for too long, it goes to "DFU mode" which is (Device Firmware Update) mode from what I understand.
You cannot power off the unit by long pressing the power button or short pressing it.
The only way to get it back to normal is to unplug all power sources from the back and replug.

So when turning on the D50III you have to short press the power button only until you see the initial prompts. Long pressing it will make you get stuck in DFU mode.

 

[Kfire85]

I haven't been able to hear a difference on any of these DACs, so just go for the features and power that you need at the best price point. I have the A50III / D50III stack and it does everything I need, including 10 band PEQ when listening on USB source (which for me is almost all of the time), so I can tweak headphone response to preference. I also have a WiiM mini for streaming and listening when the laptop is off. I run TRS balanced out on D50III to TRS in on A50III, and I do prefer the L/M/H gains of -6/+6/+17.9dB using the balanced inputs, vs -12 / 0 /+11.9dB using the SE inputs. It also means the RCA jacks are free on the D50III, so I could also use it as a pre-amp for some active desktop speakers or power amp, which is very handy.

Overall, it's a great stack but if I didn't want the PEQ / dual outputs / 4.4mm jack then I'd probably go for the DX3Pro+, as it's practically half the price and does everything else this stack does, plus to me it looks neater on a desktop (fewer cables etc). It all depends on what features / aesthetics you want, so don't listen to the reviews saying they sound different, because they really don't sound different at all in my experience (and in the objective measurements).

Happy shopping!
View attachment 404823

I am curious though for the D50III if you need it to be powered via USB brick? I just plug mines directly to the PC. I find it odd for the D50III to require additional power, when connecting it to USB via PC can provide it with USB Power decently (about 500mW if I recall to a USB 2.0 connection, and up to 900 mW for a USB-C to USB-C connection).

The A50III has its own separate, provided 15V power adapter so that's settled.

 

[davmol]

I am curious though for the D50III if you need it to be powered via USB brick? I just plug mines directly to the PC. I find it odd for the D50III to require additional power, when connecting it to USB via PC can provide it with USB Power decently (about 500mW if I recall to a USB 2.0 connection, and up to 900 mW for a USB-C to USB-C connection).

The A50III has its own separate, provided 15V power adapter so that's settled.

The answer is that if you don't hear any noise then no you don't need the separate usb power. Sone laptops introduce noise over the USB and the DAC can pick it up. I had an issue where this noise was audible from the D50III to a Yamaha speaker amp using RCA out, and using the separate power supply reduced a lot of the noise, but didn't eliminate it. I couldn't hear the noise at all on the A50III, so makes no difference there and I can just use one cable for both data and power. So if you hear no noise then one cable is fine.

 

[unpluggged]

I don't get why people love to hate Topping

And I don't get why people love to defend these half-baked products as if it was something personal.

 

[JOCoin]

And I don't get why people love to defend these half-baked products as if it was something personal.

The ones that I've owned have been great. I personally think that it's a wonderful thing that people don't need to waste thousands of dollars to have good quality audio performance any more. It's taking the hobby from the hands of the snobby better than thou type fans who crap on products that are affordable. When they haven't even taken the time to be fair and actually read features and performance before dumping on products.

 

[davmol]

And I don't get why people love to defend these half-baked products as if it was something personal.

Is there a particular Topping product you've had a bad time with? The three devices I've had from Topping so far have been excellent and their customer service has been responsive. I've had similar issue free experiences with SMSL, Fiio and Fosi. Based on what I've owned and the after sales experience, I think the only brand I'd avoid in future is Qudelix, not because of the devices but because of the support (they deleted the threads where the issue was raised, which I think is a bit shady).

 

[unpluggged]

people don't need to waste thousands of dollars to have good quality audio performance

Agree. Getting a Topping DAC from AliExpress for $70 (the E30 II Lite), as I did last year for my grandmother's TV speaker setup, is one thing. Paying a thousand bucks for a product with the same approach to quality, lifecycle, and customer support, though, is completely different. That's why I'd rather pay a premium for a well-supported product when it comes to anything that costs more than $200.

 

[unpluggged]

I think the only brand I'd avoid in future is Qudelix, not because of the devices but because of the support (they deleted the threads where the issue was raised, which I think is a bit shady).

Now this is a bit of surprise. Their product support has always been on the better side; I follow them since they announced the development of the 5K back in 2019. Yes, I experienced an issue with the 5K when it randomly shut down with a looping sound, but Qudelix did not ignore the reports and offered their customers solutions. Another similar case was with Radsone, when two of my ES100 were burnt because of a Chinese fast charger. They replaced it twice for free.

 

[JOCoin]

Agree. Getting a Topping DAC from AliExpress for $70 (the E30 II Lite), as I did last year for my grandmother's TV speaker setup, is one thing. Paying a thousand bucks for a product with the same approach to quality, lifecycle, and customer support, though, is completely different. That's why I'd rather pay a premium for a well-supported product when it comes to anything that costs more than $200.

I can agree with that. I understand there has to be sacrifices when designing products at a low price point. Companies like Topping hopefully will start to make people realize how much snake oil there is in the audio hobby. Better prices with better measuring devices based on science and research can only be good for our hobby as whole. There is no good reason based on science or performance that any dac or any consumer audio equipment should cost in the $50k range.

 

[davmol]

Now this is a bit of surprise. Their product support has always been on the better side; I follow them since they announced the development of the 5K back in 2019. Yes, I experienced an issue with the 5K when it randomly shut down with a looping sound, but Qudelix did not ignore the reports and offered their customers solutions. Another similar case was with Radsone, when two of my ES100 were burnt because of a Chinese fast charger. They replaced it twice for free.

I know, it was very frustrating given they generally have a good reputation. There was a long thread in their forum about static noise cutting in at max volume, when using the 5k in usb mode with a PC. I had contributed to it, along with others who experienced the same issue. When I went back recently to check if they had made any progress with this issue, I found the thread was gone and that my posts had been deleted from my profile. All a bit dodgy.