Topping L30 Headphone Amplifier Review

[Roland68]

I am pairing my L30 with zen air dac via RCA, which has a variable output voltage (max 3.3v from specs) depends on the volume knob and Power Match on/off,

I find that for 2v i need to turn on +9db vs 3.3v on 0db gain to get same volume with knob at 1pm position using my hifiman 400i for my usual listening volume

should i max everything out to get the 3.3v, or should keep it at standard of 2v?

I would always prefer the higher output signal and would forgo the additional amplification in the L30.

 

[Magma]

I have owned the Topping L30 and Topping E30 for a couple of years. I use them connected to my computer. Speakers and headphones are connected to them. I’ve generally been satisfied, but there has been a very annoying and serious issue for a long time: the sound starts to 'crackle' and eventually no sound is heard at all. I have to restart them to get the sound working again, and even that doesn’t always help. This issue occurs occasionally, and I haven’t noticed any pattern as to when the problem occurs. How can I fix the issue? I am really disappointed because of this issue, and I can’t recommend these unless the problem can be fixed.

(I don't have problems with any other audio device connected to my PC)

The L30 serial number starts with 2101, and the E30 serial number starts with 2104

 

[Roland68]

I have owned the Topping L30 and Topping E30 for a couple of years. I use them connected to my computer. Speakers and headphones are connected to them. I’ve generally been satisfied, but there has been a very annoying and serious issue for a long time: the sound starts to 'crackle' and eventually no sound is heard at all. I have to restart them to get the sound working again, and even that doesn’t always help. This issue occurs occasionally, and I haven’t noticed any pattern as to when the problem occurs. How can I fix the issue? I am really disappointed because of this issue, and I can’t recommend these unless the problem can be fixed.

(I don't have problems with any other audio device connected to my PC)

The L30 serial number starts with 2101, and the E30 serial number starts with 2104

Which of the two do you need to restart?

 

[Magma]

Which of the two do you need to restart?

Actually, I'm not sure. Usually, I turn off both. And the restart won't always fix the problem, sometimes it takes time until they work again.

I think I will test restarting only the amplifier or DAC and see which is the culprit.

 

[Roland68]

Actually, I'm not sure. Usually, I turn off both. And the restart won't always fix the problem, sometimes it takes time until they work again.

I think I will test restarting only the amplifier or DAC and see which is the culprit.

Do you turn off the devices using the switches or unplug them?

 

[Magma]

Do you turn off the devices using the switches or unplug them?

Switches. I think long time ago I took cables out of the devices but it didn't fix the issue.

 

[Roland68]

Switches. I think long time ago I took cables out of the devices but it didn't fix the issue.

Turning off by unplugging the devices should be more effective, but they should be left without power for at least 30 seconds to drain all the capacitors. Only pull out one plug at a time and be careful not to mix them up under any circumstances.

 

[Magma]

Turning off by unplugging the devices should be more effective, but they should be left without power for at least 30 seconds to drain all the capacitors. Only pull out one plug at a time and be careful not to mix them up under any circumstances.

There have been weeks and months where I have not used these. Yet the problem persists. Shouldn't capacitors be drained after weeks or months of being not in use and turned off?

 

[Roland68]

There have been weeks and months where I have not used these. Yet the problem persists. Shouldn't capacitors be drained after weeks or months of being not in use and turned off?

If you only turn off the front of the devices, they will continue to receive power and certain areas in these devices will not discharge.

You may need to describe the problem in more detail.
But in any case, you should proceed systematically and determine which component is causing the problem.

How do you power the E30? Perhaps the connection is not providing enough power?

 

[Magma]

If you only turn off the front of the devices, they will continue to receive power and certain areas in these devices will not discharge.

You may need to describe the problem in more detail.
But in any case, you should proceed systematically and determine which component is causing the problem.

How do you power the E30? Perhaps the connection is not providing enough power?

I think these worked well for months or even a year before the problem started. I'm not sure anyway since it's been a couple of years.

The problem happened again. I was using speakers connected to the E30 + L30 stack. It started to make a cracking sound and then a couple of seconds later all sound was gone. My monitor which has speakers plays sound normally when I switched to it - so the problem is in E30 + L30, not in the PC.

Note that when this happens the headphones connected to L30 + E30 are silent too. So the problem isn't in the speaker output; it affects both the speakers and headphones connected to the stack.

I don't think the issue is in power delivery. E30 is connected to the extension cord.

I took off the power cords from E30 and L30 and kept them disconnected for at least a minute. Let's see if it solves the issue.

 

[Roland68]

I think these worked well for months or even a year before the problem started. I'm not sure anyway since it's been a couple of years.

The problem happened again. I was using speakers connected to the E30 + L30 stack. It started to make a cracking sound and then a couple of seconds later all sound was gone. My monitor which has speakers plays sound normally when I switched to it - so the problem is in E30 + L30, not in the PC.

Note that when this happens the headphones connected to L30 + E30 are silent too. So the problem isn't in the speaker output; it affects both the speakers and headphones connected to the stack.

I don't think the issue is in power delivery. E30 is connected to the extension cord.

I took off the power cords from E30 and L30 and kept them disconnected for at least a minute. Let's see if it solves the issue.

Unplugging the power for a minute only resets the devices, so it only helps temporarily. The next time the problem occurs, I would first unplug the E30 for a minute and see if it works again. If not, try the L30 next.

What type of power supply does your E30 have?

 

[Magma]

Unplugging the power for a minute only resets the devices, so it only helps temporarily. The next time the problem occurs, I would first unplug the E30 for a minute and see if it works again. If not, try the L30 next.

What type of power supply does your E30 have?

Update. It's been 10 days since I disconnected power cables and kept them disconnected for over a minute. I haven't had a single issue since then! It's only 10 days, but this is noteworthy because that issue used to happen daily (and if I remember correctly many times a day).

So far so good. It seems that taking the power cables off from the DAC and amp did something that fixed the problem. Of course, it's only 10 days, but still it's a huge improvement. I hope it permanently fixed the issue.

 

[gino1961]

Good morning everyone, and I apologize in advance for bringing up a very old thread.
I have a very old first-generation L30, and I've attached the label on it below.

Clearly, it's way too late to return it, especially since I lost the box and accessories.
I have a question and would like your opinions on how to continue using this interesting device.

1) Could replacing the metal potentiometer with a plastic one prevent the electrical discharge problems mentioned in various threads?

If this doesn't work, I have another possible use in mind: as a variable-gain buffer, placed after a passive attenuator with a suitable impedance.
The question is:

2) may I remove the potentiometer and make a jumper at the input, possibly adding a resistor to ground (what value?)?

If I understand correctly, the input impedance is very low at 2.5K , which is usually a bad thing for a buffer after a passive attenuator.
It would be better to raise it to about 20K so I could use a passive resistor of lets say 5Klog or so.
I am sincerely trying to make the best out of this exceptional unit
Another idea is to gut it and make a very clean line preamp in another chassis I do not like too much too little boxes Mid size is the best for me
Like a width of 30-35 mm and a height of 15 The line preamp is going to be the center piece of my system ... the boss
Any suggestions are greatly appreciated, and I thank you in advance.

Best regards,
gino

 

[Roland68]

Good morning everyone, and I apologize in advance for bringing up a very old thread.
I have a very old first-generation L30, and I've attached the label on it below.

View attachment 469949

Clearly, it's way too late to return it, especially since I lost the box and accessories.
I have a question and would like your opinions on how to continue using this interesting device.

1) Could replacing the metal potentiometer with a plastic one prevent the electrical discharge problems mentioned in various threads?

If this doesn't work, I have another possible use in mind: as a variable-gain buffer, placed after a passive attenuator with a suitable impedance.
The question is:

2) may I remove the potentiometer and make a jumper at the input, possibly adding a resistor to ground (what value?)?

If I understand correctly, the input impedance is very low at 2.5K , which is usually a bad thing for a buffer after a passive attenuator.
It would be better to raise it to about 20K so I could use a passive resistor of lets say 5Klog or so.
I am sincerely trying to make the best out of this exceptional unit
Another idea is to gut it and make a very clean line preamp in another chassis I do not like too much too little boxes Mid size is the best for me
Like a width of 30-35 mm and a height of 15 The line preamp is going to be the center piece of my system ... the boss
Any suggestions are greatly appreciated, and I thank you in advance.

Best regards,
gino

I would definitely contact Topping first and ask if they can replace it; it will only take you a few minutes. You don't need the packaging or accessories for this.

The device is from the series that has both the ESD problem and the problem with the slow DC shutdown.
For the former, I would recommend three things.
1. Insulate the potentiometer/shaft from the case, which is the biggest problem.
2. Use a plastic volume knob.
3. Creating a functioning ground connection, both the circuit board ground and the housing.

You can't change the DC protection on the circuit board.
Instead, you could use the Solid State Relay Headphone Amp Protection from XRKAudio, a DIY headphone amplifier DC offset protection circuit with a solid-state relay (SSR).

 

[gino1961]

I would definitely contact Topping first and ask if they can replace it; it will only take you a few minutes. You don't need the packaging or accessories for this.

Hi thank you very much for your kind and very valuable reply It does not seem fair to me after such long time to retun the unit
Moreover Topping is based abroad ... i will have issues with customs i am afraid Maybe ending up to pay more for shipping and customs than for a new unit (another option of course that i have not abandoned Audio is my main hobby by far )
I left it in a closet for so many years after reading of the potential issues

The device is from the series that has both the ESD problem and the problem with the slow DC shutdown.

i suspected that strongly Now i have the confirmation Thank you very much
Your words hurt me but they are very welcome. As in the audio, I am always looking for transparency, for the truth. Even if it is hard to accept. Thank you sincerely

For the former, I would recommend three things.
1. Insulate the potentiometer/shaft from the case, which is the biggest problem.

no problem ... a plastic case is coming I am thinking about a nice plexigalss see-through case It can be an opportunity for a little diy

2. Use a plastic volume knob.

I wonder if after replacing the case with a plastic or wooden one is still needed I do not like much the stock one but i have seen wonderful massive aluminum knob on amazon to replace the original

3. Creating a functioning ground connection, both the circuit board ground and the housing.

maybe the plastic case will make this not necessary ? i would like to keep the circuits as stock as possible to avoid destruction

You can't change the DC protection on the circuit board.

as i am going to use it as a line stage i could add a dc coupling cap at the output ? as i said if i can keep the potentiometer i will use as standalone line preamp
If not as a very high quality audio buffer to be used after a high quality passive attenuator
This looks like perfection to me

i have never seen a cleaner spectrum ... never

Instead, you could use the Solid State Relay Headphone Amp Protection from XRKAudio, a DIY headphone amplifier DC offset protection circuit with a solid-state relay (SSR).

i forgot to mention that i am only interested to use it as a line stage I would love a dedicated line preamp But the Pre90 is quite more expensive even if astonishing
Maybe for next Christmas i will ask to Santa Claus .... but i am a bad boy I don't think he likes naughty people

 

[Roland68]

Hi thank you very much for your kind and very valuable reply It does not seem fair to me after such long time to retun the unit
Moreover Topping is based abroad ... i will have issues with customs i am afraid Maybe ending up to pay more for shipping and customs than for a new unit (another option of course that i have not abandoned Audio is my main hobby by far )
I left it in a closet for so many years after reading of the potential issues

i suspected that strongly Now i have the confirmation Thank you very much
Your words hurt me but they are very welcome. As in the audio, I am always looking for transparency, for the truth. Even if it is hard to accept. Thank you sincerely

no problem ... a plastic case is coming I am thinking about a nice plexigalss see-through case It can be an opportunity for a little diy

I wonder if after replacing the case with a plastic or wooden one is still needed I do not like much the stock one but i have seen wonderful massive aluminum knob on amazon to replace the original

maybe the plastic case will make this not necessary ? i would like to keep the circuits as stock as possible to avoid destruction

as i am going to use it as a line stage i could add a dc coupling cap at the output ? as i said if i can keep the potentiometer i will use as standalone line preamp
If not as a very high quality audio buffer to be used after a high quality passive attenuator
This looks like perfection to me

View attachment 469958
i have never seen a cleaner spectrum ... never

i forgot to mention that i am only interested to use it as a line stage I would love a dedicated line preamp But the Pre90 is quite more expensive even if astonishing
Maybe for next Christmas i will ask to Santa Claus .... but i am a bad boy I don't think he likes naughty people

The plastic casing doesn't help, and the aluminum knob would only make the problem worse.
As I said, metal casing, even a different one, with grounding, and also grounding the circuit board.
You can have a volume knob printed in any color, and it would be visually indistinguishable from metal.

But it's all your responsibility.

If Topping replaces it, shipping, customs, and taxes shouldn't exceed €30-50. But that's your decision, too.

 

[gino1961]

The plastic casing doesn't help, and the aluminum knob would only make the problem worse.

Thanks again
I expressed myself badly
If there is a problem i usually proceed removing the problem
If the problem is the case i would remove the case and even leave the unit open air caseless I can put just a big cover on to save it from dust
If the problem is the metallic knob i will replace it with a plastic one
If the problem is both i will remove the case and replace the knob with a plastic or a wooden one

Most important i wonder if when used as preamp only has given issues as well
I am going to use it only as line preamp
I am also using a different mains transformer 16 V /3,125 A here below

the stock one gets quite hot The new one gets barely warm even if completely sealed

As I said, metal casing, even a different one, with grounding, and also grounding the circuit board.
You can have a volume knob printed in any color, and it would be visually indistinguishable from metal.

But it's all your responsibility.

If Topping replaces it, shipping, customs, and taxes shouldn't exceed €30-50. But that's your decision, too.

Are there any tutorial about how grounding ? I can solder a piece of wire but i need directions about from which point to where
DC blocking is not that difficult a cap at the output will take care of it
Has anyone done that already ?
i search the thread but there are 263 pages mostly of opinions and impressions ...
the question is if it can be modded or not If not i will ditch it