Topping L50 Review (Headphone Amp)

[GearNostalgia]

Ahh, ok, I thought you connected the Bose phones to the L50. Do you connect the Bose phones to the Clarett with wire or do you have a wireless dongle on the Clarett outputs?

 

[Xyrium]

Totally wired. It probably would not make a difference what I connected it to given that they are powered headphones I'll put incidence of the amp wouldn't matter. Works great.

 

[dsnyder0cnn]

Check power supply unit. It should provide 15~20V AC.

I realize that I'm replying to an old thread, but just adding a comment in case it's helpful to others. I've been happily using my E50/L50/PA5 stack since early 2022 (almost three years). In fact, I was listening to some Dire Straits just this morning. However, after getting back from a meeting, I noticed that the white power LED on my L50 was steadily blinking on and off about once/second. Nothing helpful in the PDF manual, so I checked the FAQ:

FAQ - TOPPING

www.toppingaudio.com

Most of the symptoms seemed to be related to power supply issues, so I got out my volt meter and measured the output of the Topping "15V AC" power brick:

The internal voltage regulators in products like the L50 can usually handle variations of a volt or two, but this is 36% above the target! Likely my issue, although I'm not sure why the adapter worked fine for so long only to go crazy today.

Regardless, since I'm nearly two years out of warranty, I've ordered a 3rd party replacement:

https://www.amazon.com/gp/product/B0D2XL5HGG/

I should have it in a week or so and will report back. Kind-of bummed though since I was really enjoying that album this morning.

 

[dsnyder0cnn]

Well, I swapped out the power supply, and the white light is still blinking. Ugh!

Here's an inventory of the Topping products I've purchased over the past four years (thanks to @amirm and ASR):

• Pre90 (analog preamp)
• Ext90 (expansion for the Pre90 that I added when I needed more inputs)
• DX3 Pro+ (DAC/Amp)
• E50 (DAC)
• L50 (headphone amp)
• PA5 (speaker amp)
• LA90D (speaker amp)
• B200 (two, mono speaker amps)
• D50 III (DAC)

Of these, the L50 is the first one to fail. It's a bit ironic because I've probably used the L50 the least. I have the E50/L50/PA5 stack daisy-chained at my desk where I work 8-10 hours/day. The E50/PA5 handles audio for Zoom calls, training videos, and background music while the L50 is mostly switched off (in pass-through mode). Occasionally, I'll switch the L50 on to drive Sennheiser HD600 headphones when I want to focus more on what I'm hearing, but that's been only a few times a month. This Topping stack has worked flawlessly for almost three years...until just last week.

Lots of folks here on ASR have shared experiences with Topping products (especially the PA5) failing on them. It was only a matter of time before my luck ran out, I suppose.

Since I need a replacement headphone amp, I considered "upgrading" to a different model, but given my usage patterns, that does not make much sense. The L50 meets my needs and looks great on my desk between the E50 and PA5 (all in red). Fortunately, I found an "Apos Certified, like new" L50 available in red, so I ordered the replacement last night for $160. I'm hoping to get another three years out of this stack!

Overall, I can't complain. I've been enjoying instrument-grade audio quality that is as engaging to listen to as it is precise for a tiny fraction of what I would have spent years ago with more traditional audio brands.

 

[jdoe]

The internal voltage regulators in products like the L50 can usually handle variations of a volt or two, but this is 36% above the target! Likely my issue, although I'm not sure why the adapter worked fine for so long only to go crazy today.

L50 power adapter, or "power brick", is just a single transformer and couple wires. The 15 volts AC marked on the power adapter is likely the RMS (Root Mean Square) value of the AC voltage. However, AC voltages also have a peak value that is higher than the RMS value. For a sinusoidal waveform, the peak voltage is approximately 1.414 times the RMS voltage. This means the peak value of 15V AC would be around 21.2 volts (15V × 1.414), which is close in your case (mine L50 power adapter measures the same).
Another explanation is that transformers are designed to output their rated voltage (15V AC in your case) under a specific load. When you measure the output voltage of the transformer with a voltmeter without any load (meaning no device is connected), the voltage will often be higher than the rated value. This is because there is minimal current being drawn, and there is no voltage drop due to the internal resistance of the transformer winding.

I'm able to reproduce the same issue ("blinking on and off") only in case of bad/loose connection between adapter and power outlet (mine L50 adapter has "chinese" pins, which are slightly narrower than default EU socket holes, so I can just "jiggle" it a bit to make loose). Usually it can be fixed by reinserting adapter again or changing power extension board. I personally made a "tweak" for a few sockets of power extension board - used pliers to improve contact for chinese-type plugs (as shown on the image below, BEWARE: use common knowledge of electric safety, like unplugging power extension board before disassembly, also I don't recommend to do any changes to your high-voltage electrical equipment, if you are not sure).

 

[AnalogSteph]

Another explanation is that transformers are designed to output their rated voltage (15V AC in your case) under a specific load. When you measure the output voltage of the transformer with a voltmeter without any load (meaning no device is connected), the voltage will often be higher than the rated value. This is because there is minimal current being drawn, and there is no voltage drop due to the internal resistance of the transformer winding.

Indeed. I've measured well over 15 V coming out of a nominal 12 V dc unregulated wall wart when not loaded.

The defective L50 in question probably has some sort of internal problem. If it's power related, it should be relatively fixable, I can't imagine it's anything too outlandish.

 

[dsnyder0cnn]

I tried two different 3rd party 15V, 1A AC adapters. Both measure ~17.5V AC unloaded. Same white blinking light when I try either with my L50.

Topping service offered to repair it if I pay round-trip shipping. More than fair considering that it's two years out of warranty. I may take them up on that as a backup. I already purchased a replacement from Apos. Should arrive next week.

On AC voltage measurements, I assume my Fluke digital multimeter measures RMS, not peak voltage. I see ~120V AC when I (carefully) poke the probes into my power receptacle as expected. If I had an oscilloscope, I'd expect to see peak voltage.

 

[mike7877]

Well, I swapped out the power supply, and the white light is still blinking. Ugh!

Here's an inventory of the Topping products I've purchased over the past four years (thanks to @amirm and ASR):

• Pre90 (analog preamp)
• Ext90 (expansion for the Pre90 that I added when I needed more inputs)
• DX3 Pro+ (DAC/Amp)
• E50 (DAC)
• L50 (headphone amp)
• PA5 (speaker amp)
• LA90D (speaker amp)
• B200 (two, mono speaker amps)
• D50 III (DAC)

Of these, the L50 is the first one to fail. It's a bit ironic because I've probably used the L50 the least. I have the E50/L50/PA5 stack daisy-chained at my desk where I work 8-10 hours/day. The E50/PA5 handles audio for Zoom calls, training videos, and background music while the L50 is mostly switched off (in pass-through mode). Occasionally, I'll switch the L50 on to drive Sennheiser HD600 headphones when I want to focus more on what I'm hearing, but that's been only a few times a month. This Topping stack has worked flawlessly for almost three years...until just last week.

Lots of folks here on ASR have shared experiences with Topping products (especially the PA5) failing on them. It was only a matter of time before my luck ran out, I suppose.

Since I need a replacement headphone amp, I considered "upgrading" to a different model, but given my usage patterns, that does not make much sense. The L50 meets my needs and looks great on my desk between the E50 and PA5 (all in red). Fortunately, I found an "Apos Certified, like new" L50 available in red, so I ordered the replacement last night for $160. I'm hoping to get another three years out of this stack!

Overall, I can't complain. I've been enjoying instrument-grade audio quality that is as engaging to listen to as it is precise for a tiny fraction of what I would have spent years ago with more traditional audio brands.

Topping:
2x LA90 Discrete (Stereo Speaker Amp)
2x D90 III Sabre (ESS 9039Pro DAC)
1x D70 Sabre (ESS ES9039Pro DAC)
1x A70 Pro (Headphone Amp)
1x D70 Velvet (AKM AK4499EX DAC)
1x L70 (Headphone Amp)
1x L30 II (Single Ended Headphone Amp)
1x DX1 (DAC + Headphone Amp)
1x G5 (Portable DAC + Headphone Amp)

One of the D90 IIIs has been on pretty much since I got it, same with the A70 Pro. The D70 Pro Sabre has been on for probably as long as the previously mentioned D90 III which I got around 6 months ago. The L70+D70 Velvet combo work in tandem and have been on for over a year. The D70 Sabre probably has 3,000 hours. The L30 II has about a year on it. The LA90 Discretes, one is a few months older than the other - they get used together now and probably have 2,000-3,000 hours on them. The DX1 is used intermittently. Like you, I have a single broken Topping product, the G5. It's kind of my fault it's broken though, because I gave its input like 10V RMS... I wish I didn't do that haha!

I think the design of the L30 II is an unbalanced L50. I find the L30 II sounds like the L70 would if it had a potentiometer. That and the extra power are what I consider the difference between the L30 II and the L70.

If you're ever thinking of a better DAC to match your Pre90 and the B200s/LA90D, I really like the D90 III Sabre

 

[dsnyder0cnn]

If you're ever thinking of a better DAC to match your Pre90 and the B200s/LA90D, I really like the D90 III Sabre

That's quite a collection. Glad to hear that there's another fan out there who has had mostly good luck (knock on wood.

I've been using a Gustard X18 with my Pre90, but I've been tempted a few times by Topping's various D90 iterations over the years. I suspect the sound is quite similar, but a Topping would be a closer cosmetic match with a nicer display.

 

[dsnyder0cnn]

the L50 is the first one to fai

An update to my story: the replacement L50 that I ordered from Apos arrived today. The power adapter that shipped with it also measures 20.4V AC. I realize this is unloaded, but it still seems high.

Besides that, it sounds terrific. Better than I remember, but perhaps I've just missed having nice headphones at my desk.

I may take the dead L50 by the post office on Saturday to see what shipping to China would run. If it's less than $60, I may consider sending it back for repairs. Might be good to have a backup, and I hate putting electronics in the landfill.

 

[BeeKay]

An update to my story: the replacement L50 that I ordered from Apos arrived today. The power adapter that shipped with it also measures 20.4V AC. I realize this is unloaded, but it still seems high.

Besides that, it sounds terrific. Better than I remember, but perhaps I've just missed having nice headphones at my desk.

I may take the dead L50 by the post office on Saturday to see what shipping to China would run. If it's less than $60, I may consider sending it back for repairs. Might be good to have a backup, and I hate putting electronics in the landfill.

Edit: Mains measure 231V (nominal 230V) so almost spot on

 

[AnalogSteph]

Keep in mind that transformer output is also going to vary depending on mains voltage, so ideally one would want a measurement of both. Nominal voltage tolerance in the US and Canada is 120 V +/-5%, so a relative variation of up to 10.5% between two measurements may be normal if one person happens to get mains voltage near the top end and another near the bottom end of this range. (It tends to vary depending on location and time of day.) 20.4 V is only 6.9% higher than 19.08 V. And that's not even considering multimeter accuracy as a factor, although usually that's pretty good.

 

[Roland68]

I realize that I'm replying to an old thread, but just adding a comment in case it's helpful to others. I've been happily using my E50/L50/PA5 stack since early 2022 (almost three years). In fact, I was listening to some Dire Straits just this morning. However, after getting back from a meeting, I noticed that the white power LED on my L50 was steadily blinking on and off about once/second. Nothing helpful in the PDF manual, so I checked the FAQ:

FAQ - TOPPING

www.toppingaudio.com

Most of the symptoms seemed to be related to power supply issues, so I got out my volt meter and measured the output of the Topping "15V AC" power brick:

View attachment 431982

The internal voltage regulators in products like the L50 can usually handle variations of a volt or two, but this is 36% above the target! Likely my issue, although I'm not sure why the adapter worked fine for so long only to go crazy today.

Regardless, since I'm nearly two years out of warranty, I've ordered a 3rd party replacement:

https://www.amazon.com/gp/product/B0D2XL5HGG/

I should have it in a week or so and will report back. Kind-of bummed though since I was really enjoying that album this morning.

I can assure you that this voltage is completely normal for the transformer of the L50, L30, and L30 II. This is simply the unloaded open-circuit voltage of the transformer, which drops to approximately 17 volts when the HPA is switched on. The devices run internally at approximately +/-23.5 volts DC, but the voltage regulators can easily handle +/-35 volts, which is more than enough reserve.

If this still bothers you, you can also use a high-quality toroidal transformer with a lower open-circuit voltage, but you would have to wire it yourself and put it in its own housing.

Does the L50 also flash when nothing is connected except the transformer?

 

[dsnyder0cnn]

Does the L50 also flash when nothing is connected except the transformer?

Yes. Thankfully, the replacement i purchased works perfectly (so far...)

 

[jonwb]

I just received a brand new L50 from Apos after waiting nearly a month for it.

Strange issue when using headphones: When set to "L", the volume raises evenly as I turn up the volume control from 0. However, when set to "M" or "H", the right-hand output is slightly favored before centering as the volume is raised more. Happens with all the headphones I own and didn't occur with my previous L30II. Any suggestions?

 

[Roland68]

I just received a brand new L50 from Apos after waiting nearly a month for it.

Strange issue when using headphones: When set to "L", the volume raises evenly as I turn up the volume control from 0. However, when set to "M" or "H", the right-hand output is slightly favored before centering as the volume is raised more. Happens with all the headphones I own and didn't occur with my previous L30II. Any suggestions?

Potentiometer imbalance. All normal pots have this to a greater or lesser extent, but unfortunately, you were unlucky.
It will also be there with the L, but it won't have as much of an effect. The difference is obviously greater at higher gain levels.
Send it back.

A Topping L70 or the Sabaj A20h, which are still sometimes available on Amazon, don't have this problem; they have relay-based volume control with absolutely identical channel balance.
The A20h, a true balanced amplifier with 4.4 watts, is unbeatably cheap at a price of around €125.

 

[jonwb]

Potentiometer imbalance. All normal pots have this to a greater or lesser extent, but unfortunately, you were unlucky.
It will also be there with the L, but it won't have as much of an effect. The difference is obviously greater at higher gain levels.
Send it back.

A Topping L70 or the Sabaj A20h, which are still sometimes available on Amazon, don't have this problem; they have relay-based volume control with absolutely identical channel balance.
The A20h, a true balanced amplifier with 4.4 watts, is unbeatably cheap at a price of around €125.

Hey thanks for that information. Darn, sending it back will probably be on my end. Would it make any sense to open it up and clean the potentiometer with DeOxit?

 

[Roland68]

Hey thanks for that information. Darn, sending it back will probably be on my end. Would it make any sense to open it up and clean the potentiometer with DeOxit?

The worst of all.
This won't correct the imbalance in the potentiometer that arose during production.
And chemicals in potentiometers are only for experts or emergency solutions for a quick functional test. It's nonsense for a new device with a warranty, because you would rightfully void the warranty.

 

[jonwb]

The worst of all.
This won't correct the imbalance in the potentiometer that arose during production.
And chemicals in potentiometers are only for experts or emergency solutions for a quick functional test. It's nonsense for a new device with a warranty, because you would rightfully void the warranty.

Ok thanks Roland. You mentioned the L70 with its relay-based volume control. I noticed it has a preamp function. Do you own this unit? If so, is it fairly easy to switch between using the L70's volume control for headphone output vs the preamp output for speakers?

Thanks

 

[Roland68]

Ok thanks Roland. You mentioned the L70 with its relay-based volume control. I noticed it has a preamp function. Do you own this unit? If so, is it fairly easy to switch between using the L70's volume control for headphone output vs the preamp output for speakers?

Thanks

You can adjust it either by pressing the volume button or using the remote control, no problem.
The remote also has two storable user presets, C1 and C2, so you can save two different settings and recall them instantly.