Topping L30 Headphone Amplifier Review

[Jose Hidalgo]

Hi, sorry for insisting on this, but I think this long thread was lacking a summary about the (thankfully now fixed once and for all) L30 issues. I'm no technical expert, so I'd like to be corrected if I'm saying anything wrong here. Plus this could be useful for newer members.

As we know, some older L30 units had a design flaw that resulted in two different and consecutive issues :

1. The "frying headphones" problem (problem 1),
2. The "grounding" problem (problem 2).

AFAIK both problems were ESD-related (ESD = Electro-Static Discharge) :

• Problem 1 could happen after a ESD, because of insufficient circuit protection. It could potentially blow up headphones (and ears) and damage L30 units (an internal component could blow up).
• Thankfully, problem 1 could only happen under certain conditions allowing for a build-up of static electricity. So ultimately it only happened to some unlucky people, and no ears have been blown yet, only a limited number of headphones and L30s.
• Problem 2 revealed itself once problem 1 was fixed by Topping. It was fixed by Topping shortly afterwards. It was a grounding issue that could potentially damage L30s (but not headphones since problem 1 had already been fixed).

Now about the fixes :

• Problem 1 fix (called the "headphones fix") involved some degree of circuit protection (does anybody know more about this ? any pictures ?).
• Problem 2 fix (called the "ESD fix") basically required linking the PCB to the casing. Pictures of this have already been posted.

As for serial numbers :

• All L30 S/N 2011xxxx and lower are unprotected
• 100% of all 2012xxxx L30s are protected against problem 1
• 90% of all 2012xxxx L30 are also protected against problem 2
• All newer models (2101xxxx, 2102xxxx...) are of course protected

On page 180 I mentioned problem 1, and I asked when it could happen very precisely. I was clearly answered that it could happen anytime, but that it required physically touching the unit. It cannot happen as long as you don't touch the unit, simply because it's ESD-related so it requires physical contact.

Most importantly, it also means that for those of us with older L30 units (2011xxxx and previous), until we get our replacement L30 unit(s), as long as we avoid touching our L30s during operation (or we discharge ourselves first - and that includes the moment we plug/unplug our headphones and the moment we turn them on/off), our ears and headphones are safe and we can keep enjoying our L30s.

In other words : let's just be cautious while we wait for our replacements, let's think twice before we touch our L30s, and everything will be OK.

 

[GGroch]

Jose, good summary, and good resource for those who do not want to search through 4000 posts.

I was in agreement until the last 2 paragraphs. Headphone amps are nearly impossible to use without ever touching them. Thinking twice or even three times does not help. What if your cat touches it?

It's true that if you have a replacement L30 on the way, you may do not care if your old L30 dies. But, as your chart shows, serial 2011 and below will take the headphones with it. I really doubt Topping will pay for headphones damaged by an L30 that you have already certified as destroyed. So, I would not use it, or only use it with headphones I did not care at all about.

 

[Jimbob54]

Hi, sorry for insisting on this, but I think this long thread was lacking a summary about the (thankfully now fixed once and for all) L30 issues. I'm no technical expert, so I'd like to be corrected if I'm saying anything wrong here. Plus this could be useful for newer members.

As we know, some older L30 units had a design flaw that resulted in two different and consecutive issues :

1. The "frying headphones" problem (problem 1),
2. The "grounding" problem (problem 2).

AFAIK both problems were ESD-related (ESD = Electro-Static Discharge) :

• Problem 1 could happen after a ESD, because of insufficient circuit protection. It could potentially blow up headphones (and ears) and damage L30 units (an internal component could blow up).
• Thankfully, problem 1 could only happen under certain conditions allowing for a build-up of static electricity. So ultimately it only happened to some unlucky people, and no ears have been blown yet, only a limited number of headphones and L30s.
• Problem 2 revealed itself once problem 1 was fixed by Topping. It was fixed by Topping shortly afterwards. It was a grounding issue that could potentially damage L30s (but not headphones since problem 1 had already been fixed).

Now about the fixes :

• Problem 1 fix (called the "headphones fix") involved some degree of circuit protection (does anybody know more about this ? any pictures ?).
• Problem 2 fix (called the "ESD fix") basically required linking the PCB to the casing. Pictures of this have already been posted.

As for serial numbers :

• All L30 S/N 2011xxxx and lower are unprotected
• 100% of all 2012xxxx L30s are protected against problem 1
• 90% of all 2012xxxx L30 are also protected against problem 2
• All newer models (2101xxxx, 2102xxxx...) are of course protected

On page 180 I mentioned problem 1, and I asked when it could happen very precisely. I was clearly answered that it could happen anytime, but that it required physically touching the unit. It cannot happen as long as you don't touch the unit, simply because it's ESD-related so it requires physical contact.

Most importantly, it also means that for those of us with older L30 units (2011xxxx and previous), until we get our replacement L30 unit(s), as long as we avoid touching our L30s during operation (or we discharge ourselves first - and that includes the moment we plug/unplug our headphones and the moment we turn them on/off), our ears and headphones are safe and we can keep enjoying our L30s.

In other words : let's just be cautious while we wait for our replacements, let's think twice before we touch our L30s, and everything will be OK.

Im no electrician , or EE, but I would be wary of using any device where there is a known issue with the DC protection, regardless of whether we think we know what could cause the device to fail in a way that would need the protection to work. Consider power cuts, children, pets or any other manner of things that might trigger it outside of the main user's control.

Bottom line, Topping have offered to replace any pre 2012 units and asked for any existing units to be put out of use. I would do just that.

So no, I'm not sure its as simple as "dont touch the unit". I would take it as more a "dont use the unit".

 

[GGroch]

......Bottom line, Topping have offered to replace any pre 2012 units and asked for any existing units to be put out of use. I would do just that.

Yes.
Topping/John Yang also offered to replace the 10% of 2012 units without the chassis grounding pin fix whether you purchased it or it was sent as a replacement. I strongly suggest owners of 2012 serial units check for the ESD fix by removing the back plate and looking for the pin, or checking continuity with a multi-meter* between the outer ground sleeve on either L/R inputs and a rear chassis screw.

Edit - As per Netsat_99, changed meter to multi-meter for clarity.

 

[Netsat_99]

Or just use a multimeter...

 

[Jose Hidalgo]

I'd just like to add this. I'm no technical expert here, but I'm an engineer and I believe in causality, not in magic. Things always happen for a reason. Sometimes we can't find it. But once we find the reason why things happen, if we can control that reason, then we can either make things happen or prevent them from happening.

The point of my previous post, besides being a summary, is to tell people to get their L30s replaced of course, but also to NOT PANIC. Your L30s won't blow up magically without a reason. There is a reason why these things have sadly happened to some of us. That reason always involves an ESD. So while we wait for our replacements, if we are careful enough to prevent ESDs from happening, we can prevent issues. That is not magic, just science.

Of course we'll need to take appropriate precautions, but those are fairly easy now that we know what triggers the problem :

1. If we have pets or children, put the L30 out of their reach
2. Always discharge ourselves before touching the L30

I think it can be guaranteed that anyone following these precautions won't have any ESD issues with his/her L30. And of course if we can't follow those precautions with absolute confidence, then it's best to not use the L30s at all.

My personal case isn't relevant, but here goes : my GF and I live together, we don't have any pets or children, and our two L30s are mounted in a way that prevents accidentally touching them. Plus we hardly ever touch the volume knobs since we handle the volume digitally via foobar. If we add a master on/off switch, then we don't even need to touch the L30s at all (besides plugging/unplugging the headphones, which can be done with the L30s fully disconnected).

To answer @GGroch , we haven't requested the replacement yet, because like I said earlier in this topic, we will wait for a more recent batch so hopefully the Topping fixes will have been fully integrated into the production scheme and not made in a hurry like it was the case in december. It's our personal choice and it's not open for discussion. We will of course ask for a replacement soon (our reseller already knows about it), it's just a matter of a few weeks. In the meantime, we feel very comfortable using our L30s with the aforementioned precautions, and we firmly believe we won't have any issues with them.

The L30 potential issues are very real and very serious, and we must treat them accordingly. But people should really stop panicking, for two reasons :

1. The odds of having such problem are very small (number of failures vs. number of L30s sold prior to december - probably less than 1%, so 99%+ of users could probably keep using their L30s without any precautions and never have a problem)
2. Most importantly, now we know exactly what triggers the problem, so we know how to avoid it. Avoiding it becomes OUR responsibility.

 

[mocenigo]

Why one has to bring this up and still take it the wrong way. With 2V input you have near max output at 16Ohm and no clipping at any realistic load even at max volume high gain. Otherwise you'd get clipping driving 32ohm already.

People like to complain. I see this as the E30 not able to drive the L30 to clipping but also keeping it in a smaller, cleaner range. If one really needs more than 2.6W peak (which is not much of a difference in Db from 3.5W) then they need a different combo.

I like to have headroom. I assembled my speakers with transducers that can handle a much much higher power then I will ever need (unless I win the lottery in which case I can get a larger listening room and a different audio chain, so the problem is moot), an amplifier that can deliver more power than that as well, but not more than the transducer can bear. The way I have configured the buffer in my main power amp, I cannot drive it to clipping with the DAC (a D90 by the way), but not as tightly that I may encounter problems hearing very soft recordings at acceptable levels. To fine tune that a bit I also have JTS attenuators.

This way everything works in more comfortable ranges and no component upstream can drive to clipping or even damage the components downstream, except im case of catastrophic failure.

 

[highpurityusbcable]

Has anyone tried to change the volume knob on L30? If yes, which one did you get and how easy it is to swap them? I want to try soon for fun and maybe some placebo convenience.

 

[life.exeMPLAR]

Has anyone tried to change the volume knob on L30? If yes, which one did you get and how easy it is to swap them? I want to try soon for fun and maybe some placebo convenience.

Isn't this normal d shaft pot? You just have to use more force than you think
I replaced mine with other color topping l30
beware that this won't fix scratchiness

 

[life.exeMPLAR]

Hi, sorry for insisting on this, but I think this long thread was lacking a summary about the (thankfully now fixed once and for all) L30 issues. I'm no technical expert, so I'd like to be corrected if I'm saying anything wrong here. Plus this could be useful for newer members.

As we know, some older L30 units had a design flaw that resulted in two different and consecutive issues :

1. The "frying headphones" problem (problem 1),
2. The "grounding" problem (problem 2).

AFAIK both problems were ESD-related (ESD = Electro-Static Discharge) :

• Problem 1 could happen after a ESD, because of insufficient circuit protection. It could potentially blow up headphones (and ears) and damage L30 units (an internal component could blow up).
• Thankfully, problem 1 could only happen under certain conditions allowing for a build-up of static electricity. So ultimately it only happened to some unlucky people, and no ears have been blown yet, only a limited number of headphones and L30s.
• Problem 2 revealed itself once problem 1 was fixed by Topping. It was fixed by Topping shortly afterwards. It was a grounding issue that could potentially damage L30s (but not headphones since problem 1 had already been fixed).

Now about the fixes :

• Problem 1 fix (called the "headphones fix") involved some degree of circuit protection (does anybody know more about this ? any pictures ?).
• Problem 2 fix (called the "ESD fix") basically required linking the PCB to the casing. Pictures of this have already been posted.

As for serial numbers :

• All L30 S/N 2011xxxx and lower are unprotected
• 100% of all 2012xxxx L30s are protected against problem 1
• 90% of all 2012xxxx L30 are also protected against problem 2
• All newer models (2101xxxx, 2102xxxx...) are of course protected

On page 180 I mentioned problem 1, and I asked when it could happen very precisely. I was clearly answered that it could happen anytime, but that it required physically touching the unit. It cannot happen as long as you don't touch the unit, simply because it's ESD-related so it requires physical contact.

Most importantly, it also means that for those of us with older L30 units (2011xxxx and previous), until we get our replacement L30 unit(s), as long as we avoid touching our L30s during operation (or we discharge ourselves first - and that includes the moment we plug/unplug our headphones and the moment we turn them on/off), our ears and headphones are safe and we can keep enjoying our L30s.

In other words : let's just be cautious while we wait for our replacements, let's think twice before we touch our L30s, and everything will be OK.

does anyone know if the pcb changed between 2011xxxx and 2101xxxx?

 

[GGroch]

Has anyone tried to change the volume knob on L30? If yes, which one did you get and how easy it is to swap them? I want to try soon for fun and maybe some placebo convenience.

In an earlier post John Yang discouraged the removal of the L30 volume knob. It is quite a tight fit and could cause wobble and perhaps worse. A page or so back a couple of users have expressed wobble complaints.

 

[jannek]

So wobble of volume pot knob is a sign for a reworked unit maybe?

 

[kkeretic]

So wobble of volume pot knob is a sign for a reworked unit maybe?

Probably.

 

[Veri]

So wobble of volume pot knob is a sign for a reworked unit maybe?

Probably.

Don't think so because in the beginning of this thread some people had a bit of wobble and some don't. Seems like a standard 'tolerance' thing.

 

[Jose Hidalgo]

A wobble or a wiggle, that's the question

 

[Upped]

My new l30 volume knob is also a bit weird from about 0% to 25% and 75% to 100%. I think it gets too close to the case and is scraping against something. Also feels like it has resistance when trying to turn the knob in the above mentioned percentages? Doesn't bug me too much though usually just leave volume at 1 o clock. Would reseating it fix it maybe?

 

[bokolobs]

I have an L30 replacement on the way from China. It has a 201262xxxx serial number. Could we determine if the L30 has the two fixes just based on the serial number? I'm not comfortable unscrewing the back panel to check. But if this is the only way, what am I supposed to look for exactly? Thanks so much!

 

[Bsdzilla]

You will have to remove the volume knob, using a flat object behind the knob. It takes some force. Then you remove the nut connecting the volume control to the front panel. Now, after unscrewing the backpanel of course, you just slide the board out. It's not hard to do. There should be some connection from the pcb to the case (connecting ground to the aluminium case). That's the ESD modification. The modification that's supposed to improve the DC protection circuit is unknown. It could be discovered by comparing the old and the new board. The wobblyness of the new knobs that multiple people noticed could indicate that something may have been modified to prevent or reduce static discharge to the board via the volume control, wich would be the primary route of course.

 

[highpurityusbcable]

So wobble of volume pot knob is a sign for a reworked unit maybe?

No, I had this wobble in my first one too.

 

[somebodyelse]

I have an L30 replacement on the way from China. It has a 201262xxxx serial number. Could we determine if the L30 has the two fixes just based on the serial number? I'm not comfortable unscrewing the back panel to check. But if this is the only way, what am I supposed to look for exactly? Thanks so much!

All the 2012xx serial number L30s have the DC offset protection fix. ~90% of them have the extra contact for improved ESD protection. So far as I know that can't be checked by serial number. If you have a multimeter you can check continuity between the exposed contact of the RCA and the mounting screw at the side of the back panel. If not you can remove the back panel and check for the gold sprung 'pogo pin' contact near the edge of the board, as seen in the photo in this post. If the contact is there then all is good. If there is no sprung contact, or no continuity, then you should arrange for a replacement with your supplier if you don't want to take the diy grounding approach..