Topping L30 Headphone Amplifier Review

[solderdude]

Im comparing this one with a50s... apart from balanced and unbalanced and all the rest... Im wondering about the power suply adaptor... I am right thinking is better to have a 15Vdc than a 15vac? I think is much more easy to replace if broken right? and somehow may be more secure?

The L30 needs AC to operate. It won't work on 15VDC.

The 15VAC wallwart also can stop working. Thermal fuses (it should have one in the primary winding) can fail over time even without reaching the tripping temeperature.

John chose 15VAC because DC power supplies (SMPS) can have a relatively much higher leakage current and thus higher chance of ground loops.
It also saves 1 or 2 DCDC converters which would be needed in that case.

 

[mocenigo]

Im comparing this one with a50s... apart from balanced and unbalanced and all the rest... Im wondering about the power suply adaptor... I am right thinking is better to have a 15Vdc than a 15vac? I think is much more easy to replace if broken right? and somehow may be more secure?

Not really.

Just buy something like this PCB TRAFO 15V 16VA (this is for Europe, you may need a different input voltage for other places); then snip the cable from the old transformer to the connector, strip the cables and solder them to the output terminals. Take a one side terminated power lead for your power plugs and solder the open part to the input terminals. Put the transformer in a box with cable glands, or have it mounted on a raster PCB, with a second one separated from the first by means of spacers, so that it would be difficult to touch the live contacts.

Voilà. This is what I have done (I also have attached a pic of the contraption).

 

[mocenigo]

no need to worry about the adapter is going to be broken --- ac adapters are very simple in structure --- a solid metal plus coil wires. Very hard to be broken.
on the other hand, a switching power supply has a lot of components and has much higher failure rate.
your amp will definitely break before the adapter.

But my original one burned with an explosive sound, smoke, and protections tripping in the whole house. So bad quality AC transformers can fail as well.

 

[AdamG]

Nice, than i will go for it. Can’t wait for that satisfying feeling when you turn the volume knob

Welcome Aboard @bigfudge13.

 

[bigfudge13]

Hello, thank you

 

[TheBatsEar]

I have the opportunity to get a 2009622511 for 60€. Should i get it? Is there anything i can do to make it "safe"?

 

[solderdude]

I have the opportunity to get a 2009622511 for 60€. Should i get it? Is there anything i can do to make it "safe"?

Yes, throw it in the bin. The only safe place for it.

Should you want to only use it for yourself and not get mad when it destroys your headphone then all you need to do is connect the enclosure to the signal ground. I would not recommend it. The change in the protection circuit (from 2011 upwards) was not done without reason and the recall/exchange also is done with good reason.
The seller of that device should have destroyed it.

 

[TheBatsEar]

Should you want to only use it for yourself and not get mad when it destroys your headphone then all you need to do is connect the enclosure to the signal ground.

So i connect the case to the ground plane and i'll survive? I can do that. Easily.

 

[mocenigo]

I have the opportunity to get a 2009622511 for 60€. Should i get it?

No.

Is there anything i can do to make it "safe"?

No.

 

[mocenigo]

So i connect the case to the ground plane and i'll survive? I can do that. Easily.

It can still send a DC spike to the headphones.

 

[solderdude]

So i connect the case to the ground plane and i'll survive? I can do that. Easily.

Yes, that's easy to do. You'll survive. Your headphone may not if something goes defective in your amp. Connecting the enclosure to the signal ground only reduces the chance of that happening when it concerns electrostatic discharges only.

 

[enomiss]

Guys I'm using my replacement for several months now. One thing I noticed is that I have to turn the volume knob more than with my previous unit. I don't consider it to be a problem, but I'm curious for the explanation. Are there variations between production units or is it a result of the altered unit? Anyone else experienced this?

 

[solderdude]

Gain is determined by fixed resistor ratio's which are not changed.

The only technical explanation would be a potmeter with a different taper.

If you really want to find out you will have to measure/compare those amps.
As the L30 also works as a pre-amp and when you have a soundcard that can record it is very easy to confirm the taper of the volpot differs.

 

[enomiss]

Thanks, well, I don't have the old one anymore. Anyway, it doesn't really matter. Probably production tolerances...

Does anyone know if these can drive Aeon NOIRE or Aeon 2 Closed?

 

[velasfloyd]

Thanks guys for your great answers

I think anyway that I didnt explain myself well (probably because I am a spanish speaker )

I know I cant interchange 15vdc with 15vac. My question was more than, lets say between l30 and a50s everything is equal... And one only should buy one or the other based in which adaptor is better, the ac or the dc one.... thinking about how easy is to find a replacement (from the same type). How durable it is, quality... etc

based on your answers seems like both are equally bad hahaha

 

[LegionOfHell]

whats the maximum power output at the following impedances:?

16 ohms
32 ohms
50 ohms
300 ohms
600 ohms

Many Thanks

 

[solderdude]

Depends on the max. input voltage
The L30 spec sheet gives you the answers to your questions but not for 2V output DACs
These numbers are given in this thread but requires reading it.

You can also calculate the values for any load. max Uout = 9.15V, max current = 0.4A assuming you have a high enough input voltage.

 

[fredristair]

It is 2.6W with an E30 at 16ohm, I believe it has 1W of power at 32ohm with a 2V dac
I myself have been curious about what it would 20ohm

Would it be more than 2W? I'm trying to figure this out if one of my headphones which does best with 2W-5W of power at 20ohms?

I've been guessing that it is probably around 2W

Haven't stumbled on some kind of formula to determine or guesstimate if you know the power at two impedances, etc -

In this case 16ohm (2.6W) and 32ohm (1W)...

 

[solderdude]

20 ohm = 3.2W with 2.86V input.
1.6W using a 2V DAC.

Most likely you will never reach 1.6W peaks in practice (digital file 0dBFS, volume control at max and high gain, no EQ)

 

[hmscott]

Thanks guys for your great answers

I think anyway that I didnt explain myself well (probably because I am a spanish speaker )

I know I cant interchange 15vdc with 15vac. My question was more than, lets say between l30 and a50s everything is equal... And one only should buy one or the other based in which adaptor is better, the ac or the dc one.... thinking about how easy is to find a replacement (from the same type). How durable it is, quality... etc

based on your answers seems like both are equally bad hahaha

Yeah, not sure why noone understood that, you were communicating aok

Im comparing this one with a50s... apart from balanced and unbalanced and all the rest... Im wondering about the power suply adaptor... I am right thinking is better to have a 15Vdc than a 15vac? I think is much more easy to replace if broken right? and somehow may be more secure?

You are thinking correctly about the issue. I am not sure why Topping would go for an "odd-ball" AC power supply - this is not a good solution to an otherwise non-existent problem.

I would not want to purchase one myself due to the use of a Low Voltage AC Power Supply.

There may have been a design win using AC power to reduce cost in their design overall, but the net effect is to ruin standardization of power supplies and user-friendliness.

There are lots of discussions on why we use Low Voltage DC instead of Low Voltage AC in our designs:
why low voltage DC instead of AC power supplies? - Google Search