Amp with headphone protection?

[boogie]

Hello fellow members,

I'm really close to pulling the trigger on the JDS Labs Atom amp, however upon some research I can't find any confirmation that the unit has at least some sort of headphone protection circuit. Am I being too paranoid? I have read about some instances where amp's have fried headphones (not on an Atom amp tho).

So I am being way too overzealous? Are there any other amps with similar performance to the atom amp that have protection against DC voltage?

 

[Swtoby]

The JDS blog discusses this issue briefly. The Atom has a muting relay which prevents annoying thumps when you turn it on or off with the headphones plugged in. There is no DC offset protection, but JDS seems to feel this isn't a practical concern. I've had no issues with my unit.

 

[solderdude]

Am I being too paranoid?

When you have some very expensive headphones and have the misfortune of equipment dying on you then it could be something worth considering.
In the same price class I doubt there will be many comparable amps with DC protection or output capacitors.

 

[JohnYang1997]

I would say i feel safe using atom. lme49600 is pretty rugged not that easy to go puff. And i don't see anything else except power supply section could cause dc output. I won't hesitate to recommend atom.
However, except diy amps, I won't be happy to release an amp without dc protection if I make one. On off thump is annoying but not destructive. DC is destructive and usually it is swinging to rail when fail. Your baby headphone can go puff instantly. I have seen people have their headphones ruined because of loose opamp socket, failed output transistors, failed output ic. If relay is already implemented, a dc protection circuit may cost 1 extra dollar??(apart from occupying board space) That's just design decision. Again when something is at so low chance, you may just ignore it. So far we haven't heard disastrous incident happend to atom users. So may not be an issue after all.

 

[boogie]

Thanks for your input! You seem to know a good deal about amps, can I ask you if the output impedance of an amp bypasses/negates the output impedance from a dac?

For context, I’m thinking of pairing the atom amp with a Topping d10 which has an output impedance of 100 ohm’s while the atom amp has 0.7 ohm. My headphones have an impedance of 25 ohm.

Will sound to my headphones be affected at all by this combo?

Thanks again!

 

[Ratatoskr]

You need to be concerned with input (not output) impedance of the amp when matching to a DAC. Rule of thumb is the input impedance of the amp should be minimum 10 times the output impedance of the DAC, 100X is better. Most DACs match fine with the volume controls of amps.

Input impedance of Atom amp is the 10K Ohm volume control and line output impedance of the Topping is 100 Ohm so should be fine. The output impedance of the Atom is 0.1 Ohm which will work fine with 25 ohm headphones. Rule here is eight to one minimum. You won't have any impedance mismatch.

 

[platimn]

I would say i feel safe using atom. lme49600 is pretty rugged not that easy to go puff. And i don't see anything else except power supply section could cause dc output. I won't hesitate to recommend atom.
However, except diy amps, I won't be happy to release an amp without dc protection if I make one. On off thump is annoying but not destructive. DC is destructive and usually it is swinging to rail when fail. Your baby headphone can go puff instantly. I have seen people have their headphones ruined because of loose opamp socket, failed output transistors, failed output ic. If relay is already implemented, a dc protection circuit may cost 1 extra dollar??(apart from occupying board space) That's just design decision. Again when something is at so low chance, you may just ignore it. So far we haven't heard disastrous incident happend to atom users. So may not be an issue after all.

Sorry to revive an old thread, but does this mean all Topping amp products have DC protection? I returned my A30 Pro because it failed and got a Monoprice THX but I may have another go at Topping since I'm paranoid about DC offset now. AFAIK only Monoprice's top o'the line Cavalli amps have DC protection advertised so I assume they skimp on that elsewhere.