Schiit Magni Headphone Amplifier - Page 92

Quote:

Originally Posted by xezi 

Not true. For example, my headphone is 32ohm/30mW max power. If you supply more, it will be damaged.

I guess he meant that given a certain volume control position the headphone will only draw as much current as it needs.

Quote:

Originally Posted by Asr 

The only way to "break" a set of regular dynamic headphones with the Lyr (low-impedance or not) is to take the headphones off your head and turn up the amp volume to max, using really, really loud music (dynamically-compressed material would help). That would definitely do it.

Which is exactly what I did, I mentioned the song I used was Redneck Vanilla by Zection, the drop of that song goes from a banjo to a very hard bass hit. Thats what broke the drivers, listen to it on some bassy headphones and you will get how it happened.

Quote:

Originally Posted by xezi 
Not true. For example, my headphone is 32ohm/30mW max power. If you supply more, it will be damaged.

 

It means exactly that.

Your 32 Ohm/30 mW example will just pull 30 mW from the Lyr - no more than that, which is what I meant. The Lyr won't try to force more power on it and the headphone won't try to take more either.

In "Turning up the volume does not mean the amp is sending more power to the headphones", I missed typing a word so it should've said "does not automatically mean". In instances when music is not being played, or is briefly silent, or really quiet, an amp isn't outputting as much power into a set of headphones as when the music is louder. That's what I meant.

Quote:

Originally Posted by xnor 
I agree to most of what you wrote but this doesn't make sense to me.

 

Volume is directly related to power. P = V * V / R. Turning up the volume, lets say doubling the output voltage, increases the power that is put out by a factor of 4.

 

Also, how do you define "powerful"? A tiny battery-powered amp can be quite powerful and clean, enough to ruin your hearing.

I wrote that as a response to the general attitude of Head-Fiers who think "This amp goes really loud, it's powerful!", which as we know is inaccurate. Pretty much every amp can push loud enough volumes to ruin anyone's hearing. However, not all amps are necessarily powerful enough to drive very inefficient headphones. For example, does a tiny 1.5V battery-powered amp have enough power to drive the Audeze and HiFiMan orthos without distorting or clipping at moderate volumes? Heck, how many 15V AC-powered amps have enough power to amp those headphones? IMO that's the true definition of "powerful", because most other headphones are really easily driven.

And I kinda already said it above, but volume is also a function of the music, not just the position of the knob. Seems like most people forget about that part. Heavily dynamically-compressed music won't require much volume boost and I wonder how many people would still attribute that to the amp.

If it goes loud it is powerful in my book. Powerful doesn't say anything about distortion, noise or the like.

I guess "powerful" is a very relative term. 10 mW can be crazy loud with certain headphones so it would already be too powerful. Others are insensitive/inefficient and will produce much lower SPL. That's why many amps have gain switches.

I think I've mentioned this before, but if you are getting hearing damage with the volume control below 10 or even 9 o'clock that's definitely too high gain. (I'm using the term "gain" here because "power" seems to have this "the more the better" overtone. What's the point of a lot of power if you cannot control it precisely or if it's not clean?).

Dick Olsher said regarding power amps that "the first watt is the most important watt."

I'd argue the same is true for headphone amps but replacing "watt" with "milliwatt", for most headphones anyway.

I didn't forget. 1 mW into the headphones is 1 mW regardless of the music. Sure, with heavily compressed music you don't have to turn up the volume control as much. Still, even a HE-6 doesn't need as much power as people say. 300 mW should be enough. No, you won't be able to damage your hearing instantly with that. Over a few hours, certainly.

Quote:

Originally Posted by xnor 

I agree to most of what you wrote but this doesn't make sense to me.

 

Volume is directly related to power. P = V * V / R. Turning up the volume, lets say doubling the output voltage, increases the power that is put out by a factor of 4.

 

Also, how do you define "powerful"? A tiny battery-powered amp can be quite powerful and clean, enough to ruin your hearing.

Correct equation.

However the "volume knob" is a potentiometer.  Thus you are turning Down the resistance (R) to increase the power (P)

Quote:

Originally Posted by Iamnothim 

Correct equation.

However the "volume knob" is a potentiometer.  Thus you are turning Down the resistance (R) to increase the power (P)

No, we're talking about output power. The volume pot comes (way) before the output stage, so it has nothing to do with the load resistance.

Also check the theory of operation of potentiometers. It's basically a resistor "split" in two and the total resistance of the pot doesn't change.

Let's hope op don't get mad with us taking a longer detour from topic... :)

But as long as P=V^2/R is correct, it doesn't imply the potentiometer is turned down. In fact,

it's usually the opposite in most designs, since the pot is usually placed in the input and,

the greater its value, the bigger is the input (usually dac output) voltage applied to the pre-amp

or 1st stage of the amp. This equation applies to the power available to the phones,

and its equivalent resistance.

About the headphone break event: if the knob was at 12 o'clock, for example. This defines,

regardless the headphone, the maximum power the amp will deliver. However, if the music

is silent at certain point, the power delivered to the phone is nearly zero, at that moment.

Following this tought, in the 1st chunk of the song, the instruments/melody were more 

hi-freq content. Due to that music's content, there was less spectral power in this freq,

so less energy was delivered to the phone.

When the bass line entered, a much bigger energy packet was driven to the phone. 

Remember that the pot is at the same position. Initially, the power was available, but not in use.

Now, let's extrapolate and think what if a hi-freq synthesized sinus, say 15kHz, was applied to the amp input.

With enough power, it could damage the phone as well, since the amp frequency response includes

this frequency range, them some.

To sum up, if enough energy with right spectral content (within the freq response of

the amp under analyisis) is applied to the amp input,

it will go through the amp, be amplified, and damage the out of spec load, 

in this case a headphone.

Quote:

Originally Posted by xezi 

Let's hope op don't get mad with us taking a longer detour from topic... :)

 

But as long as P=V^2/R is correct, it doesn't imply the potentiometer is turned down. In fact,

it's usually the opposite in most designs, since the pot is usually placed in the input and,

the greater its value, the bigger is the input (usually dac output) voltage applied to the pre-amp

or 1st stage of the amp. This equation applies to the power available to the phones,

and its equivalent resistance.

 

About the headphone break event: if the knob was at 12 o'clock, for example. This defines,

regardless the headphone, the maximum power the amp will deliver. However, if the music

is silent at certain point, the power delivered to the phone is nearly zero, at that moment.

 

Following this tought, in the 1st chunk of the song, the instruments/melody were more 

hi-freq content. Due to that music's content, there was less spectral power in this freq,

so less energy was delivered to the phone.

 

When the bass line entered, a much bigger energy packet was driven to the phone. 

Remember that the pot is at the same position. Initially, the power was available, but not in use.

 

Now, let's extrapolate and think what if a hi-freq synthesized sinus, say 15kHz, was applied to the amp input.

With enough power, it could damage the phone as well, since the amp frequency response includes

this frequency range, them some.

 

To sum up, if enough energy with right spectral content (within the freq response of

the amp under analyisis) is applied to the amp input,

it will go through the amp, be amplified, and damage the out of spec load, 

in this case a headphone.

good stuff.

Thanks

Quote:

Originally Posted by Aaron94 

I offered to get him some M80s but he said no, seems like hes just one of the lost ones.

 

And to clarify the song was Redneck Vanilla by Zection, the drop on it goes from a banjo to a intense hit, and I had it on 80% volume. Thankfully they werent on my head at the time or Id have some hearing problems. I skipped the opening 40 seconds of the song so I could hear the drop, turns out it was a bad idea, cant help but wonder if it would have been fine if I had let the headphones warm up on the opening sequence. 

 

 

Ah well, at least you tried. I'd not heard that song but listening to it I can understand why that could have caused problems 

 

Quote:

Originally Posted by xezi 

Couldn't retrieve Beats Solo HDs' impedance, even reading the user manual...

 

32 ohm maybe?

My guess would be 32Ω too, they don't like to publish that sort of thing, probably so you can't compare them..

Not sure if anyone cares, but the Magni drives the AKG K400 with ease. It seems to be the most power hungry headphone i've tried yet. A little harder to drive than my old K601 and Q701.

Needs to be 11 O'clock on the volume dial with everything maxed. K501/K500 and K400/K401 need about the same amounts of power I believe. I did the calculations last year I think and I was really surprised.

Nothing really lacking (that's not caused by the headphone itself!). Soundstage of the K400 seems even larger than that of my Q701 and old K601. It's more trebly than my Q701 for sure though.

Seriously is there ANY headphone that needs to be past 50% on the Magni with a good source (such as ODAC)?

BTW I could crank the Magni to 100% and it's not too loud. With every other headphone I would never ever ever do that. Not even my HD-650.

Strangely the Magni and K400 sounds just as smooth as my Headroom Micro. The K400 is really trebly to my ears though on my amps.

Well, volume potentiometer position is very relative of course. Meaning, not only is source a factor, but individual track levels due to mastering can vary quite a bit.

Gee this thread has died out. I am still using number 171 with my AKG 701s to great avail . Using a wide range of source gear as listed in my profile.

It is nice to have a relay in a headphone amplifier. None of my previous ones did.(besides of course speaker amps with ladder dropdowns for the HP)

If anything, this rig is too transparent.

Ditto with my 129 and LCD-2 Rev. 2's.

se

Quote:

Originally Posted by sunseeker888 

Well, volume potentiometer position is very relative of course. Meaning, not only is source a factor, but individual track levels due to mastering can vary quite a bit.

 

Gee this thread has died out. I am still using number 171 with my AKG 701s to great avail . Using a wide range of source gear as listed in my profile.

 

It is nice to have a relay in a headphone amplifier. None of my previous ones did.(besides of course speaker amps with ladder dropdowns for the HP)

 

If anything, this rig is too transparent.

Really enjoying mine,one of the best $99 I've ever spent on audio, but now I'm almost thinking if the Magni is this good, how much better would the Asgard 2 be? Damn you Head-Fi :)

Quote:

Originally Posted by defguy 

Really enjoying mine,one of the best $99 I've ever spent on audio, but now I'm almost thinking if the Magni is this good, how much better would the Asgard 2 be? Damn you Head-Fi :)

only one way to find out, goodluck wallet