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Am I the first owner ??? Qualia 010 !!! - Page 26

post #376 of 645
Is there a sensitvity measurement for headphones like for speakers. I know we talk about impedences, which are important for an idea of how hard a headphone is to drive. I wonder if you could do a measurement like decibels/watt at 5 cm.

BTW, what is the impedence of the Qualia. Is it really low? I have noticed that its harder to drive the Senn 650s than the R10. I guess the Qualia must be harder than those, huh?
post #377 of 645
Quote:
Originally Posted by einolu
i dont think sony will let you crash at their "crib" for 3 weeks like you guys are planning...
we got some odd stares just tramping downstairs with bozebutton's stuff - i can imagine this meet's reaction!
post #378 of 645
Quote:
Originally Posted by dolifant
Is there a sensitvity measurement for headphones like for speakers. I know we talk about impedences, which are important for an idea of how hard a headphone is to drive. I wonder if you could do a measurement like decibels/watt at 5 cm.

BTW, what is the impedence of the Qualia. Is it really low? I have noticed that its harder to drive the Senn 650s than the R10. I guess the Qualia must be harder than those, huh?
Rane has some kind of documents IIRC that explains how to understand that, and they ahve measure most of the ehadphones available today, justtake a look here

PDF here
post #379 of 645
Quote:
Originally Posted by dolifant
BTW, what is the impedence of the Qualia. Is it really low?
It is 70ohms
post #380 of 645
Quote:
Originally Posted by Sovkiller
Rane has some kind of documents IIRC that explains how to understand that, and they ahve measure most of the ehadphones available today, justtake a look here

PDF here
According to this my DT770 can go up to the threshold of discomfort, while the grados go up to the threshold of pain/thunder. yowza.


edit - and the HS25 can go up to irreparable damage. um, just great.
post #381 of 645
doliphant --

Getting volume from the 010 did not seem to be an issue -- if we cranked the Krell up more we'd be deaf, especially with the upper end extension and emphasis!

Driving it correctly to get it to perform properly is the difficulty. Some earlier remarks were posted about its specified requirements (amp output, THD, etc.).

One example, from Kevin Gilmore post on page 14:

"Here is a little more (directly from rudi's page)

Thech Specs ( lab measured)
Maximum Output: 500mW
Bandwith: DC -100.000 Hz within 0.3db
THD: 0.1% (output 3Vpp 1Khz -)

Now the sony specs.
Maximum power 1500mw impedance 70 ohms

Which would be 10 volts RMS for maximum dynamic range."

???

__________________

Sovkiller -

Bring your eager ears -- another critical perspective would be great!!

__________________

Jahn -

Oh, Yeah! Stares coming in ... and I remember feeling really creepy caravaning the stuff OUT -- with no escort from Josh!!!
post #382 of 645
Quote:
Originally Posted by kevin gilmore
quick pics

the first completed prototype
(warning huge)
http://gilmore.chem.northwestern.edu/dynahif2.jpg


mother of all power supplies
http://gilmore.chem.northwestern.edu/dynomiteps.jpg
(those are 1 foot floor tiles)

finished boards
(warning: huge)
http://gilmore.chem.northwestern.edu/dynahipro.jpg

parts parts i need more parts...
I must admit, those first pics of the new dynahi look very impressive.

I got something started here.
Mr. Gilmore is showing his new creation and you guys can't wait to organize a meet.
post #383 of 645
Thread Starter 
How to Understand about headphone sensitivity and power needed to be fully driven

---------------------------------------------------------------------------------

Doctor FTLD said; "the headphone specs are 100db 1500mW, so this headphone need at least 1.5W amplifier, better if 4-5 W!! " This guy probably dive 100mt to watch time, since on his watch is writen 100mt water proof!!

How much power must deliver an headphone amplifier? Simple, enough to fully drive the cans and not too much to damage cans and listeners hears if misadjusted.

First of all we must read properly the headphones specs. Sensitivity and maximum power are the most important figures to determine the amp power.

The cans builder use two ways to indicate it, Sennheiser and other German producer use the sound pressure per Vrms. For example the HD650 deliver 103db vith a signal of 1Vrms ( or 3Vpp ) 1Vrms on 300Ohm means about 3 mW. Therefore with 3mW output you have on you hears the sound pressure of 103db.

Sony and other jap builders make things easier, they calculate sound pressure directly in db * mW. Example the Qualia 010 is 100db for mW, this mean 100 db with only 1mW on 70 Ohm ( headphone impedance)

How much is 100db? 100db Is the level of noise of a train passing at 10mt or in a more audiophile way the maximum sound pressure in a classic music concert hall. So with 1mW and the related 100db of sound pressure you can hear a classic concert at natural sound pressure!! Incredible!!

What happen increasing power?

Doubling the power ( measured in mW ) means increase sound pressure of 3db ( decibels are logarithmics, decibels related to power dbw increase of 3 db at power doubling) therefore with a100db*mW headphone, like Qualia 010, you will reach 112 db ( the level of a live rock concert or techno disco) with only 16mW, and the threashold of pain and hear damages of 121db with 125mw, to use of this headphone with more then 125 mW is impossible and very dangerous for health

Therefore an amplifier delivering 500mW on 70 Ohm ( example of RP010 with Qualia 010 ) give four times more power of really needed by headphone This amplifier fully drive the headphone at ¼ of his power.

You say : "the builder indicate a maximum power of 1500mW, why?" Simple this mean that headphone burn at 2W, this do not mean that headphone must be driven at this limit. This is the safety limit! Since Qualia 010 is a very well built headphone the safety limit is very far from real usable limits.

A clear example of this is what declared in official Sony CD3000 specs: -104 db*mW/maximun handling power 100mW/ rated power 500mW-, this mean a sound pressure of 104 db with 1mW, a real listening limit of 100mW ( ~123db), and a headphone safety limit of 500 mW!
--------------------------------------------------------------------------

You can find it evene here: http://www.rudistor.com/soundsystems/hdpwr.htm,
post #384 of 645
Quote:
Originally Posted by kevin gilmore
I did. It is called the dynahi. Many people are building them now. A few
are finished. It was specifically designed for these headphones when i
first found out about them more than a year ago. It will put out
20 volts rms into 70 ohms which gives about 3db of headroom. It can output
5 watts of pure class A power into 70 ohms.

It has a thd of better than .002% at rated power.
DC to 100khz absolutely flat. -3db at 1mhz.
s/n of better than 100db.

Nope, specs are not everything. They are however a good place to start.
IIRC this project was presented here in headfi, around thanksgiving last year, (Octuber 2003) and you were working on it some time before, you evne offer it as a thnaksgiving present IIRC, look here what I don't remember is having heard of the Qualia at that time, it could be a really good amp, but designed for the Qualia???? Are you sure of that?.....LOL....
post #385 of 645
Quote:
Originally Posted by Nik
How to Understand about headphone sensitivity and power needed to be fully driven

---------------------------------------------------------------------------------

Doctor FTLD said; "the headphone specs are 100db 1500mW, so this headphone need at least 1.5W amplifier, better if 4-5 W!! " This guy probably dive 100mt to watch time, since on his watch is writen 100mt water proof!!

How much power must deliver an headphone amplifier? Simple, enough to fully drive the cans and not too much to damage cans and listeners hears if misadjusted.

First of all we must read properly the headphones specs. Sensitivity and maximum power are the most important figures to determine the amp power.

The cans builder use two ways to indicate it, Sennheiser and other German producer use the sound pressure per Vrms. For example the HD650 deliver 103db vith a signal of 1Vrms ( or 3Vpp ) 1Vrms on 300Ohm means about 3 mW. Therefore with 3mW output you have on you hears the sound pressure of 103db.

Sony and other jap builders make things easier, they calculate sound pressure directly in db * mW. Example the Qualia 010 is 100db for mW, this mean 100 db with only 1mW on 70 Ohm ( headphone impedance)

How much is 100db? 100db Is the level of noise of a train passing at 10mt or in a more audiophile way the maximum sound pressure in a classic music concert hall. So with 1mW and the related 100db of sound pressure you can hear a classic concert at natural sound pressure!! Incredible!!

What happen increasing power?

Doubling the power ( measured in mW ) means increase sound pressure of 3db ( decibels are logarithmics, decibels related to power dbw increase of 3 db at power doubling) therefore with a100db*mW headphone, like Qualia 010, you will reach 112 db ( the level of a live rock concert or techno disco) with only 16mW, and the threashold of pain and hear damages of 121db with 125mw, to use of this headphone with more then 125 mW is impossible and very dangerous for health

Therefore an amplifier delivering 500mW on 70 Ohm ( example of RP010 with Qualia 010 ) give four times more power of really needed by headphone This amplifier fully drive the headphone at ¼ of his power.

You say : "the builder indicate a maximum power of 1500mW, why?" Simple this mean that headphone burn at 2W, this do not mean that headphone must be driven at this limit. This is the safety limit! Since Qualia 010 is a very well built headphone the safety limit is very far from real usable limits.

A clear example of this is what declared in official Sony CD3000 specs: -104 db*mW/maximun handling power 100mW/ rated power 500mW-, this mean a sound pressure of 104 db with 1mW, a real listening limit of 100mW ( ~123db), and a headphone safety limit of 500 mW!
--------------------------------------------------------------------------

You can find it evene here: http://www.rudistor.com/soundsystems/hdpwr.htm,
the health limit is 80db.
if you listen to sounds constantly all day above 80db, you'd (slowly)become deaf.

the pressure level of 116 db is like a f16 taking off right in front of you! dangerously loud!

In other words, you don't need that much power to play it loud.

especially with headphones it is tempting to play loud but it'll kill your ears and hearing in long terms.

In most cases the amp starts clipping before you can fry your headphone anyway.

Nik,
you are getting your amp tomorrow isn't it?
post #386 of 645
power supply wired (24.5 lbs)

http://gilmore.chem.northwestern.edu/dynomiteps2.jpg

now waiting for the rest of the parts.


Quite clearly and quoted elsewhere to make sure the peaks are not
clipped or compressed at least 10db of amplifier headroom is necessary.
But there is more to the picture like balanced rise and fall times, damping
factor and other factors. So this amplifier is not really as much overkill
as it looks.

There is no way i can recommend even short periods of spl's that exceed
95 db. But there have been plenty of times especially with the wilson
speakers where i have exceeded this level.

The qualia line was announced about 1.5 years ago. I'm actually more
interested in the qualia-004, but sony found a way to break that.
post #387 of 645
Quote:
Originally Posted by kevin gilmore
power supply wired (24.5 lbs)

http://gilmore.chem.northwestern.edu/dynomiteps2.jpg

now waiting for the rest of the parts.
Mr. Gilmore,

Does this mean you designed a two box version?
a box with the powersupply and a box with the amp itself?
post #388 of 645
So, Nik,

From what you say, the Qualia can be fully driven by a headphone amp that outputs 500mW. In fact that is 4X the useful power required, maybe really 30X, since you should not listen for long at even 112 dB (16mW).

So an amplifier whose first 16, maybe 32mW (115dB) is clean and linear should drive the Qualias well. If, as KG says you need 10dB headroom to do this, that would mean being able to drive the cans easily to, say 125 dB,meaning roughly3 more doublings of the power, equaling 256 mW. So a 500mW amp seems quite adequate. I bet there are many that can do that, even into an impedance of 70 ohms. Does it really take a monster amplifier? The calculations you gave seem to say not. Of course, there might be unfavorable phase angles at certain frequencies, like speakers.

What is all this discussion about needing huge power supplies, etc.?

I can understand wanting a very good quality amp for a great set of cans, but power quantity is not the real issue, is it?
post #389 of 645
Quote:
Originally Posted by dolifant
So, Nik,

From what you say, the Qualia can be fully driven by a headphone amp that outputs 500mW. In fact that is 4X the useful power required, maybe really 30X, since you should not listen for long at even 112 dB (16mW).

So an amplifier whose first 16, maybe 32mW (115dB) is clean and linear should drive the Qualias well. I bet there are many that can do that, even into an impedance of 70 ohms. Does it really take a monster amplifier? The calculations you gave seem to say not. Of course, there might be unfavorable phase angles at certain frequencies, like speakers.

What is all this discussion about needing huge power supplies, etc.?

I can understand wanting a very good quality amp for a great set of cans, but power quantity is not the real issue, is it?
unless it is needed to get "pure" sound.

a 300 watt high end amp is not driven to it's limits but the power is used to have a huge reserve to be able to tackle fast peaks and linearity.

In fact;
a 8 watts or 15 watts amp wich produces high quality sound is even able to fill a normal sized room with music. that's why alot of tube amps are not rated that high watts wise.
post #390 of 645
Take a look at Mikhail's latest monster power supply.
Silly, maybe. But the people who have bought it say it
definitely sounds better than the standard version.
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