[dsavitsk]

Grado's web site says that 1mV will drive their phones to 98db. Can anyone verify that this is actually true? And if it is, does this suggest that an amp that can supply plenty of current and about 1 volt is more than enough?

 

[kramer5150]

Quote:

Originally Posted by dsavitsk Grado's web site says that 1mV will drive their phones to 98db. Can anyone verify that this is actually true? And if it is, does this suggest that an amp that can supply plenty of current and about 1 volt is more than enough?

really???

I cant even think of an amp that runs that low. PA2V2 needs 2.4 max.

 

[grawk]

Garrett,

You're comparing apples to oranges. Voltage in and voltage out aren't the same thing.

Most amps can drive the grados plenty loud. They like quality but don't require quantity of power.

 

[kramer5150]

Quote:

Originally Posted by grawk Garrett, You're comparing apples to oranges. Voltage in and voltage out aren't the same thing. Most amps can drive the grados plenty loud. They like quality but don't require quantity of power.

Right!!! I knew that

 

[Clutz]

Pssh. Since when is 98 decibels enough.

And Canada just scored against Sweden. Sweet.

 

[amb]

Grado's website is in error. What they meant is 1mW will give 98dB SPL. Since these have 32Ω impedance, and P = V^2 / R, solving for V gives you 177mV for the 98dB SPL.

 

[JahJahBinks]

Yes, sensitivity of headphones is rated mW/dB.

 

[Jam_Master_J]

That makes much more sense. Having sensitviity defined using mV seemed very wrong.

 

[ECM]

Speaking of grados, I emailed grado labs a while back about dc offset and they said my 125's could handle 100mV offset. This seems a bit high...

 

[Nisbeth]

100mV offset sounds about rigbht, but they are probably referring to the max. you can get away with without burning the drivers. I believe that much offset would impact the sound quality.

dsavitsk: The error in the sensitivity spec on Grado's website was discussed a few weeks ago on headwize. Morsel emailed Grado for clarification anjd they confirmed it should be mW

/U.

 

[dsavitsk]

Quote:

Originally Posted by Nisbeth dsavitsk: The error in the sensitivity spec on Grado's website was discussed a few weeks ago on headwize. Morsel emailed Grado for clarification anjd they confirmed it should be mW

Either way, so long as the needed volts are few. I am looking into a 2A3/45 based ultrapath without a driver tube for headphone listening. Rather than amplifying, it looks like I'll actually have a gain of a little less than 1. Well, that is, the tube will amplify, but the OPT will do the opposite, but I think I should be fine. I have more OPT reading to do before I am confident enough to buy the parts, but I think things should work out more or less -- maybe.

-d

 

[Garbz]

Headwize recently ran a very interesting thread on Grado's and their ratings, and actual performance. It was quite a long read too.

There was also a thread there about DC-offset. Headphones can handle an insane DC offset before the driver burns up realistically though before you see this it will audibly distort because of driver excursion. By insane I mean not the 20mV many state as a maximum safe buffer. I've frequently hit my 60ohm test phones with about 500mV for 10s of seconds at a time and they haven't burnt yet.

 

[bjackson]

I accidently hit my Shure E4s with 9volts for around 10 seconds or so... miss wiring a pimeta. They still work and sound as good as new... I was very suprised.

I noticed because they got really hot in my ear with no noise... wow....