RJW1138
New Head-Fier
- Joined
- Jan 15, 2005
- Posts
- 20
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- 0
Hey all,
As an experiment, I hooked up my headphones (Grado SR125) directly to the line level outs (not headphone out) on my CD player (Cambridge Audio 640C) through an RCA -> 1/4" stereo adapter, and I was surprised by what I heard. (I first tested my concept with an old junky pair to make sure that they wouldn't blow up, and satisfied that they were fine, proceeded to do so with my Grados).
Why was I surprised? Because they were LOUD! Too loud to be listened to! The level was much too loud to be listened to as is, probably about 7 or 8 dB louder than what I would consider to be a normal loud listening level. I was expecting it to be quiet! So, I put in a disc that I knew was recorded with a lower average level, and was actually able to listen to it, though it was still pretty darn loud. So, my first observation here is that 2V RMS line level is an excessively high level for these headphones.
My second observation is that, well, it sounded phenomenal! This is the most detail and the blackest, clearest background I've ever heard out of these components. My regular setup is the CD player connected to a NAD T742 receiver with Nordost Blue Heavens and using the headphone output on the NAD. The difference between these two setups is significant. It's much more transparent without the interconnects and receiver in the way. I love it! Too bad it's not a functional setup, unless I want to listen to literally ear-bleeding levels on most of my recordings.
So then, the obvious question is this: Why do we need headphone amps, when the 2V RMS line level is LOUDER than the level that I need to be driving these headphones with? I need an attenuator, not an amp!
Seriously, this is perpexling. Now, knowing a bit about these things, enough just to know what the possibilities are, but that I don't know anything about them, I'm assuming that his has to do with the types of loads involved. I know that my headphones have a 32 Ohm impedance, and I know that the pre-ins on my receiver (which should be the load seen by the line outs on my CD player) are much, much higher than that, in the tens of kilo-Ohms. However, I don't know the significance of this.
Am I damaging my CD player by running it hooked up to this low 32 Ohm load, or not?
Is my wish correct, that I could run these headphones directly off my CD player by putting an attenuator between them (a couple $ part) instead of my pricey receiver, or a headphone amp? I'm assuming not, otherwise why wouldn't everyone be doing it? So can someone PLEASE explain the science of this to me? I'd really love to understand it in all its technical glory.
Thanks a ton in advance,
Ryguy
As an experiment, I hooked up my headphones (Grado SR125) directly to the line level outs (not headphone out) on my CD player (Cambridge Audio 640C) through an RCA -> 1/4" stereo adapter, and I was surprised by what I heard. (I first tested my concept with an old junky pair to make sure that they wouldn't blow up, and satisfied that they were fine, proceeded to do so with my Grados).
Why was I surprised? Because they were LOUD! Too loud to be listened to! The level was much too loud to be listened to as is, probably about 7 or 8 dB louder than what I would consider to be a normal loud listening level. I was expecting it to be quiet! So, I put in a disc that I knew was recorded with a lower average level, and was actually able to listen to it, though it was still pretty darn loud. So, my first observation here is that 2V RMS line level is an excessively high level for these headphones.
My second observation is that, well, it sounded phenomenal! This is the most detail and the blackest, clearest background I've ever heard out of these components. My regular setup is the CD player connected to a NAD T742 receiver with Nordost Blue Heavens and using the headphone output on the NAD. The difference between these two setups is significant. It's much more transparent without the interconnects and receiver in the way. I love it! Too bad it's not a functional setup, unless I want to listen to literally ear-bleeding levels on most of my recordings.
So then, the obvious question is this: Why do we need headphone amps, when the 2V RMS line level is LOUDER than the level that I need to be driving these headphones with? I need an attenuator, not an amp!
Seriously, this is perpexling. Now, knowing a bit about these things, enough just to know what the possibilities are, but that I don't know anything about them, I'm assuming that his has to do with the types of loads involved. I know that my headphones have a 32 Ohm impedance, and I know that the pre-ins on my receiver (which should be the load seen by the line outs on my CD player) are much, much higher than that, in the tens of kilo-Ohms. However, I don't know the significance of this.
Am I damaging my CD player by running it hooked up to this low 32 Ohm load, or not?
Is my wish correct, that I could run these headphones directly off my CD player by putting an attenuator between them (a couple $ part) instead of my pricey receiver, or a headphone amp? I'm assuming not, otherwise why wouldn't everyone be doing it? So can someone PLEASE explain the science of this to me? I'd really love to understand it in all its technical glory.
Thanks a ton in advance,
Ryguy
