[RJW1138]

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

 

[rickcr42]

Quote:

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!

We don't NEED headphone amps in all cases because it is totally system to system dependant,expectations and need dependant and musical taste dependant.
With Grado cans there is not a single audio device I have ever plugged mine (RS-1+Alessandro MS-1) into that could not drive them to full volume and that mostly with excellant sonics so in the strictest sense an amp is not needed,totally optional.
What an amp does bring to the table is more control over the electro-mechanical transducers much as goes on with the power amp/loudspeaker interface.This translates into (usually) a far better,more powerful bass line and superior note separation when the signal gets "busy" .This is when there are a lot of individual notes fighting for power so they can be heard as a distinct sound rather than just part of the sonic stew where you have a single overall "tone" but no real instruments until it is intentionally highlighted in the recording.

If you want to go past "just listening to the song" and deeper into the music where every note is as important as the overall sound then an amp is a plus.The available power and drive will allow each to take what it needs and still have some reserves for the unexpected which a dynamic medium like music is all about.Is this enough to be worth the added cost ? Totally up to the individual expectations combined with music taste.
Highly compressed pop music usually means an amp is a waste of good loot since all it will bring is the ability to play louder before clipping and that is actually DANGEROUS to our long term hearing.Blues and jazz you gain power that you would otherwise not have but not missed ecept in direct A/B evaluation.
We have a strange way of accepting lesser music and calling it good until we have the noticeablty better to compare it to and that not from memory but NOW.Again for some reason what we remeber becomes clouded by preconception and it is my belief we talk ourselves into things then rationalise them at the subconcious level because deep down we know we have system limitations we do not want to face because almost always it means $$$$$$

I find I can enjoy my music at all levels since my gear is mostly built/chosen to play music but what an amp adds to the mix is that startling thing that goes on where you think you know a song because you have heard it over and over and over then when you plug into an amp you find you really did not know it at all and this is a "new thing" rather than same old because there is content you previously never heard so had no idea it existed.

bottom line is let your ears be the guide and not fashion.If you don't need an amp cool.you just saved yourself a couple of hundred bucks (or more

).If you would like an amp yet can not yet afford one and you can still enjoy the music cool.But it is also my thought once someone hits on the amp/headphone sysnergy that works there is no going back to ampless all else being equal even though you can still enjoy the music without.

Just an opion and mine