See Inline, I hope this works, cause I hate this new Forum Interface.
I apologize for confusing you with my previous posts. I will attempt to address your questions as systematically and thoroughly as possible in the hope that we might be able to determine the nature of the issue I am having with the Compass (Audio-GD is not replying to me anymore).
You keep saying that, and it appears you are trying to bring pressure to bear here.
I understand an iPod can't power full size headphones well, or really at all. I also understand IEM's are designed for a low output device like an iPod and do not need much to drive them. When I use the Compass to drive the IEM's I leave the VOLUME control at about 8:30 (if you were looking at a clock). I compared the Compass to the iPod and computer because both are not high end audio equipment and both do a better job reproducing music with the SE420's. The Compass, in my mind, should not produce any humming or buzzing no matter what headphones are used, if they are used at listening volume.
Not true, he can't make them work with everything. Humming can be a sign of being overdriven. Not saying that's for sure, but you're using a big piece of Hardware to drive IEM's.
You are correct that I did not buy a new Compass two weeks ago. I am fairly certain the model was discontinued a few months back. I paid for my compass March 30th, 2009. It probably arrived a few weeks later.
When the Compass arrived I used it almost exclusively with my AKG K701 headphones. The Compass was always set to the lower of the gain options. I could never get the optical setting to work with the Compass, so I use the USB from my computer to deliver the digital signal.
So, it worked fine one minute, you started using the IEMs and they buzz. Doesn't matter that they don't buzz with a POS iPod opamp. The real interest here is how they do with your 701s when you get them back working. As far as the optical not working. Don't take this the wrong way, but most people don't know how to switch the output of their soundcards. I've been sent a number of pieces of gear that the optical was austensibly not working and it was a Windows Control panel issue or a SC software issue with being able to switch the output. Not saying that is what is going, just something to consider.
Here's an important part. I believe I used the SE420 IEMs with the compass at some point. I do not remember hearing the buzzing I hear now, though I might have just never noticed it since music drowns it out at normal listening volumes. I am to uncertain to say whether I heard it or not.
That of course would be an interesting fact to KNOW.
As I state before, I had to send in the balanced to 1/4th inch connector I use with my balanced 701s, and thus, have been using the SE420 IEM's with the compass for the past nearly three weeks. I noticed the buzzing the first time I listened to music with the Compass.
You noticed it the first time you used it with the IEMs, not the 701s ever, Correct?
Allow me to clarify what the buzzing sounds like. The buzzing noise is just that, buzzing (or maybe a hum, I really don't understand there to be a difference between the two). Not static, not hissing, not noise. It is a buzzing that sounds like a medium frequency sound at a constant pitch. It is not piercing or low, but in the medium range of noises. It sounds like there may be an emphasis on the left channel of audio, but both channels have some buzzing. It is difficult to determine if one is louder than the other.
Does this noise only occur at high volume? NO. As I have tried to explain before it occurs at ALL volumes, regardless of the gain setting and regardless of whether the VOLUME is turned up. It does appear to become slightly amplified when the volume is turned up, but never rises above an annoying whisper (still clearly audible, but not amplified like music).
You might want to look over any wire connection in the box and see if any wire looks loose or a cracked solder joint.
The Bose headphones I used I can't really tell you much about. They were just over the ear Bose nonsense that my roommate uses. What I can tell you is that when I cranked the gain or volume or whatever it is called, the Bose produced a nice static hiss. The same static hiss you get with all headphones when the gain is increased. The Bose headphones raised the noise floor much higher than the K701's at the Compass's maximum volume however. They also raised the noise floor higher than the SE420's at the Compass's maximum volume. The Bose did not however reproduce the buzzing of the SE420's.
So, the bose don't buzz and the 701s don't buzz, n'est-ce pas? The place where hiss/noise occurs on a set of headphones will change with each set of different phones you use. Has to do with the impedance and sesnsitivity.
I also used a no-name cheap pair of Sony earbuds I listen to when I go to bed, and they produced the buzzing/hum that the SE420's experience when plugged into the Compass. The buzz/hum was at a much lower level than with the SE420's however.
I'm thinking that IEMs are not the strong suit of the Compass, nor really should they be. It is called a Headphone amp after all. Although, after I typed that, makes me remeber when the Chinese translation was EarAmp. Which adds at least one layer of amusement.
Can I listen to music? Yes I certainly can listen to music. Can I enjoy music? That really depends. I ran across this browsing Head-Fi a few days ago. I apologize to the author for not remembering her name.
The Compass buzz/hum completely destroys this experience and makes any music that employs silence un-enjoyable. The hum is still there with louder music, but difficult to detect because it is a much lower volume.
As I said before, I have taken extreme caution with the Compass and have never damaged it in any way.
Here is my laundry list of circumstances that produce the Buzzing/Hum:
- Placing unit in any location. Buzzing not from external RF noise
- Using "S" Super mode
- Earth HDAM
- Moon HDAM
- No HDAM
This bothers me, because I have no idea what running a system with part of the circuit missing would do to it. The fact that you know this fact, is cause for at least worry that you damaged it on my part. The HDAMs in themselves lend themselves to being plugged in halfway and backwards. That is an issue with a piece of gear that encourages experimentation like the Compass does.
- Increasing gain makes buzzing slightly louder
- USB, COAX, and OPT produce buzzing
- Using no input produces buzzing
- Buzzing heard with sensitive headphones like Sure SE420 (In ear headphones)
- Different power cords
Does not cause buzzing:
- Unit turned off
- switching unit to Pre-Amp only mode (not using DAC
So, you should make sure it is broken. That's the first thing. It is a headphone amp, does it work with headphones? The fact that your IEMs are buzzing/humming does not prove there is a problem to me. I don't know if you have noticed or not, but a common question on this forum about amps is "how does amp X work with brand X headphones". Secondly, you might want to parse over the Compass threads. I think there are two threads because the forum screwed up and I think a second was started. There is a place in there where a mod had to be done related to Super Mode use, I think. It might have been a hum issue. I didn't have the issue, so didn't pay much attention to it. Third, are you asserting that A-GD is failing to fulfill their warranty provided when you bought the unit? You are like at the 19th or 20th month of ownership and it seems they are saying they will fix it if you send it back, which I think was the original warranty. I understand it is expensive to send it back, but you are insinuating they are not supporting their product, so make your justification for that. It sounds to me that they said, send it back, we'll fix it. That's what all companies do. The issue is that "Large" companies in Asia have depots in many countries, A-GD hasn't progressed to that level yet. But it really comes back to, you need to make sure it is broken in some fashion. It may be just an incompatability with low impedance high sensitivity IEMs. That would be the real question for the thread here.
I got rid of my Compass or I would try it out. I didn't want to get rid of it, I just had too many other pieces of gear. I liked the Compass, a lot.