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Matrix M-Stage amp review: simple, cheap, and excellent. - Page 250

post #3736 of 4833
Quote:
Originally Posted by Suopermanni View Post

Hey guys, I would like to know how much power the M-Stage outputs at 50 ohms? I'm only asking this as someone asked for my M-Stage and wants to know this before they make a decision on whether to purchase it.

There is a list with specs here http://www.head-fi.org/products/matrix-m-stage

400mW in 60 Ohms
post #3737 of 4833

I just got an m-Stage (amp only), and it has a low-level hum that is probably at 60Hz.  It's there regardless of what's plugged into either input, or even if there is nothing on the inputs.  Its level isn't changed when I change the gain dip switches, and it doesn't change with the volume know (0 - full, hum is the same level).  It also doesn't go away if I plug directly into the wall, or into a power strip, or into a computer UPS, or another wall plug in a different room.  (I haven't tried a different house -- that's a 'to-do').

 

I've searched this thread and several others.  The only idea I saw was to tighten and loosen the screw on the bottom of the case, which I believe holds the transformer in place.  That didn't help.  I opened up the case because...well, who can resist doing that when they have a problem, and didn't see anything obvious.  The op-amp was well-seated.

 

BTW, I only hear this with my 1964Ears V.3s, not with my Panasonic RP-HFT600 -- that may be an isolation factor as I have fantastic isolation with the V.3s and the Panasonics may be allowing enough ambient noise in to mask the hum.  I'll check that tonight when the house should be quiet enough to tell.

 

Any ideas?


Edited by LCMusicLover - 2/24/13 at 2:31pm
post #3738 of 4833
Quote:
Originally Posted by LCMusicLover View Post

I just got an m-Stage (amp only), and it has a low-level hum that is probably at 60Hz.  It's there regardless of what's plugged into either input, or even if there is nothing on the inputs.  Its level isn't changed when I change the gain dip switches, and it doesn't change with the volume know (0 - full, hum is the same level).  It also doesn't go away if I plug directly into the wall, or into a power strip, or into a computer UPS, or another wall plug in a different room.  (I haven't tried a different house -- that's a 'to-do').

 

I've searched this thread and several others.  The only idea I saw was to tighten and loosen the screw on the bottom of the case, which I believe holds the transformer in place.  That didn't help.  I opened up the case because...well, who can resist doing that when they have a problem, and didn't see anything obvious.  The op-amp was well-seated.

 

BTW, I only hear this with my 1964Ears V.3s, not with my Panasonic RP-HFT600 -- that may be an isolation factor as I have fantastic isolation with the V.3s and the Panasonics may be allowing enough ambient noise in to mask the hum.  I'll check that tonight when the house should be quiet enough to tell.

 

Any ideas?

 

That's probably a function of the very high sensitivity of the 1964Ears. Is it noticeable when playing music, as well?

post #3739 of 4833

Shows up in quiet passages, especially with acoustic music, or solo piano classical.  It's funny about the sensitivity thing -- the Panasonics are also very sensitive -- I use them both on the same (lowest) gain setting.  Comfortable listening level on the IEMs is around 8:00 - 10:00, on the Panasonics it's about 9 - 11.

 

But that somewhat lower sensitivity, coupled with the much lower isolation seems to eliminate the problem.

 

Funny thing is, I bought the mStage because I was having trouble with the EF2A playing low enough without running into channel imbalance, but the EF2A is dead quiet, even with the 1964Ears, up to about 12:00 when I start noticing some hiss.  But at that setting, the EF2A's gain would have already made me deaf or killed me.  The 'zero' point on that volume pot is about 7:30, and I couldn't listen to it much above 8:30, at which point the channel imbalance has just resolved itself.  So I traded one problem for another.

 

I know everybody says 'you don't need an amp with such sensitive IEMs' but I do need one in order to listen to computer audio through a DAC, unless I want to control the volume in iTunes, which is sub-optimal for several reasons.

 

I just want a clean, resolving low-gain amp that isn't noisy.  Too much to ask?


Edited by LCMusicLover - 2/24/13 at 9:34pm
post #3740 of 4833
What dac are you using with it? If your source volume is at 100% does the hum persist if you lower it to 50-60%?

Since you mention it's a hum, and not a hiss, it may actually not be sensitivity dependent....could be some kinda ground loop issue instead. I know you've tried different outlets, but that's about all I can think of.
post #3741 of 4833

Centrance DacPort LX, but the Dac doesn't matter --- it's there even if nothing is connected to the inputs.

 

And yes, it's definitely a hum.


Edited by LCMusicLover - 2/25/13 at 8:17am
post #3742 of 4833

You may be picking up magnetic interference on your headphone signal cables. You say it is not dependent on signal presence?

 

How about with the volume control - does it get louder or softer through the headphone when you change the gain? Is it in both channels or just one?

 

If not - you should try re-positioning your headphone cable, or changing it, if that is possible.

 

Otherwise - it sounds like you have a bad capacitor in your power supply.

post #3743 of 4833

@jkorten

 

Correct, not dependent on signal presence -- still there when there is nothing connected to either input.

 

Also, gain setting (either on volume knob or DIP switch settings) has no effect.  I do have 2 othe sets of cables, although the set I'm using are BG-Audio Starlight, and have performed well with other amps (E11, EF-2A, VAMP, iPod & iPhone). I'll try other cables tonight when I get home.

 

@All -- can anyone confirm no hum with low impedance, highly sensitive IEMs? Mine are 1964Ears V.3s

post #3744 of 4833
Quote:
Originally Posted by LCMusicLover View Post

@jkorten

 

Correct, not dependent on signal presence -- still there when there is nothing connected to either input.

 

Also, gain setting (either on volume knob or DIP switch settings) has no effect.  I do have 2 othe sets of cables, although the set I'm using are BG-Audio Starlight, and have performed well with other amps (E11, EF-2A, VAMP, iPod & iPhone). I'll try other cables tonight when I get home.

 

@All -- can anyone confirm no hum with low impedance, highly sensitive IEMs? Mine are 1964Ears V.3s

I have to admit my mstage didnt like my westone um3x also..still dont know why...i thought it was because of my source, the hm602. I heared a hum also..with my hm300,400, 500 and my beyers mmx300 i didnt have any problems..dead silent!! So maybe the mstage is choosy bout high sensitive iems? My 337 hates iems also by the way..did u try another powercord? Or put the powercord directly into the wall?sometimes that helps..if u dont have anything connected and u touch the imput rca connectors..do u hear change of humming?

post #3745 of 4833

I've tried different plug-in options (different socket, USP, surge protector/line conditioner) to no avail.  And I actually just received a new DAC (Ultra-Fi DAC-41) with which the seller included a Ridge Street Audio power cord.  That didn't help either.

 

BTW, I absolutely F*&$%NG love the Ultra-Fi DAC.  It's hands-down the single biggest upgrade I've made to my system since I went from cheap ear buds to ER4Ps.  I mean it JUMPED out at me with the first track I played.

 

I immediately noticed three big differences:

 

1. Much more sustain on piano music, also on acoustic guitar.

 

2. Much more spaciousness in the music as a whole -- it actually seems like a completely different sound stage.  On music I've listened to many times, the instruments moved apart and re-positioned themselves.

 

3. More detail overall (not always a good thing).  For example, if you listen to the Jefferson Airplane song 'Today' from Surrealistic Pillow, the end is just a mess.  It's a quiet acoustic number for the first maybe 2 minutes (single voice, tamborine & guitar). Drums come in, and slowly become louder and louder, as they also add backing vocalists.  The levels are too high, so the last minute or so is more and more distorted.  But with the Ultra-Fi, you can hear each instrument and its distortion separately :)  It's actually kind of wierd.  There are lots of positive examples, where with my DacPort, the music just got too thick and jumbled together, while the Ultra-Fi keeps everything separate.  (Cranberries Zombie is one example).

 

But one problem is that I tend to want to listen at lower levels, since I can still hear all the music, but as a result I hear the my m-stage's hum more in quiet passages, It's actually enough worse that if I can't solve it, I'll have to move to a different amp, which is unfortunate, since I really like it otherwise. 

 

If I have to move on, I'm thinking about a Meier Corda Jazz (extremely low output impedance).

post #3746 of 4833
I do hear an extremely faint hum when I use my Shure SE210 IEMs with the M Stage. Damn!

I hear no hum when I use my iBasso D12 running off batteries. biggrin.gif

But my FiiO E17 has a faint buzzy whine to it, and I'm running it off battery! Damn!
My FiiO E09K has a very faint hiss.

Just a suggestion:
use a good battery operated headphone amp.
I don't have a lot of experience with IEMs.

I normally use the SE210s with my iPod........which runs off batteries!
post #3747 of 4833

Update -- changing cables didn't help.

post #3748 of 4833
Quote:
Originally Posted by LCMusicLover View Post

Update -- changing cables didn't help.

 

I would not expect changing a headphone cable to fix this.

Or an interconnect cable either.

 

Sounds like your problem is power supply noise.

I don't think the M Stage was designed to drive IEMs.  frown.gif

post #3749 of 4833

Yep i think so also..so good reason to buy urself a hifiman full size can nowwink.gif

post #3750 of 4833

Stupid question, are you sure you're at 0 gain?

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