Matrix M-Stage amp review: simple, cheap, and excellent. - Page 235

That's the strange thing...

The Q701 sounds clear and normal directly through iphone's or PC's headphone jack, so I would assume it's not Q701's issue...

ER4P sounds normal with both PS3 and iphone as the source and M-stage in between, so I assume it's not the source or M-stage's issue...

The only possible explanation is that Q701 requires a better source than ER4P??

With gain as 0db, PS3->M-stage->Q701, I have to push M-stage's volume almost all the way up. Is that normal, or an indication of bad source?

Thanks!!

Change the gain to 18 or 20 for something like the Q701

Thanks.

Setting it to 20dB, the Q701 still sounds funny, and ER4P is unbalanced: left side is a lot more upfront than right.

I will probably try to go to a local stereo store and find a better source to test Q701 again...

Since it requires more power than ER4P to drive, it's possible that the distortion and amplification of source noise is much bigger, and thus the source needs to be much cleaner.... But based on what I read on this forum, that shouldn't be so dramatic... But again, I am not expecting different gain settings would mess up ER4P's balance, so anything is possible and only trial and error can tell...

Will definitely report back when I do have a chance to test again.
 

Quote:

Originally Posted by jc89 

Thanks.

Setting it to 20dB, the Q701 still sounds funny, and ER4P is unbalanced: left side is a lot more upfront than right.

 

I will probably try to go to a local stereo store and find a better source to test Q701 again...

Since it requires more power than ER4P to drive, it's possible that the distortion and amplification of source noise is much bigger, and thus the source needs to be much cleaner.... But based on what I read on this forum, that shouldn't be so dramatic... But again, I am not expecting different gain settings would mess up ER4P's balance, so anything is possible and only trial and error can tell...

 

Will definitely report back when I do have a chance to test again.
 

This is very strange indeed. If you had the imbalance in both the headphones and earphones it would be easy to track down. Good luck! 

This is probably not it, but are you sure it's not the headphone socket on the M stage?-Occasionally my K701 sounds weird and unbalanced when i first plug them in, but when i give the headphone jack a little spin in the socket it becomes normal again..

Just thought i would mention it. 

yeah i know.

I'm looking into it. Just thought it might be a possible answer for jc89's problem too.

You save my day!!

The problem is Q701's 3.5mm to 1/4 inch converter that comes with it!

I changed it to the old one coming with my AKG 240, and it solves the issue! It works with DT880's converter, too.

I'm so stupid.... in retrospect, the cause was quite obvious, when Q701 sounds better through iphone's 3.5mm headphone jack than M-stage's 1/4 inch output....

Thank you musicbased!

This is quite dissapointing on AKG's part... Good thing the headphone itself is not a lemon, just the converter...

about the unbalance... it's completely due to my noobiness and carelessness...

I didn't realize that the two sets of gain controls are controlling left and right channels separately... I thought they are for input 1 and input 2 separately.

I'm confused by this design though... Why would anyone want to have different volumes coming out from left and right sides?

Are there any technical reason for this design? 

Thanks!

Quote:

Originally Posted by hifimanrookie 


I dont know also...maybe just a joke of the designer?..but check my amp..its even worse!..i even have two volume knobs, two on-off switches and even two power cables..lolz..

Many other amplifiers have this same design on the gain switches. 

Quote:

Originally Posted by jc89 

about the unbalance... it's completely due to my noobiness and carelessness...

 

I didn't realize that the two sets of gain controls are controlling left and right channels separately... I thought they are for input 1 and input 2 separately.

 

I'm confused by this design though... Why would anyone want to have different volumes coming out from left and right sides?

Are there any technical reason for this design? 

 

 

Thanks!

Nobody wants two different volumes from left and right! 

They would have to use a more expensive switch than the little switches you see on the bottom of the M Stage.

So you could say it keeps the costs down.

Most people set gain to 10 dB with Q701 and leave it there.....forever.

I just compared 5 different phone pre-amps, they all have that funny feature: separate switches for left and right.

It's even worse, because you can adjust:

input resistance

input capacitance

pre-amp gain

subsonice filter

but all switches are separate for left and right! 

But once you set the switches the way you want them, you never change them unless you change to another phono cartridge.

Seems to be  mark of passage for M Stage owners, they all need to mix up gain settings.

Jc89, glad you got it figured out. Now open the case, remove the opamp, and replace with 637AP. I bet you'll like what you hear.

Quote:

Originally Posted by etys rule 

Jc89, glad you got it figured out. Now open the case, remove the opamp, and replace with 637AP. I bet you'll like what you hear.

Do NOT do this!

Under certain conditions (Gain set to 0 or 10 dB) the Op Amp will probably oscillate.

Stick to the OPA627 or any other unity gain stable Op Amp.