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Matrix M-Stage amp review: simple, cheap, and excellent. - Page 311

post #4651 of 4904
Quote:
Originally Posted by Maxvla View Post

So, do we want to keep the HPA-2 talk in this thread instead of moving to the 2014 M-Stage thread?

The new HPA-2 has increased power due to lowering the output impedance from 15 ohms to 10 ohms, which drives the transistors harder. The unit runs noticeably hotter, so be careful how you have it placed. I will be doing a comparison soon, but expect most of it to be centered on the DACs for the version with the USB DAC. The amp section is mostly the same parts.


 I didn't see another thread, but would be more than happy to re-direct my inquiries to a more specific thread.

post #4652 of 4904
Quote:
Originally Posted by elwappo99 View Post

Hi! 

Have an older M-stage, Schiit Vali, and Emotiva A-100 on hand. I think the M-stage does a pretty good job with the HE-500. On medium gain the volume easily goes past to what I think of as comfortable listening levels. 
Was the Emo/Vali better though?
I used to have the Mini but went for the Mstage after selling it.
Do you feel like the headphone was loud but underamped (dynamics lacking, little bass, etc)?
Thanks;)
Edited by conquerator2 - 1/29/14 at 12:13am
post #4653 of 4904
Quote:
Originally Posted by blueangel2323 View Post

I didn't mean power in a technical sense (watts or whatever), but that +10db sounds subtly more powerful and dynamic. The difference is very slight. I do find that +18db does sound quite different though, in terms of sound stage, separation, and warmth. But yes, Nina is still hot. As ever.

Oddly enough, I don't hear a difference between 0, 10 and 18 dB of gain, (after volume matching) but I do not like 20 dB of gain.
Weird? Yes, I know. Weird!
post #4654 of 4904
Quote:
Originally Posted by Chris J View Post

Oddly enough, I don't hear a difference between 0, 10 and 18 dB of gain, (after volume matching) but I do not like 20 dB of gain.
Weird? Yes, I know. Weird!

18 sounded a lot more intimate than 10 to me, and thicker in the lower mids too.

post #4655 of 4904
Quote:
Originally Posted by conquerator2 View Post
 
Quote:
Originally Posted by elwappo99 View Post

Hi! 

Have an older M-stage, Schiit Vali, and Emotiva A-100 on hand. I think the M-stage does a pretty good job with the HE-500. On medium gain the volume easily goes past to what I think of as comfortable listening levels. 
Was the Emo/Vali better though?
I used to have the Mini but went for the Mstage after selling it.
Do you feel like the headphone was loud but underamped (dynamics lacking, little bass, etc)?
Thanks;)

 

Vali is a tough call. It definitely has a good synergy, but doesn't necessarily do well with bass heavy music. The Emotiva has a notable leg up on both in terms of detail and bass control/depth. 

 

I don't really get the impression of the HE-500 being underdriven by the M-stage in the typical signs that orthodynamics give.

post #4656 of 4904
Quote:
Originally Posted by blueangel2323 View Post
 

18 sounded a lot more intimate than 10 to me, and thicker in the lower mids too.

 

Maybe I should give it another go around the DIP switches!

post #4657 of 4904
Quote:
Originally Posted by Maxvla View Post

So, do we want to keep the HPA-2 talk in this thread instead of moving to the 2014 M-Stage thread?

The new HPA-2 has increased power due to lowering the output impedance from 15 ohms to 10 ohms, which drives the transistors harder. The unit runs noticeably hotter, so be careful how you have it placed. I will be doing a comparison soon, but expect most of it to be centered on the DACs for the version with the USB DAC. The amp section is mostly the same parts.

 

That don't make no sense.

 

Lowering the output impedance should make the amp more efficient, hence, run cooler.

I suspect the real change was they reduced the series output resistor.....assuming the output impedance really did drop when they revised to HPA-2.

post #4658 of 4904

 I can confirm one thing: It runs hot. Not Lyr hot, but definitely a lot warmer than most amps I've had. /end super technical analysis/

post #4659 of 4904
Quote:
Originally Posted by blueangel2323 View Post
 

18 sounded a lot more intimate than 10 to me, and thicker in the lower mids too.

My observation about the gain thing is that when you change the resistor setting you are raising or lowering the gain to the opamp section .i.e driving it harder or slower. Depending on the specific opamp in use this could have a sonic result. Secondly but less important is that as you raise the volume pot you are putting less of the pot in the circuit. If the pot was wide open it would be out of the circuit. As you decrease the setting you are introducing more of the effect of the volume pot (which should be minimal but may be audible for some). So there is a rational argument that as you raise the gain you are driving the opamp harder and may notice some change in the sound. I do hear a slight difference between 10db and 18db setting but it is slight to be sure. It is about finding the sweet spot for the opamp you have selected.


Edited by Chodi - 1/29/14 at 11:31pm
post #4660 of 4904
Quote:
Originally Posted by Chodi View Post

My observation about the gain thing is that when you change the resistor setting you are raising or lowering the gain to the opamp section .i.e driving it harder or slower. Depending on the specific opamp in use this could have a sonic result. Secondly but less important is that as you raise the volume pot you are putting less of the pot in the circuit. If the pot was wide open it would be out of the circuit. As you decrease the setting you are introducing more of the effect of the volume pot (which should be minimal but may be audible for some). So there is a rational argument that as you raise the gain you are driving the opamp harder and may notice some change in the sound. I do hear a slight difference between 10db and 18db setting but it is slight to be sure. It is about finding the sweet spot for the opamp you have selected.

Define "driving the Op Amp harder".

You are not really driving the Op Amp harder......whatever that means.

I would argue most people increase the gain and decrease the volume to compensate, so the Op Amp output voltage is still the same.
Or decrease the gain and increase the volume to compensate.
So they are actually changing the SPL they normally listen at.
So it's not being "driven harder".

Raising and lowering the gain actually decreases and increases negative feedback.
So you could argue:
Less gain = more feedback = less distortion i.e. less THD, less IM
Less gain also leads to wider bandwidth and a higher SNR.
Edited by Chris J - 1/30/14 at 4:23am
post #4661 of 4904
Quote:
Originally Posted by Chris J View Post


Define "driving the Op Amp harder".

You are not really driving the Op Amp harder......whatever that means.

I would argue most people increase the gain and decrease the volume to compensate, so the Op Amp output voltage is still the same.
Or decrease the gain and increase the volume to compensate.
So they are actually changing the SPL they normally listen at.
So it's not being "driven harder".

Raising and lowering the gain actually decreases and increases negative feedback.
So you could argue:
Less gain = more feedback = less distortion i.e. less THD, less IM
Less gain also leads to wider bandwidth and a higher SNR.

So...if I understand correctly you are saying that the opamp is working at a fixed voltage and that the resistor/gain change follows the opamp to attenuate the output of the opamp? Of course, the output of the opamp is feeding the the input of the transistor modules.

post #4662 of 4904
Quote:
Originally Posted by Chodi View Post

So...if I understand correctly you are saying that the opamp is working at a fixed voltage and that the resistor/gain change follows the opamp to attenuate the output of the opamp? Of course, the output of the opamp is feeding the the input of the transistor modules.

 



Hard to relate some of these comments to Negative Feedback, but I will try. It's more accurate to say the Op Amp operates at a fixed voltage gain determined by the DIP switches . The DIP switches adjust the amount of resistance from the output stage to the input stage.

So we are actually controlling the amount of Negative Feedback.
The DIP switches adjust feedback by changing the resistance from output to input in the Op Amp circuit.
Really, Negative Feedback is a method of improving many amplifier charateristics by returning a portion of the output back to the input of the Op Amp to cancel or reduce distortion, increase bandwidth and decrease output impedance and a few other things.

You can't really say the Op Amp operates at a fixed voltage, but you can say the amount of feedback determines the amount of Voltage Gain, or Voltage amplification.

0 dB of voltage gain means 0.1 Volts at the input = 0.1 Volt at the output. So gain is 1:1

20 dB of gain will work out to 0.1 Volts at the input = 1.0 Volts at the output. So you could say Gain is 10:1

It's a rather complicated topic.....................and involves something no one likes (except Sheldon Cooper) called "Mathematics".
Edited by Chris J - 1/30/14 at 9:44am
post #4663 of 4904
Quote:
Originally Posted by Chris J View Post
 
Quote:
Originally Posted by Chodi View Post
 

So...if I understand correctly you are saying that the opamp is working at a fixed voltage and that the resistor/gain change follows the opamp to attenuate the output of the opamp? Of course, the output of the opamp is feeding the the input of the transistor modules.

 



Hard to relate some of these comments to Negative Feedback, but I will try. It's more accurate to say the Op Amp operates at a fixed voltage gain determined by the DIP switches . The DIP switches adjust the amount of resistance from the output stage to the input stage.

So we are actually controlling the amount of Negative Feedback.
The DIP switches adjust feedback by changing the resistance from output to input in the Op Amp circuit.
Really, Negative Feedback is a method of improving many amplifier charateristics by returning a portion of the output back to the input of the Op Amp to cancel or reduce distortion, increase bandwidth and decrease output impedance and a few other things.

You can't really say the Op Amp operates at a fixed voltage, but you can say the amount of feedback determines the amount of Voltage Gain, or Voltage amplification.

0 dB of voltage gain means 0.1 Volts at the input = 0.1 Volt at the output. So gain is 1:1

20 dB of gain will work out to 0.1 Volts at the input = 1.0 Volts at the output. So you could say Gain is 10:1

It's a rather complicated topic.....................and involves something no one likes (except Sheldon Cooper) called "Mathematics".

Chris, we are actually in complete agreement. All I was saying is that the amount of voltage amplification through the opamp can possibly account for some sonic difference in the sound of the amplifier.Different opamps handle voltage amplification with slightly different specs so there is that factor also. So...someone claiming they hear a difference in the M Stage at different gain settings can't be tossed off as silly. Although those differences, if any, should be small.  I wasn't trying to launch this topic into Sound Science. 

post #4664 of 4904
Quote:
Originally Posted by Chodi View Post
 

Chris, we are actually in complete agreement. All I was saying is that the amount of voltage amplification through the opamp can possibly account for some sonic difference in the sound of the amplifier.Different opamps handle voltage amplification with slightly different specs so there is that factor also. So...someone claiming they hear a difference in the M Stage at different gain settings can't be tossed off as silly. Although those differences, if any, should be small.  I wasn't trying to launch this topic into Sound Science. 

 

 

Ohhhhh...........I happen to hate the Sound Science forum!

:veryevil:

Too much BS piled on top of BS for me thank you!

 

I have no problem with anyone hearing a difference in different Op Amps and different gain settings!   :D

post #4665 of 4904

You guys are overcomplicating it...

 

Headphone plugs into the hole in the front.  Turn the knob to the right to make it louder.  ;) 

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