[qib]

A pictorial guide would be amazing for us newbies wanting to mod!
Quote:

 
  After reading all the information from this thread and trying to choose the most efficient set of changes that can have positive impact in my m-stage (but keeping it as simple as possible), I plan to:
  
- Replace input fuse with high quality one
- Check DC offset of my several sources and decide if I remove input caps Blue caps C22 e C23 and little Red C21 e C24 and replace by shunt wire
- Replace OpAmp PSU caps bypass (two red WIMAs in between opamp power caps) with 160V Vishay MKP 1837 0.01uF
- Replace the output 4 PS caps bypass (WIMA MKP 0.022uF) with 160V Vishay MKP 1837 0.01uF.
- OpAmp resistors R33/ R36 Bypass with 50V Kemet Ceramic 56pF
- Replace output resistors with 10R 1W Allen Bradley Carbon
 
   After this , try several opamps types / configurations with:
- Psu bypassing on opamp, using 50V Kemet Ceramic 1000pF and 160V Vishay MKP 1837 0.1uF    film cap.  across pins 4 & 8
- Class A 3.9KOhm polarization or not
 
  I would appreciatte to have your comments regarding my options and aditional changes you suggest I should try. Thank you.

 

 

[Mikesin]

Anyone? 

 
Quote:

Currently I have the OPA627AU (Class A Biased) in my M-stage, now I see theres also the OPA637AP (Class A Biased) on Tam Audio, it costs significantly more than the one I currently have, is there any differences and what are they? (Is it night and day different?)

 

 

[chicolom]

 
Quote:

Currently I have the OPA627AU (Class A Biased) in my M-stage, now I see theres also the OPA637AP (Class A Biased) on Tam Audio, it costs significantly more than the one I currently have, is there any differences and what are they? (Is it night and day different?)
 
Anyone? 

 
I assume it's a newer version that perhaps replaces the OPA627...?
 
 

 

[kyoshiro]

Quote:

 
 
I assume it's a newer version that perhaps replaces the OPA627...?
 
 

apparently its nearly the same and doesnt gain any improvements unless you're at higher gain from what i have been reading.
 

 

[Tribbs]

From the OPA627/637 datasheet here http://www.ti.com/lit/ds/symlink/opa627.pdf
 
OPA627AP Dual Inline Package (DIP)
 
OPA627AU Small Outline Integrated Circuit (SOIC)
 
According to the datasheet there is no difference.
Ask on what basis is there a difference?
 
It looks like they are using only one channel of the dual OPA627AP opamp using two OPA627APs.  Why?  Based on what measured data?
 
If you want a "better" opamp go to the OPA627BP.
If you really want to go to town get the OPA627BM or SM!
Be prepared to open your wallet.

 

[Majestyk]

Quote:

The two inputs should sound identical.
Why would they sound different?
 
 

 
The inputs on the Yamaha COULD be different volume wise or even hiss/noise wise.  I just haven't checked it out yet.

 

[Chris J]

Quote:

 
The inputs on the Yamaha COULD be different volume wise or even hiss/noise wise.  I just haven't checked it out yet.

Technically, they should be identical.
 

 

[DivergeUnify]

Dumb question: is this usb version DAC sufficient, or will cause a bottleneck?  I assume it would work just fine?...

 

[chicolom]

Quote:

Dumb question: is this usb version DAC sufficient, or will cause a bottleneck?  I assume it would work just fine?...

It works fine, but they're are better dacs.  Probably none for $30 though (maybe the FiiO D3). 

 

[DivergeUnify]

So my 325is and hd650s should sound pretty good through usb?

 

[Mad Max]

Even better with a better DAC. 

 

[Mikesin]

So there is no difference of my cheaper OPA627AU versus the OPA627AP and OPA637AP?
Also upgrading to the OPA627BP, would it be a significant difference that would be notice-able? 

 
Quote:

From the OPA627/637 datasheet here http://www.ti.com/lit/ds/symlink/opa627.pdf
 
OPA627AP Dual Inline Package (DIP)
 
OPA627AU Small Outline Integrated Circuit (SOIC)
 
According to the datasheet there is no difference.
Ask on what basis is there a difference?
 
It looks like they are using only one channel of the dual OPA627AP opamp using two OPA627APs.  Why?  Based on what measured data?
 
If you want a "better" opamp go to the OPA627BP.
If you really want to go to town get the OPA627BM or SM!
Be prepared to open your wallet.

 

 

[DivergeUnify]

Quote:

Even better with a better DAC. 

i plan on getting a better DAC in time.  Will this amp, paired with a proper DAC be able to drive other phones such as some of the orthos?   I might as well and try to be future proof while I'm at it
 
*******it I've only started browsing again for about 3 weeks and I'm already about to pull the trigger on some new gear

 

[genclaymore]

I just bought a Matrix M-Stage V2 from another user on these forums, Cant wait for it to get here.The amp I had before it was the Fiio E9. Gonna like the fact I have more room for op-amp rolling. Without having to put a flash light in my mouth while changing op-amps. Like I did with the E9.

 

[Chris J]

Quote:

So there is no difference of my cheaper OPA627AU versus the OPA627AP and OPA637AP?
Also upgrading to the OPA627BP, would it be a significant difference that would be notice-able? 
 

Gimme 24 hours or so, you've got me curious.
Don't worry, I really know how to read Op Amp datasheets.
I suspect the difference is packaging only. Nothing more. Probably no audible difference.