[BmWr75]

Quote:

For anyone using the M-Stage with a Beyerdynamic DT880 600 ohm, please let me know was the power from the M-Stage sufficient to power the beyers with plenty more reserve.  Thanks for your input.

YES, great combo.  

 

[One Fan To Another]

Hey, where are people normally getting their opamps from?  I got the Class A OP627AP from the usual place but what about the rest?
 
I'm mostly interested in hearing the OPA1641.  I'd also like to know if the Class A adapter that came with the dual OP627APs that coolfunguy sells is useable with other opamps.

 

[purrin]

The dual-to-single Class A adapter from coolfungadget takes DIP (the chips with the pins that you can stick in and take out). I believe the OPA1641 only comes in surface mount, which require soldering.
 
 

 

[Pratt]

Is there any danger in biasing the M-Stage into Class A, as in driving it too hard? It already runs warm/hot; I don't want to fry it or cut it's life short! lol

 

[purrin]

Quote:

Is there any danger in biasing the M-Stage into Class A, as in driving it too hard? It already runs warm/hot; I don't want to fry it or cut it's life short! lol

Only to the op-amp. Of course a catastrophic failure to the op-amp could lead to failures down the signal path. Most of the values you see recommended or implemented (as in coolfungadget's stuff) are fairly conservative and will keep the op-amp well within it's operating parameters.
 

 

[purrin]

Quote:

Also I'm wondering if there's other threads with more mods for the M-stage than this thread? I've perused this one from the beginning and it seems to mainly be focused on swapping Opamps.
 

 
Other mods have been mentioned, but I don't blame you since this thread has gone to 122 pages.
 

• Shunt the coupling caps - in other words, make the amp DC coupled from input to output (another BIG jump in transparency)
• Bypass the midsize PS caps (the 4x ~440uF that feed the output BJTs and the x2 that feed the opamp) with small WIMAs or similar under the PCB (extends treble and smooths it a tiny bit)
• Replace the midsize caps - you can select your choice of boutique caps (this may change the sound, possibly for the worse). Try different combos of  PS caps for the opamp and output transistor sections.
• Replace the big caps (this may change the sound, possibly for the worse)

 

[Pratt]

Quote:

Only to the op-amp. Of course a catastrophic failure to the op-amp could lead to failures down the signal path. Most of the values you see recommended or implemented (as in coolfungadget's stuff) are fairly conservative and will keep the op-amp well within it's operating parameters.
 

 
Ok, thanks! I've had the M-Stage for a year or so now but have yet to mess with it in any way. Partly that is because it sounds great to me stock, partly because I only listen to headphones 20% of the time anyway, and partly because I don't want to screw anything up, never get around to ordering anything, and am skeptical as to whether opamps make all that much difference in sound anyway.
 
 

 

[MilesDavis2]

Thank you.
 
Quote:

YES, great combo.  

 

 

[n00kie]

 
Quote:

 
Other mods have been mentioned, but I don't blame you since this thread has gone to 122 pages.
 

• Shunt the coupling caps - in other words, make the amp DC coupled from input to output (another BIG jump in transparency)
• Bypass the midsize PS caps (the 4x ~440uF that feed the output BJTs and the x2 that feed the opamp) with small WIMAs or similar under the PCB (extends treble and smooths it a tiny bit)
• Replace the midsize caps - you can select your choice of boutique caps (this may change the sound, possibly for the worse). Try different combos of  PS caps for the opamp and output transistor sections.
• Replace the big caps (this may change the sound, possibly for the worse)

 

 

 

[n00kie]

Nice listing! Do you think it's possible to handle this by someobody who's non-versatile in electronic system?

 

[purrin]

^ A good way to start is to construct your own CMOY:http://tangentsoft.net/audio/cmoy-tutorial/
 
You'll learn how to solder and de-solder pretty good after that. Move up to a DIY PPA and you'll realize similarities in the circuits between that and the M-Stage - and start to understand how most amps work. I'm not the genius behind the Class A mod for this amp - I got it from the PPA schematic. And I believe this sort of circuit goes all the way back to Nelson Pass.
 

 

[Sganzerla]

 I think I'll try the "remove the coupling caps" mod, but I need to make sure my NFB-3 DAC signal will not destroy my headphone, how can a person with very little knowledge (me) be sure this is not going to happen?

 

[purrin]

Quote:

 I think I'll try the "remove the coupling caps" mod, but I need to make sure my NFB-3 DAC signal will not destroy my headphone, how can a person with very little knowledge (me) be sure this is not going to happen?

Do you have multi-meter? Put it on VDC and measure the DC voltage from your DAC's outputs. Make sure the DC is zero or very close to it. A few mV should be OK. To double check, measure the DC component from the headphone out too.
 
Also, after you remove the big blue and small red box caps, remember to run straight wire across where the blue caps used to be. Make sure you have some soldering wick handy to remove excess solder.
 
Warning: this mod will change the tone of the amp - it will sound leaner. 
 

 

[Sganzerla]

 Thanks Purrin, I think I'll wait a little to see what my new powercords will bring to my system before trying this.
 
 My new Furutech GT2 USB cable brought everything a tone up, while improving transparency, so another step at this side may be too much for my system right now.

 

[castlevania32]

Looking for an upgrade of my m-stage. I actually have 2xOPA627AU class-a biasing mod from jtam's website. Would 2xAD797BRZ be the "best upgrade", or at least a substantial one ? Also, what is the difference between ARZ and BRZ and which one is better ?