[wildwestgoh]

  Looks great! I found those opamps on eBay, but I'm not sure who's the manufacturer and what's the "scene name" for these.
In their specs the max. operating voltage would be +/-/22V, so there should be no problems to operate perfectly in HPA-3B.
 
Can you please measure the DC-output on single & balanced output plugs (without music playing and no source connected to inputs)? Also, any change of getting some scope plots or an RMAA, if possible please?
 
And ofc, how do they sound?

My friend got it on Taobao, so I tempted to listen after the other said it's pretty darn clean opamp.
I just got few quick listen and compare it against my LME49990.
Overall, more bass and body (warm?) than LME49990, treble is a bit peaky at a certain high frequency, not all but noticeable at very high frequency, mid-high is laid back compare to LME49990, mid however remain similar throughout all the tracks I listen to.
Some said it's colored cause I am listening to it using my T1 (gen 1), for T1 is known to lack of amount of bass, and that opamp brings out the bass like a boss, like listening to gen 2 of T1 at some point.
Those are quick comparison, on shopping complex ambient, take it as grain of salt as 2 of my friends has different perspective of the sound.
I also do not know what kind of chips they use... I will update once I found out from my friend.
 
And about your request for measurement, I am sorry cannot help you because I don't own all of those stuff... haha, unless someone can sponsor me.

 

[canthearyou]

Spoiler

Something came in today.

Does the cover for with those op-amps?

 

[wildwestgoh]

Does the cover for with those op-amps?

Erm... do you mean does the top cover able to close properly? The answer is "no".
The opamp are much higher than we expected, and with the way it was soldered into the sockets, if only they could just solder into 1 socket only would make it a just-nice height.
My friend did suggest to drill a hole for the opamps through the thick cover... lol.

 

[canthearyou]

Erm... do you mean does the top cover able to close properly? The answer is "no".
The opamp are much higher than we expected, and with the way it was soldered into the sockets, if only they could just solder into 1 socket only would make it a just-nice height.
My friend did suggest to drill a hole for the opamps through the thick cover... lol.

Yes, lmao! I'm not even sure what the heck I typed.

 

[loserica]

Happy New Year!!!

 
I replaced the stock Op-amp with MUSES02 (I have the HPA-3U) and as he said Raoul the sound it has got consistency (a better texture especially on highs and female voices). Is felt a better instrument separation and it increased the soundstage depth.
I can perceive more micro details. Absolutely zero audible hiss/noise! It is a worthy upgrade.

 

[xenithon]

Hi all. Wanted to ask if anyone has had more opportunity to listen to this amp paired with the HD800 and what their impressions were in terms of synergy. The HPA03B is meant to have some warmth to it, which can possibly offset some of the HD800's edge?

 

[ruinedx]

Hi all. Wanted to ask if anyone has had more opportunity to listen to this amp paired with the HD800 and what their impressions were in terms of synergy. The HPA03B is meant to have some warmth to it, which can possibly offset some of the HD800's edge?

The headphone guru review said it paired fantastically with HD800:
http://headphone.guru/the-impressive-m-stage-hpa-3b-balanced-headphone-amplifier/

 

[loserica]

I replaced the 6th Nichicon caps with Elna Silmic II (470uf/25V) and after a few days of listening, compared with Nichicon Muse Elna sounds better! 

 I notice a richer, lush texture , bass has a powerfull presentation, good impact. I love how Silmic presenting the sound. It is laid back, warmth mid-range and relaxing. 

 

[alpovs]

  I replaced the 6th Nichicon caps with Elna Silmic II (470uf/25V) and after a few days of listening, compared with Nichicon Muse Elna sounds better! 

 I notice a richer, lush texture , bass has a powerfull presentation, good impact. I love how Silmic presenting the sound. It is laid back, warmth mid-range and relaxing. 

Can anyone briefly explain how electrolytic capacitors in an amplifier can affect sound? It's probably off-topic but it came up here.

 

[alpovs]

  Here we go! Just finished modding my HPA-3B.
 
My main reason for this mod was to lower the voltage to allow me to swap other op-amps. I went with Sparkos Labs discrete regulators in 15V.
 
I started by removing all necessary components. 

 
Here is the new discrete regulator mounted to the heatsink. The reg is not insulated so I used an adhesive thermal pad, some thermal paste and a nylon shoulder washer to make sure it was well insulated.

 
I had to make room for the new regs and that meant moving the caps closest to it.

 
 
As you can see in the above photo, the new reg interferes with the capacitor directly in front of it. To remedy this I ordered a pair of ELNA Silmic II caps. I angled the wire leads to offset the position of the cap.

 
Here is the completed board.

 
And here it is ready to test. I am running Sparkos Labs discrete op-amps.

 
Here it is in its fan cooled case I did a few weeks ago.

 
I want to thank Mr. Andrew Sparks of Sparkos Labs for his patience in answering all my questions.
 
I will get some listening impressions in a little bit.

canthearyou,
 
If you still monitor this thread... I checked the specs of the Sparko's Labs SS3602 OpAmps and they call for +/- 18 Vcc Max which is the original voltage in the HPA-3B. That means one wouldn't need to replace the voltage regulators if they wanted to use Sparko's Labs SS3602 OpAmps only. Right? I understand you wanted to "roll" different OpAmps in your HPA-3B. 
 
And based on your one post you ran the Sparkos in unmodified HPA-3B before you modded it. Did you notice any problem? High heat? The Sparkos call for 18V max and absolute maximum of 22V.

 

[raoultrifan]

 
Can anyone briefly explain how electrolytic capacitors in an amplifier can affect sound? It's probably off-topic but it came up here.

 
https://ez.analog.com/thread/3465, http://sound.whsites.net/articles/capacitors.htm etc. Everyone agree that capacitors, but also any other devices placed in signal path will alter the sound. This was proved, so no argue here.
 
Well, if capacitor is not in signal path, let's say is in the power supply than all it matters is it's ESR and filtering capacity (how much amps can sustain for that voltage). most likely best sounding caps in signal path might no be the best for use inside power sources. 
 

  canthearyou,
 
If you still monitor this thread... I checked the specs of the Sparko's Labs SS3602 OpAmps and they call for +/- 18 Vcc Max which is the original voltage in the HPA-3B. That means one wouldn't need to replace the voltage regulators if they wanted to use Sparko's Labs SS3602 OpAmps only. Right? I understand you wanted to "roll" different OpAmps in your HPA-3B. 
 
And based on your one post you ran the Sparkos in unmodified HPA-3B before you modded it. Did you notice any problem? High heat? The Sparkos call for 18V max and absolute maximum of 22V.

 
Looks like SS3602 can work to 36V indeed, so if you can give'em a try just be sure to monitor temperature and check for any possible oscillations. God luck and keep us posted!

 

[alpovs]

   
https://ez.analog.com/thread/3465, http://sound.whsites.net/articles/capacitors.htm etc. Everyone agree that capacitors, but also any other devices placed in signal path will alter the sound. This was proved, so no argue here.
 
Well, if capacitor is not in signal path, let's say is in the power supply than all it matters is it's ESR and filtering capacity (how much amps can sustain for that voltage). most likely best sounding caps in signal path might no be the best for use inside power sources. 
 
 
Looks like SS3602 can work to 36V indeed, so if you can give'em a try just be sure to monitor temperature and check for any possible oscillations. God luck and keep us posted!

I would be surprised if this amp had capacitors in the signal path. I am not sure what loserica meant by saying "I replaced the 6th Nichicon caps". Probably just 6, not 6th. Maybe some of them could be the shunt capacitors, given the number is not 2, 4 or 8. I doubt it could affect the sound if those capacitors were not in the signal path (if there are any). But point taken - I can see how it can matter if there are capacitors in the signal path.
 
I don't have the amp to try the Sparkos. I am only thinking about it.

 

[raoultrifan]

He replaced power supply caps with better ones (able to sustain mode ripple current); that should decrease ripple at opamp pins.

 

[alpovs]

  He replaced power supply caps with better ones (able to sustain mode ripple current); that should decrease ripple at opamp pins.

How do you know? Wouldn't the two huge caps be the power supply ones. 470uF seems too little for power supply. I can see 6 smaller caps on pictures. I think they must be what s/he is talking about. Two of them could be the shunt ones. Don't know what the other 4 do.

 

[raoultrifan]

The 6 caps are part of the power supply, just their location is after power regulators (JRC/NJM 7815/7915). The only caps in signal path are the WIMA MKS that are replaceable too, of course: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/45#post_12120336. Anyway, it's a good thing to upgrade parts in any amplifier, especially caps, as long as specs are better...of course.