burdie said:

  Discrete opamps is one of the way to improve sound, but right now I am quite satisfied with LME49720 on 3B.
[...]

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Hi burdie, 
 
I recently got 2xV5-duals from BURSON and I'm so waiting to test'em in my HPA-3B. I only did a test with my Objective2 headamp and I couldn't believe this solid-state op-amp is able to provide more details for O2 when used in voltage-gain stage. I'm so hoping I'll have the time to test'em both in my HPA-3B, but that means time to change power regulators first, to decrease voltage to +/-15V.
 
Regards, 
Raul.

raoultrifan said:

   
Hi burdie, 
 
I recently got 2xV5-duals from BURSON and I'm so waiting to test'em in my HPA-3B. I only did a test with my Objective2 headamp and I couldn't believe this solid-state op-amp is able to provide more details for O2 when used in voltage-gain stage. I'm so hoping I'll have the time to test'em both in my HPA-3B, but that means time to change power regulators first, to decrease voltage to +/-15V.
 
Regards, 
Raul.

Click to expand...

If the outcome is good, it will be great for all the 3B owners.

Well, someone already did this test and even didn't bothered of replacing power regulators: http://www.audiofanatyk.pl/recenzja-wzmacniacza-dyskretnego-burson-supreme-sound-v5/; looks like both V5s survived this test at +/-18V and this is a good thing I'd say. Test looks very promising, but until I'll do a test myself with V5s and my HPA-3B I will not be able to comment (also, I'm not sure the upfront case will fit, because the height of V5 is too much, but I'll see about this soon).

raoultrifan said:

  Well, someone already did this test and even didn't bothered of replacing power regulators: http://www.audiofanatyk.pl/recenzja-wzmacniacza-dyskretnego-burson-supreme-sound-v5/; looks like both V5s survived this test at +/-18V and this is a good thing I'd say. Test looks very promising, but until I'll do a test myself with V5s and my HPA-3B I will not be able to comment (also, I'm not sure the upfront case will fit, because the height of V5 is too much, but I'll see about this soon).

Click to expand...

Hi Raul,
Have you ever check on the actual voltage supply to opamps? We knew the power regulator supplied 18V but have yet to find out the exact voltage for opamps.
If it still supply roughly 18V to opamps, a minor mod to put DC step down voltage regulator like LM7815, in between V5 and opamps socket, and isolated +18V DC power to pin 7 of the socket, so that the regulated 15V (perhaps clean DC) was supplied to pin 7 of opamps (if space allowed)

HPA-3B has exactly +/-18V, so I'll need to change regulators with NJM7815 (already bought them). BURSON confirmed that max. voltage for V5's is +/-15V; perhaps their next solid-state op-amp version will be designed for a higher voltage.

raoultrifan said:

  HPA-3B has exactly +/-18V, so I'll need to change regulators with NJM7815 (already bought them). BURSON confirmed that max. voltage for V5's is +/-15V; perhaps their next solid-state op-amp version will be designed for a higher voltage.

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Good luck on lowering the voltage by using NJM7815, which hopefully will not affect other components that may require +18V. There must be a reason why 18V regulators were used.
Assuming you also replace NJM7918 to NJM7915 as well for -15V.

Thank you burdie, output stage should be perfectly fine with +/-15V and headphone output protection I believe has a dedicated rail (this I'll need to investigate further). I'll get back to you when I'll have some news; in case will not work, then I'll see if I'll be able to make some space nearby the 2 op-amps for 2x7815 regulators and do what you suggested.
 
Thanks, 
Raul.

I'm watching this post with interest as I'll try the same thing with my HPA-3B once I see how you get on.
 
I'm wondering whether your WIMA upgrade went far enough or whether some even better caps might have made an even bigger difference. Some Jupiters or Mundorf SGO's? but I note your point about it all still fitting within the case. And I will end up spending more on the caps than on the amp!
 
What do you think about the power supply? Scope for improvement here? Caps again?
 
Really very interested in the Burson V5 and the effect that will have.

Well, I'm not sure I'll be able to close HPA-3B's case with BURSON V5 inside. I'll see about it when I'll have the time for.
 
JB JFX Premium Film Cap are polypropylene caps and theoretically should be an upgrade in audio signal over polyester WIMA MKS caps, though I was unable to get any noticeable differences between JB and WIMA, especially because I had no access to an identical HPA-3B to A/B test it and I also don't have another amp at home to sound close enough to HPA-3B to compare with so I can tell differences.
 
What I really think it was great: the GOSS steel sheet around the transformer and the EMI filter on mains, because with sensitive headphones I really have no other noise besides normal amplifier's noise.
 
In one of my previous posts I think I published ripple & noise measured with my scope for HPA-3B internal PSU and I believe it was less than 1mV peak-to-peak value, which is quite OK for me. The CMRR/PSRR for LME49860 is quite high and I believe less than 1uV of PSU noise will get injected into audio signal, so no need to get worried about internal PSU's noise I'd say. With gain=Low my HPA-3B is about as dark as my Objective2 amplifier (aprox. the same gain used in O2) when AKG K550 headphones are used in A/B test.

I have a HE-500 on the way. Would this amp have enough power for it?

It should. Lol

I'll know soon enough.

Hi, 
 
I believe I did some measurements here: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12250417. Looks like we're speaking about 1.5 Watts in single-ended and about 4.5 Watts in balanced operation (tests done with about 60 ohms cable + resistor). So, I'm pretty sure you'll mostly listed to lowest gain of +5dB on your Matrix HPA-3B.
 
Looking forward for your review with your new headphones,
Raul.

burdie said:

  Good luck on lowering the voltage by using NJM7815, which hopefully will not affect other components that may require +18V. There must be a reason why 18V regulators were used.
Assuming you also replace NJM7918 to NJM7915 as well for -15V.

Click to expand...

Hi again, 
 
Looks like I did it after all.
 
 
I was actually able to get rid of existing JRC7818/7918 by removing all the 12 screws from both lateral black aluminum heat-sinks from power transistors, then with a small clipper/cutter I cut, one by one, all the legs for each power regulator. The new NJM7815/7915 were placed above by carrefull soldering (legs were also carefully cut to accommodate with heat-sink holes, of course). I choose NJM manufacturer because they say noise from 10-100KHz would be 90uV/170uV RMS for 7815/7915 regulators, quite a decent value I'd say; bought them from PROFUSION UK, authorized JRC/NJM/MUSES dealer.
 
First thing I noticed was a lower noise than original LME49860, which is quite an improved I'd say, because with max. gain of +20dB and sensitive 32 ohms headphones we all know that there is some noise out there, especially when volume is fully max.
 
Noise estimation was done by comparing left channel with right channel with AKG K550 headphones and my own ears. Right channel had installed the default LME49860 op-amp and left channel had installed the below op-amps, in order of background noise estimated by my own ears:
- BURSON V5-dual: about 30-40% lower noise than original LME49860
- MUSES8920: about 25% lower noise than LME49860
- LM4562: about the same noise
- AD8599: about 3 times the noise of LME49860 (have no idea why, I thought this op-amp is low-noise, based on it's datasheet).
Headphones used for these tests: AKG K701 (used for scene presentation and layering), BEYERS DT880/600 (used for details, saxophone and women voices) and AKG K550 (used to get background noise and overall musicality).
 
CONCLUSION: I perceived a very good sound presentation from BURSON V5-D solid state op-amps and I can strongly recommend them for serious DIY-ers. I very much liked women voices  and instrument separation, so I'm going to keep the BURSONs inside my HPA-3B for awhile and I hope I'll have the time to do some more tests and reviews.
 
Please keep in mind that besides replacing both power regulators you also need to remove both DIP8 sockets and to solder V5s directly onto the PCB, because HPA-3B case can't be perfectly closed otherwise; BURSON V5s are about 2mm taller than HPA-3B can support!
 
PROS:
- BURSON V5-D are definitely having a lower noise than original HPA-3B's op-amps, so great job BURSON! These are definitely the lowest noise op-amps I ever tested.
- I liked women voices and instrument separation a lot.
- Cymbals sound a bit more clean and natural with V5s.
 
NEUTRALS:
- Details are about the same as LME49860, with just a slight advantage for V5s (BURSON V5 did a great job in revealing more details and clarity with my Objective2 amplifier: http://www.head-fi.org/t/616331/o2-amp-odac/4965#post_12382477).
- Sound-scene is about the same as original op-amp, but I'll test this again the next days and get back to you.
 
CONS:
- Need to replace power regulators for decreasing the voltage from +/-18V to +/-15V, otherwise lifetime of V5s will decrease.
- Height is 2 mm more than it should be to perfectly fit inside HPA-3B, so you'll need to remove the DIP-8 sockets and solder V5s directly onto motherboards to fit the case
- A bit pricey (about 25% of the price of Matrix HPA-3B).
 
Note: Many thanks to BURSON for providing these solid-state op-amps for this test!
 
Will get back here when I'll have the time to compare more op-amps and more songs,
Raul.

canthearyou said:

I have a HE-500 on the way. Would this amp have enough power for it?

It should. Lol

I'll know soon enough.

Click to expand...

enough to drive HE500, but suggest mod your HE500 stock cable to balanced or get a custom balanced cable to enjoy with 3B.

raoultrifan said:

Hi, 

I believe I did some measurements here: http://www.head-fi.org/t/770610/introducing-the-matrix-m-stage-hpa-3u-and-hpa-3b-review-to-follow/60#post_12250417. Looks like we're speaking about 1.5 Watts in single-ended and about 4.5 Watts in balanced operation (tests done with about 60 ohms cable + resistor). So, I'm pretty sure you'll mostly listed to lowest gain of +5dB on your Matrix HPA-3B.

Looking forward for your review with your new headphones,
Raul.

Click to expand...

Nice! And I like your mod to use the Bursons

burdie said:

enough to drive HE500, but suggest mod your HE500 stock cable to balanced or get a custom balanced cable to enjoy with 3B.

Click to expand...

It comes with a balanced cable.

Wow, well done, you have done such a neat job of that soldering.
 
When you remove the DIP8 socket does the V5 fit straight into the mother board without any further modification? It looks like a perfect fit from the pictures. But for 2mm I think I would be more inclined to drill a couple of holes in the roof!
 
From you description it sounds like it raises the HPA-3B up to the next level.
 
I also note that on other mods you are not afraid to say that you can't tell any difference in sound quality, which is a good thing. It gives us confidence that the differences that you do describe are real.