Introducing the Matrix M-Stage HPA-3U and HPA-3B, review to follow!

[staxstax]

Thanks again for helping me
i already tried all three positions on the gain switch, the problem stays
if i listen to an orchestra the problem is not so big but on solo instruments guitar violin etc they all move to the left
connecting the ibasso dx200, the headphone output (only there i can change the balance) to the HPA3B, i have to correct the balance on the dx200 6 lines to bring the guitar in the middle
the same headphones direct to the dx200 headphone output sounds perfect in the middle
i also tried different cables balanced or RCA

 

[raoultrifan]

When switching the gain switch, while listening to the music, was the volume changing on both headphones with the same amount (percentage)?

BTW, please post here your testing setup:
- Single-ended DAC and headphones used
- Balanced DAC and headphones use

 

[staxstax]

Hi
again Thanks a lot for the help
I really appreciate
I know almost nothing about electronics, because after 3 years there is no guaranty,
if it is completely broken i will give to a friend to play with and ...never matrix again
so yesterday I opened the case and I re-soldered the connections of the pot
and everything I could,
well it works now perfect, for how long I dont know
but right now I listen to a recent guitar recording (ibasso dx200 canare cable LV-77S to chord Hugo kimbel silver cables to Matrix single ended with the transformers) the guitar is right in the middle
the headphones I use, with balanced and single ended cables are sony z7 , Audeze LCD-X creator new edition
denon 2000 sennheizer HD 600 Nad HP50only single ended
the problem was always there what ever items I used
also switching the gain the problem was the same on all three positions
I will try a Nad D 1050 balanced dac to see if the problem is gone
Thanks again for helping

 

[raoultrifan]

OK, so after resoldering the big ALPS potentiometer issue seems to go away, right?

 

[staxstax]

yes for the moment the problem is solved
also the balanced output of the NAD with the same balanced cables on all headphones work perfect
I dont know what was, I just re- soldered everything I could, at the back side of the plate
sometimes (very rare) stupid reactions of ignorant people give good results, I was just lucky

 

[omegaorgun]

If anyone feels like trading for a Jotunheim hit me up.

 

[Atgm1]

Guys, do not tell me how to get to the back of the board? What bolts do you need to twist?

 

[Atgm1]

figured out

 

[Atgm1]

Guys, do not tell me how to get to the back of the board? What bolts do you need to twist?

figured out

 

[mikaelmark]

yes for the moment the problem is solved
also the balanced output of the NAD with the same balanced cables on all headphones work perfect
I dont know what was, I just re- soldered everything I could, at the back side of the plate
sometimes (very rare) stupid reactions of ignorant people give good results, I was just lucky

I also had the similar issue earlier this year, when I first listened to a well known headphone amp from a big manufacturer - but for me there was a lot of background noise/crackling all the time, mostly heared when listening at silent passages.

First tried to swap the OpAmp, but the noise still remained. I then unscrewed the PCB from the enclosure and when looking at the back of the PCB (secondary side), I found the six soldering for the Alp RK75 volume pot was horrifying! I assume the manufacturer had cut the pot pins with a nipper after soldering (see below montage picture and also see the included RCA cable with unsoldered middle pin).

About connecting the HPA3B to a balanced DAC and balanced headphone, how to do that as balanced standard has 4 pin DIN-connector? This headphone amp only has RCA line in and phone 1/4 (6,35mm) phono jack out, right?

 

[mikaelmark]

By default, this amp are having fast recovery rectifier diodes BYV27 (not the cheaper and slower "standard" 1N400x) bypassed with 0,1 uF capacitor for each diode to eliminate unwanted high voltage peakes.

But some people say those bypass cap´s should only been used for standard slow rectifier diodes, eventually also combined with a low ohm resistor in serial. If BYV27 has bypass caps, there may be a worser result as there will be a small amount of quiscent/leakage AC current.

Maybe it will be better if removing those 0,1uF bypass caps (the four square in the power supply)? Any thoughts?

 

[raoultrifan]

It's been 4 years since I bought this headamp and I'm enjoying this balanced headamp since then, feel free to read the first pages from this thread.

Today I was playing PVZ1 and Grid2 with Audeze LCD-2 Fazor + HPA3B and since about 2 hours I'm listening to music.

AFAIK there is a standard bridge rectifier inside, place vertically, between transformer and the two big caps. However, the ripple & noise measured across opamps is somewhere below 1mV RMS (try to search my scope measurements from the beginning of this thread). I don't recommend replacing this bridge, because there will be no gain, other than messing with the internals and risking to do more damage than good stuff.

The only mods I might recommend would be:
- decreasing the rails voltage (this will lower the internal temps and provide the ability to use more opamps to roll)
- shield the transformer (only if you have audible hum)
- upgrade the four coupling caps with MKP 4.7uF instead of the default MKS 2.2uF (you need to measure twice, then do the purchasing).

 

[raoultrifan]

About connecting the HPA3B to a balanced DAC and balanced headphone, how to do that as balanced standard has 4 pin DIN-connector? This headphone amp only has RCA line in and phone 1/4 (6,35mm) phono jack out, right?

HPA-3B is the balanced one and HPA-3U is non-balanced, the one with built-in DAC inside, right?
However, there are 3-pin XLR to RCA adapters that can be used for line level.

 

[omegaorgun]

It's been 4 years since I bought this headamp and I'm enjoying this balanced headamp since then, feel free to read the first pages from this thread.

Today I was playing PVZ1 and Grid2 with Audeze LCD-2 Fazor + HPA3B and since about 2 hours I'm listening to music.

AFAIK there is a standard bridge rectifier inside, place vertically, between transformer and the two big caps. However, the ripple & noise measured across opamps is somewhere below 1mV RMS (try to search my scope measurements from the beginning of this thread). I don't recommend replacing this bridge, because there will be no gain, other than messing with the internals and risking to do more damage than good stuff.

The only mods I might recommend would be:
- decreasing the rails voltage (this will lower the internal temps and provide the ability to use more opamps to roll)
- shield the transformer (only if you have audible hum)
- upgrade the four coupling caps with MKP 4.7uF instead of the default MKS 2.2uF (you need to measure twice, then do the purchasing).

Does this affect the power output and can you do a guide on how to do that. Even in the wake of THX I crave another one and might be picking one up soon. I absolutely loved the OPA1656 in this, was super tight. Bass is so visceral and superior to a Jotunheim.ans perhaps more body to the sound over THX.

 

[raoultrifan]

No need to lower voltage rails to use OPA1656, as these are already supporting 36V, per http://www.ti.com/lit/ds/symlink/opa1656.pdf, unless you want to lower the internal temps. Also, check for overheating on the OPA1656, in case you want to use them inside HPA-3B or 3U.
Check out the first 10 pages or so from this thread, you should find many answer, measurements as well. If I remember well, for 60 Ohms resistive load, after lowering power rails I got 1.05W/ch. from the initial 1.45W/ch in single-ended, and in balanced I got 3.45W/ch instead of 4.5W/ch., so plenty of power left anyway (for 32 Ohms power is higher anyway).