hello guys,
Long time reader, not much post here, but I am an avid hifi and headphone enthusiast
I received my HA-6A juste a few days ago, and I am still in the burn-in phase.
What I can say now is that this amp sound really amazing, but as a diva, it is exigeant with the setup...
What a beauty !
pics or it didnt't happen
I have 3 headphones to use it with :
- hifiman ARYA
- sennheiser HD650
- Kennerton Magni
I tested 3 dacs with it:
-marantz hd dac 1
-topping dx3prov2
-schiit bifrost 2 ( retrieved from the main hifi system for testing puposes )
First I will not comment on the sound just yet, because it is still not burned in fully yet, and well, i am not fully decided on the tubes..., but I can already say that the sound quality is very much to my liking...
I read the entire thread, and noticed some of you are experiencing issues with noise and/or hiss.
I would like to share my experience with this beast.
First, I am in france so my unit is 230V/50hz . I planned to use the amplifier for my computer rig, so digital only. First try was with my hd650, connected via RCA to the marantz dac, and usb to the PC....
This was not so good... lots of very loud noise, i could hear blips and high ptiched noise... something was definetely wrong here!
the amp was grounded to the power plug properly, good connection with the rca to the marantz DAC, but it was really unlistenable at first, I was puzzled ! I tried switching dac, with the topping, same problem ! then I scavenged the bifrost 2 from the living room to try a balanced connection.
Strange pc Noise was gone ! and the unit was silent ! ( almost... more on that later )
I understood from my testing that this amp, with all the power available, is very sensitive to grounding...
The bifrost 2 is grounded to the mains...not the other two dacs, so they were connected to the ground via the USB plug on the pc, which is connected to the ground. So there was a ground loop with the PC Usb cable and the rca connector... I confirmed this by connecting an optical cable between the marantz dac and the noisy pc, thus eliminating the shared ground from those two = bingo ! silence !
Now we can talk about the hiss issues you guys are talking about.
I tested with the arya, no problems whatsoever, regardless of the impedance settings, sounds gorgeous
with the hd650 however, on the high impedance setting, I don't get hiss, but I get HUM, very noticeable. on the low impedance, hum is almost non existent.
I think it is related to the very high power the amplifier gives to a 300ohm load.... or maybe to much gain ? with xlr IN in can turn the volume 3 cliks and i have loud music already !
The preamp part is very sensitive to the quality of your tubes as well, I tried NOS 5814a RCA blackplates, JJ ECC802S and the 12au7 from my primaluna main amp , and the quietest one is actualy the original EH that comes with it.
I get hiss and microphonics with the NOS 5814a and low hum, no hiss or microphonics with JJecc802s but louder HUM ! so my advice is check your preamp tubes !
I have some 6189 and 6L6 on the way, i'll report back when I get them !
Also i have a question, how hot does the power transformer get on your devices ? on mine After 2h of playing, I can barely touch it ! I know it is Class A but it feels really hot ! much hotter than my primaluna for exemple.
here is my first experience, I think it is a great amp but It need some work to give the best.
regards