[GU1DO]

Let me help you to trace your case, I need the serial number of your HA-6A, will send you an PM to start the follow up process.

i just tried the 4.4 output ,, it also has the hiss as the XLR output ,, this may help ?

 

[Andykong]

Andy - wouldn't higher power to balanced vs. SE explain the hiss / noise?

Reading through the thread has left me wondering how loud the hiss is, it seems like it’s only with the balanced output.
Considering the balanced lowest power output 1000mw and can reach 4500mw (depending on tubes and setting) It doesn’t seem that unexpected to me.
On my 1A-HA mk2 I never even go to half volume... maybe I should consider something with less power

If this is power related background noise, then the determining factor should be impedance and sensitivity of the headphones: you won't hear background noise with high impedance or low sensitivity headphones. For instance, the headphone amplifier should be silent with 300Ohm HD6xx and HD800S. This doesn't seems to be the case here, so I don't think this is background noise related to high output power.

 

[Andykong]

on earlier HA300 forum, some also had hissing issue.... think they've fixed it by now.

Actually we have same comment at the earlier date of HA-1AMk2 as well. In other word, all our previous tube headphone amplifier are facing the same problem when released.
So how do we solve the problems?

It turns out that most of the noise problems are caused by:

1. interference
2. power noise and ground loop;
3. tubes or installation of tubes
4. defective parts

So when there were several HA-300 or HA-1AMK2 users reported various noise problems, and then rectified their problems after get rid of the interference in their system, we don't see any complaints any more, because when someone raise the question again, other uses will shared their experience and encourage them to debug their system (check HERE and HERE for examples).

I'll try to explain (1) to (3) in detail later, but trust me, you'll be amazed by the variety of interference. When we discuss about interference, we probably have "dirty" devices such as RF mouse, WiFi Router, mobile phones in mind, but what if I told you that your USB cable, light dimmer and computer keyboard are the source of interference?

 

[IPMano]

Hi all,

I have an HA-1A MKII, at the beginning with a DAC Nuprime DSD wired in USB on my PC and from DAC in RCA to the HA-1A MKII, I had a noise, it was the power supply of the PC which feeds the DAC in USB, I isolated the 5V power supply from the USB cable and powered the DAC by an external source, ouffff more noise.
Second problem, when I turn on the amplifier there is a background noise like a purring it is quite loud and after 15 - 20 seconds it becomes weaker but it is still there, I have not yet found the reason for this background noise, wouldn't it be heating AC tubes?

I really want to buy the HA-6A but I'm afraid of this hiss.

Sorry for my English, I am from Belgium and I use google translate.

 

[Pictograms]

Hi all,

I have an HA-1A MKII, at the beginning with a DAC Nuprime DSD wired in USB on my PC and from DAC in RCA to the HA-1A MKII, I had a noise, it was the power supply of the PC which feeds the DAC in USB, I isolated the 5V power supply from the USB cable and powered the DAC by an external source, ouffff more noise.
Second problem, when I turn on the amplifier there is a background noise like a purring it is quite loud and after 15 - 20 seconds it becomes weaker but it is still there, I have not yet found the reason for this background noise, wouldn't it be heating AC tubes?

I really want to buy the HA-6A but I'm afraid of this hiss.

Sorry for my English, I am from Belgium and I use google translate.

Do you have a wifi router close by?

 

[Pictograms]

Not directly related to the Ha-6a, but related to tube amps. Some tubes pick up more radio frequency interference other and it can sound like scratching, purring or intermittent static. Moving an amp away from a signal generator can remove these noises.


It’s also a good idea to make sure the tubes are properly socketed, that can generate some noise as well

Edit* missed Andy’s post above noise, he would be much better at explaining than I

 

[Pictograms]

Since I brought this up I am interested if different varieties of tubes have different propensities for noise?
If I roll EL34 for example are they more temperamental than KT88? Or are all tubes about the same?

 

[GU1DO]

I think HA6A is on different level to HA1A.... i will consider it's top end HP amp for those who don't prefer 300B..... once the hissing issue is sorted.

If you can describe the 300B sound in comparison to other tubes that would be helpful,
if i need to ship my HA6A to Cayin i may ask to exchange it to HA300

 

[IPMano]

I delete my request, i waiting.

 

[Gr3g277]

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

 

[IPMano]

Bonjour,

Je vais écrire en français car j'ai trop de peine avec l'anglais, tu l'a reçu il y quelques jours ? il vient de chez Son-Vidéo ?
Le 18 mai il était de stock, je le commande, je le paye et quand je vérifie le lendemain il n'est plus de stock je me dis ok il n'y en avait qu'un, mais pas pour moi, quelqu'un est passé juste quelques minutes avant moi pour le paiement, ne serait ce pas toi ?

Il me plait vraiment, j'ai déjà le HA-1A MKII donc ça va je peux attendre surtout que demain matin je vais chercher un Euphoria.

Bonne écoute.

 

[Gr3g277]

Bonjour IpMano !
En effet c'est bien moi... je l'ai commandé le 18 aussi ! Désolé d'avoir été plus rapide, je l'ai recu ce mardi
J'ai lorgné sur l'euphoria aussi mais je mebsuis tourné vers le ha-6a car je voulais pouvoir driver autant mon magni que mon hifiman .
De plus j'ai deja une petitz collection de tubes compatibles avec ce modèle, venant de mon primaluna prologue classic dans le système du salon !
Si tu es pas loin de la region de metz, tu seras le bienvenu pour ecouter la bête

 

[IPMano]

Bonjour Gr3g277

Tu l'as reçu que mardi ? ça été long la livraison.
J'ai eu de la malchance, je l'avais commandé le 17 une 1ere fois mais mon paiement avait été refusé, je ne comprenais pas pourquoi et quand ton paiement a raté il faut refaire la commande, ça je le savais pas j'ai cherché et cherché pour voir comment refaire le paiement, pour finir j'ai contacté le service clientèle, j'ai donc refait la commande le 18 et de nouveau paiement refusé, j'ai contacté ma banque, je payais via paypal et j'avais reçu il y a 2 mois une nouvelle carte, je devais donc mettre à jour ma carte dans paypal, chose faite allez hop 3eme commande paiement accepté, le 20 toujours pas envoyé je les contact et voilà plus de stock.

C'est vrai que c'est du costaud, mon HA-1A MKII déjà a de la réserve, j'ai pas dépassé mi course du volume, ce qui m'ennuie c'est le très faible ronronnement, si je met la sélection sur 8-32ohms on ne l'entend plus, au fur et à mesure qu'on monte ça devient plus fort tout en restant trsè faible, j'ai bien l'impression que c'est du 50hz.
Ce HA-6A m'a fait peur avec ce problème de sifflement j'ai donc annulé ma commande pour finir et comme par hasard te voilà ^^
Je regardais beaucoup sur FB sur audiophile détendu pour voir si je voyais pas qqun montré son nouveau joujou.

Avec le peu d'écoute que tu as dessus en es tu content ?

Je suis de Belgique région de Charleroi c'est pas tout près.

Je vais me préparer pour aller chercher le Feliks à Bruxelles.

Bonne écoute et bon Week End

 

[Zachik]

@IPMano and @Gr3g277 - guys, Head-Fi rules call for English posts only!
I see you're both very new users, so I assume you were not aware...

 

[Relaxasaurus]

@IPMano and @Gr3g277 - guys, Head-Fi rules call for English posts only!
I see you're both very new users, so I assume you were not aware...

That's really a rule? I wish there was a translate button after each post