[Fatdoi]

Please. Let us know what was the problem.
Seems, like I need to send my too. I have like hiss/humm sound on all 1/4, Pentagone, and 4 pin XLR at no any source plugged in. Only plugged power cable.
Humm/hiss noise is noticeable at minimum (Zerro) volume position, in all Impendances (L, M, H), and all planar and dynamic headphones especially when switching the output sources, lets say from 1/4 to XLR 4 pin (very big contrast from dead silence to a this humming/hissing noise, where headphone is plugged to 4pin XLR only). Seems like this noise starts to be distorted, when increase the volume around 1 or 3 o'clock position (depends of impedance position) again without any input cables plugged IN (only power cable).
Summary: In my case the humm noise happens in all my (planar and dynamic headphones) from all 1/4, Penta, 4pin XLR outputs and prone to be distorted at the higher volume 1-3 o'clock (depends from which Impedance is selected). Not sure what is the problem. Noise/ distortion is not listenable for me. Will do investigation further. Kim

Seems they still haven't addressed the hissing issue yet.... will see what they'll do about it..... hope they'll give us an update on the actual fixes

 

[kimdeug]

Seems they still haven't addressed the hissing issue yet.... will see what they'll do about it..... hope they'll give us an update on the actual fixes

Yaa. Seems like has not fixed it yet. Any way in Auzee you have the daeler: https://a1futureshop.com.au/
And you can address all problems to them. In New Zealand it is more complicated. So, will try to eliminate all non amplifier related issues by myself and if not, the last thing - I will send it back, I hope Andykong will help me with my unit. Kia Ora. Kim

 

[Gr3g277]

Yes I have hiss too. Right now I am using Sennheiser HD800S. Hiss or distortion on 4 pin XLR output in all L, M, H impedance positions. Hiss starts when Volume at 3 o'clock (assuming that the Volume knob traveling from min 7 o'clock to max 5 o'clock position). I am using XLR input from DAC with max volume for me no more than at 9 o'clock position).
In my situation hiss comes from all 1/4, pentagone, and 4pin XLR outputs. Looks like loud valves, but very noticeable when switching between headphone's outputs even on minimal volume.
Control test: Unplug everything. No any inputs. Only Power cable. Sennheiser HD800S plugged in into 4 pin XLR output. Hiss starts on the last 2-3 actuators steps on each L,M, H impedances.
Next test: RCA input from DAC. Music on pause. Hiss starts from 1 o'clock volume position, very loud on maximum volume on each L, M, H impedances.
Next test: XLR input from DAC. Music on Pause. Hiss starts from 3 o'clock volume position, noticeable hiss when volume on maximum on each L, M, H impedances again.
RCA input gives the most loud hiss. Usually I am using XLR input and at volume at 9 o'clocks it is inaudible. Will play with better shielded RCA and XLR cables tomorrow.

Also will play tomorrow with Power filtering, DC blocker, Power filter conditioner, good shielded power cable and will do very short run/cable from DAC. may be 3.0inch XLR and RCA with extra shielding.
Also will do more tube burning may be 100 hours.
Will post my results here.
At this moment try to exclude any other reason of hiss.

I replicated your tests on mine with my kennerton magni and my hd 650, with approx same results

I have a supra LO-Rad power strip and good power shielded power cables, I did not notice any differences in hum or hiss with it

Curious to hear if you have good results with a DC blocker, I was thinking about getting one as well !

Please. Let us know what was the problem.
Seems, like I need to send my too. I have like hiss/humm sound on all 1/4, Pentagone, and 4 pin XLR at no any source plugged in. Only plugged power cable.
Humm/hiss noise is noticeable at minimum (Zerro) volume position, in all Impendances (L, M, H), and all planar and dynamic headphones especially when switching the output sources, lets say from 1/4 to XLR 4 pin (very big contrast from dead silence to a this humming/hissing noise, where headphone is plugged to 4pin XLR only). Seems like this noise starts to be distorted, when increase the volume around 1 or 3 o'clock position (depends of impedance position) again without any input cables plugged IN (only power cable).
Summary: In my case the humm noise happens in all my (planar and dynamic headphones) from all 1/4, Penta, 4pin XLR outputs and prone to be distorted at the higher volume 1-3 o'clock (depends from which Impedance is selected). Not sure what is the problem. Noise/ distortion is not listenable for me. Will do investigation further. Kim

The hiss with high volume position does not really bother me, because the max I went with my (hard to drive, low sensitivity 90db/mw) hifiman arya is about 12 o'clock, and that is REALLY Loud.
with hd 650 and magni ( around 104db/mw ) 9 o'clock is plenty loud, 10 is really loud ( using schiit bifrost2 XLR as source )

What's more bothersome to me is the noise floor with my sensitive headphones. WIth the magni, at 32 OHM; impedance set to L, volume at min, I can barely hear as tiny white noise. If I raise the impedance setting to High, the white noise is now pretty distinct , but this is not how you are supposed to use it

With the hd650, Impedance setting to H , I can hear the white noise clearly.... so not really using them at the moment.
I wanted to get a set of utopia's, but the high sensitivity cold me down a bit

With my arya , no matter the impedance setting, everything is dead quiet

On the other hand, you were mentionning distortion, and I can't hear any , no matter how hard I am trying... I can turn my arya's into small speaker with that thing

The preamp section is really sensitive to tube quality as well, some tubes are noisier than other. But Everything I sayed here was after selecting the quietest tubes. ( the OG 12au7 EH and JAN Sylvania 6189 were the quietest from my tube stash I got from my primaLuna)

That said, this amp sounds great, and I really enjoy it with all the firepower it can give to my arya's !
I hope this noise/hiss issue can be solved easily,and waiting for the results .

 

[kimdeug]

How is Pathos Aurium in your setup ?
i am eyeing that amp for long time but i never pulled the trigger

Pathos Aurium is a great Italian piece of art. I have bought it for 1/3 of price second hand. Selectable direct out is very convenient option, as can work on standby and redistribute all signals from all inputs and outputs. It is heavy and full of hardware inside (not like CTH from MD). On official website it has been mentioned output 3.6W at 16 Ohms, but from my measurements it is more like 1.8W. It means: It is quiet and not very powerful. Sennh. 6XX on volume 70% for normal listening.
Inside it is full balanced design, as result very nice 3 dimensional soundstage. Dead silent, no any distortions, background noise, hissing, humming, buzzing etc. Good response for driver tube rolling 6922 family. I am using Siemens CCa now. But Russian 6N23 Reflector 65-77 are very good too and 100 times cheaper than CCa. Have around 200 different 6922 tubes (E88CC, E188CC, E288CC. Mullard CV2492 or CV2493, 7308, PCC89 etc). The same tubes as for CTH and monoprice Liquid platinum (MLP). Soundwise it is more lush than CTH and MLP but all details are present and even more clear. But it sounds more like tube amp.
I will keep Aurium in my collection, as I really like the Pathos Aurium sound signature and will utilise my 200 tubes), but for you I will suggest the second hand unit for the half price, as this is a 2013 model and there are a lot of competitors for the same full price. Definitely, for me it sounds much better than MLP. That is why I sold my MLP and keeping Aurium. Custom power supply does not change too much in terms of sound quality so,don't waist the money and keep the original one.

Regards,
Kim

 

[GU1DO]

Please. Let us know what was the problem.
Seems, like I need to send my too. I have like hiss/humm sound on all 1/4, Pentagone, and 4 pin XLR at no any source plugged in. Only plugged power cable.
Humm/hiss noise is noticeable at minimum (Zerro) volume position, in all Impendances (L, M, H), and all planar and dynamic headphones especially when switching the output sources, lets say from 1/4 to XLR 4 pin (very big contrast from dead silence to a this humming/hissing noise, where headphone is plugged to 4pin XLR only). Seems like this noise starts to be distorted, when increase the volume around 1 or 3 o'clock position (depends of impedance position) again without any input cables plugged IN (only power cable).
Summary: In my case the humm noise happens in all my (planar and dynamic headphones) from all 1/4, Penta, 4pin XLR outputs and prone to be distorted at the higher volume 1-3 o'clock (depends from which Impedance is selected). Not sure what is the problem. Noise/ distortion is not listenable for me. Will do investigation further. Kim

I had the same issue as you ,, hiss very clear with dynamics little with planers, beside that last day there was another problem with the power with one of my dacs , but i think it was glitch and am not sure about it , Anyway i had to ship it (on my expanse) to Germany because no dealers in my country, and last week i was informed they fixed it and now its on the way but it will take little longer than expected.

 

[GU1DO]

Pathos Aurium is a great Italian piece of art. I have bought it for 1/3 of price second hand. Selectable direct out is very convenient option, as can work on standby and redistribute all signals from all inputs and outputs. It is heavy and full of hardware inside (not like CTH from MD). On official website it has been mentioned output 3.6W at 16 Ohms, but from my measurements it is more like 1.8W. It means: It is quiet and not very powerful. Sennh. 6XX on volume 70% for normal listening.
Inside it is full balanced design, as result very nice 3 dimensional soundstage. Dead silent, no any distortions, background noise, hissing, humming, buzzing etc. Good response for driver tube rolling 6922 family. I am using Siemens CCa now. But Russian 6N23 Reflector 65-77 are very good too and 100 times cheaper than CCa. Have around 200 different 6922 tubes (E88CC, E188CC, E288CC. Mullard CV2492 or CV2493, 7308, PCC89 etc). The same tubes as for CTH and monoprice Liquid platinum (MLP). Soundwise it is more lush than CTH and MLP but all details are present and even more clear. But it sounds more like tube amp.
I will keep Aurium in my collection, as I really like the Pathos Aurium sound signature and will utilise my 200 tubes), but for you I will suggest the second hand unit for the half price, as this is a 2013 model and there are a lot of competitors for the same full price. Definitely, for me it sounds much better than MLP. That is why I sold my MLP and keeping Aurium. Custom power supply does not change too much in terms of sound quality so,don't waist the money and keep the original one.

Regards,
Kim

That was more than i wanted to know , i appreciate your time and feedback , Thank you

 

[kimdeug]

I had the same issue as you ,, hiss very clear with dynamics little with planers, beside that last day there was another problem with the power with one of my dacs , but i think it was glitch and am not sure about it , Anyway i had to ship it (on my expanse) to Germany because no dealers in my country, and last week i was informed they fixed it and now its on the way but it will take little longer than expected.

Good news, congrats. Only the real owner can feel what does that news mean. If it possible to get any info from repair person, it will be very helpful and highly appreciated. Now I am only guessing and playing around what is wrong.
Will do some investigation test this week and publish my finding here. Regards, Kim

 

[GU1DO]

Good news, congrats. Only the real owner can feel what does that news mean. If it possible to get any info from repair person, it will be very helpful and highly appreciated. Now I am only guessing and playing around what is wrong.
Will do some investigation test this week and publish my finding here. Regards, Kim

Thank you ,, will give feedback once i have it ,, Cayin never disclosed what was fixed in there repair center , i guess they updated the amp with new parts or somthing , am not sure , hopefully it keep being as powerful as before because it is really good to have a tube amp that can power heavy headphones like the HE6se.

 

[Fatdoi]

Yaa. Seems like has not fixed it yet. Any way in Auzee you have the diller: https://a1futureshop.com.au/
And you can address all problems to them. In New Zealand it is more complicated. So, will try to eliminate all non amplifier related issues by myself and if not, the last thing - I will send it back, I hope Andykong will help me with my unit. Kia Ora. Kim

I've bought some gears from A1... they used to have a shop but now a home based business so there's no demo on anything.... this hissing issue worried me quite a lot as i see this amp as my ideal tube amp for my cans...

so would like yours and others input on the return (fixed) units and see if they have really fixed the problem..... thanks in advance

 

[kimdeug]

I've bought some gears from A1... they used to have a shop but now a home based business so there's no demo on anything.... this hissing issue worried me quite a lot as i see this amp as my ideal tube amp for my cans...

so would like yours and others input on the return (fixed) units and see if they have really fixed the problem..... thanks in advance

Thanks for info. Good to know about this. I was very close to order HA-6A via A1 shop, but ended up with local dealer in NZ.
Collecting all equipment to conduct some investigation test: Power filter, DC blocker, Good shielded power cables, handmade short XLR etc.
Will do some experiments and will post results here on weekend. Still waiting replay from Andykong..........Regards, Kim

 

[kimdeug]

To be exact, this problem. hiss on XLR4 outputs when using dynamic headphones, only appear on @Relaxasaurus unit, this is the first instance reported and we are studying it closely. We haven't encountered any other case that exhibit similar problem. We are working with Andrew from Musicteck to resolve this problem, unfortunately Andrew sold his demo unit recently, otherwise they can send a demo unit to Relaxasaurus for crosschecking and as temporary replacement.

Hi Andykong.

Please, contact to me on PM.
I have the same issue with my Cayin HA-6A

Regards,
Kim

 

[Fatdoi]

Hi Andykong.

Please, contact to me on PM.
I have the same issue with my Cayin HA-6A

Regards,
Kim

I'm reading the HA300 thread and some users still have humming issues which Andy still trying to debunk.... which i'm curious regarding Cayin's quality of design towards their headphone amps....

 

[kimdeug]

TERMINOLOGY

Hi all Cayin HA-6A lovers.

While waiting response from Andykong try to do some trouble shooting by myself. But before, I have looked through my previous posts and have found a lot of inaccuracy in description of noise coming out from Ha-6A.

In this post I want to do some clarification in terminology used. Hope it will help for better understanding and be sure that we are talking about exactly the same things. Lets start.....

Noise by type of sound (Hiss, Humm, Buzz)

Hiss (Hissing noise) - Sibilant sound without any tonality. Sounds like Ss_Ss_Ss_Ss_Ss or like Sh_Sh_Sh_Sh_Sh.Similar like switching the stations on old radio. Can be only measured by level of loudness (amplitude).

Humm (Humming noise) Has own tonality. Sounds like Mm_Mm_Mm_Mm_Mm. Looks like sound from working transformer and can be measured by level of loudness and tonality (Ex.50-60Hz)

Buzz (Buzzing noise) - combination of Hiss and Humm noises. From here, have both characteristics to measure. In addition, the proportion of Hiss to Humm can be varied. As result, depends of proportion, it could be sound like Zz_Zz_Zz_Zz_Zz or like Zh_Zh_Zh_Zh_Zh. Or can be as two separate Humm and Hiss sounds at the same time. (In my situation exactly as two separate simultaneous sounds Humm/Hiss in proportion 30/70%).

Zero Point - is a reference point of Zero noise. Equivalent of physically unplugged headphone cable from your headphone amplifier. Broken (unplugged) circuit, no any current goes through the headphone cable, as result absolute silence. In Cayin Ha-6A instead of plug/ unplug headphone cable we can use output switch (1/4, Penta, XLR) to brake the circuit.

Noise by location (White, Background (all variants))

White Noise - is a noise, which has been produced by (headphone) amplifier itself only. It means NO any signal cables connected to the amplifier input XLR or RCA. Only power cable to operate. So, from here white noise can be affected by Quality/clarity of supplied power and amplifier's internal hardware/parts (tube interference).

Background Noise - is a combination of White Noise + All noises coming IN via connected XLR or RCA Input cables to (headphone)amplifier from all peripheral equipments (Computer, DAC, Phono Stage, Mixers, Processors etc) including DC loop noise, all sort of interference noise. in other words It is a summ of White Noise + All noises produced outside of amplifier.
In real life if you are listening music on computer via DAC >> Headphone Amp>>Headphone and press music on PAUSE you will hear this noise.
Originally Background noise is the noise which is recorded on original music tracks (vinyl etc), but in our case we are more interested in Cayin Ha-6A amplifier faults, so will put all external (out of amplifier) noises in this category.

Initial Noise -(quantity characteristic) is amount of any noise at minimal (zero) Volume. Some times (in good/not faulty amplifiers) it is hard to hear it audibly (only can be seen on oscillators on amplitude zooming), so needs to increase the volume to hear it, but need to mention the volume position when it happens. In my case, initial noise is very noticeable at Zero volume.
In my situation, switching between Zero Point to any plugged Headphone output with different Impedances, makes Initial Noise so noticeable and almost unlistenable for music. Which destroys all concept of headphone music listening. This is a main reason of my complain about HA-6A.
Do not take me wrong. I really like the sound coming out from HA-6A, but this White Noise and amount of initial Noise are killing all joy of this 2500$ experience.

Distortion - at the presence of Initial Noise try to increase Volume. In some point the loudness of noise from linear progression/increases will suddenly jump non-proportionally louder (exponentially). At the same time it will bring new harmonics and tonality, which is very audible. After this point the next Volume actuator step will increase previous volume level almost as double.
In my previous posts I have mentioned this Distortion as Hiss starting on 1-3 o'clock depends of RCA or XLR input, and Sensitivity selected.

I think the most important parts are covered.
If something is missing, please reply with your suggestions.
I am not a professional electrical person, just little above basic knowledge.
The practical part is coming soon....
Regards,
Kim

 

[kimdeug]

I replicated your tests on mine with my kennerton magni and my hd 650, with approx same results

I have a supra LO-Rad power strip and good power shielded power cables, I did not notice any differences in hum or hiss with it

Curious to hear if you have good results with a DC blocker, I was thinking about getting one as well !



The hiss with high volume position does not really bother me, because the max I went with my (hard to drive, low sensitivity 90db/mw) hifiman arya is about 12 o'clock, and that is REALLY Loud.
with hd 650 and magni ( around 104db/mw ) 9 o'clock is plenty loud, 10 is really loud ( using schiit bifrost2 XLR as source )

What's more bothersome to me is the noise floor with my sensitive headphones. WIth the magni, at 32 OHM; impedance set to L, volume at min, I can barely hear as tiny white noise. If I raise the impedance setting to High, the white noise is now pretty distinct , but this is not how you are supposed to use it

With the hd650, Impedance setting to H , I can hear the white noise clearly.... so not really using them at the moment.
I wanted to get a set of utopia's, but the high sensitivity cold me down a bit

With my arya , no matter the impedance setting, everything is dead quiet

On the other hand, you were mentionning distortion, and I can't hear any , no matter how hard I am trying... I can turn my arya's into small speaker with that thing

The preamp section is really sensitive to tube quality as well, some tubes are noisier than other. But Everything I sayed here was after selecting the quietest tubes. ( the OG 12au7 EH and JAN Sylvania 6189 were the quietest from my tube stash I got from my primaLuna)

That said, this amp sounds great, and I really enjoy it with all the firepower it can give to my arya's !
I hope this noise/hiss issue can be solved easily,and waiting for the results .

Hello my Friend.

Really appreciate your efforts to replicate my tests and share your findings.
At this moment I have canceled order of 6L6 and KT66 tubes, until the hiss issue will be solved.
But I am very curious how 6L6 tubes sounds like, compare to stock KT88 or EL34?
Also, please, look my previous post with Terminology.
I was in the same boat and was thinking: "OK, I am only using 6XX at 9 o'clock volume maximum, and the hiss is not so noticeable. May be I will keep like this?"
But, when I have done Initial Noise Test (6XX, 4 pin XLR out, High Impedance, Music on PAUSE) and compared to Zero Point, I have found that this Hiss/Humm noise was so loud!!! It was on all outputs: 1/4, Penta, 4pin XLR (slightly less on 1/4, but still very audible). At Volume position 9 o'clock (for normal volume listening), we are talking about this amount of hiss noise coming to your headphone on top of the sound from music track. And this is unacceptable for me.
So, doing further investigation, while waiting response from Andykong.

Regards,
Kim

PS: Also you can do Initial Noise Test for White Noise, to see how much exactly noise your amplifier produces by itself.

 

[kimdeug]

White Noise Test

Hello Cayin HA-6A lovers.

Finally have got little bit time, so have conducted some tests to investigate the hissing issue on HA-6A.
To eliminate all speculations about dirty signal coming IN, this test has been conducted without any audio inputs XLR or RCA connected. Means: No any input cables has been plugged to HA-6A, except power cable to operate. In this situation, I tried to create the most ideal for HA-6A operation room environment, with attention to Clean power supply. OK, Lets do the White Noise Test......

Equipments: Ha-6A, Power Filter Belkin PureAV PF40, Heavily Shielded Power Cables KRELL 20A, DC Blocker Supra MD Mk3
Headphones: Sennh HD800S, 6XX, ZMF Auteur, Focal Elex, Sony MDR Z-7

Room environment: All electronics are plugged OFF (except the lighting), Wi Fi is off, Mobile phone in the next room.

DC Block >> Power Filter >> HA-6A >> Headphones

Results: In my situation, adding or removing the power filter and DC blocker from the power chain has not changed the noise coming out from HA-6A. It means no any changes in tonality, loudness, and character of noise - all was the same. The same about Heavy shielded power cables.
The noise can be described as combination of Humm and Hiss in proportion (Humm/Hiss) as 20/80 or 30/70 at Volume position Zero/Minimum.
The noise becomes louder with increasing the Volume.
The humming noise does not increase with hissing noise.
While Hissing noise increases linearly with Volume Up (but much slower), Humm noise remains at the same level, and only with Volume around 3 o'clock, suddenly becomes more loud and creates distortion.
The noise was present at all impedances and all outputs.
The noise was more noticeable/louder on high impedance and XLR output selection,while on 1/4 and Low impedance was the lowest.
Switching from Triode to Ultra-linear mod, made the noise more louder.
Low sensitivity headphones made the noise less noticeable.
Only one Volume step above zero makes 6XX sound loud. Next 3 steps - too loud. Other 21 actuator steps are not usable on Hi Impedance for 6XX, HD800S and ZMF Auteur.

Conclusion: At this stage it is clear that the source of Hissing noise is coming out from Ha-6A and not related to the power supplied. Very high gain does not benefit hi impedance headphones to shine. In opposite, it brings distortion on the last Volume actuator steps. By the character of noise, I can assume, it relates to Transformer power filtering and impedance matching issues, probably before amplifying stage.
The presents of noise is very audible and unacceptable for this price range equipment. Looks like you are listening music via old radio with all existing interferences.
In this stage I will pack the unit and will send it back to the dealer tomorrow.

Regards,
Kim