[ken6217]

A user who spent over 4 grand on an amplifier has been experiencing humming issues on said amp, expresses frustration and seeking help for the past few days on a community thread created specifically for said amp, and yet the sponsor of said amp company decides the best way to respond is to sarcastically comment on something that was written in frustration by a paying customer who has experienced potentially a product fault instead of reaching out and trying to resolve said issue.

Bravo.

Edit. Multiple users.

 

[wazzupi]

Pretty sure he has responded with cause of the issues, the possible fixes of said issues. But he hasn’t responded directly to @ken6217.

 

[Andykong]

Yes. Through the headphones.

I thought Inhad read a week or so ago about somebody having a similar issue with the HD 820 I think. Andy supposedly said that and they never tested it with that headphone.

So they didn’t test it with Sennheiser and I guess ZMF. That’s a pretty big size of the 300 ohm market.

I said we haven't tested HD820 with HA-300 or HA-300MK2 when someone asked this question, explicitly through PM. On the other hand, we have tested HD800 and used HD800S as a demo headphone with HA-300MK2 in multiple shows and events. We didn't test ZMF headphones in our lab, because there is no ZMF dealer in China, at the time we develop HA-300MK2. Fortunately Zack becomes a Cayin dealer, and he used HA-300MK2 as one of the reference demos in CanJam Chicago, there is numerous impression mentioned HA-300MK2 with various ZMF headphones (HERE, HERE and HERE, just to name a few) and none of them mentioned excessive noise during their audition.

Let's be fair, when I was asked whether we have tested HD820 with HA-300MK2, he didn't mention the noise problem. He just asked specifically did we test this headphone with that particular amp., If the discussion was more transparent, I could have provided more information related to HD800 and HD800S before the message was spread. I am sorry that you were misled to assume that we didn't test it with Sennheiser at all.

 

[ken6217]

I said we haven't tested HD820 with HA-300 or HA-300MK2 when someone asked this question, especially through PM. On the other hand, we have tested HD800 and used HD800S as a demo headphone with HA-300MK2 in multiple shows and events. We didn't test ZMF headphones in our lab, because there is no ZMF dealer in China, at the time we develop HA-300MK2. Fortunately Zack becomes a Cayin dealer, and he used HA-300MK2 as one of the reference demos in CanJam Chicago, there is numerous impression mentioned HA-300MK2 with various ZMF headphones (HERE, HERE and HERE, just to name a few) and none of them mentioned excessive noise during their audition.

Let's be fair, when I was asked whether we have tested HD820 with HA-300MK2, he didn't mention the noise problem. He just asked specifically did we test this headphone with that particular amp., If the discussion was more transparent, I could have provided more information related to HD800 and HD800S before the message was spread. I am sorry that you were misled to assume that we didn't test it with Sennheiser at all.

No problem. I was just frustrated and bummed out by hearing the hum. I am in the midst of trying a couple of things to see if I can resolve the issue, if it is indeed outside the amp itself. I will report back the results.

 

[linziyi]

No problem. I was just frustrated and bummed out by hearing the hum. I am in the midst of trying a couple of things to see if I can resolve the issue, if it is indeed outside the amp itself. I will report back the result

if you don’t mind me asking, how is the ifi ground defender/isolator? Does it reduce or eliminate the hum?

 

[ken6217]

if you don’t mind me asking, how is the ifi ground defender/isolator? Does it reduce or eliminate the hum?

I’ll give you a hint. I just sent it back to Amazon.

 

[Andykong]

The DAC is already only using 2-prong, iPad and laptop runs off its own electricity. I am in a house and have tired turning off all the breakers except for the one powering the amp.

US outlet is 120V 60 Hz, and from my understanding a rectifier doubles the frequency. So if I am hearing 120 Hz, it is from the electric outlet after all??

Unfortunately no I don’t have any source that doesn’t go through USB. Will a better power conditioner/filter resolve the issue? I am only using a relatively cheap power filter from Furman.

I'll respond to you first since you are the first user to mention the hum problem in this round. I'll respond to Ken separately tomorrow or the day after because I am not 100% sure you and Ken are having the same problem (and this is 3am in my timezone). From what I read, you heard the hum from the outboard Power Supply and it is 120Hz in your assessment, while Ken only mentioned noise from headphone output.

Your observation is correct, when you head 120Hz, it is likely a doubled of 60Hz after rectifier and that's why my immediate response was to check out the various frequently-mentioned sources of hum. For those who joined the thread only these few days, please check my test recommendation HERE. For the record, switching power supply and power supply with non-digital dimmer features are the two biggest sources of ground hum. If you use a computer as your USB Audio source, the noise from the switching power supply will go into the DAC and then be passed to the amplifier via the USB Audio connection. Some USB has better isolation in their USB receiver circuit and stopped the pollution, others don't.

If it is indeed a ground issue then it will fix my issue as well!!

i am experiencing the exact same hum! Volume independent

What would be an easy way to eliminate ground fault?

Is this similar to what you are hearing?

https://voca.ro/1et7cYEA6XAP

This was recorded from my headphone by putting the mic close to the earcup. It’s about 120Hz

From my understanding Cayin used HD800 and HD800s as part of their reference headphone when developing the amp, shouldn’t they be able to mitigate the background hum from these headphone? That’s why I am particularly surprised by the background hum given I am using one of their development headphones.

Yes, as mentioned in my previous post, we used HD800 and HD800S with HA-300MK2 and we didn't notice any excessive noise or hum in our test. We didn't use HD820. Since we have used HD800 and HD800S, we didn't perceive the need to test HD820 specifically, we just assume they are similar enough electrically.

You have mentioned that noise is volume independent, how about impedance setting? I assume you are using High impedance setting with HD8xx headphones, can you try Low and Mid impedance settings and tell us whether the noise level will lower when you switch the impedance setting to Low or Mid. If that's the case, the hum noise level is directly related to output power, so it is not a bug in the signal path, it can be an external noise that gets amplified LOUDER at high impedance because of higher rated output at this setting.

Will a better power conditioner/filter resolve the issue? It depends. In my experience, a filtering type power conditioner won't solve the hum problem you are dealing with. Isolation Transformer power conditioner might work (very likely), and Re-gen Power Conditioner will work in most cases, but you cannot connect your PC (with switching power supply) to the Power conditioner.

Hum coming out from transformer most likely caused by bad transformer or electricity.

Again, for your case, I suggest you bring your amp to dealer or technician to be checked.

You'll find out by process of elimination.

As I alluded, it's also contextually dependent on how present the hum is and that is asking what nominal dB are you listening at for the noise to occur.

Erwinatm's comment is right on: bad transformer or electricity.
paradoxper provided the guideline to debug the sound system: by process of elimination.
If we can, through a series of tests, eliminated electricity as a source of your hum problem, then we'll arrive at the final hypothesis that the power supply transformer is having some problem. It can be a broken transformer shield that caused leaking of electromagnetic interference from the power transformer into the power supply circuit, just an example of different outcomes.

 

[linziyi]

I'll respond to you first since you are the first user to mention the hum problem in this round. I'll respond to Ken separately tomorrow or the day after because I am not 100% sure you and Ken are having the same problem (and this is 3am in my timezone). From what I read, you heard the hum from the outboard Power Supply and it is 120Hz in your assessment, while Ken only mentioned noise from headphone output.

Your observation is correct, when you head 120Hz, it is likely a doubled of 60Hz after rectifier and that's why my immediate response was to check out the various frequently-mentioned sources of hum. For those who joined the thread only these few days, please check my test recommendation HERE. For the record, switching power supply and power supply with non-digital dimmer features are the two biggest sources of ground hum. If you use a computer as your USB Audio source, the noise from the switching power supply will go into the DAC and then be passed to the amplifier via the USB Audio connection. Some USB has better isolation in their USB receiver circuit and stopped the pollution, others don't.






Yes, as mentioned in my previous post, we used HD800 and HD800S with HA-300MK2 and we didn't notice any excessive noise or hum in our test. We didn't use HD820. Since we have used HD800 and HD800S, we didn't perceive the need to test HD820 specifically, we just assume they are similar enough electrically.

You have mentioned that noise is volume independent, how about impedance setting? I assume you are using High impedance setting with HD8xx headphones, can you try Low and Mid impedance settings and tell us whether the noise level will lower when you switch the impedance setting to Low or Mid. If that's the case, the hum noise level is directly related to output power, so it is not a bug in the signal path, it can be an external noise that gets amplified LOUDER at high impedance because of higher rated output at this setting.

Will a better power conditioner/filter resolve the issue? It depends. In my experience, a filtering type power conditioner won't solve the hum problem you are dealing with. Isolation Transformer power conditioner might work (very likely), and Re-gen Power Conditioner will work in most cases, but you cannot connect your PC (with switching power supply) to the Power conditioner.





Erwinatm's comment is right on: bad transformer or electricity.
paradoxper provided the guideline to debug the sound system: by process of elimination.
If we can, through a series of tests, eliminated electricity as a source of your hum problem, then we'll arrive at the final hypothesis that the power supply transformer is having some problem. It can be a broken transformer shield that caused leaking of electromagnetic interference from the power transformer into the power supply circuit, just an example of different outcomes.

Thanks for your follow up! The hum from the headphone does get louder with higher impedance settings.

I do hear the same frequency of hum through the headphone, and also when I put my ear Against the base of the outboard power supply As well as the transformer in the power supply. I am actually bringing the amp to the dealer in a week and we will see if the hum persist in more ideal electrical environment than my house!

 

[Palyodgree]

I have never heard my 3 year-old Susvara headphones produce the human pitch (musical tone/timbre) accurately despite having tried it with 5 different solid state amplifiers (Vioelectric V281, Niimbus US4+, Audio-GD M19, Kinki Studio Vision THR, Vioelectric V550). My Susvara sounds too thin and bright with not enough tonal weight. At the present time, I mainly listen to my Meze Empy Elite headphones which are much more accurate in my audio system from a musical timbre/tone perspective. I would be very interested in hearing the Susvara with a 300B tube amplifier.

Jeff.

p.s. My audio system is as follows-: Jays Audio CDT2Mk3 CD-Transport => Musical Aquarius DAC => Vioelectric V550 headphone amplifier => Headphones.

Sure , it’s my own subjective taste a reference for testing my wife a studio vocalist a voice I know intimately along with a verity of commercial recordings mostly Jazz female categories , Im quite pleased what I am hearing now though it took time to get there, I find the Susvaras to be an absolutely beautiful fit in the chain .

 

[steve468]

In terms of noise, on my mk1 I do find there’s a high noise floor with sensitive headphones, mostly on high impedance. I have found this noise is greatly affected by the 6sn7s - the pairs I have can vary wildly in how quiet or noisy they are, but all including the stock tubes have some noise. I haven't changed the 300bs to know if they also make a difference.

What I did was buy an attenuation cable meant for using iems with desktop amps (top of this page, from Garage 1217: http://garage1217.com/g1217_011.htm). It drops the noise floor considerably, and as a bonus allows for more play in the volume dial. There's PROBABLY a trade off in sound quality, but for me it would take some heavy duty abx testing to find it.

I don't know if this would help with hum problems (my noise is more tape hiss-like), but I just thought I'd throw this suggestion out there.

 

[Ysound]

I ended up returning my replacement unit because of the power supply buzzing noises.
$4400 amp and I can only use with the Susvara and not my daily HD820.
I think the amp is not quite ready for primetime with a few kink need to be work out.
Sticking with the Benchmark amp for now and shall revisit this amp at a later time.
Anyone looking for a brand new pair of ACME 300B for the MK2.

 

[Erwinatm]

In terms of noise, on my mk1 I do find there’s a high noise floor with sensitive headphones, mostly on high impedance. I have found this noise is greatly affected by the 6sn7s - the pairs I have can vary wildly in how quiet or noisy they are, but all including the stock tubes have some noise. I haven't changes the 300bs to know if they also make a difference.

What I did was buy an attenuation cable meant for using iems with desktop amps (top of this page, from Garage 1217: http://garage1217.com/g1217_011.htm). It drops the noise floor considerably, and as a bonus allows for more play in the volume dial. There's PROBABLY a trade off in sound quality, but for me it would take some heavy duty abx testing to find it.

I don't know if this would help with hum problems (my noise is more tape hiss-like), but I just thought I'd throw this suggestion out there.

I just changed the 6SN7 with Sylvania VT231 (not the Bad Boy tho), I can tell you that the hum from Atrium/VC has dropped significantly compare to stock TungSol 6SN7-GTB Brown base or TungSol 6SN7-GTB Black plate.

It confirms steve468's statement.

 

[tdx]

Quick question for fellow owners: there is no way to plug in active speakers directly to the amp right? Only passive?

 

[llamaluv]

I'm kind of like a broken record, here on this thread, posting every few months about headphones that I think work well with the HA-300. The latest is the Solitaire P.

The way I hear it, this headphone has a kind of understated quality about it, and I was pretty underwhelmed by it for the couple hours listening to it on solid state to be honest. Some of the best gear that we grow to understand and appreciate better over time has this quality, but yea we'll see.

Anyway, it opens up a great deal out of the HA-300, which deepens and widens the soundstage, and really brings out the headphone's imaging capabilities. Its imaging is my favorite quality of the Solitaire P so far.

The imaging on this album is amazing, and really creates an impression with this combo:

Qobuz link

 

[Erwinatm]

I'm kind of like a broken record, here on this thread, posting every few months about headphones that I think work well with the HA-300. The latest is the Solitaire P.

The way I hear it, this headphone has a kind of understated quality about it, and I was pretty underwhelmed by it for the couple hours listening to it on solid state to be honest. Some of the best gear that we grow to understand and appreciate better over time has this quality, but yea we'll see.

Anyway, it opens up a great deal out of the HA-300, which deepens and widens the soundstage, and really brings out the headphone's imaging capabilities. Its imaging is my favorite quality of the Solitaire P so far.

The imaging on this album is amazing, and really creates an impression with this combo:


Qobuz link

Nice post. After few weeks of reading noise, hum distorsion in this thread, this one is like a cold beer in hot summer day.

Let me add another one with my experience rolling 6SN7 tubes.

Out of the box, this HA300-Mk2 is already good sounding 300B amp. Far from old style 300B amps sound which are slow, fat loosy bass, warmish, roll of highs, mid centric etc. It is open, fast, wide and tall soundstage and still has the 300B magical midrange.

I am lucky enough to have several 6SN7s to play with. My impression below is reffered to standard Tungsol 6SN7-GTB come with the amps.

1. Sylvania VT231 : black plate 2 holes, oval mica, black base.
- sweeter and more forward midrange, warmer, narrower but taller n deeper ss, same bass quantity, black background.
- very quiet tubes, a cure for noise on ZMFs headphones.

2. KenRad VT231: black glass
- superior bass, warmer, big sounstage, this is for bass head and good for bass pumping music.
- quieter than stock TS but not as quiet as Sylvania.

3. Mullard ECC33 : brown base, round mica, grey plate.
- very high gain. I only tested it for 10 mins. It is not direct replacement for 6SN7, I think it draws too much current and I'm afraid might fry transformer for long run. However, the sound is beautiful, like sylvania with more extended top and bigger midrange.
- noisy and not recommended.

4. NOS Tungsol 6SN7-GTB : black plate, black base.
- sweeter and more forward mids, same highs but smoother edges, same bass, same size staging. It is a better TS than the stock one.
- a little bit noisier than stock TS. I like this NOS TS. Recommended if you can live with a bit of noise/hum.

Hope this find you well and enjoy the music.