[Andykong]

Hello everyone,
It's my first post on this board, and I'm kinda new to the hifi world, so maybe some part of my post will sound dumb or maybe I won't use the right words.

I bought this amp 10 days ago (new).
I chose it because I want to be able to use high impendance headphones, like the 600 ohms ones from BeyerDynamic. But I'd also like to use low impedance headphones (like a Grado GS1000e), on the balanced output.
At the moment I only own an AKG K612 Pro (120 ohms). This heaphone is plugged on the low impedance unbalanced output of the amp, with low gain and low current.

During the firsts days, I had no issue with the amp at all.
Since a few days, I start getting some kind of static noise, that I can easily hear in the headphone. When I turn on the amp, it's fine during maybe 10 mins, then the static noise starts to happen. It can happen when I'm doing nothing at all, but it can change when I touch or wrap the headphone cable, or when I play with the volume knob of the amp. If I turn on the high gain, or the high current, the static noise goes away. I also tried plugging the headphone on the high impendance output, it seemed okay. I didn't try the balanced output, since I don't own a balanced headphone yet.
This static noise happens even when no source is plugged to the amp.

At the store where I bought the amp, I was told that this static noise could be a ground loop problem, but that it should be amplified/louder when I turn on the high gain, not disappear.
I tried plugging the amp on another electric outlet in my home, where there's nothing else plugged; I tried turning off things like my fridge or my water heater, since I was told it could mess up with the power. But same result. I don't own a power conditioner or a power regenerator, to test if that could help.

So I'm gonna go to the store with my amp, so they can test it themselves. They told me that if they can reproduce the problem, they would replace the amp directly with a new one (instead of having to wait for a repair). But when I look at the latests messages in this thread, it seems the problem I have isn't uncommon, so I'm a bit afraid I might get another amp with the same exact problem.

I only owned things like USB sound cards before, and a Topping L30 (that I had to send back), and I never had this kind of problem, so I'm not sure about what I should do.

Thank you.

We have tried to replicate your condition in our lab. with our demo iHA-6, but we failed to do that. We didn't have any iHA-6 in our inventory right now, we sold out a lot of models during the Christmas period. We can conduct a larger scale of testing when we start our new iHA-6 production batch but that will be after Chinese New Year holiday (due to start later this week), and that delay till March 2021.

Maybe we can do something during this period. You can PM your iHA-6 serial number to me, and the name of the shop that you bought your iHA-6, and I'll reach out to your dealer to collect all necessarily information and arrange warranty coverage on your behalf.

Also very interested in finding out more about this hum issue, as I'm considering the iHA-6 for Meze Empyrean (31,6 Ohm, 100dB/mW). Seems that not every unit has this issue... what I'm a bit concerned about is that Cayin just seems to be avoiding comments regarding this issue.

We didn't avoid the problem. We have read the cases reported here, and tested our iHA-6 production samples but failed to replicate the problem. Now we know maybe we didn't test it correctly, ProfesseurMoriarty has provided a guideline for our future test: it's fine during maybe 10 mins, then the static noise starts to happen. Our previous test didn't wait that long before we pass to next test unit.

To be honest, we feel perplexed about the instance, the iHA-6 has been in production since 2015 without any problem. We didn't change the circuit design since day 1 but this low-gain-low-current noise pop up suddenly few months back. The strange thing is, we didn't receive any report from our dealer, we only read this on HeadFi forum.

Given the amount of iHA-6 we produced and sold in past 6 months, we are quite sure that "not every unit has this issue" and the occurrence rate is not very high. We need to find a sample that exhibit the problem and examine the unit in detail. Since we can't identify a faulty unit from our own test after reading the user reports here, we can only keep our eyes open and wait for a return unit with similar problem from our dealers.

 

[ProfesseurMoriarty]

Hello,

@Andykong, sorry for the late answer.
Yesterday I brought the amp to the store, so they could test it. And... they had no problem at all with it.
So I went back there today, to test the amp with them. And the problem happened.
So what's the difference here ? The headphones used for the tests. I asked to do the test with the same AKG as mine.
With every AKG headphones they had (a K612Pro like mine, a K702, a K712Pro), the problem happened, after ~10mins, only with low gain and low current.
With every other headphone they tested and I tested with them, whether they were low impendance like some Focal and a Meze Classic (32 ohms), or high impendance (a HD660S), no problem at all.
Are the AKG headphones more sensitive to small disturbances ? Is it something else ? With my previous amp, a Topping L30, I didn't have this kind of problem at all.
I'm gonna keep the amp, but I'm not sure what I should do with my AKG headphone (I love how AKG headphones sound, it's my third one). I don't like using high gain on this headphone, I think it slightly changes the sound. And I don't really get what the high current setting does. Is it only for IEMs ? Or is it safe for any headphone ?

Thank you.

 

[Andykong]

Sorry to hear that. So that also explained why we can't replicate the problem in our lab. in past few months, it is headphone dependent.

If fact, you should try to use high current with your AKG. High current setting is applicable to all headphones, and it is designed for low impedance and planar headphones specifically.

 

[Andykong]

I'll explain the current mode once again. Let's start with the iHA-6 rated output of different modes:

When you set the current mode to HIGH, you'll lower the output power (from 7000mWx2 to 5000mWx2 in Balanced mode, and from 2200mWx2 to 1100mWx2 in Single-ended Low impedance mode. Since Power = Voltage x Current (P=IV), when we lower the output voltage, we can increase the current capacity of the amplifier, and that's why we called it High Current mode.

In our experience, high impedance headphones (e.g., 250 ohm to 600 ohm) prefer amplifier with better voltage swing, and low impedance headphones (e.g., 32ohm - 85ohm) prefer amplifier with ample current. The lower the loading impedance, the more demanding on current, this rule apply to both headphone and speaker based sound system.

Planar headphones operated differently because they have flat impedance across the complete frequency spectrum, so voltage swing is not relevant to these headphones. The thin diaphragm of Planar headphones are controlled by the magnetic flux induced from the surrounding magnets, and these magnets, be it single-sided array or double signed array, will consume a lot of current, that's why high current mode should pair well with planar headphones.

The high current mode is definitely safe for all headphones, it will sound slightly different from low current mode. It might have technical merit for some headphones, but its totally up to you to decide which mode sound better to you.



(Diagram extracted HERE)

 

[SludgeSwan]

Hello,

@Andykong, sorry for the late answer.
Yesterday I brought the amp to the store, so they could test it. And... they had no problem at all with it.
So I went back there today, to test the amp with them. And the problem happened.
So what's the difference here ? The headphones used for the tests. I asked to do the test with the same AKG as mine.
With every AKG headphones they had (a K612Pro like mine, a K702, a K712Pro), the problem happened, after ~10mins, only with low gain and low current.
With every other headphone they tested and I tested with them, whether they were low impendance like some Focal and a Meze Classic (32 ohms), or high impendance (a HD660S), no problem at all.
Are the AKG headphones more sensitive to small disturbances ? Is it something else ? With my previous amp, a Topping L30, I didn't have this kind of problem at all.
I'm gonna keep the amp, but I'm not sure what I should do with my AKG headphone (I love how AKG headphones sound, it's my third one). I don't like using high gain on this headphone, I think it slightly changes the sound. And I don't really get what the high current setting does. Is it only for IEMs ? Or is it safe for any headphone ?

Thank you.

Thanks for the update, that's very interesting! I wonder what it is then that makes AKG headphones react in this way. Higher sensitivity?

 

[SludgeSwan]

Finally got my Meze Empyrean and hooked it up to the balanced output of the iHA-6 for the first time yesterday evening. There is no hiss or hum with this headphone, and I use the low gain - high current setting. Sounding great!

 

[beemarman]

Finally got my Meze Empyrean and hooked it up to the balanced output of the iHA-6 for the first time yesterday evening. There is no hiss or hum with this headphone, and I use the low gain - high current setting. Sounding great!

Same here. Using this with my Meze Empyrean as well and it sounds bliss. Better amp than on my Chord TT2 for sure.

 

[beemarman]

Loving this combo a lot. For me I prefer the sound out of the Meze was connected to the Cayin using balanced cable, then when using the SE connection on the HugoTT2.

 

[Andykong]

Loving this combo a lot. For me I prefer the sound out of the Meze was connected to the Cayin using balanced cable, then when using the SE connection on the HugoTT2.

Thank you, we take that as a big compliment since TT2 is a well respected reference at their price point.

 

[Melting735]

Finally got my Meze Empyrean and hooked it up to the balanced output of the iHA-6 for the first time yesterday evening. There is no hiss or hum with this headphone, and I use the low gain - high current setting. Sounding great!

I'm also using IHA-6 to drive empyream. It pairs Empy better than Feliks Elise. I have Jotunheim2 and Burson C3XR coming. I will do some more comparisons

 

[uptildawn53]

I'm also using IHA-6 to drive empyream. It sounds better than Feliks Elise. I have Jotunheim2 and Burson C3XR coming. I will do some more comparisons

Same here. Using this with my Meze Empyrean as well and it sounds bliss. Better amp than on my Chord TT2 for sure.

 

[SludgeSwan]

I'm also using IHA-6 to drive empyream. It pairs Empy better than Feliks Elise. I have Jotunheim2 and Burson C3XR coming. I will do some more comparisons

Would be interested in reading your impressions, particularly on the comparison between iHA-6 and Burson C3XR. Just compared the Cayin with the Topping A90, and to me the Cayin is the winner - better deep bass, almost the same level of detail, and better stage depth.

 

[audiophonicshz]

I love my iha-6. I paired it with a Topping D70 and Z1Rs. Man the bass control is out of this world. Tons of PRAT. Recently the amp developed a scratchy right channel as some have also gotten. I bought it 2 years ago so I'm out of warranty. Where can I go to get the amp repaired? I haven't gotten any dealer responses (US)

It would be such ashame to stop using the amp due to the scratchyness. It seems to get worse as the longer the unit is powered on. Just a couple of hours.

Has anyone had success repairing their amp or using a repair service?

 

[audiophonicshz]

I'm also using IHA-6 to drive empyream. It pairs Empy better than Feliks Elise. I have Jotunheim2 and Burson C3XR coming. I will do some more comparisons

Also interested as I've been looking into the Burson Soloist 3XP. I have a Singxer sa-1 that is also interesting. Its a different animal but a good addition to my collection.

 

[Andykong]

I love my iha-6. I paired it with a Topping D70 and Z1Rs. Man the bass control is out of this world. Tons of PRAT. Recently the amp developed a scratchy right channel as some have also gotten. I bought it 2 years ago so I'm out of warranty. Where can I go to get the amp repaired? I haven't gotten any dealer responses (US)

It would be such ashame to stop using the amp due to the scratchyness. It seems to get worse as the longer the unit is powered on. Just a couple of hours.

Has anyone had success repairing their amp or using a repair service?

Please email service@cayin.cn for repair and service support.

You have contacted your dealer already? Did you purchased the amplifier from MusicTeck?