What cause tweeters hiss ?

I’m not sure how you get any sound at all with the power cord unplugged. 😁

But we generally hear ground loops as a hum, except!! Digital ground loops. They are a real thing that can occur with USB or coaxial digital connectors.  I have never heard of this causing more than excess jitter though.

Seriously though, it should be 100% illegal to sell a DAC that doesn’t have complete galvanic isolation for it’s digital inputs.

Tweeters do not hiss. Electronics can hiss.

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I’m not sure how you get any sound at all with the power cord unplugged. 😁

😆  My bad, just illustrate how to remove the hiss/hum by discharge to the ground.

They are a real thing that can occur with USB or coaxial digital connectors.  I have never heard of this causing more than excess jitter though.

Right, it could be USB cable , will test it later. Thanks

If my system has hiss I check for snakes since snakes hiss.

@auronthas have you tried another DAC? Using in my sys Gustard A-22 DAC, which has discrete ckt sound path, I think it is class-a, no op-amp ICs, all noise incl. hiss I had with previous DACs disappeared, dead silent! 

Try plugging the amp and the digital into the wall to rule out the power conditioner.

Does the Sony CD player have a two prong plug or three? If it is a two prong plug all you are doing is lifting the ground, which is why the hissing disappears.

The problem could be in the XLR connections of the digital sources. If the ground is tied to signal or circuit ground, it may cause noise problems and picked up by high gain amplifiers. XLR grounds should only be attached to the chassis, but some designers think otherwise.

Hiss can be solved in most cases, unless a component is very, very noisy. Here's a linky: A Discussion About Idle Hiss – Upscale Audio

If nothing above works , you may try this :

between your  DAC and your amp.

https://www.jensen-transformers.com/pro-audio/isolators/

I had hiss like yours and I have put Jensen Isolator between an integrated amp

( Soulution INT 330 )and a HT processor ( Acurus ACT4 ) . No more hiss.

Sounds to me like OP is conflating hiss and hum. Two very different issues. 

I think hiss is from speakers

hum is from electronic gears 

something is not quite clear here.  If the amplifier has the volume all the way down, no sound ought to come from the inputs. It MUST be in the amplifier stage(s) following the volume control. Typically a circuit is switches --> volume --> preamp line stage --> power amp/current amp.

So i suspect this is not electronics hiss at all, but some kind of high frequency interference that comes from whatever device (Denefrips????) is connected.  Note i have  Denefrips and it is very, very quiet.  It is also isolated at its USB input.  That said i also isolate my bridge and power them independently.

@westcoastaudiophile

have you tried another DAC?

I don’t have extra DAC, only D90 and Ares II.

@gs5556

Does the Sony CD player have a two prong plug or three?

Two prong without ground.

The problem could be in the XLR connections of the digital sources.

Isn’t XLR connection a balanced analog type ? I have tried RCA connection Ares II to E280 after removed XLR, I can hear hiss too.

So i suspect this is not electronics hiss at all, but some kind of high frequency interference that comes from whatever device (Denefrips????) is connected.

@itsjustme Valid point and noted.  Ares II is connected via USB from music streamer Auralic Aries Mini, Auralic Aries Mini is powered by Topping P50 Linear PSU recently bought. 

I will test with another USB cable or original Auralic power adapter to observe the hiss issue.

If the volume is turned a long way up a low level hiss will usually be audible if you put your ear close to the tweeter.  The hiss is a noise product of the amplifier but will be at a very low level relative to that of any signal that is connected (don't connect a signal at that volume level).  The level of the hiss can be defined as its level relative to that of the signal - signal to noise, S/N, ratio.  In a well-designed amplifier the noise level will be less than 1/1000th of the signal level.

All amplifiers generate noise, but if the amp is functioning correctly it will always be inaudible from the listening chair at any sensible volume level.

@clearthinker Thanks for your reply.  I have read several topic about hiss at Audiogon forum on faint hiss issue is not uncommon.  However, when my CD player is connected to amplifier (without playing music) , there is no hiss from tweeters .  Only when I connect my both DACs , I hear the hiss.  As @itsjustme pointed out , could be USB cable ground loop issue from my music streamer  ?! 

I will check it up later by isolating USB cable , turn on DAC, turn on integrated amplifier (zero volume) with interconnect connected.

@auronthas 

I am very surprised, assuming you are saying that when you select CD input on your amp/preamp and turn the volume up with no signal you do not hear hiss; whereas it is audible when you select other inputs and do the same.

I am not clear how the selection of a different input can alter the noise generated by the (power)amp.

Re your initial post, I don't think hiss is likely to be caused by grounding issues; they invariably lead to hum.

And, frankly, DACs can cause all kinds of issues.  I regard them as the black art of digital sound reproduction and its Achilles heel.

I don’t think it’s the tweeters. 

@clearthinker When I tested with the CD player, I isolated the DAC power supply, CD player using RCA out to Integrated Amplifier , no hiss.  

I just tested my Ares II , removing both toslink and USB input, hiss is still there , it is very minimal though.  I will leave it now.

Thanks guys for your input and sharing. 

not a ground loop. ground loops occur at 60 Hz (or 50 Hz in most parts of the world). Not tweeter frequencies. A ground loop is essentially a "signal" caused by the difference between two different ground reference points being amplified.

Can you explain this again from the beginning? We are all missing something

When you refer to "power off", what precisely are you powering off?  The accuphase?  The denefrips?  Pls be very precise.

Is there no preamp in this system? I see no mention of it. Or I missed it.

What about with no input to the [preamp?  magic box? whatever is before the volume] whatsoever?  This is the "null hypothesis" and reveals the amp / preamp hiss.

is this a typo?:

"Hiss sound disappear only until power cord is disconnected."

When you connect the power cord the noise goes away.  When you disconnect the power cord the noise returns?

@itsjustme

My bad. English is not my native speaking language. Let me rephrase my sentence.

1. Accuphase E- 280, as I mentioned in my first post , integrated pre/power amp. I further check E280 spec, their preamp to balanced output gain is 18dB, looks like quite high.

2. Hiss disappear when I disconnect power cord of Ares II

3. Power off my Denafrips Ares II

Easy solution: don't stand so close to the speakers! Just enjoy the music!

Yes, i guessed that English might be your second language, and thanks for the clarification.  Your English is vastly better than my mastery of most languages!

Your situation is a mystery.  Since the volume being down (essentially off) should black any noise coming from the Denefrips, the ONLY answer that makes possible sense is some high frequency interaction. As noted the frequency is totally wrong for grounding, plus, you seem to have it grounded correctly.

I forgot to ask. Is this s new problem? If so what changed?

I had the same problem it tends to drive u crazy. Whatever outlet your using in the house isolate it from everything else. Then get a copper ground rod and hammer it into the ground just outside the outlet you’ve isolated . And that’s it hiss be gone, good luck 

I had the same problem it tends to drive u crazy. Whatever outlet your using in the house isolate it from everything else. Then get a copper ground rod and hammer it into the ground just outside the outlet you’ve isolated . And that’s it hiss be gone, good luck 

Tahquitz, you are saying that you had a 4,000+ Hz ground loop?

Elaborate please.

Possibly he needs to shield his chassis, but that's very different.

I have owned many expensive and moderately priced amps over the years and none are dead silent. If you can't hear from your listening chair don't worry about it. If you have to know, then you have to isolate what is the source. So the only way to do that is to disconnect the entire system. Then you connect the amp and speakers and listen. Then keep adding 1 piece of equipment at a time until you isolate the offending device or cable. Once isolated, then you can work on a solution. You may even discover that your system is fine & there is something on your homes electrical grid that is causing the hiss.

It seems to me that if the noise goes away when you unplug the DAC, then the problem is in the DAC or its source.
 

Try floating the ground with a cheater plug and see if it dissappear. Generally, the only component that you have to ground is the preamplifier. 

I should have stated to try a cheater plug on the Denafrips Ares II power cord. Many cheater plugs sold today are polarized and have a green tab on them. You should leave the tab in place.  If the cheater plug eliminates the hiss than you are good to go.

Sometimes, due to the polarized (for the common side of the outlet) plug you may have to carefully remove the wide areas of the polarized side of the plug to make both prongs equal.  That way you can rotate the plug in either direction.  It can make a difference.

Second, if your interconnects are single ended then make sure to wrap them around each other in a helix configuration.

From your description, you do not have a preamplifier.

Hope this helps and the cost is inconsequential.

Consider the obvious.  The tweeter is a transducer, it has no intrinsic energy of its own (other than the kinematic energy imparted to it by gravity which will not produce a sound unless you drop it on the ground).  If you take the tweeter out of the speaker and hold it to your ear you may hear noise.  Obviously the tweeter alone has no power going to it so it can't be 'transducing" so what you hear is similar to what you hear when put a seashell to you your ear at the beach (go look that up, the education will be good for you).

Tendinitis is another possibility for a un-powered tweeter appearing to be hissing.  If you have a mild case of it there is there is a chance that by concentrating on the tweeter, you are perceiving the results of this medical issue.

Otherwise this question is wrong.  One must as 'Where the signal coming from?"  The answer would have to be the electronics driving the driver.  Something is producing energy, this is a great trouble shooting exercise to sharpen you inductive (not deductive, no matter what you think of you readings of Sherlock Holmes, he was a master of inductive rather than the deductive reasoning processes.  Again, do some homework, it will be good for you.

@itsjustme @perazzi28 @oldrooney @gs5556 @jb1 @clearthinker @erik_squires Dear all, thanks for your advise and sharing thoughts.

Finally I have discovered the culprit, it’s my 15 years old Cardas XLR interconnect. (even I have had tried phase invert at both Ares II and E280) .

After I replaced with a normal decent Ugreen XLR interconnect. No more hiss on both tweeters.

Should I get a better XLR interconnect?

@perazzi28 all high-end audio equipment here are 3-pin UK with ground connected and with IEC 60320 C13 power cable.

Interesting.

So premium interconnect can worsen SQ as well as improve it!

@auronthas I’m glad to hear you solved your problem. Getting a better interconnect is up to you. The purpose of spending more money is to get better sound, and to give yourself peace-of-mind that you’re doing everything, within your means, to achieve it. 
 

I would be interested to learn more about the XLR cable you replaced. Have you opened it up to check its connections? One of them could be loose or the victim of a cold solder joint. A poor connection would, I think, add a great deal of capacitance to the line.
Have you checked the cable with an Ohmmeter? I have found pin 3’s (ground) and even pin 1’s (opposing signal) tied to the XLR shell’s tab, sometimes at both ends. Pin 3 (ground) should only be tied to the cable’s shield at one end if it is to perform its proper function. If it tied to ground at both ends it is no longer a shield, but a conductor, connecting one chassis’s ground to another, or even connecting signal ground to chassis ground.
I think I’ve read, on this forum, that the connection should be made at the ‘male end.’ Which begs the question, for me, if it is the XLR connector or the actual pins which are referenced. The male XLR connector houses the female pins; whereas the female XLR connector houses the male pins. The male XLR connector plugs into the ‘source;’ the female XLR connector plugs into the ‘destination.’ Others on the forum have recommended ‘grounding at the preamp,’ which is the destination for an analog source or a DAC; but a source for the amp. Perhaps someone with more insight can clarify matters for us both. 
 

Again, I’m glad you managed to solve your problem. 

@oldrooney hi, thanks for your detail explanation on the XLR pin terminals construction,  i am not electronic savvy, and furthermore this XLR interconnect may have reached its life span after 15 years ? I will leave it, lucky that I have a spare XLR that connect to my headphone amp. Temporary this will replace my old Cardas. Thanks again.

Unspecified, but i will assume that this is the XLRs (balanced cables) between your DAC and integrated amp? Therefore analog.

Yes, unless there is some major defect in the XLR cable, this really makes very little sense.  I have seen, very occasionally, that when a ground is lifted or weak, rather than simple hum (60 Hz, 120 for rectified power) there can be a complex noise that includes higher frequency stuff. So maybe, just maybe the XLR ground is damaged (broken).  This raises a simple way to triangulate is it one or both tweeters? If BOTH then it would have to be both XLRs - which is unlikely.

I don't think you have found the true culprit yet.

I have absolutely no idea under what mechanism bad XLR cables would cause hiss.  At most, better shielded cables would reduce noise.

I do check and isolate one by one interconnect  as well audio equipment connected to my integrated amplifier .  As for Ares II, it was not recommended to have both RCA and XLR to be connected due to the R2R design with high output impedance.  Thus I have dropped and removed the RCA cable , left XLR cable. 

The hiss remains until I removed my Cardas XLR cable from  Ares II to Accuphase E280 while both DAC and integrated amp power on.  Then I used another pair of cheap Ugreen XLR cable to test.  The hiss went dead silent. 

I just read through this article and it explains the hiss, buzzing could be due to broken cable. 

Plug in Air Fresheners can cause tweeter hiss.   I had a weird noise coming through speakers and traced down to that.   

I have absolutely no idea under what mechanism bad XLR cables would cause hiss.  At most, better shielded cables would reduce noise.

Nor do I.  Buit the entire question as posed is a mystery.

Try turning off ceiling fans, tv's refrigerator, etc. to try to isolate if the issue is a gremlin in your house.

Bad performances give rise to hissing, no?

@auronthas Interesting article, thank you for posting. I agree with you about the cable, it served a useful life. Not sure what to recommend to replace it, different cables have different sounds and some equipment works better with some than with others. You just have to try different ones and let your ears decide. 

One thing to note ... my old Cardas XLR cables are longer 2m each,  new one is 1m.  A longer XLR cable may subject to noise interference than shorter one.  Also the 15 years old XLR may not have a good shielding against WIFi ... perhaps.

Some of the answers are funny though.  You guys make my day more joyful.

lso the 15 years old XLR may not have a good shielding against WIFi ... perhaps.

Many of these guesses are interesting ....except, everyone seems to forget that the OP stated that the volume of the integrated amp is at Zero - which is AFTER all these cables and will block all signals and signal-mixed noise.  For clarity i placed a flow chart of a typical signal flow in my original reply, waaaayyyyy above.

I do, but for $100.00 I will get rid of it for you.

Cash only...next Thursday at midnight at the gas station...be there or prepare for more NOISE...

You will find that the hiss reduces in volume as you upgrade and tweak for noise: primarily cables along with a good conditioner. Hold the hairspray! 😉

RFI radiated from someware or through the power being supplied can sound like hiss on the output. It is above human hearing so you the hiss might sound as a harmonic. RFI power filter may do the trick. Good grounding will help. I use power isolation transformer with RFI filtering after a Furman RFI power strip. I have no hiss.