Hissing tweeters with amps in standby mode

[TerryB]

As far as i can tell, all speakers do this to some degree, but i've just bought a pair of B&W Nautilus 802, and i'm assuming that due to their high sensitivity, this effect seems to be quite pronounced. I've straightened out all cables as far as possible, but they're still hissing at me.
Does anybody have any recommendations as to what can be done to minimise this? It's not what i'd call intrusive, but it's certainly noticeable. Fortunately, the speakers' abilities far outweigh this as a niggle, but it's still something i'd like to eradicate if possible. Any suggestions welcome! Thanks.

[TerryB]

In fact, having been talking to as many people as i can think of about this today, it's been suggested to me that changing the interconnects between the pre and power amps from RCA connectors to full AES/EBU balanced interconnects will have a significant effect, as well as offering additional sonic benefits.

Is this the expereince of people on here?

[E-Stat]

As far as i can tell, all speakers do this to some degree, but i've just bought a pair of B&W Nautilus 802, and i'm assuming that due to their high sensitivity, this effect seems to be quite pronounced. I've straightened out all cables as far as possible, but they're still hissing at me.
Terry, speakers don't hiss - electronics hiss. Speakers simply reproduce what is sent to them. What exactly do you mean by "amps on standby"? Where is the gain control?

rw

[Pat D]

As far as i can tell, all speakers do this to some degree, but i've just bought a pair of B&W Nautilus 802, and i'm assuming that due to their high sensitivity, this effect seems to be quite pronounced. I've straightened out all cables as far as possible, but they're still hissing at me.
Does anybody have any recommendations as to what can be done to minimise this? It's not what i'd call intrusive, but it's certainly noticeable. Fortunately, the speakers' abilities far outweigh this as a niggle, but it's still something i'd like to eradicate if possible. Any suggestions welcome! Thanks.
What you are hearing appears to be electronic noise which is transmitted to the speaker. All your electronics will make some and there is usually a specification for signal to noise ratio, hum and noise, or some such, in the owners manuals. The two main questions are: 1) how loud is the noise? and 2) which piece(s) of equipment causes the most?

Well, if you stick your ear next to the tweeter, one can expect to hear some hiss. Your speakers are spec'd as reasonably sensitive but your electronics are quite high quality so the noise should be quite low. But actually, if you can't hear the noise from your listening positions with the sorts volume control settings you actually use, it shouldn't be a problem.

By a process of elimination you can find out which component(s) are causing the noise.How is the level of hiss affected by the volume control? By turning off the preamp and any source components you can see what the noisiest ones are. Phono inputs generally are noisier than line level inputs.

[TerryB]

Pat,

Thanks for the reply. To answer your questions as best i can;

With the pre-amp turned off, or disconnected from the power amps, there is still some tweeter hiss, but it's at an "acceptable" level, ie i can't hear it at more than about 1.5 metres away from the speaker, and it certainly doesn't interfere with the listening experience.

However, with the pre-amp on, and connected to the power amps, the hiss is noticeably louder. It's audible from three metres easily if you're in line with the tweeter, and if i'm sitting in the listening seat, you can TELL that there's an underlying hiss before you've begun. Sure, i have very good hearing, and many people would accuse me of being fussy i'm sure, but as you say, my components are top quality, and this isn't what i would expect or what i should have to put up with, surely?

To experiment last night, i disconnected one channel of EVERY component plugged into the pre-amp. Even with every component disconnected in this way, the increased hiss was still there. I tried unplugging the mains conditioner - no change. Made sure every component was turned off - no change. Altering the volume control on the pre-amp - no change. Only disconnecting the pre to power connection made any difference.

I really want to get this right, as it's making me cry knowing how much i've spent and not being totally happy with it! Are balanced connections supposed to have RF-eliminating qualities as a feature? If so, this could be the thing i need, no?

cheers,
Terry

[markw]

Granted, all electrical components produce some noise (hiss). Generally, the better the components, the less there will be but there will always be some. Now, down th the specifics.

First, your power amp is not in standby. It's on and fully operational simply waiting for an input sighal. ...and, unless you have gain controls on it (not the preamp), it's running at full gain. When everything is disconnected, that hiss you have to strain to hear is it's residual noise.

Likewise, when the preamp is plugged in and on, you're hearing the added noise from that. When you have the volume all the way down, you're again hearing residual noise from the preamp. If you turn it up, you're hearing the noise added by the gain circuity as well.

Now, for the speakers. The speakers simply reporduce what's fed them from the preceeding chain of electronic devices. Extremely efficient speakers, or those with an exaggerated (or tilted up) high end will be most likely to reproduce that hiss. This might be an area to look at for a cure.

Since it seems to be exacerbated when the preamp in in the circuit, I'd say that's the culprit. You may want to have it looked at or replace it. Likewise, speakers that don't accentuate tha high end might help somewhat.

Afgain, all electronics have some hiss and it's generally below the listening level. Are you sure you can hear it from your listening position or are simply aware that it's lurking there in the background and you are focusing on it?

...sometimes good hearing is not always a blessing.

[Pat D]

Granted, all electrical components produce some noise (hiss). Generally, the better the components, the less there will be but there will always be some. Now, down th the specifics.

First, your power amp is not in standby. It's on and fully operational simply waiting for an input sighal. ...and, unless you have gain controls on it (not the preamp) \it's running at full gain. When everything is disconnected, that hiss you have to strain to hear is it's residual noise.

Likewise, when the preamp is plugged in and on, you're hearing the added noise from that. When you have the volume all t he way down, you're again hearing residual noise from the preamp. If you turn it up, you're hearing the noised added by the gain circuity as well.

Now, for the speakers. The speakers simply reporduce what's fed them from the preceeding chain of electronic devices. Extremely efficient speakers, or those with an exaggerated (or tilted up) high end will be most likely to reproduce that hiss. This might be an area to look at for a cure.

Since it seems to be exacerbated when he preamp ins in the circuit, I'd say that's the culprit. You may want to have it looked at or replace it. Likewise, speakersa that don't accentuate tha high end might help somewhat.

Afgain, all electronics have some hiss and it's generally below the listening level. Are you sure you can hear it from your listening position or are simply aware that it's lurking there in hte background and you are focusing on it?

...sometimes good hearing is not always a blessing.
It does seem that the preamp is somewhat noisy for whatever reason, although the amp doesn't seem to be that quiet, either. I must say I am not familiar with Chord Electronics. Their site is rather short on specifications other than power output. There is no spec for Signal to Noise Ratio for the preamp, for example.

http://www.chordelectronics.co.uk/products_detail.asp?id=26

B & W's voltage sensitivity specs seem to be close, although I have not found a set of measurements for the 802N, and they give 91 dB. I presume the tweeter response would be similar to that of the 801N, and there is a small peak centered at 10 kHz, but this should make only a small difference to the hiss:

http://stereophile.com/loudspeakerreviews/207/index9.html

My speakers are somewhat less sensitive at around 86 dB but I can't hear the hiss more than a few inches from the tweeter, but I am no doubt older than TerryB. They also have no peak in the highs. While the amp noise itself does not seem to be a problem, it does seem to be noisier than I would expect from expensive equipment. The preamp shouldn't add that much noise and it may be defective.

As well, quieter electronics might be called for. Bryston makes the quietest preamps and amps I can think of.

[TerryB]

Again, thanks for the input Pat and Mark.

I'd *hate* to think i have to change speakers, as the Nautilus 802 is in every other respect a wonderful speaker. If you check out all the reviews of them on this site, you'll notice, like i did, that another reviewer mentions tweeter hiss, so maybe they're particuarly sensitive to which amps they're connected to? Having said that, Abbey Road studios apparently use exactly the same amp/speaker combination as i do, yet i haven't heard *them* criticise the hissing tweeters! But no, unfortunately it isn't just me imagining it from the listening position, it's definitely there. I just cannot accept that this is something i have to "get used to" in order to benefit from the speakers' other strengths.

As far as replacing the amps - that would crush me if i had to do that. This is a £20,000 combination, and with my previous Ruark Equinoxes, was a formidable combination. With the addition of the 802s, i was just expecting more of everything, which is what i've got, but along with more tweeter hiss too!! Financially, getting rid of them isn't an option.

This evening i'll try another pre-power interconnect, and see what happens...

Terry

[TerryB]

PANIC OVER!!!

Ok, after *much* connecting, disconnecting and back again, i've narrowed this down to the radio and the television. Both are fine when connected to the pre-amp without an aerial, but when the aerial is connected, the additional interference returns.

I can't live without radio, and i don't *want* to live without the ability to play television sound through the 802s, so does anybody know how i can supress this effect?

thanks again in advance,
Terry

[Pat D]

PANIC OVER!!!

Ok, after *much* connecting, disconnecting and back again, i've narrowed this down to the radio and the television. Both are fine when connected to the pre-amp without an aerial, but when the aerial is connected, the additional interference returns.

I can't live without radio, and i don't *want* to live without the ability to play television sound through the 802s, so does anybody know how i can supress this effect?

thanks again in advance,
Terry
You've learned the method! Process of elimination is usually easy once you think of it.

I didn't think the interconnects had much to do with it.

I am not much of an expert on radio frequency (RF) interference. My first inclination would be to try some sort of switcher to isolate the problem components from the preamp when not in use. Here in North America I would try Radio Shack's Realistic Tape Control Center Cat. No. 42-2105 but I have no idea what is available to you. This would be more convenient than removing the interconnects when the radio and TV are not in use and replacing them when they are.

You haven't listed your tuner and TV in your profile. Do you connect the audio outputs from the TV to the preamp? My TV's electronics are rather noisy for use with wide range speakers and we attach the VCR's audio outputs to the audio inputs of the AV receiver downstairs as its electronics are much quieter. When we want the sound from the AV system rather than the TV itself, we use the TV tuner section of the VCR to change channels, etc. We are on cable but it would be the same with an antenna: attach the antenna or cable to the VCR's inputs. When the VCR is off, it simply passes the signals through to the TV, but otherwise it sends the programs out on Channel 3 or 4 and that's where we set the TV's channel selector.

I can think of a few people who might advise you on RF interference but they seldom post here anymore. You might try Audioholics.com

[TerryB]

Pat,

Going back to the people i've already spoken to with an identified problem certainly helped!! Apparently i have "ground loop interference", and need a ground loop isolator to eradicate the problem on both the tuner (Audiolab 8000T) and television (Sony KD36NX200U). Apparently it's quite common when connecting aerialed components to a higher spec amp/speaker combination. These isolators are only GBP 5.50 each, yet claim not to degrade the sound - hmmm, we'll see about that! But if they work, i think there are better quality alternatives out there to experiment with.

I'll update the thread with my findings when they arrive!

Terry

[Buzz Roll]

I have a similar problem of extra noise when I listen through the TV. When I upgraded from Arcam to McIntosh, I heard a Huge reduction in noise, but I just deal with the TV. I's just not as critical to me, and I do not like adding ANYTHING to my system to "control" noise.

[TerryB]

THEY WORK!!


Even though the guy at Russ Andrews Accessories scoffed at me, these things really DO work!! I couldn't believe it! So far, i haven't really had the opportunity to test whether the sound quality has been affected in any way, but radio and television sound is less critical to me, generally. I did need to use one isolator on each of the radio and television - they're plugged into the back of each component, and then the regular interconnect back to the pre-amp. No more excessive hissing - one happy bunny!!

Terry