Heading to 80+ hours in on my new Feliks Arioso 300B and I’m mostly liking what I hear but…
vocals are biased to left of centre. I may have an ear blockage or, assuming my 300Bs are well matched, may have to think about some speaker repositioning. At the moment the left speaker also fires at a Christmas tree about 2m away so until that find it’s hard to judge but I’d have thought that would have introduced a right speaker bias?
had some low level noise on the left speaker not dissimilar to what I had when I first tried streaming and had the cheap Vonets extender next to the streamer. Only audible when stepping right up to the speaker. Tried moving the ethernet cable away from the speaker cable (there’s not much scope) but it seems to have stopped when the dishwasher finished.
appear to have a deep hum on both speakers at a very low level. Only audible at first on the right speaker but now on both when stepping right up to the cones. Had this previously with Naim system and put a cheap DC blocker on the TV interconnect. Ironically binned it a while back when it appeared to be no issue any more.
Powered down streamer and it’s not that. Powered down TV and unplugged interconnects. It’s not that.
That leaves some kind of cabling issue or the DAC. Could the DAC be too close to the amp? Could it be running the streamer and amp off the Powerigel. Amp mains cable won’t reach my sockets so only the streamer could come off and go on an unswitched socket.
Not liking the sound of either of those options. What to do next beyond contacting the dealer?
Not sure how one cable could impact both channels?
The valve one is an interesting one. Having spent a day protecting the amp from family members I ironically became the person who accidentally touched the rectifier. I’m unable to see any marks but Mrs. H. donned a glove; thought she could see something and gave it a quick clean. No hot spots or anything. Surely they couldn’t be related? Certainly playing music fine.
My trusty assistant and I are about to remove and reset the rectifier then reboot the whole thing and see if it makes a difference.
If it is constant and does not get louder as you turn up the volume then it is a hum coming from the power amp side or potentially the speakers themselves (less likely)
If you have some does it hum through headphones as well? If so this suggests it is not the speakers.
It could be being induced by an outside source but more likely from inside the power amp. Most amps will generate a small amount of hum through the speakers but at a very low level.
Amps can often be slightly biased to one channel, especially at low listening levels. But room issues are just as likely to have this effect. Experimentation of placing the speakers and toe-in or out may show some results. It can help to slightly step one speaker back slightly from he other but not much as you may introduce timing issues if it is too pronounced.
Positioning the speaker may help, but it will only compensate for the room issues. It is worth considering if you have a reflection that is adding to one side of the image, making it seem louder that side. This can come from the back wall or something else behind the listening position as well as to the side.
You do say these noises are audible only when close to the speakers - if so, that’s quite normal with valve power amplifiers IME and nothing to worry about in terms of faults.
Most valve amps have too much gain for modern 2 Volt source components and are not as quiet as they could be, which tends to lead to what you’re hearing.
The Christmas tree seems like the culprit for the balance issue.
The amp does not have a headphone option. I don’t use them because of mild tinnitus. The DAC does have a headphone option. Not sure what that would tell me.
The amp has a reputation for being deadly quiet. This is not that.
Much less worried about imaging as previous amp had no issues; there is a Christmas tree 2m in front of the left speaker to be removed and I did have an ear blockage which may not yet have gone.
The deep hum is the concern.
As I say, it’s not an amp with a rep. for any background noise.
whether it is an integrated or separate pre and power amp does not matter. An integrated amp has a pre-section that deals with input sources and switching that hands the signal to a power circuit with a variable signal that then in turn powers the speakers.
if you have no headphones the point is mute but using a pair would tell you if the speakers are generating the hum or not.
Looking at your photos there is more in the way than just the tree. But as we cannot see your whole room or listen to your speakers it is impossible to be definitive. Only your own experimentation will help.
And are you saying this hum has developed, or has it been there all along? The speakers cannot produce a hum themselves, so it has to be the power amp. Iif it is inaudible at the listening position I’d ignore it if my amp.
As for balance, as has been said, could be room or could be amp. Try swapping left and right power amp inputs, reversing the image - that will tell you if power amp or before it. If power amp, and remains after return of room to normal following removal of Xmas tree, you could try making the room as near left/right symmetrical as possible if not already, on a temporary basis would do, and if balance still off you could return the amp as faulty. If not feasible then if you have a preamp with balance control then just set and ignore.
Is that a Chord Hugo TT DAC? If so, you could try setting it’s output to the lowest setting, it might help a bit with the channel imbalance and possibly more.
I used to get a transformer hum which I stoped with a DC Blocker.
But one time after some changes to the system had a hum through the speakers which hadn’t had before. After checking found it was the speaker cables being too near a mains power cable. Once moved and redressed the hum went away.
Could your speaker and mains power cables be too close?
Wasn’t initially audible to me at all. As it’s a brand new amp with a reputation for absolute silence it seems daft to ignore it.
I had a speaker hum years ago with the Naim stuff. Cheap DC blocker sorted it but never stopped transformer hum. My HC DR 2 has always loved a good Sunday morning hum.
I am very much hoping that it’s speaker cables too close to power cables albeit that’s nothing moved since initial set up last week. However, I need to get a day with the grandchildren out of the way; taking the offspring back to Sheffield and then getting the tree down before I look closer and without constraint.
Feliks say the amp will take the 3V in DAC mode but as a precaution I’ve started in PRE mode and 2V. Have always found zero difference with balance on any of the voltages with this and the Qutest. However, as previously noted, sorting the channel balance will come after the tree is down and the hum addressed.
Curious - is it something you’ve heard yourself? I’m aware that ceramic capacitors can sometimes buzz, so acknowledge that it might be possible for other capacitor types to exhibit a low frequency hum, however it could only happen when power is applied to them. When the amp is not fed with a signal, which is the situation here, there is, or should be given it is claimed to be a very quiet amp, effectively no audio frequency AC energy, while I wouldn’t expect DC to cause a sound - in any case most unlikely if no more than a few milliamps in a device capable of handling many watts, especially audible outside the speaker box, while a DC current of more than a few mA would suggest an amp fault.
@mikehughescq, I understand your speakers are high sensitivity, 100dB, so hum output that would may be inaudible or virtually so with speakers of more common high 80s dB/W will be 10dB or more louder with yours.
I was more thinking of the gain structure of the whole system rather than the performance of Chord’s digital volume control, which itself is likely not an issue. The speakers look like high sensitivity Zu maybe? With the amp likely having a decent gain it’s unlikely 2 or 3V is required to get the volume control up much, so the lower setting is worth a try. And as we know, most volume controls have improved channel balance as it goes clockwise which will be helped by using a lower output from the DAC.
Just read the above post about the speakers being 100dB sensitivity! If that’s the case, the low amount of hum you have when near the speaker is not a bad result. That kind of sensitivity will reveal ANY noise from a valve amp - even more so if it isn’t specifically designed for this kind of speaker, which most valve amps are actually not. Reviews rarely mention noise with valve amplifiers but IME there is practically always some audible noise.
A capacitor can begin to fail, and as it may not be able to control the storage and discharge of energy correctly, this can create a “ripple” into the signal path, which in a speaker can translate as an audible low hum—not very loud, though. I have heard a speaker doing this, and when the cross-over cap was replaced on the mid/bass unit, the hum stopped. More accurately the whole cross-over was replaced as it was under warranty. and simpler to do that.
There must be energy reaching the speakers as the OP reports a low hum they only hear when close to the speakers. If there was none the speaker could not produce a sound. An amp set to normal listening volume (say) will be sending some energy to the speaker, even without source signal.
In speakers, the caps are usually electrolytic or polycaps but other types are used.
As I said above, it is not very likely, and more likely the amp or transferred/induced noise along the signal path the amp is picking up.
Exactly - and there shouldn’t be with no signal input, other than very low level electrical noise, so the question is whether the noise is excessive for the amp in question, or whether itis simply the high speaker sensitivity that is making it audible, thoug I wouldn’t have thought an issue if only audible very close.
To @mikehughescq : did you check ground/earth connections?
The speaker’s crossover caps can introduce a low hum when energised. As long as some energy is getting to the crossover the cap can produce a hum if it is faulty.
Surrounding the element you selectively quoted I also said
There must be energy reaching the speakers as the OP reports a low hum they only hear when close to the speakers. If there was none the speaker could not produce a sound. An amp set to normal listening volume (say) will be sending some energy to the speaker, even without source signal.
