Strange ticking noise when amps were powered on from cold

Any one encountered this phenomenon? I have a pair of Aesthetix Atlas Monos. When they were powered on from cold I could hear some continuous ticking noise (10-15 beat per second) if I stick my ear right next to the speakers. VERY faint. The noise was gone in about 5 mins once the monos were warmed up. As long as the monos’s main switches were on the noise would not return regardless the monos were playing or stand by. It only happened when they were turned on from cold (e.g. after a power failure in the neighbourhood ). searched online and some people suggest that it is the capacitors charging?


Steps I’ve done to diagnose the problem:

1. Turn off preamp-same problem

3. Replace 6SN7 tubes

3. use other amps-no noise

4. plug them in other main sockets-same problem

5. switch off all other appliances at home (fridges, dishwasher, modem, router, down lights)-same problem

6. Disconnect all rechargeable devices (laptops, robot vacuum cleaner, power bank, electric toothbrush)-seemed to quiet the noise a bit but not to sure as it was very faint in the first place

At the moment it’s not very practical for me to take the monos to other places to try.

Your input is much appreciated. 




Strange ticking noise when amps were powered on from cold

      Probably the amp going from low bias to high bias.




Is there another issue other than the cold start? It never did it before and now it does or what?

They have always done it?

They sound great? 

You just noticed it?


Class Ds?

50 years old?

You woke up in a cornfield and went back to the house and the stupid thing had been invaded. 

Your wife's/partner is messing with you.

Your having a start up stroke?

Your dreaming.

That's it for now.. I'll check back..

Forgot to mention that after 5 mins from cold start up the ticking noise just suddenly stopped on both speakers simutaleously...Also it's a very faint ticking noise that I couldn't even capture it with my iphone sticking next to the drivers. 

If I leave the units on till the noise stops, then switch off the main, then swtich the units back on, I could not hear any noise. It only happens when the units are swtich on from completely cold (discharged??).


No other issues other then the ticking noise. They sound great as usual. 

I just noticed it as I was planning to sell them so I removed my current amps and powered on the Aesthetix monos to make sure everything's fine. It could have been happening for a while as the ticking noise is so faint so I didn't notice it before? or because the monos were in standby when not used. I only switched off the mains if I do not plan to use them for an extended time (e.g. traveling overseas)

The monos are hybrid amps with one 6sn7 in each channel.

8 year old silly things done or noticed.

I'm really baffled here...



I think your just fine. The location you had it before and the fact most of us don't turn off the main switch could be all it is. It was always there just the location may have masked the sound. I have a few class Ds and A/B preamps all the same way. You hear the soft start relay charging up discharged caps..  Some units are set up to bleed off the filter caps and some stay charged up.


   Copied from Aesthetix owner's manual see below:

It is normal that a slight pop may be heard when going into or coming out of Standby. This is due to the amplifier switching from high bias to low bias.



Thanks mate but what I heard is continuous ticking (10-15 beat per second) instead of some random pops.


Thanks mate. One of the potential buyers acutally contacted Aesthetix regarding this and was advised that they never heard of such probem before. 

I should add that I might not have the best AC in our house. Previously whenever my wife switched on the dimmable down lights I could hear a pop from the speakers. A Torus isolation transformer fixed it. However, now even with the down lights switch off I could still hear the ticking noise in the first 5 mins.


You may be right that the monos are just fine but I just feel a bit hesitant selling them if there is slightest chance that they are faulty. Just trying to be a responsible and ethical seller. But how could the noise appear and disappear on both units simutaneously? What's the chance of them becaming faulty at the same time? This is really beyond me...


Are yours the stereo version or the monos? You sure you couldn’t hear the same ticking noise? As I said it’s VERY faint and one really has to stick the ears to the drivers to hear it. I didn’t notice it before either. Could you please switch off the mains on tour Atlas, wait for at least one hour,  power then back on from cold then listen to the speakers closely?

Have you checked the voltage with just an old analog volt meter? Maybe it's something in your house that's causing the noise. Something weird. Can you move them to a different system or speakers or location? 

The source? The preamp? Both at the same time is before the amps. At the exact same time they switch. Look before the amps..

Just thinking out loud...


I don’t have a volt meter. The voltage on my UPS screen shows the correct local voltage of 230v

Not very practical for me to move them to a different system. No audiophile friend living close by…

Tried with the preamp and DAC disconnected. Same symptom.

If it's common to both amps, then It's most likely mechanical noise from the 6SN7 tubes as they heat up. Tubes are microphonic and the high gain of the amp makes it audible.


Tried replacing the 6sn7 tubes…same.


I should mention that the noise doesn’t get any louder when the volume is turned up. 

It seems pretty clear that the noise is thermally related - and notwithstanding the fact that changing valves didn't make a difference, mechanical noise from the tubes seems the most likely explanation. As the noise is very faint and only last's a short time, and the amps are stable in operation it's probably best to just live with it as it doesn't seem to be indicative of a problem that's going to cause any kind of catastrophic failure.

Are you sure the noise is coming from your speakers?

It may just be mechanical from the amps warming up

Since it stops both speakers at the same time and you have mono amplifiers,  maybe it's coming from up to chain?


Your preamp? 


Try turning on the amplifiers with the input disconnected and see what happens. 


I would try to change components further up the chain. Or turn those on cold with the amps and then turn the preamp on first. You are supposed to turn on source- preamp- then amp. When you shut down you should turn off on the order Amp- Preamp- and finally sources. 
In the Chicagoland area I use this company called Deltronics to check out / repair gear. The tested an amp I bought on eBay which they can run on a Variac first to check it out. They rebuilt the motor board on my Linn Axis TT, plus a few other things. Take it to an expert. They charge $50 to check it out. If it needs more they tell you. 
Also, Start with the manufacture. I hope this helps


Sorry it took a while to get back tried it two ways with interconnect in and out 

sorry to say only single little pop when it go to play mode I have a stereo amp

You should call Jim directly if he can help I don't know who can if I might ask why you are selling them

Best of Luck


Update: an informed buyer took the plunge and bought the Atlas monos last night. Tried at his place this morning with no ticking/hum what so ever…dead quiet….actually quieter than his solid state….so there does seem be some problem with my AC…Happy ending for both of us nevertheless.

Time to get dedicated AC.

Thanks everyone one for your input. Much appreciated.


That is interesting. I had an Atlas stereo amp. I sold it to a friend who said it had hum in the signal (no hum when I sold it). Before we could deal with the situation, he moved. No hum at the new house. Problem solved.