What causes amps or powered monitors to buzz and is there a reason for the different buzzing?

[canidoit]

I got a set of JBL305 and the amps are quiet. Then I have my hafler amp and I just got these new more expensive Adam Audio monitors and they buzz like the Hafler.

Their all on the-same power board.

The Adams, the buzzing is different on both monitors. The buzz doesn't change sound when I raise the volume.

It is a consistent buzz, but one is more smoother and the other more raspier and a little louder. Does one style buzz mean one type of problem is happening?

I can't hear them when the music is playing.

Is this an issue or concern, I mean I do know that amps do buzz, but I wasn't expecting it on the expensive monitors and also different buzzing on each speaker.

I am impressed with the JBL305 being quiet.

How could I lower the buzz, power conditioner, or is it just built in?

Thank you.

 

[ccaudle]

I wasn't expecting it on the expensive monitors

The price of the speakers you connect does not change the design or operating condition of the amplifier.

How could I lower the buzz

You will have to identify the cause.
Hafler has produced a lot of different amplifiers over the decades, and I cannot find indication that any amps are currently produced under Hafler branding.
If you have an older amp then you first will have to untangle whether the noise is intrinsic to the design and the way you have the source connected to the amp (e.g. balanced vs. unbalanced connection, pin 1 problems, interference from nearby equipment), or if there has been degradation due to age (e.g. electrolytic capacitors drying out, input devices damaged from ESD, etc.).

 

[ccaudle]

As a first step I would check whether the noise is present with the input cables disconnected from the amp or not.
If the noise is still present then the cause is internal to the amp, and at that point you can decided whether to modify or repair the amp, or just change to a different amp.

If the noise is not present with the cable disconnected, that indicates that most likely the noise is coming in through the input connectors in some way.
If that is the case then my response from your 2022 thread is still relevant:
post pointing to Bill Whitlock presentation

 

[CJ]

Put a scope on the main offenders,

 

[Audio1Man]

I think that your BUZZ is coming from the internal SWITCHING POWER SUPPLY. HUM would typicall come from some type of a ground loop, this would stop by removing the input signal cable.
Duke

 

[ccaudle]

coming from the internal SWITCHING POWER SUPPLY

Do you have information not publicly posted about the model of amp in use? Why do you think there is a switching power supply involved?

 

[ccaudle]

It appears that at least some of the Adam monitors are active, so perhaps the OP could clarify exactly which model monitors are in use, and how an older Hafler amp is involved.

 

[NoisyIndividual]

I think I would be taking one of the buzzing speakers into a different building, and see if it still buzzes there.

 

[NoisyIndividual]

Well actually it won't.

It is a system problem, nothing to do with the speakers.

 

[canidoit]

I think audio1man is correct, might be the power supply, as it sort of reminds me of some switching power supplies I have and when you put your ear next to it, it has similar noise. I tried unplugging the XLR and the noise remains. It is not a hum, it sort of sounds like capacitor whitish noise.

The Hafler amp is running NS10's and the Adam Audio is their A series A77H.

 

[Matt Syson]

You have to define EXACTLY what the unwanted noise is and whether it is electrical or mechanical (transformer laminations vibrating would be an example of mechanical noise). Also don't just unplug the audio cable it must be terminated with a shorted input 'plug' 9short circuit tip to ring or pin 2 to 3 if an XLR.
A switching supply may have a slight 'whistle' sound emanating from it's power transformer or even capacitors (ceramic, not necessarily electrolytics) as it may be that with no significant audio signal it's supply runs into 'skip' mode(low power but insufficient load to really work properly) which MAY incite the transformer to create a mechanical noise because it is cheaply made and not properly potted in resin.
Most 'cheap' hi Fi amplifiers manage to have hum and mechanical npoise levels almost inaudible with odinary speakers so WHY so called ' powered studio monitors' manage to bugger things up so frequently is a bit of a mystery. Also their inability to reject RF interference from mobile phones etc, perhaps becquse they are a 'niche' market and slide around FCC and other regulations and put the responsibility for the 'environment' on the owner.
Charlatans I say!

 

[sodderboy]

There should be plenty of hits here if you search speakers buzzing etc.
What is connected to them? It is a simple interface issue. In a studio with a patchbay it is easy to suss stuff. If you have a small setup directly connected it is more difficult to try different connections at the equipment. Console or monitor controller?
Make a shorty mic cable and lift the shield at the MX end. "shield lift cable" (SL) use it now, keep for later equipment testing.
Does the buzz happen with everything else off but the source and speaker/amp-speaker? Does it change with the speaker/amp-speaker rotated or moved? Does the SL in-line make it go away? You try different sources, lifting, etc asking which is quieter. If the SL works, then lift the shield at the destination and proceed listening.
I lift speaker/amp destination shields as a design rule no matter what size the studio. Seldom do I need to connect them to eliminate a buzz/hum during commissioning.
In the end you should have only hiss on all sets of monitors with volume cranked listening to different sources that are muted or not playing. De-buzzing, much easier these days. . .
Mike

 

[Electrobumps]

Is this an issue or concern, I mean I do know that amps do buzz, but I wasn't expecting it on the expensive monitors and also different buzzing on each speaker.

I spent ages chasing emf in my monitoring system that had been fine in the UK and very noisy in the USA. I thought it was a grounding issue. It turned out to be some failing caps in my amp.

I would suggest spending time locating where this is noise is being introduced. Remove your monitoring controller from the setup. Try a different amp, etc. Good old fashioned fault finding, once you work out where the noise is being introduced then you can can try and work out why.

 

[JohnRoberts]

There are multiple possible sources of hum/buzz. The fact that your noise does not track with the volume control suggests that it isn't input related. A potential noise source in amplifier stages is PSRR (power supply rejection ratio). The character of that noise can vary with nature of the power supply noise.

or something else...

JR

 

[RCAguy]

Are we talking physical\mechanical buzz or acoustic\air-born? With traditional power transformers, it was age-loosened lamination screws, solved by tightening them. If it’s 120+180Hz hum sound, it’s either one or more weak filter electrolytic capacitor(s) needing replacement, or an input ground loop (possible the unit’s design flaw “pin1 problem?).”