• WANTED: Happy members who like to discuss audio and other topics related to our interest. Desire to learn and share knowledge of science required. There are many reviews of audio hardware and expert members to help answer your questions. Click here to have your audio equipment measured for free!

Should an amplifier (NAD M33) be completely silent?

JktHifi

Senior Member
Joined
Mar 9, 2023
Messages
387
Likes
195
But in most (all?) cases of the M33 it is not. I checked for my own unit and another out of the box. If nothing is connected to the unit, a few moments after turning on, the noise starts from the unit itself. Of course on a grounded power supply line.

Many owners of the M33 verified this in this thread and others.
Is the Class D amp prone to electricity? The NAD M33 use class D amp from Purifi, right?
 

voodooless

Grand Contributor
Forum Donor
Joined
Jun 16, 2020
Messages
10,223
Likes
17,799
Location
Netherlands
It's just my suspicion. The user must handle it with care.
I still have no idea what your talking about or what your are suspicious of. So again, what does “prone to electricity” mean? Be concrete, be precise, be concise!
 

fpitas

Master Contributor
Forum Donor
Joined
Jul 7, 2022
Messages
9,885
Likes
14,191
Location
Northern Virginia, USA
I still have no idea what your talking about or what your are suspicious of. So again, what does “prone to electricity” mean? Be concrete, be precise, be concise!
Maybe he means ESD?
 

Sal1950

Grand Contributor
The Chicago Crusher
Forum Donor
Joined
Mar 1, 2016
Messages
14,068
Likes
16,598
Location
Central Fl
The worst part as I see it, is that NAD won't look into the issue for customers of this fairly expensive
product. I don't know but do the Class D amps being built by our friend at Buckeye Amps have these issues? Is it a NAD thing or a Class D thing? I've read a lot of the Buckeye amp threads but surely not all of them. Just Curious ???
 

Doodski

Grand Contributor
Forum Donor
Joined
Dec 9, 2019
Messages
20,745
Likes
20,756
Location
Canada
I don't know but do the Class D amps being built by our friend at Buckeye Amps have these issues?
All switch mode PWM (pulse width modulation) power supplies are prone to this issue but most of them don't whine, hiss or buzz. I've repaired thousands of PWM power supplies and I replaced maybe a dozen toroidal transformers. So not as common in good quality PWM power supplies.
Is it a NAD thing or a Class D thing?
It's neither. It's a switch mode PWM power supply thing.
 

Sal1950

Grand Contributor
The Chicago Crusher
Forum Donor
Joined
Mar 1, 2016
Messages
14,068
Likes
16,598
Location
Central Fl
It's neither. It's a switch mode PWM power supply thing.
True but from what you say above it is a bit of a NAD thing as some component either as a result of poor build quality or board design has the propensity to sing. Bummer as it should be a problem that
is addressable.
 

vco1

Active Member
Joined
Jun 9, 2021
Messages
155
Likes
153
The hum from my Cambridge 840A was so bad that I replaced it. A pity, cause there was nothing wrong with the amp, apart from that unbearably loud hum/buzz from the toroidal transformer.

As for OP's question: should an amp be silent? In my humble opinion the answer to this questions is Yes. In practice though it seems it's hard to control.

Sidenote: I never had this kind of humming with the cheaper amps I owned. More expensive is not always better in this regard.
 

JktHifi

Senior Member
Joined
Mar 9, 2023
Messages
387
Likes
195
I still have no idea what your talking about or what your are suspicious of. So again, what does “prone to electricity” mean? Be concrete, be precise, be concise!
Prone means: (from google translate)
[adjective]
likely to or liable to suffer from, do, or experience something, typically something regrettable or unwelcome.
 
Top Bottom