NAD C 298 Power Amplifier With Purifi Eigentakt Amplification

[MaxBuck]

Return the item, get a refund and move on.

No excuses for residual noise.

Correct. My C298 is silent as the grave.

 

[restorer-john]

Correct. My C298 is silent as the grave.

You gotta turn it on to hear the noise... kidding.

 

[MaxBuck]

You gotta turn it on to hear the noise... kidding.

Trust me, when I turn it on, you can hear the noise.* And so can the neighbors!

*Many people call my favorite music noise. What can I say? I've always been a Charles Ives fan.

 

[restorer-john]

And so can the neighbors!

 

[bloodshoteyed]

at least you guys made me clean mine up a bit while putting my ear on it

 

[roog]

Trust me, when I turn it on, you can hear the noise.* And so can the neighbors!

*Many people call my favorite music noise. What can I say? I've always been a Charles Ives fan.

Sorry, my liking this was very. very naughty and I would just like to say that I do not condone such behavior ever :0(

 

[ebslo]

Just had a response from SevenOak & NAD
"I’ve spoken with our NAD engineer, and he suggests all C298 will make a slight low level due to an inductor in their switching mode power supply. If it’s only audible when you place your ear next to the unit it’s not something to worry about and doesn’t effect it’s performance."

What's your thoughts?

This response irks me way more than the actual problem. Won't effect it's performance???

TLDR: How many of us would have bought this amp if the spec SNR was 93dB instead of 120dB?

One of the main performance specifications is SNR, which is spec'd (and confirmed) at 120dB A-weighted re 185W into 8Ohms. Through a representative speaker with 88dB @1W sensitivity, that should give a noise floor of -9dB SPL at 1 meter. I measured my first C298 which had the hum, it was 120Hz and (from memory) around 45 dB SPL at 1 meter, which is around 27dB A-weighted. So comparing to max power through representative speakers, the hum lowers the in-room A-weighted SNR from 120dB to 93dB.

 

[ENG]

Correct. My C298 is silent as the grave.

I have two NAD C298 at two different adresses. There is no noise at any DB, just clean music.

 

[aslan7]

I picked up a NAD C298 which was still in warranty, to replace some Hypex NC500MP mono blocks (OEM & in Ghent Cases)

The c298 is exhibiting the same hum/buzz from the PSU. I popped into the SevenOaks where it was purchased and they tested another unit they had (both around 1306 serial number) running v1.8. This had the same sound, in a fairly busy environment you had to put your ear on the unit to hear it, but it sounds like oscillation/as loud as a quite hard drive spinning. When I changed the unit to high sensitive input detection it cycled off after about 15 mins. Back on medium and no problem (not 100% sure this is the cause)

The Hypex units with the same power rating were dead silent. I have a concern that SevenOaks policy doesn't allow the transfer of warranty although the eBay selling I purchased it from was kind enough to send me the original receipt. The guy in the shop seemed to imply some noise was typical of high power amps! I didn't get to plug in the M33 to see if that had the same problem.

With mine the buzz is audible from within 1m of the unit, but is so faint you cannot hear it at listening, it's present whether there is speakers and XLR inputs or fully disconnected.

Any ideas where (UK) consumer rights does stand? I don't think its right for a £1800 amp to buzz, its sat above a fully passive music server and it sounds like there is a hdd spooling up. I'm reluctant to send it back and wait 8 weeks for them to tell me its operating normally. What warrants a defective fault or allowed noise an amplifier can make?

Just had a response from SevenOak & NAD
"I’ve spoken with our NAD engineer, and he suggests all C298 will make a slight low level due to an inductor in their switching mode power supply. If it’s only audible when you place your ear next to the unit it’s not something to worry about and doesn’t effect it’s performance."

What's your thoughts?

I have heard similar complaints about this unit which is why I bought a Nord. It is dead quiet and powerful.

 

[vermouth]

I have two NAD C298 at two different adresses. There is no noise at any DB, just clean music.

Just checking, the noise isn't from the speakers, its from the amp chassis, sounds like its coming from the PSU, front left corner. When muted, unless I have my pre at 95%+ there is no noise coming from the speakers. The unit I heard in the shop seemed quite you had to put your ear against it to hear but it was a noisy shop environment.

 

[mocenigo]

Just checking, the noise isn't from the speakers, its from the amp chassis, sounds like its coming from the PSU, front left corner. When muted, unless I have my pre at 95%+ there is no noise coming from the speakers. The unit I heard in the shop seemed quite you had to put your ear against it to hear but it was a noisy shop environment.

Often one hears this noise because it is transmitted mechanically through the chassis. Glueing some Alubutil sheets to the inside of the chassis sometimes considerably reduces the buzzing.

 

[Bnergi]

Hello all,
I just purchased C298 to match it with my c658.
Unfortunately, when I turned it on I heard the buzz in the attached file I recorded with my phone.
I don’t think this is normal, I wrote to NAD, too.
What could be wrong?
Sound is there when there is no connection to speakers and c658.
Thanks.

 

[ehowarth]

...when I turned it on I heard the buzz in the attached file I recorded with my phone.

It is not normal for the sounds to emanate from the case -- except for the clicking of relays when the amplifier switches between power modes.

Some people have complained of humming from the case. If actually audible, that is a quality control issue that demands a warranty repair.

Your m4a file has many clicks that sound vaguely like relays. Does toggling the power button cause the same sounds? Do you have any inputs attached and auto-sense toggled?

 

[vermouth]

It is not normal for the sounds to emanate from the case -- except for the clicking of relays when the amplifier switches between power modes.

Some people have complained of humming from the case. If actually audible, that is a quality control issue that demands a warranty repair.

Your m4a file has many clicks that sound vaguely like relays. Does toggling the power button cause the same sounds? Do you have any inputs attached and auto-sense toggled?

Hello all,
I just purchased C298 to match it with my c658.
Unfortunately, when I turned it on I heard the buzz in the attached file I recorded with my phone.
I don’t think this is normal, I wrote to NAD, too.
What could be wrong?
Sound is there when there is no connection to speakers and c658.
Thanks.

I’m sending mine back for a check and hopefully repair/replacement/refund.

There is audible sound from the speakers when the amp is on and a mild sense of dis-ease when I turn it on, with a small amount of noise coming through the speakers.

 

[TimF]

Annoyances. The C 298 has annoyances some of which are being corrected by the company. Apparently, a firmware update or two was necessary. Practically new units have been sent to NAD service centers for servicing. I have another complaint. As home appliances go, the NAD C 298 looks morbid like something you'd use to hold your grandfather's ashes. It is the epitome of an anonymous black box. Something on a shelf in a horror movie with one very little ruby-red light flickering in the lower lest corner that comes on before each death or injury. Each time you tell a lie the light flickers. NAD seems to have its own particular flat black finish. The lettering is about the size of that in the warning leaflets that come with over-the-counter medicinals. Why not spend a couple dollars on some pizzaz? Look what soda pop and beer companies do for very little cost to brighten up aluminum cans. And isn't the NAD an aluminum can?

 

[roog]

I think that I could live with that annoyance

 

[ebslo]

Annoyances. The C 298 has annoyances some of which are being corrected by the company. Apparently, a firmware update or two was necessary. Practically new units have been sent to NAD service centers for servicing. I have another complaint. As home appliances go, the NAD C 298 looks morbid like something you'd use to hold your grandfather's ashes. It is the epitome of an anonymous black box. Something on a shelf in a horror movie with one very little ruby-red light flickering in the lower lest corner that comes on before each death or injury. Each time you tell a lie the light flickers. NAD seems to have its own particular flat black finish. The lettering is about the size of that in the warning leaflets that come with over-the-counter medicinals. Why not spend a couple dollars on some pizzaz? Look what soda pop and beer companies do for very little cost to brighten up aluminum cans. And isn't the NAD an aluminum can?

There's the M23 for those who want to spend an extra grand for the same amp in a prettier box.

 

[vermouth]

My C298 is going back for an engineer to have a look this week.

I hope they can fix the problem or refund if not. I could hear any particular advantage over my NC500MP Hypex monoblocks especially for twice the price. But they are only running some small 4” full range speakers so Probably overkill.

 

[ENG]

There's the M23 for those who want to spend an extra grand for the same amp in a prettier box.

I think the M23 is a tiny bit better than the C298 - but to about twice the price. Well, I have two C298 that work impeccable.

 

[Redwine]

I think the M23 is a tiny bit better than the C298 - but to about twice the price. Well, I have two C298 that work impeccable.

Since you use two C298’s, what’s your setup?