NAD C 298 Power Amplifier With Purifi Eigentakt Amplification

[sumpao]

Standby is <0.5 W. You don't need to go to the back for standby. Switch off on the back is off (0 W).

Ok that good to hear

 

[Moto]

Yes, only the first song. If there is no signal, the C298 goes into standby (after the usual time). The auto sense settings have no effect on standby. They only regulate how loud the input signal has to be for the C298 to operate - however useful that may be. To your last question: The wisdom of turning off amplifiers is to save us all from climate change. Idling power consumption is 23.2 W.

@JoetheLion does yours go into standby automatically? With the SMSL SU-9 mine does not. If I put it into standby manually( orange light) by pressing the button it is indeed wakened by the SMSL SU-9 starting to play music ( any sensitivity setting seems to work here)but never goes back to standby by itself.

 

[JoetheLion]

If I put it into standby manually( orange light) by pressing the button it is indeed wakened by the SMSL SU-9 starting to play music ( any sensitivity setting seems to work here)but never goes back to standby by itself.

I use a trigger, so I didn't test it. The manual says:

"AUTO STANDBY

The C 298 can be setup to automatically go to standby mode if there is no active input signal for 15 minutes. Auto standby mode can be enabled or disabled by the following steps.

Enable Auto Standby mode

At operating mode, press and hold front panel Standby button and then release after more than 15 seconds. The Bridge mode indicator light flashes three times.

Disable Auto Standby mode

At operating mode, press and hold front panel Standby button and then release after more than 15 seconds. The Bridge mode indicator light flashes two times."

Strange. This is the price you have to pay for a cool one-button-design....

However, some people here have reported having problems with auto standby. Maybe that was fixed with the firmware update. (To check the firmware version: count the blinkings....)

 

[Shoaibexpert]

Nothing to do with hum, I think some people had issues with the v1.7 firmware randomly shutting down when auto-sense was enabled.

Thanks. Good to know. Ill push my dealer for the right SW version.

@Shoaibexpert , I am running the smsl into the c298 directly and using an svb-3000 sub. Per communication with NAD the line out is unchanged going to the sub from the c298. Per communication with SVB, keep input <3vrms and gain on the 3000 betweem -20 and -5db.
I use roon for volume so keep the smsl in dac only mode. If you are using the smsl for volume control I’d set the c298 gain at a level which allows you to keep the smsl output at less than 3vrms for the svb-3000 constraint.

Thanks. This is helpful

es, only the first song. If there is no signal, the C298 goes into standby (after the usual time). The auto sense settings have no effect on standby. They only regulate how loud the input signal has to be for the C298 to operate - however useful that may be. To your last question: The wisdom of turning off amplifiers is to save us all from climate change. Idling power consumption is 23.2 W.

Thanks, makes sense!

 

[Moto]

@JoetheLion I had tried the button press but did it from the standby state not the active state and it didn’t seem to work. Just retried from the active state, held it until the 3 flashes occurred and now it works. Thx for reminding me again!

 

[crbdrb]

With amp in standby, hold front panel button in for 10-15 seconds and release. Count blinks of the front panel LED. 7 blinks => firmware v1.7, 8 blinks => firmware v1.8.

Interesting. I just received mine and while in standby (amber), it will not blink at all following 10, 15 or 20 second button holds.

 

[Moto]

It needs to be in active mode.

 

[crbdrb]

Two questions for owners if someone wouldn’t mind helping me out.

1. Did your amp come with the manual? All I got was the quick-start, warranty card and the safety notice.

2. I am getting a wicked hum (hear it in the next room loud) when a trigger cable is connected from the Denon receiver to the trigger input on the NAD. I have never had a hum before and all power goes through a power conditioner. I have zero noise when I unplug the trigger. Anyone else experience this?

 

[ebslo]

Two questions for owners if someone wouldn’t mind helping me out.

1. Did your amp come with the manual? All I got was the quick-start, warranty card and the safety notice.

2. I am getting a wicked hum (hear it in the next room loud) when a trigger cable is connected from the Denon receiver to the trigger input on the NAD. I have never had a hum before and all power goes through a power conditioner. I have zero noise when I unplug the trigger. Anyone else experience this?

Ground loop. Are you using RCA's? If you can switch to XLR do that. If not, bundle the trigger wire together with the RCA's using zip ties, velcro, or your cable management solution of choice. At the ends where they are necessarily unbundled, make sure no other wires run between the RCA's and the trigger wire. Imagine the loop made by the RCA's, amp and receiver chassis, and trigger cable; you want the area of this loop as small as possible and no other wires going through the loop. Try this before more extreme measures.

 

[crbdrb]

Ground loop. Are you using RCA's? If you can switch to XLR do that. If not, bundle the trigger wire together with the RCA's using zip ties, velcro, or your cable management solution of choice. At the ends where they are necessarily unbundled, make sure no other wires run between the RCA's and the trigger wire. Imagine the loop made by the RCA's, amp and receiver chassis, and trigger cable; you want the area of this loop as small as possible and no other wires going through the loop. Try this before more extreme measures.

I am currently using a Denon x3700 and BlueJean cable RCAs. No XLR possible right now until I upgrade the receiver. I will try bundling and report back. Considering the shielding on the BlueJean cable and how loud this is, I am not sure it’s going to make a dent, but I will try anything.

I am very familiar with ground loops generally, I have just never experienced it in my own setup, and never thought I would with how all of my equipment is connected.

 

[Jukebox]

I am currently using a Denon x3700 and BlueJean cable RCAs. No XLR possible right now until I upgrade the receiver. I will try bundling and report back. Considering the shielding on the BlueJean cable and how loud this is, I am not sure it’s going to make a dent, but I will try anything.

I am very familiar with ground loops generally, I have just never experienced it in my own setup, and never thought I would with how all of my equipment is connected.

I have exactly the same problem with the same products, C298 +Denon 3700. Tried a ground cable between both chassis, tried to ground the Denon with ifi groundhog but without succes.
The only thing that worked was to remove the trigger and use auto switch on/off.
The ground loop was gone 95%. I still have a slight hum if I put the ear next to the speakers, maybe I will trey the new ifi GND defender.

 

[crbdrb]

I have exactly the same problem with the same products, C298 +Denon 3700. Tried a ground cable between both chassis, tried to ground the Denon with ifi groundhog but without succes.
The only thing that worked was to remove the trigger and use auto switch on/off.
The ground loop was gone 95%. I still have a slight hum if I put the ear next to the speakers, maybe I will trey the new ifi GND defender.

Well, misery loves company I guess. I am not even sure I am willing yet to call this a ground loop issue. Either way, in the next few days, I am going to try a different receiver, and I am also going to try sending the NAD output trigger (while the NAD input is still connected to the Denon) to my power conditioner. I will report back what I find.

I wish my power conditioner had an input and output trigger, but it only has an input.

 

[Cooltool]

With amp in standby, hold front panel button in for 10-15 seconds and release. Count blinks of the front panel LED. 7 blinks => firmware v1.7, 8 blinks => firmware v1.8.

No, you do that in operational mode

 

[crbdrb]

No, you do that in operational mode

The manual states that what you are describing is for activating/deactivating Auto Sense Mode.

Enable Auto Sense mode
At operating mode, press and hold front panel Standby button and then release within 10-15 seconds. The Bridge mode indicator light flashes three times.

I still can’t figure out how to see which Firmware I have.

 

[Cooltool]

The manual states that what you are describing is for activating/deactivating Auto Sense Mode.

Enable Auto Sense mode
At operating mode, press and hold front panel Standby button and then release within 10-15 seconds. The Bridge mode indicator light flashes three times.

I still can’t figure out how to see which Firmware I have.

Hmmm, checked with the manual, you are correct! But I just did that and after I released the standby button it flashed once and bridge mode indicator flashed blue 8 times. Go figure!

 

[aslan7]

I read this thread with great interest. I am in the market for a class D amplifier and the C298 was high on the list. My finger has been hovering over the order button for a Nord Purifi amp but I keep thinking about the NAD. Well, in view of all these problems I may press that button. But the Nord review here of the Hypex unit that was miswired is a little disconcerting, especially considering it was a review unit. Decisions, decisions.

 

[Kal Rubinson]

The instructions I have say:
At operating mode, press and hold front panel Standby button and then release within 5-10 seconds. The Power Light should flash once and the Bridge mode indicator light will flash a number of times with the count indicating the firmware version (i.e., 8 flashes indicates v1.08). Worked for me. Go figure!

 

[Matias]

I read this thread with great interest. I am in the market for a class D amplifier and the C298 was high on the list. My finger has been hovering over the order button for a Nord Purifi amp but I keep thinking about the NAD. Well, in view of all these problems I may press that button. But the Nord review here of the Hypex unit that was miswired is a little disconcerting, especially considering it was a review unit. Decisions, decisions.

I would also suggest considering the cheaper, smaller and just as capable VTV unit with the EVAL-1 board for 999 usd.
https://vtvamplifier.com/product/vtv-amplifier-purifi-eigentakt-stereo-amplifier-based-on-eval-1/

 

[mocenigo]

I read this thread with great interest. I am in the market for a class D amplifier and the C298 was high on the list. My finger has been hovering over the order button for a Nord Purifi amp but I keep thinking about the NAD. Well, in view of all these problems I may press that button. But the Nord review here of the Hypex unit that was miswired is a little disconcerting, especially considering it was a review unit. Decisions, decisions.

Depending on where you are, I strongly recommend Apollon. They won’t ever wire wrong, and the little mini stereo Purifi amp in the premium enclosure is just a little gem to look at as well.

Roberto

 

[ebslo]

No, you do that in operational mode

The instructions I have say:
At operating mode, press and hold front panel Standby button and then release within 5-10 seconds. The Power Light should flash once and the Bridge mode indicator light will flash a number of times with the count indicating the firmware version (i.e., 8 flashes indicates v1.08). Worked for me. Go figure!

Yes, thanks for the corrections. That will teach me (once again) to never rely on memory, even for something I did within the last hour! As reference for others, original post with instructions was #222 and there are subsequent reports of it not working if the trigger is connected.