NAD C 298 Power Amplifier With Purifi Eigentakt Amplification

[RGibran]

Hang in there. Perhaps Crutchfield had some early production models. It's been speculated the problem lay with those units although my original defective unit was drop shipped directly from Lenbrook America. Fortunately everyone's replacement seems trouble free.

Interesting tidbit on Auto sense off. Where did you gather that info? I was under the impression the unit did not include the "off" feature and I don't believe it documented in the manual?

Speaking of the manual I find the following note most curious. Why offer selectable switching if important to maintain default?

IMPORTANT NOTES
Maintain default settings of the following control switches:
• LEFT and RIGHT SELECT towards SINGLE-ENDED
• INPUT SELECT to FIX
• AUTO SENSE LEVEL to MID

Anyway, very happy with my purchase.
Robert

 

[nothingman]

Hang in there. Perhaps Crutchfield had some early production models. It's been speculated the problem lay with those units although my original defective unit was drop shipped directly from Lenbrook America. Fortunately everyone's replacement seems trouble free.

Interesting tidbit on Auto sense off. Where did you gather that info? I was under the impression the unit did not include the "off" feature and I don't believe it documented in the manual?

Speaking of the manual I find the following note most curious. Why offer selectable switching if important to maintain default?

IMPORTANT NOTES
Maintain default settings of the following control switches:
• LEFT and RIGHT SELECT towards SINGLE-ENDED
• INPUT SELECT to FIX
• AUTO SENSE LEVEL to MID

Anyway, very happy with my purchase.
Robert

Please see attached manual “version 3” by the file name, that I downloaded when I took deliver of the unit mid-December. I can’t seem to get NAD’s website to work for me to see if there have been any updates.

Page 5 (left column) of manual (attached) says “auto standby” can be enabled/disabled in the “operating mode” by pressing and holding the power button for “more than 15 seconds.” I’ve tried this and it works as described. My unit used to turn off when it didn’t detect a signal, but I found myself using the power button anyways so I disabled it and it stays on as long as it doesn’t totally self-destruct under my unit’s apparent defect.

Page 6 (right column) dedicated to “auto sense” gives the same exact same instructions about holding the power button while in operating mode, but says “10-15 seconds.” Same description of the light indicators and what they mean. I have found this does not work at all. I have tried to see if there is one set of light flashes between 10-15 seconds, indicating auto on function, and another set of flashes after 15 seconds, indicating auto off function, and there isn’t. Mine only flashes exactly at 15 seconds, and seemingly only controls auto off. Meanwhile, whether showing two or three flashes, my unit turns on when it detects a signal.

And none of this should be triggering the red light and disabling the unit altogether until a hard reset is done. It should either be from amber standby to blue operational, or the other way around.

I’m hopeful since you guys have seemed to have better units already. I can’t imagine Crutchfield has sold all that many since December 15 when I bought mine, so I’m a little worried the new one will be from the same batch, but let’s see.

 

[nothingman]

Speaking of the manual I find the following note most curious. Why offer selectable switching if important to maintain default?

IMPORTANT NOTES
Maintain default settings of the following control switches:
• LEFT and RIGHT SELECT towards SINGLE-ENDED
• INPUT SELECT to FIX
• AUTO SENSE LEVEL to MID

Anyway, very happy with my purchase.
Robert

I think those are supposed to just be a “quick start” type direction, e.g. most people are using single ended, shouldn’t mess with the gain, and should leave the auto sense in the middle to start off.

 

[RGibran]

Please see attached manual “version 3” by the file name, that I downloaded when I took deliver of the unit mid-December. I can’t seem to get NAD’s website to work for me to see if there have been any updates.

Page 5 (left column) of manual (attached) says “auto standby” can be enabled/disabled in the “operating mode” by pressing and holding the power button for “more than 15 seconds.” I’ve tried this and it works as described. My unit used to turn off when it didn’t detect a signal, but I found myself using the power button anyways so I disabled it and it stays on as long as it doesn’t totally self-destruct under my unit’s apparent defect.

Page 6 (right column) dedicated to “auto sense” gives the same exact same instructions about holding the power button while in operating mode, but says “10-15 seconds.” Same description of the light indicators and what they mean. I have found this does not work at all. I have tried to see if there is one set of light flashes between 10-15 seconds, indicating auto on function, and another set of flashes after 15 seconds, indicating auto off function, and there isn’t. Mine only flashes exactly at 15 seconds, and seemingly only controls auto off. Meanwhile, whether showing two or three flashes, my unit turns on when it detects a signal.

Thanks for the heads up on the revised manual. Not sure which version I had since I renamed it but there is no mention of the page 5 or 6 info contained in the new version.

So I take it from your description disabling "auto sense" does not work. It appears it's just ON by default, at least on your unit?

Thankful I use a trigger!

Robert

 

[nothingman]

Thanks for the heads up on the revised manual. Not sure which version I had since I renamed it but there is no mention of the page 5 or 6 info contained in the new version.

So I take it from your description disabling "auto sense" does not work. It appears it's just ON by default, at least on your unit?

Thankful I use a trigger!

Robert

Interesting. I haven’t seen a different version of the manual myself.

Correct. Auto-sense is always on for me, and the instructions in the v3 manual don’t work because there aren’t actually two functions of the press-and-hold-power scheme. Yes, I have tried press-and-hold-power in standby mode instead of operational mode and nada.

One more reason I’m annoyed with miniDSP that they didn’t bother to include a 12V trigger on a device they market as a preamp! I love the simplicity of a basic mono trigger cable compared to this auto sense and auto off stuff.

 

[nothingman]

Y’know, I had no problem downloading the manual from their website when I first got the unit. I went to “downloads” clicked the manual, clicked “i agree” and it served up the v3 pdf.

https://nadelectronics.com/product/c298-stereo-power-amplifier/

Now, two weeks later, when I try the same process on both on a windows machine using chrome and an ipad pro running safari, both with blockers turned off, I get nothing. Just kicked back to the product page. Let me know if you’re any different. Not to be conspiratorial, but maybe there’s something going on behind the scenes over at NAD with this thing.

 

[lappy]

The manual is located at
https://nadelectronics.com/wp-content/uploads/2020/06/C298-OM-EN-v04.pdf

 

[nothingman]

The manual is located at
https://nadelectronics.com/wp-content/uploads/2020/06/C298-OM-EN-v04.pdf

Thanks! V4!

No change to the auto on/off on pages 5 and 6, however.

How did you access this? Like I mentioned, the C298’s product page stopped working for me.

 

[lappy]

The manual is located at
https://nadelectronics.com/wp-content/uploads/2020/06/C298-OM-EN-v04.pdf

This is new to me:
"Enable Auto Standby mode At operating mode, press and hold front panel Standby button for more than 15 seconds until Bridge mode indicator light flashes three times. "

 

[lappy]

I wonder if the auto standby works on the earliest models since it is not mentioned in the earlier versions of the manual? I bought my unit on the release date here in sweden....will test this later. Early answer from NAD support was that the C298 does NOT have auto standby. Very strange.

 

[nothingman]

For those wondering, I just ran v3 and v4 through a document comparison tool and literally the only change is “V03” changed to “V04” on the bottom of the final page.

 

[nothingman]

Guys, I figured out the “auto-sense on” instructions on page 6 which are not just unclear, but totally inaccurate.

When NAD says, “At operating mode, press and hold front panel Standby button for 10-15 seconds until Bridge mode indicator light flashes two [or three] times,” what they mean is press and hold standby button and have a stopwatch ready because you have to let it go between 10 and 15 seconds to toggle the auto-sense on feature. When you let go it will flash either the two or three times. That is absolutely not “hold until light indicator flashes” so I make no apologies for missing this.

This still has zilch to do with my unit completely shutting down and giving me a red light for no reason, but I’ll keep a close eye on it until the replacement arrives.

 

[RGibran]

This is new to me:
"Enable Auto Standby mode At operating mode, press and hold front panel Standby button for more than 15 seconds until Bridge mode indicator light flashes three times. "

Exactly! I downloaded the manual from your link back on page 4 of this thread. There was no inclusion of the paragraphs of how to enable/disable auto sense or auto standby. And I recall your relaying to us the response from NAD that the unit did not include Auto Standby! So...was there a firmware upgrade and revision of the manual? I will be interested in the outcome of your test of the feature on your unit.

Robert

 

[RGibran]

Y’know, I had no problem downloading the manual from their website when I first got the unit. I went to “downloads” clicked the manual, clicked “i agree” and it served up the v3 pdf.

https://nadelectronics.com/product/c298-stereo-power-amplifier/

Now, two weeks later, when I try the same process on both on a windows machine using chrome and an ipad pro running safari, both with blockers turned off, I get nothing. Just kicked back to the product page. Let me know if you’re any different. Not to be conspiratorial, but maybe there’s something going on behind the scenes over at NAD with this thing.

Product page working the same for me.

 

[lappy]

The "new" feature auto standby seems to work, or at least the enable/disable part of it. Had to remove the trigger cable for it to work though. This is really good news for me. I'm currently running the C658 as preamp/streamer/dac to the C298....and I'm not that impressed by it. But it has 12v trigger out and it goes into auto standby bringing the C298 down with it. It also wakes up the C298 from standby. Having the same functionality without a trigger cable means that I can look at a lot more candidates to replace the C658 if I decide to return it.

 

[nothingman]

Once I figured out how to decode the NAD manual and disable both auto-off and auto-on yesterday I was feeling a little sheepish about jumping to do an exchange and hitting this forum since I figured my C298 would probably work perfectly now, but nope. It’s been on for a couple hours, playing your normal medium levels, and just went into red light limp mode. No heat from the unit or anything like that. My streamer is still chugging along happily playing the track.

 

[TomekNet]

Hi. Will C 298 be measured anytime soon?

 

[mSpot]

Hi. Will C 298 be measured anytime soon?

Has anybody volunteered to send their C298 to Amir?

 

[kenchai]

I wonder how using an external streamer and driving the C298 directly from an RME Adi2 fs dac would compare to using the C658 or any preamp if you don't have analogue sources. Thoughts?

 

[Jukebox]

Count me as number four with a shutoff problem. Something is going on in terms of quality control. Paging @Kal Rubinson just in case he might be able to bring this up with NAD since they’re not very responsive (I had a very simple, short question over email for them two weeks ago and they acknowledged receipt but never took the time to follow up).

What happens to me is, I’m listening normally for an hour or two, not touching the remote or my smartphone or anything that might cause a spike in signal, and the sound just stops and the unit is unresponsive and the red light is on and stays on until I do a hard reset with the rear power switch. After that, the amber standby light reappears, and the unit powers on and goes back to delivering the SHD’s signal that never stopped playing. This has happened three times now.

So that we’re all clear, the unit has three LED colors at the power button: amber for standby, red for the transition from standby to operational and for power protect shutoff (and other fatal errors I assume), and blue for operational.

My preamp is a miniDSP SHD, so I’m forced into using auto sense because of lack of 12V trigger, but I don’t think this problem we’re having has anything to do with it becuase my “auto sense on” turns on fine (set to low), and I don’t have “auto sense off” activated (press and hold power button while unit is operational for ~15 seconds — two flashes from the bridge mode light mean auto sense off has been disabled, and three flashes mean it has been enabled). When auto sense off is activated the unit goes into standby, which means the light turns from blue to amber and can be turned back on with a fresh signal.

Crutchfield has me covered, so after a 5mins phone call a new unit is on the way. Hoping I get a perfectly functioning replacement like @Canth but this is troubling from a long term reliability standpoint. Part of the reason to go with someone like NAD over the small scale assemblers is the sense that all kinks are worked out.

It is a common unfortunate problem and also an easy fix via software update over the USB service port by authorized personnel.
My unit is working just fine. I think only the first ones had this issue