Nord One Up Ncore NC500 amps, Class D ready for prime time .....
- Thread starter joeinid
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Randy Myers
Well-known member
Got ya.... didn't want to state the obvious but I have seen some one use adapters rather than an XLR cable before.
Randy Myers
Well-known member
That should be correct....
jadedavid
New member
That is correct Tomy2. The pin you are describing is pin 2 and should be the hot. and is as you have tested it. The other two pins are tied together and will show continuity to the outside of the RCA plug. Should be good to go.
jadedavid
New member
Looks like a well thought out and executed build. Nothing sticks out from the photo's. Where is the noise coming from? The larger yellow transformer? As has been stated previously, the use of cheater AC plugs are useful for troubleshooting problems like this. Use them on both amps and go through all the possible plug in combinations to see if any of them correct the issue. Also a white paper from Jensen transformers describes a simple RCA shorting plug build for isolating the interconnect connection of one component from the other and is also worthwhile to use in tracking down the issue. A simple online search should turn it up for you. It is not recommended to permanently leave the cheater plugs in as it defeats the safety ground. I do have a circuit schematic (super hum buster) provided by James Bongiornio if all else fails. But I would recommend that you communicate directly with Colin as he is the builder and knows his product best.
The buzz is coming from that yellow transformer on the power supply. Its a switching power supply and I have heard similar buzz from other switching psu before. You really hear it if you stick your ears like 3" closer to the chassis, otherwise not. Others who are saying theirs is dead silent is what is worrying me. Can you guys one more time go up and close and see if you can hear anything ? I had the Merrill Veritas a while back for couple of days in my room. The Veritas uses the similar Hypex SMPS power supply but I didn't hear anything from the Amp but it could that they use thick aluminum billet which prevented it from hearing.
Jack
Active member
Devg
I just put my ear directly against the face plate which is as close as I can get and nothing. To me if you have to get that close to hear electrical hum it is a non issue. And yes the thinner heavily vented case is probably making it easier to hear, especially though the bottom vents where it would reflect off of the shelf.
I just put my ear directly against the face plate which is as close as I can get and nothing. To me if you have to get that close to hear electrical hum it is a non issue. And yes the thinner heavily vented case is probably making it easier to hear, especially though the bottom vents where it would reflect off of the shelf.
jadedavid
New member
Devg, having your listening chair 3" from your amps might be a little too close. I think if you would move your listening position back further it would solve the noise problem. LOL
boggit
New member
- Joined
- May 16, 2016
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- 84
I called both Devg and tomy2 this evening about 7.30 UK time. Before I did I went out to the workshop and listened to the amps nothing dead silence. I put my ear to the top grill which has full grill holes and yes a very slight hum from the SMPS, came in checked 2 other amps that were on test, ear to the grill slight hum as you would get from a TV if you put your ear against the area with the PSU. I even checked my demo amp that's older and yes slight hum with my ear on the grill. I have never noticed this before and you can not hear it if you are stood over the amps or indeed plugging XLR and speaker cables in and out which I do on a regular basis. Don't forget the Veritas has a thick expensive case with no grill on top so it should be in a $10K amp that's probably why you did nit hear the SMPS.
I hope from our conversations that this is just a case of being sensitive to new equipment and wanting to make sure all is well. Its very difficult to find the balance of what could be a genuine problem and what is normal operation especially when its played out on a public forum. Rest assured if there is a problem we will remedy it.
I hope from our conversations that this is just a case of being sensitive to new equipment and wanting to make sure all is well. Its very difficult to find the balance of what could be a genuine problem and what is normal operation especially when its played out on a public forum. Rest assured if there is a problem we will remedy it.
I could not hear anything and really do not want to stick my head in the rack to hear something that causes no problems. With my Krells (now gone) you could get a variety of noises as the cooling fins warmed up or worse when they were cooling down. I always got 'clicking' noises. And 800w of heat at idle. There were always buzzing and humming noises audible near (1-2 feet) depending on the time of day (yep out in the UK boondocks so the mains is not the highest quality). And if you put your head close to the speakers there was a variety of quiet noises. The Nords have nothing.
My Audionotes also have a variety of noises and if you place your head a few inches away from the amp you burn your ears
The XLR/phono adaptor caused a real problem in that we could not get full power from the amp even with the volume controls to the max. I hope no one else has had a similar problem and a quick swap resulted in normality. Make sure your adaptor has the right pin hot and watch out for the pin numbers. They do not run clockwise or anti-clockwise.
Never tested the amp at 'full power' as 600w/channel (for my speakers) will give about 120db at 12 feet which is somewhat loud. I SAID IT IS LOUD.
Overall though I and friend preferred the XLR connection straight, rather than (even more expensive) phono cables with an adaptor. Of course if you only have phono connections then there is no choice. Having said that it was fairly subtle
My Audionotes also have a variety of noises and if you place your head a few inches away from the amp you burn your ears
The XLR/phono adaptor caused a real problem in that we could not get full power from the amp even with the volume controls to the max. I hope no one else has had a similar problem and a quick swap resulted in normality. Make sure your adaptor has the right pin hot and watch out for the pin numbers. They do not run clockwise or anti-clockwise.
Never tested the amp at 'full power' as 600w/channel (for my speakers) will give about 120db at 12 feet which is somewhat loud. I SAID IT IS LOUD.
Overall though I and friend preferred the XLR connection straight, rather than (even more expensive) phono cables with an adaptor. Of course if you only have phono connections then there is no choice. Having said that it was fairly subtle
Another data point.
Off I go to another pal's place over in sunny Cambridge. He has a tidy set up consisting of the Linn Renew DS, which is the Klimax in a grey box. That goes into a McIntosh integrated amp (6500 or 6700). Feeding a set of PMC Fact 8s. I brought along the Nuforce P9s, Khozmo passive preamp and the Nord, of course. So off we go with his eclectic music. David Gilmour, Yes, Michael MacDonald (organist), Pink Floyd. And his system sounded very tidy indeed. Power, dynamics and great clarity. The bass had a hard time as the room reinforces the bass a little. OK on goes the Nords/NuforceP9 and over to him......Oddly enough it was very similar to my other friends experience. First few tracks were.....'not heard that before' ....'that's nice'......'that's clearer'. McIntosh amps are good so I should not be surprised that there was not a night and day difference. It was more subtle but easily heard differences that makes the amps better. For me the aggression in the sound had gone/reduced. I suspect the Linn and PMCs are very sensitive here and if the recordings had it then they will show it. I was a bit surprised as my previous Mcs were calmer, quiet and not aggressive amps. Not an enormous difference but there it was. The bass was now totally under control and at first sounded less impressive. But there was more info. and drive.
We then swapped in the passive preamp and got the bad adaptor issue. Ho hum. So no useful information there.
I have tried the passive/active preamps at home and big surprise......not.....the active pre has great drive, detail and top end...the passive has a wonderful 3D ssoundstage, super natural, less drive and impact and does not extend as far at the top end.....What is my preferences? Well it depends. Mostly the active set up with good quality XLRs.
He has ordered a Nord; big surprise.
Off I go to another pal's place over in sunny Cambridge. He has a tidy set up consisting of the Linn Renew DS, which is the Klimax in a grey box. That goes into a McIntosh integrated amp (6500 or 6700). Feeding a set of PMC Fact 8s. I brought along the Nuforce P9s, Khozmo passive preamp and the Nord, of course. So off we go with his eclectic music. David Gilmour, Yes, Michael MacDonald (organist), Pink Floyd. And his system sounded very tidy indeed. Power, dynamics and great clarity. The bass had a hard time as the room reinforces the bass a little. OK on goes the Nords/NuforceP9 and over to him......Oddly enough it was very similar to my other friends experience. First few tracks were.....'not heard that before' ....'that's nice'......'that's clearer'. McIntosh amps are good so I should not be surprised that there was not a night and day difference. It was more subtle but easily heard differences that makes the amps better. For me the aggression in the sound had gone/reduced. I suspect the Linn and PMCs are very sensitive here and if the recordings had it then they will show it. I was a bit surprised as my previous Mcs were calmer, quiet and not aggressive amps. Not an enormous difference but there it was. The bass was now totally under control and at first sounded less impressive. But there was more info. and drive.
We then swapped in the passive preamp and got the bad adaptor issue. Ho hum. So no useful information there.
I have tried the passive/active preamps at home and big surprise......not.....the active pre has great drive, detail and top end...the passive has a wonderful 3D ssoundstage, super natural, less drive and impact and does not extend as far at the top end.....What is my preferences? Well it depends. Mostly the active set up with good quality XLRs.
He has ordered a Nord; big surprise.
Last edited:
tomy2
New member
- Joined
- Sep 20, 2014
- Messages
- 131
I put in a cheater plug yesterday and it did indeed take the hum away I was getting in the left channel amp. It's plugged into a surge protector right now but I may just take the cheater plug out because as I told Colin in the end its not that big of a deal because when I turn on the music I get fantastic performance from these amps. I have to be real close to the speaker to hear it.
As I mentioned before, the hum has reduced since I first got the amps so I'm guessing after further burn in they'll be just fine. Sorry if I turned a mole hill into a mountain. Sometimes the ocd side of this audio hobby kicks in and you want everything perfect but at the end of the day I'm a happy camper with these Nords.
Coiln was great to talk to and offered to do whatever to make me happy but I told him I wasn't giving up these amps. I see why everybody says Colin is one of the good guys, he seems like the kinda guy you would love to hang out at a pub with. I'd feel very comfortable ordering from him again...
Cheers Colin and all the Nord owners, happy listening!
-Tom
As I mentioned before, the hum has reduced since I first got the amps so I'm guessing after further burn in they'll be just fine. Sorry if I turned a mole hill into a mountain. Sometimes the ocd side of this audio hobby kicks in and you want everything perfect but at the end of the day I'm a happy camper with these Nords.
Coiln was great to talk to and offered to do whatever to make me happy but I told him I wasn't giving up these amps. I see why everybody says Colin is one of the good guys, he seems like the kinda guy you would love to hang out at a pub with. I'd feel very comfortable ordering from him again...
Cheers Colin and all the Nord owners, happy listening!
-Tom
Jack
Active member
Tom
Just as a quick experiment swap the two input cables between the amps and see if it follow that particular cable/adaptor left to right. Might completely solve the mystery.
Just as a quick experiment swap the two input cables between the amps and see if it follow that particular cable/adaptor left to right. Might completely solve the mystery.
tomy2
New member
- Joined
- Sep 20, 2014
- Messages
- 131
Yep, tried that yesterday but no luck. However.....I dug deep in my bag of old goodies and found a set of Neutrik brand xlr cables and low and behold the hum goes away! :disbelief: Without the cheater plug I should add.
So even though the one end is attached with an adapter to connect to the RCA input on both the Tisbury passive and tubed preamp the balanced cable did the the trick. With the passive I get dead silence and the tubed pre I get the usual slight hiss from the tweeter but no hum from the mid driver.
So what is it about the Cardas adapter I showed a pic of that has the hot pin on it correctly? Why does....ahhh who cares.
Randy Myers
Well-known member
Excellent... glad you got it figured out!
Jack
Active member
Tom
Apparently the wiring inside of one of the Cardas adaptors is not right. Might want to contact the seller and swap them out. You might find a pair of Neutrik adaptors locally. Also if you are still using Dave's cables see if he can re-terminate the amp end. Glad you figured it out.
Apparently the wiring inside of one of the Cardas adaptors is not right. Might want to contact the seller and swap them out. You might find a pair of Neutrik adaptors locally. Also if you are still using Dave's cables see if he can re-terminate the amp end. Glad you figured it out.