Nord One Up Ncore NC500 amps, Class D ready for prime time .....

The GAT output impedance is 100 ohms or less and the C52 is 200 ohms balanced.

Both worked great.

Jack said:
Mike

If Joe got them to work with the GAT and the C-52 they should be good to go. I will know soon with the W4S STP-SE and the Modwright LS-100.
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Hi Folks,

I am contemplating buying the Nord Up monoblock amp. I am auditioning a Merrill Veritas in my system but the nc500 got me thinking. Asked Colin how would the Nord compare with the nc1200 - he replied back saying that the difference is 5%. Its hard to believe that an amp with almost 1/5th the cost of nc1200 would fair so well. I am thinking of getting the SI 994 opamp to pair with the Cary slp-05 preamp and Acoustic Zen Crescendo speakers. While I think the speakers at 90db sensitivity will be super easy to drive, I don't know how would it fair with the Cary. The output impedance is 400Ohms and have read somewhere it actually reaches 600Ohms in some part of the spectrum. I had no problem pair with the Veritas as its at 100K. Does anyone would know the input impedance for the Nord ? Would it depend on the opamp ? Also wanted to see if the newer amps Nord is shipping with the updated revision of the input board to reduce the noise floor further ?

Thanks in advance.
 
Hi Folks,

I am contemplating buying the Nord Up monoblock amp. I am auditioning a Merrill Veritas in my system but the nc500 got me thinking. Asked Colin how would the Nord compare with the nc1200 - he replied back saying that the difference is 5%. Its hard to believe that an amp with almost 1/5th the cost of nc1200 would fair so well. I am thinking of getting the SI 994 opamp to pair with the Cary slp-05 preamp and Acoustic Zen Crescendo speakers. While I think the speakers at 90db sensitivity will be super easy to drive, I don't know how would it fair with the Cary. The output impedance is 400Ohms and have read somewhere it actually reaches 600Ohms in some part of the spectrum. I had no problem pairing with the Veritas as its at 100K. The input impedance for the Nord is 1.2K which seems pretty low. Is that a typo and wanted to mean 1.2M (megaohm) instead ? Would it depend on the opamp used ? Also wanted to see if the newer amps Nord is shipping with the updated revision of the input board to reduce the noise floor further ?

Thanks in advance.
 
Devg said:
Hi Folks,

I am contemplating buying the Nord Up monoblock amp. I am auditioning a Merrill Veritas in my system but the nc500 got me thinking. Asked Colin how would the Nord compare with the nc1200 - he replied back saying that the difference is 5%. Its hard to believe that an amp with almost 1/5th the cost of nc1200 would fair so well. I am thinking of getting the SI 994 opamp to pair with the Cary slp-05 preamp and Acoustic Zen Crescendo speakers. While I think the speakers at 90db sensitivity will be super easy to drive, I don't know how would it fair with the Cary. The output impedance is 400Ohms and have read somewhere it actually reaches 600Ohms in some part of the spectrum. I had no problem pairing with the Veritas as its at 100K. The input impedance for the Nord is 1.2K which seems pretty low. Is that a typo and wanted to mean 1.2M (megaohm) instead ? Would it depend on the opamp used ? Also wanted to see if the newer amps Nord is shipping with the updated revision of the input board to reduce the noise floor further ?

Thanks in advance.
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The 1.2k is the input impedance without the buffer. It should be around 100k with the buffer. And yeah in the world of audio it foolish to use cost as a quality gauge. Keep in mind that Colin builds these in his garage and sells direct. If he had a big operation, and went through the usual distributor/dealer chain, based on the BOM they would easily be triple the price. His cost to build these are substantially higher than the $5000 Bel Canto Ref600m that uses the same amp modules and power supplies.
 
Mivera Audio said:
The 1.2k is the input impedance without the buffer. It should be around 100k with the buffer. And yeah in the world of audio it foolish to use cost as a quality gauge. Keep in mind that Colin builds these in his garage and sells direct. If he had a big operation, and went through the usual distributor/dealer chain, based on the BOM they would easily be triple the price. His cost to build these are substantially higher than the $5000 Bel Canto Ref600m that uses the same amp modules and power supplies.
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Thanks Mike. When you say with buffer its around 100k, would it also depend on the opamps used ?
 
Hi.
A few weeks ago I designed a buffer for the NC500 as EPM2 improvement model.

I'm testing with operational amplifiers LM4562, LM49720 and JRC MUSES01.
When you have the new board, I'll check with Burson Audio V5, Sparkoslabs SS3602 and Sonic Imagery 994 Enh-Ticha
 

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jalejos said:
Hi.
A few weeks ago I designed a buffer for the NC500 as EPM2 improvement model.

I'm testing with operational amplifiers LM4562, LM49720 and JRC MUSES01.
When you have the new board, I'll check with Burson Audio V5, Sparkoslabs SS3602 and Sonic Imagery 994 Enh-Ticha
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Hi Jalejos,

You should consider using the Hypex HxR, or Bellenson regulators. They are much better than those IC regulators.

You will probably have a hard time fitting the SIL 994's with so little clearance between the Dip8 socket and caps.
 
Thanks for the tip. Both are covered in version 2. When I got in touch with Richard to give me budget of the operational amplifiers 994, I said, very kindly, to make some changes in my design to reduce noise. These modifications are contemplated in this V2.
 

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jalejos said:
Thanks for the tip. Both are covered in version 2. When I got in touch with Richard to give me budget of the operational amplifiers 994, I said, very kindly, to make some changes in my design to reduce noise. These modifications are contemplated in this V2.
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That's good. Just make sure those caps aren't in the way. The SIL 994 is a big opamp. And you want to keep the leads as short as possible or they can pickup noise
 
Mivera Audio said:
That's good. Just make sure those caps aren't in the way. The SIL 994 is a big opamp. And you want to keep the leads as short as possible or they can pickup noise
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Have you tried the NC500 on any low Z loads , like large ESL's and or ribbons ? Is there an inductor output mod for Low-Z loads ..?


Regards
 
a.wayne said:
Have you tried the NC500 on any low Z loads , like large ESL's and or ribbons ? Is there an inductor output mod for Low-Z loads ..?


Regards
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I tried them on a pair of Martin Logan ascent 2's that dip down to 1.2 ohms. We had them cranked up to levels far beyond what I thought those speakers could put out for over 30 minutes. The sound was ultra clean with no sign of strain. And the amp modules were barely warm to the touch. These amps can handle 1 ohm loads. They will just be current limited to around 500w at 1 ohm.
 
Mivera Audio said:
I tried them on a pair of Martin Logan ascent 2's that dip down to 1.2 ohms. We had them cranked up to levels far beyond what I thought those speakers could put out for over 30 minutes. The sound was ultra clean with no sign of strain. And the amp modules were barely warm to the touch. These amps can handle 1 ohm loads. They will just be current limited to around 500w at 1 ohm.
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Mike, Which amplifier and configuration was that specifically? Quad spoken here.
 
Thanks for the response , drive was never the issue when i have tried class-D it's there tonal balance that took a dive , Timbre , especially on classical and piano sounded odd ..

Interested in trying a pr of these NC500 to see if much improved there ....

Regards
 
Dizzie said:
Mike, Which amplifier and configuration was that specifically? Quad spoken here.
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That was some NC 500 based amps I built. But all are the same power wise as long as they use the SMPS1200A700 power supply. I wouldn't be afraid to recommend these for any speaker.
 
a.wayne said:
Thanks for the response , drive was never the issue when i have tried class-D it's there tonal balance that took a dive , Timbre , especially on classical and piano sounded odd ..

Interested in trying a pr of these NC500 to see if much improved there ....

Regards
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I've found the same to be true with every class D amp I've heard besides the NC500's with a premium input stage. If you need more low impedance grunt I recommend the Bel Canto blacks.
 
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