Class D amplifiers

nc42acc

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Do class d amplifiers require break in time? Do they get better as they warm up? Due to the different nature in the class d design do they differ in these respects to other amplifier topologies?
 

Blizzard

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Do class d amplifiers require break in time? Do they get better as they warm up? Due to the different nature in the class d design do they differ in these respects to other amplifier topologies?


I find the output stages don't require burn in, but sound better once warmed up for a long time. Best to never turn off. However the input stages need burn in. Especially if discrete.
 

spazmatron

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I find the output stages don't require burn in, but sound better once warmed up for a long time. Best to never turn off. However the input stages need burn in. Especially if discrete.

mike, i just found the off switch for the eco mode on my CDP (two weeks ago) before that it would switch its self off every 30 when idle. i think it sounds better now its left on but why?
 

Blizzard

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The Hypex NC400 mono amps are sounding really good after a 24 hour burn in.

Just leave them on for days and then listen. Leave them play on random at low volume overnight and listen in the morning. You should hear the NC-500's when coupled with this discrete class A Jfet folded cascode input stage. Anyone who has ever turned their nose up at class d only did so because they haven't heard this. However the cost of this input stage is 10X what the NC-500's cost.

Jfet folded cascode class A.jpg
 

Blizzard

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mike, i just found the off switch for the eco mode on my CDP (two weeks ago) before that it would switch its self off every 30 when idle. i think it sounds better now its left on but why?

Once all the components are warmed up to optimum operating temperature, they perform better. I think having the electrons settling in nice also helps. I'm not 100% sure.
 

Blizzard

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nc42acc

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Mike I am patiently waiting, I have no issues with class A to Z as long as it sounds good. I can see the op amp inputs as being a limiting factor.


Just leave them on for days and then listen. Leave them play on random at low volume overnight and listen in the morning. You should hear the NC-500's when coupled with this discrete class A Jfet folded cascode input stage. Anyone who has ever turned their nose up at class d only did so because they haven't heard this. However the cost of this input stage is 10X what the NC-500's cost.

View attachment 25982
 

Blizzard

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Mike I am patiently waiting, I have no issues with class A to Z as long as it sounds good. I can see the op amp inputs as being a limiting factor.

The NC400 has a discrete input stage. No IC opamps. It's extremely good, however designed to be 100% neutral. Some people don't like that because they are used to amps that sweeten the sound. But combined with the Gustard that has a warm sounding output stage, it should be a good match.
 

nc42acc

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Mike thanks for the clarification on the NC400. Not trying to be argumentative but the Gustard is not warm sounding.

The NC400 has a discrete input stage. No IC opamps. It's extremely good, however designed to be 100% neutral. Some people don't like that because they are used to amps that sweeten the sound. But combined with the Gustard that has a warm sounding output stage, it should be a good match.
 

Blizzard

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Mike thanks for the clarification on the NC400. Not trying to be argumentative but the Gustard is not warm sounding.

Well compared to DAC's that use straight IC opamp output stages it is according to what most say about it. The reason they used the output stage design they did was to take the edge off the 9018 chip. Compare it to the L.K.S MH-DK003 DAC with IC opamps in place and you will hear what I mean.
 

nc42acc

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I think we both are saying the same thing with different adjectives. To me the X20 is very neutral compared to other DACs. No glaring deficiency anywhere.

Well compared to DAC's that use straight IC opamp output stages it is according to what most say about it. The reason they used the output stage design they did was to take the edge off the 9018 chip. Compare it to the L.K.S MH-DK003 DAC with IC opamps in place and you will hear what I mean.
 

Blizzard

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I think we both are saying the same thing with different adjectives. To me the X20 is very neutral compared to other DACs. No glaring deficiency anywhere.

I'm not saying there's any deficiencies, I'm just saying they voiced it to have a warmer sound signature than most DAC's that use IC opamp based output stages (most). What have you compared it with for reference? I know the Auralic vega was one of them, but they did the same thing. Maybe even more so. If someone had a $1000 DAC that used an IC opamp based output stage, and wanted to drive the NC400's direct with it, I'd say get different amps.The combination would be too cold and dry.
 

nc42acc

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I have direct compared to the Schiit Yggdrasil, Auralic Vega, Teac UD-503, Line Magnetic LM503ca, Oppo BDP-105



I'm not saying there's any deficiencies, I'm just saying they voiced it to have a warmer sound signature than most DAC's that use IC opamp based output stages (most). What have you compared it with for reference? I know the Auralic vega was one of them, but they did the same thing. Maybe even more so.
 

nc42acc

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Mike my use of the word deficiencies was a poor choice.

I'm not saying there's any deficiencies, I'm just saying they voiced it to have a warmer sound signature than most DAC's that use IC opamp based output stages (most). What have you compared it with for reference? I know the Auralic vega was one of them, but they did the same thing. Maybe even more so. If someone had a $1000 DAC that used an IC opamp based output stage, and wanted to drive the NC400's direct with it, I'd say get different amps.The combination would be too cold and dry.
 

Blizzard

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I have direct compared to the Schiit Yggdrasil, Auralic Vega, Teac UD-503, Line Magnetic LM503ca, Oppo BDP-105

Okay the Oppo is the perfect comparison. Drive the NC400's direct from the Oppo and compare to the X20U and share what you hear as far as difference in tonal signature.
 

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