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Hypex NCx500 Class D Amplifier Review
- Thread starter amirm
- Start date
cheapmessiah
Active Member
2ohm sounds like too little of a load to push so much power, but im far from an expert
In my mind, having a pedal format power amp that can output 200w@8ohm for less than a 100€ and a larger enclosure one that can output 800-1000w @ 4ohm for 500€ would be great products that the market is ready to consume.
Please forgive this tangent.
I have a Topping Pre90 (40Ω balanced output impedance) and a pair of MPA-M400ET (1ET400A). I'd fully intended to set the Purifi to bypass the buffer since the Pre90 should have no trouble into 4.4 kΩ, even at over 10V according to the reviews. But when I switched it over after a day of listening to the Purifi at the default 25.3dB/94kΩ, something seemed off. I gave it a few days but the Pre90 didn't sound all that "happy"; the sound was a bit bland and colorless, less dynamic. No obvious distortion, just kind of a bleaching of textures.
So I switched the jumpers to 94kΩ/20dB (where they have remained since) and all was sweetness and light, magnificent.
Is this nuts?
You are wise enough to suspect 2 Ohms is danger zone and it is danger zone for amplifiers of most designs. Stay away from it.
Wouldn’t the speaker cabinet be the limiting factor in transportability of guitar amplifiers?
cheapmessiah
Active Member
They are and arent at the same time. Modeling and DSP are so good at the moment that you dont need the cabinet unless theres absolutly no other way to produce loudness. Most touring bands plug directly to PA on venues, and to a computer with studio monitors or headphones at home or rehearsing, most recording studios have gear on site that they know how it works, how to mic it and how to mix it, so the cabinet a musician would transport is redundant there too.
However you need to have backup if you want to jam or go to a venue that lacks proper PA, theres where having the poweramp separated from the signal chain becomes convenient, as you would only move power and cab when its needed, and the rest of the time you move around with just your signal chain as much as you can.
As for the weight of he cab, a super light weight cab can be made relatively easy nowadays, as long as the enclosure suffers minimal deformation at maximum volume and it is mechanicaly decoupled from the floor/room, both factors have traditionally been the main constrains that made heavy enclosures necessary.
Thank you but how is that related to a high power amplifier like this one to possibly be used for guitar amplification?
OK it is a reason I rarely contribute to forums these days and probably won't be again here - the abuse is too tedious. But please make sure in future you are even handed in your deletions and don't give special treatment to Grand Contributors and Forum Donors.Some more posts deleted as off topic. Some of you are flirting with disaster. Last verbal (typed) warning.
If you look up you will see everything was deleted. Sometimes the forum doesn’t update because you still have the page loaded in your computers buffer. Hit refresh and you will see it’s all gone.
OP
- Thread Starter
- #352
OK, I investigated the cause of excess distortion at higher power. I had noticed that with buffer setting distortion had gone down which should not have been the case. I noted on the graph that my dummy load connection may need revisiting. Indeed that was the case. I use screw terminal locking banana plugs. The screws sometimes come loose. I checked and they were tight. But under instrumentation I could see that wiggling the wiring caused good few dB change at higher power. So I tightened them to death and result was much improved performance:
Due to lower distortion, we could eek out some more power at 1%THD so I updated the max and peak measurements as well:
As I expected, the impact here is lower due to much less current travelling through the wiring terminal. Still, we get closer to state of the art. As an aside, I verified that the Purifi measurements were with high gain (re-ran that measurement as part of testing the wiring).
Finally, the lowered distortion exists at all frequencies:
The buffered results would likely get a bit better as well. I will see if I can re-test those.
These results show the Hypex NCx500 to be even more remarkable than my original testing showed!
Due to lower distortion, we could eek out some more power at 1%THD so I updated the max and peak measurements as well:
As I expected, the impact here is lower due to much less current travelling through the wiring terminal. Still, we get closer to state of the art. As an aside, I verified that the Purifi measurements were with high gain (re-ran that measurement as part of testing the wiring).
Finally, the lowered distortion exists at all frequencies:
The buffered results would likely get a bit better as well. I will see if I can re-test those.
These results show the Hypex NCx500 to be even more remarkable than my original testing showed!
OP
- Thread Starter
- #353
FYI the review is updated as well.
JSmith
Master Contributor
Hello Rod, I'm sure many members here would be interested in your experience in speaker design, so I would suggest to take the comments about your Hypex NCore DIY amp posted with a grain of salt (although she wasn't pretty) and stick around.
Is that a highway to the?
Ah, excellent!
JSmith
OK, I investigated the cause of excess distortion at higher power. I had noticed that with buffer setting distortion had gone down which should not have been the case. I noted on the graph that my dummy load connection may need revisiting. Indeed that was the case. I use screw terminal locking banana plugs. The screws sometimes come loose. I checked and they were tight. But under instrumentation I could see that wiggling the wiring caused good few dB change at higher power. So I tightened them to death and result was much improved performance:
Due to lower distortion, we could eek out some more power at 1%THD so I updated the max and peak measurements as well:
As I expected, the impact here is lower due to much less current travelling through the wiring terminal. Still, we get closer to state of the art. As an aside, I verified that the Purifi measurements were with high gain (re-ran that measurement as part of testing the wiring).
Finally, the lowered distortion exists at all frequencies:
View attachment 257942
The buffered results would likely get a bit better as well. I will see if I can re-test those.
These results show the Hypex NCx500 to be even more remarkable than my original testing showed!
That’s more like it! Thanks for the follow up.
Michael
Awesome the fix was so easy to rectify. Some days we can’t see the Forrest through the trees.
In this particular case you did actually have a Screw loose!
OP
- Thread Starter
- #357
For those questioning the APx555 analyzer ability to produce high output voltage into very low impedances, you owe the box an apology! Here is the internal sweep into just 600 Ohm which is much lower than the impedance of NCx500:
The steppiness is due to AP input scalar switching ranges and with it, losing some performance. The actual output is clean without those drops.
FYI max voltage I needed for NCx555 was 15 volts. Above test goes to 20 volts.
Here is the internal sweep into just 600 Ohm which is much lower than the impedance of NCx500:The steppiness is due to AP input scalar switching ranges and with it, losing some performance. The actual output is clean without those drops.
FYI max voltage I needed for NCx555 was 15 volts. Above test goes to 20 volts.
AndreaT
Addicted to Fun and Learning
Does this point to the need to employ a torque instrument when tightening speakers terminal? I love my Wiha! Would the same tightening improve the recently reviewed Buckeye performance?OK, I investigated the cause of excess distortion at higher power. I had noticed that with buffer setting distortion had gone down which should not have been the case. I noted on the graph that my dummy load connection may need revisiting. Indeed that was the case. I use screw terminal locking banana plugs. The screws sometimes come loose. I checked and they were tight. But under instrumentation I could see that wiggling the wiring caused good few dB change at higher power. So I tightened them to death and result was much improved performance:
Due to lower distortion, we could eek out some more power at 1%THD so I updated the max and peak measurements as well:
As I expected, the impact here is lower due to much less current travelling through the wiring terminal. Still, we get closer to state of the art. As an aside, I verified that the Purifi measurements were with high gain (re-ran that measurement as part of testing the wiring).
Finally, the lowered distortion exists at all frequencies:
View attachment 257942
The buffered results would likely get a bit better as well. I will see if I can re-test those.
These results show the Hypex NCx500 to be even more remarkable than my original testing showed!
Attachments
Last edited:
OP
- Thread Starter
- #360
I get them tight but the copper fibers of the wire compress over time making them looser. I then have to take them out get the strands together and tighten once more. I am thinking about using solder with a different ones.....
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