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VTV Hypex Ncore NC252MP (It's all Amir's fault)

emildev

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When was this change made?

No idea - see picture below;
DB.PNG
 

emildev

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Ok had some time to play with the NC252MP and all working well barring one little niggly that im trying to sort out. When I break the standby connection there is a small pop, is audible enough to irritate me - have tried a couple of permutations by first muting the amp before cutting main SMPS power but is always the same - small pop - any body experienced and solved this?

@Chromatischism if you can please check if your does same it would be great :)
 

emildev

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Much appreciated - will try another circuit today with opto's for mute and power on to see if I can reduce noise.
 
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CDMC

CDMC

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My amp also has a turn off thump. I assumed it was normal, as I have had other amps in the past that do the same thing.
 

stunta

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I purchased the above-mentioned NC252MP amplifier from Audiophonics (RCA version). It took roughly 2.5 weeks to initiate shipment (during COVID-19 and with product out of stock), then arriving in only 5 days to the Central U.S. from Floirac, France.

You are correct that the listed costs include VAT, so you will be surprised to pay less than advertised. The total cost, including foreign transaction fee and shipping, was $485.94. Not bad for what you're getting. I do prefer the slim case as it takes up less space. Connectors are high quality and the 12v trigger connected to my AVR means no extra buttons to turn my system on. Soft power on and off. It works perfectly but I have not popped the case open - I could if anyone is interested.

Were their any import tax/duties? If so, how much? Thanks
 

tmtomh

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My Audiophonics amp (stereo Purifi model in the full-width case) produces a soft sound when the relays kick in shortly after turning it on. It is not a pop or a thump - it is much too quiet to be that, and has no low-frequency component. I would describe it as a small "click" or "tick." I have to be within about a foot or two of one of the speakers to hear it.

I don't hear anything when I turn it off.
 

Chromatischism

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Were their any import tax/duties? If so, how much? Thanks
Not that I'm aware of. If any, they were probably figured into the cost.

I later found out that if I used the right credit card I could avoid the foreign transaction fees, which were like $15 or so. Oh well.
 

Rick Sykora

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I wanted to thank @CDMC and other contributors to this thread. I have been looking to get some better amps for a while now and was leaning towards the Outlaw Audio 2220 (which still seems like a great amp). I had been looking at Class D amps, but not finding much that fit my price/performance/availability requirements. I am looking for about 4-5 channels of amplification in at least 2 boxes. Was about to buy the Outlaw, when I came across this thread. While I can see you struggled with the original wiring, I was pleased to see that the owner acknowledged and addressed. His prices fit my value orientation and, after getting a hold of Warren (he lives about 40 minutes away from me), I knew availability was not an issue.

I was still struggling with going the Class D route as I was unable to readily compare the Outlaw 2200 to the NC252MP-based VTV. The power for these amplifiers were rated differently (based on bandwidth and distortion). Here is where ASR came to the rescue again. I found the IOM NC252MP-based amplifier review and so could use it as a proxy for the VTV and compare to the Outlaw review with consistent test conditions. While the Outlaw is more powerful, it is also a bit pricier, so power output became a wash for me. In the end, the better SINAD and the ability to bridge the amplifier for more power, won me over. I ordered the VTV amp and was pleased to find I could have it within a day!

Will pick up my amp tomorrow and look forward to putting it to the test. :D
 

Rick Sykora

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Well my first try was a bust and am not entirely sure why.:confused:

The VTV amplifier sounded fine from power, imaging and noise perspective, but there was a nasty power down pop. It was worse on my bg radia z7 speakers than some of my others, but it was bad enough that I would have to be concerned over tweeter damage. Warren and I discussed and I tried a couple of things, but did not improve. I decided to return it and Warren promptly refunded me. :cool:

As Warren pointed out, the Hypex module is self-contained, so not much he could do. Am not sure if it was characteristic of the Hypex design or possibly a defective module, but I am back to shopping for other options.
 
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stunta

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Well my first try was a bust and am not entirely sure why.:confused:

The VTV amplifier sounded fine from power, imaging and noise perspective, but there was a nasty power down pop. It was worse on my bg radia z7 speakers than some of my others, but it was bad enough that I would have to be concerned over tweeter damage. Warren and I discussed and we tried a couple of things, but did not improve. I decided to return it and Warren promptly refunded me. :cool:

As Warren pointed out, the Hypex module is self-contained, so not much he could do. Am not sure if it was characteristic of the Hypex design or possibly a defective module, but I am back to shopping for other options.

That sucks but its good that you got a prompt refund! I wonder what service we can expect if we in the US order from overseas folks like Nord or Audiophonics.
 

Matias

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Well my first try was a bust and am not entirely sure why.:confused:

The VTV amplifier sounded fine from power, imaging and noise perspective, but there was a nasty power down pop. It was worse on my bg radia z7 speakers than some of my others, but it was bad enough that I would have to be concerned over tweeter damage. Warren and I discussed and we tried a couple of things, but did not improve. I decided to return it and Warren promptly refunded me. :cool:

As Warren pointed out, the Hypex module is self-contained, so not much he could do. Am not sure if it was characteristic of the Hypex design or possibly a defective module, but I am back to shopping for other options.
Try asking Hypex about it? Or maybe you have DC on the mains and a DC blocker may help (Emotiva CMX-2 strip)?
 
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Rick Sykora

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What speakers are you using again? Maybe some are more sensitive than others.

Speakers are BG Radia Z7s. They are rated at 89 dB sensitivity, so are not all that high. Impedance is 5 ohms or higher and no major phase issues. Unlike many speakers, it has a rise in frequency towards 15K Hz. So whatever transient the amp was creating, it would tend to emphasize. In fairness, did try a couple of other speakers that had Dayton RS28s as tweeters. The silk one was more tolerable, but the aluminum dome was more like the BG's planar.
 
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Rick Sykora

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If I had built myself, would have checked with Hypex. I did run through a Isobar surge protector, but not sure how well it would block DC...

Power here is pretty clean (house wiring was recently updated to latest codes and new grounds were run). My system has a dedicated 20A line too. Have lots of other amps that do not have issues, so not inclined to try power fixes just because one amp misbehaves.
 
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tmtomh

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I find it very strange that there is such variation in folks' experiences and reports of power-on and power-off thumps, loud and soft or none. Especially since you would think the modules would be pretty standardized and consistent unit to unit.
 

Rick Sykora

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I find it very strange that there is such variation in folks' experiences and reports of power-on and power-off thumps, loud and soft or none. Especially since you would think the modules would be pretty standardized and consistent unit to unit.

Oops, had my REW setup right there, I could have measured. Since I knew there was not much I could do to remediate, did not consider measuring...

If I might hypothesize a bit though and assume the Hypex modules are nominal, and the transient fundamental is around 1-2Khz. This would put it in the crossover range of many 2-ways. Likely the transient has some harmonic content that makes it sound worse in a 3-way speaker (with rising high frequency response). In the 2-way, it then falls more in the woofer response side and presents as a thump. For a speaker like my BG's (2.5-way), the transient hits the mid-woofer and the tweeter emphasizes more of the harmonics and presents as more of a popping sound.

Unless someone else has the equipment, might have to wait to test until I build my own Hypex amp. :)
 
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