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NCx500 or 1ET6525SA with Denon AVC-X3800H

oshelby

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Mar 25, 2025
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Hello

First time posting, long time following and learning from everyone's experience. Though I just noticed all the good reviews when I did a search came from ASR. Kudos!

I have a Denon AVC-X3800H powering 9 speakers and processing 11 channels in a 7.1.4 setup. My LCR are powered currently by Emotiva Basx-A3. I am located in Egypt and products are VERY limited over here. My floor level speakers are all Polk Audio Reserve series. R700s, R400, R100s and heights are RCi80.

My question is, I read Amir's review about the X3800H and I understand that the pre-outs deliver around 1.4V. I am considering an upgrade for my frontstage through 1 Stereo and 1 monoblock (maybe start with just the stereo). The vendor that meets my travel pattern is Audiophonics. Based on many threads on ASR I get that there is basically no audible difference between these amplifiers Purifi,NcoreX,Nilai (at the same level/variables). Now since I am bound by the low preout voltage on the Denon. Would it be best to go with 1ET6525SA with around 25db gain to get full power AND better signal quality? Or NCX500 at 31db buffer?

I noticed in Amir's review of the Apollon implementation of NCX500 that using the buffer reduces SINAD slightly. Would this mean that I should always opt for amplifiers with lower buffers that match the preamp's output voltage (assuming both amps are of similar quality like these 2).

They offer HPA-S600NCX (NCx500 modules) which offer these gain settings: I figured I should be around 31db to get full power.
Bypass : 11.5dB
19dB
25dB
31dB
33dB

They also offer HPA-S450ET (1ET6525SA) which offer (in RCA):
12.5dB / 5.03Vrms
20dB / 2.12Vrms
25dB / 1.24Vrms
29dB / 0.75Vrms
 
Most likely the noise floor and distortion of the Denon pre-outs will be higher than the amplifiers' buffers, so I would not bother with that.

Instead why not a 3 channel amp for the front trio?

Edit: and welcome to ASR!
 
That was quick! Appreciate the response. Yeah, that would be a good choice for powering my LCR. Budget was initially 1K Euros, iI bumped it and included the NCX500 but recently I noticed this second gen Purifi amp. If I can get a 3-channel I definitely will.

Now that we have addressed the scientific part; On with the controversial part: I found a thread talking about musicality and what not and read through explanations from Tibor about slight differences in sound when comparing purify and ncoreX (some of which were perception based, as long as we are not doing blind AB test)If i plan to use Dirac/audyessey anyway, would I notice any difference between these 2 amps?

What if I use pure direct mode with no EQ (I am starting to appreciate stereo listening). Will there be any tonal differences?

So there is no significant advantage to picking one of those over the other except for efficiency and power output (at least in my case)?
 
Hi @oshelby! Welcome to ASR.

If I read Amir's review of the X3800H correctly, then the Preamp only clips at 1.4V if for example the FL/FR signal is sent to both the preamp out and the internal Amp.

If you turn off the FL/FR/C Amps by setting those channels to "Pre-out Only" in the Manual setup submenu, then your X3800H should output 2V or more without clipping, even if the internal Amps are still active for the other channels.
 
Hi @oshelby! Welcome to ASR.

If I read Amir's review of the X3800H correctly, then the Preamp only clips at 1.4V if for example the FL/FR signal is sent to both the preamp out and the internal Amp.

If you turn off the FL/FR/C Amps by setting those channels to "Pre-out Only" in the Manual setup submenu, then your X3800H should output 2V or more without clipping, even if the internal Amps are still active for the other channels.
I think I read something like that at some point, though I am not sure if this applies if I have the other 6-7 channels AVR’s amp engaged. I think what I understood at the time was I needed to have them all in pre-out only mode. Then again I could have misunderstood.
 
So there is no significant advantage to picking one of those over the other except for efficiency and power output (at least in my case)?
There is absolutely no tonal/sonic/audible difference between Purifi and NCOREx.
 
Update:
I noticed discrepancies in NCX500’s gain settings on Audiophonics website:

Description
Total gain of 11.5dB - Maximum power reached with a 13.03V RMS signal.
Total gain of 19dB (default) - Maximum power reached with a 5.5V RMS signal.
Total gain of 24dB - Maximum power reached with a 3.09Vrms signal
Total gain of 28dB - Maximum power reached with a 1.95Vrms signal

In the table at the bottom of the page:
Gain (selectable) Bypass : 11.5dB 19dB 25dB 31dB 33dB

I emailed them (they are very responsive, it is impressive really).

Their response: The table at the bottom was outdated. 28dB is the maximum gain and requires 1.95vrms, they fixed it. Which is outside the Denon’s comfort zone (if i take into consideration the preout only mode and 2.0vrms, I would still be cutting it close in terms of getting the full output power of the amp)

I know I will never need 600w for my setup, but the perfectionist in me wants everything to work as it should

I am more inclined towards the 1ET6525SA now which costs around 200 euros extra. Anyone here tried it yet?
 
I am more inclined towards the 1ET6525SA now which costs around 200 euros extra. Anyone here tried it yet?
If it helps, we have had dozens of Denon owners use the Hypex NCX500 and Purifi 1ET6525SA. No issues, no worries of not working properly, etc.
 
If it helps, we have had dozens of Denon owners use the Hypex NCX500 and Purifi 1ET6525SA. No issues, no worries of not working properly, etc.
It helps a lot really :) Use cases are always good indicators for mainstream users. If (big if) my calculations are correct, even if the Denon outputs 1.4v, that should deliver around 308 watts into 4 ohms at 28dB gain. Which is over the power recommendations by Polk (Max 300W), and I don't plan to max out my speakers. If the Denon outputs 2.0, I can get the full 600W (which I won't need). Thanks again!
 
It helps a lot really :) Use cases are always good indicators for mainstream users. If (big if) my calculations are correct, even if the Denon outputs 1.4v, that should deliver around 308 watts into 4 ohms at 28dB gain. Which is over the power recommendations by Polk (Max 300W), and I don't plan to max out my speakers. If the Denon outputs 2.0, I can get the full 600W (which I won't need). Thanks again!
Consider supporting buckeye, u can save alot!
 
Consider supporting buckeye, u can save alot!
Would love to! Unfortunately, shipping to my country is complicated. I travel to Italy once/twice a year and rely on brands I can buy from Europe during my trips.
 
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