Apollon NCx500ST Stereo Amplifier Review

[proux]

could i ask anyone who ordered an Apollon in the UK- did you get billed 20% VAT on the cost (including delivery), or did customs add extra charges? (I think they shouldn't, but being a bit paranoid....)

 

[DimensionX]

Just getting to grips with all the various choices... so I guess the "Lux" is the same as the basic model with a fancy case, making it quite heavier? Any benefits apart from looks?

I bought the lux version, but mostly just because I thought it looked significantly better than the standard case. Mine doesn't run very hot at all, so I kind of doubt that thermal management is a big factor here.

oh, and the power button moves to the underside of the unit, near the front

 

[GigaChunk]

could i ask anyone who ordered an Apollon in the UK- did you get billed 20% VAT on the cost (including delivery), or did customs add extra charges? (I think they shouldn't, but being a bit paranoid....)

UPS charged me 20% VAT on the cost inclusive of delivery, plus a ~£20 brokerage charge. No additional duty was due.

You will likely get an email from UPS while the package is on its way requesting payment before delivery.

 

[F1Fan72]

UPS charged me 20% VAT on the cost inclusive of delivery, plus a ~£20 brokerage charge. No additional duty was due.

You will likely get an email from UPS while the package is on its way requesting payment before delivery.

Same when I got mine the other month ..

 

[proux]

Same when I got mine the other month ..

thanks so much to both

 

[TemploAztlan]

1. Sure. Conversely, you wouldn't go up a gain level if you have high-sensitivity towers that reach the desired SPL with less power.

2. Correct

3. Correct

4. Sure, some integrated amps or AVR pre-outs clip at higher output levels, but high-quality preamps usually work best at max level and power amps can reach their max output power in low gain.

5. Higher output power is the same point as 1.
Example: If speakers need 15W to reach 85dB SPL (the preferred listening level at the listening distance). To get 90dB SPL 31W is needed with the same speakers. Capping the amp's power to 100W by staying in low gain is fine. Improved dynamic range: Modern music has a 10 dB dynamic range and 100W (with the same speaker) will be enough for 15dB of amplifier headroom. Of course, if the speaker is low sensitivity then, by all means, go up a gain setting.

6. Not sure about this whole point and what it has to do with gain setting? The damping factor varies with frequency and the current is dependent on the speaker impedance dips and desired SPL.

7. Yes, louder equals better

Selectable gain levels are super useful, but what gain to set has more to do with the preamp output level, speaker sensitivity, and desired SPL at a listening position. Level-matched Ncx500 should sound the same in all gains, but low gain has the lowest noise.

I set my gain to 20.5 dB. I'm driving it with a Marantz AV 10. According to amirm's review of the AV 10, it has same performance at 2.5 to 4v output. So I made my calculations based on 4v output from AV 10.

So the Apollon outputs 423w into 4 ohms [load I am driving]. That works out to 41v. Using the formula Voltage Gain (Av) = 20 * Log (Vout/Vin), I get the gain needs to be 20.2 dB.

Would appreciate comments and/or corrections about this.

 

[Chagall]

I set my gain to 20.5 dB. I'm driving it with a Marantz AV 10. According to amirm's review of the AV 10, it has same performance at 2.5 to 4v output. So I made my calculations based on 4v output from AV 10.

View attachment 465994

So the Apollon outputs 423w into 4 ohms [load I am driving]. That works out to 41v. Using the formula Voltage Gain (Av) = 20 * Log (Vout/Vin), I get the gain needs to be 20.2 dB.

Would appreciate comments and/or corrections about this.

Yes, set the Apollon to 20.5 dB gain, and ensure all speakers output the same SPL (typically 75 dB) at volume 82.5 on the Marantz. In REW, to generate 75 dB pink noise, start with a low-level signal (e.g., –30 dBFS) and adjust as needed. Adjust the trims in the AVR to ensure level matching across all channels. For actual listening, don't go much over 82.5 volume, where Marantz delivers optimal performance.

 

[peng]

I set my gain to 20.5 dB. I'm driving it with a Marantz AV 10. According to amirm's review of the AV 10, it has same performance at 2.5 to 4v output. So I made my calculations based on 4v output from AV 10.

View attachment 465994

So the Apollon outputs 423w into 4 ohms [load I am driving]. That works out to 41v. Using the formula Voltage Gain (Av) = 20 * Log (Vout/Vin), I get the gain needs to be 20.2 dB.

Would appreciate comments and/or corrections about this.

Calculations seem correct but I see not much point doing it as there are multiple factors involved, so basically any of the Apollon's settings can be great in terms of minimizing noise and distortions based on the best matched gain, depending on the following (not limited to):

1) the load impedance vs frequency, not just a single so called nominal impedance figure
2) your speaker's sensitivity
3) your listening habit such as the maximum spl you think you may be listening to
4) your seating distance

If I were to ignore the above, I would set it to 27.5, and call it a day. Otherwise, in theory, even the lowest setting, i.e. 12.8 dB might be the best, under specific conditions.

 

[David_M]

UPS charged me 20% VAT on the cost inclusive of delivery, plus a ~£20 brokerage charge. No additional duty was due.

You will likely get an email from UPS while the package is on its way requesting payment before delivery.

If the order was destined for the US, would UPS charge me an extra tariff fee from country of origin before delivery?

 

[antcollinet]

If the order was destined for the US, would UPS charge me an extra tariff fee from country of origin before delivery?

you'll need to find out what current tarrif rates are between US and country of origin. If I understand correctly - it's somewhat volatile at the moment.

 

[TemploAztlan]

If the order was destined for the US, would UPS charge me an extra tariff fee from country of origin before delivery?

Yes, this is what they charged me on an Apollon amp that cost $1,349.

Although after I paid it, I got an email that said:

Thanks for prepaying your fees and taxes! ​

Total Amount Paid​

139.90 USD ​

 

[pablolie]

Yes, this is what they charged me on an Apollon amp that cost $1,349.

View attachment 466042

Although after I paid it, I got an email that said:

​

​ Thanks for prepaying your fees and taxes! ​

​ Total Amount Paid​

​ 139.90 USD ​

That actually seems very reasonable.

 

[Acerun]

Just a short post to recognize how a follow-up string from a long time ago can be the genesis for new thoughts. I have the Apollon purifii version and have always kept it on highest gain. But I've realized that I have 90db Revel towers and listen at approximately 75 or 80db (city boy). So I moved the gain to the lowest setting and still have plenty of power and the least possible amount of noise and distortion. I won't bore you with subjectivity but I'm glad I made the switch. ASR continues to provide value even when you disengage with it a little bit (because my system is already basically perfect for what I need)

 

[daniboun]

Speaking of the NCX500 modules, I would like to take this opportunity to ask you: I have had confirmation via Audiophonics and Nord acoustic that we can use the Buffers from the old NC500 without any problem with the NCX500s and that they are 100% pin to pin compatible with the NCX500. Any idea here ?

By the way, if anyone is looking for a pair of NCX500, don't hesitate to send me a PM

 

[RickS]

Speaking of the NCX500 modules, I would like to take this opportunity to ask you: I have had confirmation via Audiophonics and Nord acoustic that we can use the Buffers from the old NC500 without any problem with the NCX500s and that they are 100% pin to pin compatible with the NCX500. Any idea here ?

By the way, if anyone is looking for a pair of NCX500, don't hesitate to send me a PM

Yes, see here…

Post in thread 'Hypex NCx500 Class D Amplifier Review'

Jan 15, 2023

@Rick Sykora please give us a little explanation. What type of building blocks are populated on the "interface board" for me, it seems the "buffer" is on the power module?
would be great because no assembler can mess it up.

Correct, the interface board used here is the original NC500 eval board modified by Hypex for the NCx500.

Afaik, the differences are that buffer op amp has been removed and the jumpers set to use the regulators on the amp module.

P.S. PLEASE NOTE THE FOLLOWING

Post #175 in this thread (now removed) mods are questionable at best as those...

• RickS

• 

 

[daniboun]

Yes, see here…

Post in thread 'Hypex NCx500 Class D Amplifier Review'

Jan 15, 2023

@Rick Sykora please give us a little explanation. What type of building blocks are populated on the "interface board" for me, it seems the "buffer" is on the power module?
would be great because no assembler can mess it up.

Correct, the interface board used here is the original NC500 eval board modified by Hypex for the NCx500.

Afaik, the differences are that buffer op amp has been removed and the jumpers set to use the regulators on the amp module.

P.S. PLEASE NOTE THE FOLLOWING

Post #175 in this thread (now removed) mods are questionable at best as those...

• RickS

• 

Finally got the official process from Hypex, one step was missing in the shared link :


If you want to make the NC500 Eval board compatible with the new Ncx500, follow this :

 

[RickS]

Finally got the official process from Hypex, one step was missing in the shared link :


If you want to make the NC500 Eval board compatible with the new Ncx500, follow this :
View attachment 466176e

Mine was from Hypex too but did not remove the regulators. Seems like extra work if you are already bypassing them with the jumpers.

 

[Alexx]

I just got a Hypex NCX500 ST.

I was hesitating for weeks about the Purifi Eigentakt 1ET6525SA ST model, but then I got the Hypex NCX500ST.

Have any of you had a chance to compare them? At least to see if there are any audible differences, and what they might be...that way I can clear up any doubts -

I got the Hypex NCX500 for the ease of swapping speakers in the future (it's more powerful than the Purifi) and because it should have a more "present" bass.

But the Purifi "little voice" is still there!!!

I think the mid-high range is comparable on both models, right?
Thanks in advance.

 

[Buckeye Amps]

I just got a Hypex NCX500 ST.

I was hesitating for weeks about the Purifi Eigentakt 1ET6525SA ST model, but then I got the Hypex NCX500ST.

Have any of you had a chance to compare them? At least to see if there are any audible differences, and what they might be...that way I can clear up any doubts -

I got the Hypex NCX500 for the ease of swapping speakers in the future (it's more powerful than the Purifi) and because it should have a more "present" bass.

But the Purifi "little voice" is still there!!!

I think the mid-high range is comparable on both models, right?
Thanks in advance.

They sound completely identical, which is to say they don't have a sound at all. Transparent is transparent.

 

[Alexx]

@Buckeye Amps
Okay, thanks.

So one is as good as the other, probably except for small differences.

Could they remotely recall the sound of the Nad C399 I had?

Paired with the Wiim Ultra and Monitor Audio Studio 89 speakers, might they be too powerful?
Thanks again for your help.