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Apollon Audio Class-D Amp Build Quality

Redwine

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Nice Amp!
Greetings from my new Ncx500 ST in titan grey. Far simpler case than the one shown above but I like it as well.
Power is sufficient even at lowest gain setting (12,8)…absolutely quiet

It is as if a veil had been lifted…just kidding!
S.M.S.L as pre? Driving what and soundwise when compared to your Denon?
 

Tom22

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S.M.S.L as pre? Driving what and soundwise when compared to your Denon?
Yes, I use the DAC attenuation (as also discussed by Amir in his DO100 review). I am aware of the „safety debate“, but the DO100 reliably „remembers“ the volume setting and the amp runs with the lowest gain setting.

Driving Martin Logan Impression ESL 11A, works fine so far but I did not have time for extensive listening…whereas my Lyngdorf TDAI-1120 does not work with the ML (loud hissing noise, even high noise floor when using only as pre with the Denon), the Apollon is dead silence. I like the new setup so far, uses quite little power and is very efficient, sounds great, no noise…
 

CleanSound

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@Apollon Audio

Can you post AP measurements for your Hypex NCx500 DM Lux Dual Mono?

Are the measurements the same for the different op amp choices?

I'm very much considering putting in an order soon to match with my new speakers.
 

Apollon Audio

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@Apollon Audio

Can you post AP measurements for your Hypex NCx500 DM Lux Dual Mono?

Are the measurements the same for the different op amp choices?

I'm very much considering putting in an order soon to match with my new speakers.
Of course. Here are the measurements of the dual mono and with different op amps (Sonic Imagery 994, OPA1656, LM4562).

THD+N Ratio vs Measured Level @ 1Khz-4Ohm (op amp comparison).png

Screenshot 2023-08-29 213459 copy.png

Screenshot 2023-08-29 at 22.49.28 2.png

Crosstalk 4Ohm.PNG

RMS Level Maximum Output 4Ohm (CEA-2006)4.PNG

Signal to Noise Ratio 4Ohm (maximum power).png

Frequency Response 4Ohm.PNG
 

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  • THD+N Ratio vs Measured Level NCx500 DM (op amp test).png
    THD+N Ratio vs Measured Level NCx500 DM (op amp test).png
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  • RMS Level Maximum Output 4Ohm (CEA-2006).png
    RMS Level Maximum Output 4Ohm (CEA-2006).png
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Matias

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A friend just received his NCx500 dual mono in nice discreet black chassis.

WhatsApp Image 2023-09-04 at 13.46.10.jpeg


WhatsApp Image 2023-09-04 at 13.46.10 (1).jpeg
 

CleanSound

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A friend just received his NCx500 dual mono in nice discreet black chassis.

View attachment 309733

View attachment 309732
I've been on the market for a new amp for a very long time. 430mm case and aesthetics is just as important to me as the performance, in fact, I would say 430mm case, aesthetics and reliability is more important than performance by a small margin.

I narrowed down my search to a Nord and Apollon. But I think Apollon wins. It's probably the best looking amp to my eyes on the market. I like the fact that you can switch the gain without opening the case and the standard speaker binding post seem pretty robust. Also like the fact that the XLR has screws even though it's soldered to the buffer board (extra sturdy) also the RCA seems to be bolted to the chassis, also extra sturdy.

And Tibor seems to be super transparent and open in providing evidence of it's performance and construct (I just came out of having a terrible experience with a DAC where the manufacturer blatantly lied about it's spec.).
 
Last edited:

Sokel

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A friend just received his NCx500 dual mono in nice discreet black chassis.

View attachment 309733

View attachment 309732
The only thing I don't "like" is the RCA input right under the speaker connectors.
I understand that they probably tried to keep them as far from mains as possible though,as measuring rigs are a constant danger these days! :)

Edit:I absolutely love the case (but with a much smaller logo)
 

CleanSound

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Of course. Here are the measurements of the dual mono and with different op amps (Sonic Imagery 994, OPA1656, LM4562).
I also sent an email, literally around the same time you reply.

I asked about few other questions as well on the email.

Thanks Tibor for being patient and answering my questions.
 

Redwine

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I also sent an email, literally around the same time you reply.

I asked about few other questions as well on the email.

Thanks Tibor for being patient and answering my questions.
Anyone knows the damping factor for these amps?
 

CleanSound

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View attachment 309751

I would loose my sleep on it ;)

(from Hypex's NCx500 datasheet)
Am I reading and converting this right?

For f<20kHz, it's 2 milli-ohms. Which is .002 ohms.

To calculate the damping factor when driving an 8 ohm speaker, you take 8 ohms divide by .002, which gives you a damping factor of 40k?

Am I doing this right?
 

Sokel

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Am I reading and converting this right?

For f<20kHz, it's 2 milli-ohms. Which is .002 ohms.

To calculate the damping factor when driving an 8 ohm speaker, you take 8 ohms divide by .002, which gives you a damping factor of 40k?

Am I doing this right?
4K,not 40K.
 

kchap

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I'm impressed, though the tests seem to indicate that there is only a very minor difference between the op amps, I would go for the cheapest.
 

AkodoGilador

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I'm impressed, though the tests seem to indicate that there is only a very minor difference between the op amps, I would go for the cheapest.
Well, the Sonic Imagery 994 seems to have significant benefits in the 200-400W range, so if you think you'll frequently be in that area it might be worth consideration.

OTOH, at 300W you're going from ~102dB to ~105dB THD+N (right?), so it's likely to be a consideration to which you say no...

Alex
 

Sokel

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@Apollon Audio
Can we please have couple of high freq (10-15-20Khz) sweeps (THD+N vs Power) with high bandwidth so we can compare with other implementations?

Thanks!
 

kchap

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Well, the Sonic Imagery 994 seems to have significant benefits in the 200-400W range, so if you think you'll frequently be in that area it might be worth consideration.

OTOH, at 300W you're going from ~102dB to ~105dB THD+N (right?), so it's likely to be a consideration to which you say no...

Alex
Depending on the cost, I would say no thanks. Worst case, the THD+N is still about 102db below the signal. No one is going to detect that.
 

MCH

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I was going to say that there is a good 20% less noise up to 5w and if the difference was like 20 euros, bah, why not. But then I went to check the actual prices on the website.... yikes
 

AkodoGilador

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Up to about 100W, the performance of the OPA 1656 (Apollon's default, apparently, despite the website saying they're using the 1612), and the Sonic Imagery 994 are the same. The LM4562, which is the one in the graphs above that's worse up to 5W, is not offered by Apollon (AFAICT).

Alex
 

kchap

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I was going to say that there is a good 20% less noise up to 5w and if the difference was like 20 euros, bah, why not. But then I went to check the actual prices on the website.... yikes
Yikes indeed! OPA16xx for me please.
 
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