Apollon Audio Class-D Amp Build Quality

[maty]

This morning I received a long and neat email from Tibor (Apollon owner), with a diagram and many photos. I think it is the first time that we share correspondence or maybe time ago, respect the ICEpower 1200AS2.

Compare yours with the Mola Mola in terms of connection and so on. I had no doubt, except for the one regarding the "pin 1 problem" mentioned and that it is not possible to appreciate in the photo, which has been taken into account, as expected, in other words, it is not a problem.

And, of course, Tibor denies any RF/EMI interference problems.

For that of privacy in communications I do not reproduce the content. A small screenshot so nobody doubts. If someone else has doubts he can write a mail or ask that the previous e-mail be forwarded to him.

This thread is about another manufacturer, so it is quite logical that he does not want to comment on it, I say.

 

[McFly]

Maty; i understand English is not your first language but i just cannot, and i think i speak for a few people, understand what you're saying

 

[maty]

Tell me what. I must miss sugar. They call me to cook a fideuá. https://www.google.com/search?q=fideua

 

[Matias]

If I understood correctly, NielsMayer raised several assumed issues with the Apollon amplifier, which should be an even worst layout than Nord.
Maty contacted Apollon's designer and owner, named Tibor, who shared his implementation of a monoblock amplifier and asked to compare to Mola Mola's monoblock amplifier. For those who don't know, Mola Mola is a company that was co-founded by Bruno Putzeys, designer of Hypex nCore modules. That is to say, Tibor asked Maty to compare his amps to Bruno's reference design and see that he is doing right. So that Maty answered NielsMayer criticism except the pin1 issue which cannot be seen in the pictures sent by Tibor.

Now this is a Brazilian trying to understand a Spaniard conversation with an Austrian, all in English, so I may have gotten it wrong. Phew!

 

[maty]

I can not see if there are or not pin1 issue in the previous picture:

It is connected according to the Hypex recommendations for balanced connections. The drawing shows how it is made. Therefore, this problem is non-existent.

He tells me even the length of the wiring used in the Mola Mola and in the Apollon.

My words: In short, if the Apollon is wrong Mola Mola too. And Bruno Putzeys has no idea about anything!

 

[Matias]

Interesting, Mola Mola Kaluga amp uses 2 wires per connector, in a star quad configuration. Now this is not done by both Nord and Apollon. Plus some fancy Furutech connectors and stylized case to justify charging $16,5k.

 

[Matias]

That's nc1200 module not Nc500. It has 2 sets of output connections on the plug. You can use this to make bi wiring easy or to reduce connection impedance. The module can kick out 40 amps!

Yes, NC1200 is a beast. I am very curious to see such a beast refreshed from Purifi, let's see.

As for the dual wires per connector, I understand it is possible to do it even with NC500 too. Here they used both wires to do dual connectors but both wires could be used for a single connector too.

 

[maty]

Btw, I have a picture -the last picture of the e-mail- from the new Apollon with Hypex NC1200 mono x2 (amps have asymmetric architecture, one with the heatsink on the left and the other on the right) and... it looks spectacular in photo and the characteristics.

But last week I decided that I did not change my second amplifier... and usually I listened my coaxials in near field, too much power to me. And the main system continues to be kidnapped.

 

[maty]

I have permission. He tells me that it is already on sale!

The picture, optimized to see better the details:

With a new buffer, very different from the others Apollon.

 

[maty]

From the first mail, at the end:

[ ...In attachment you can also find pictures of our new amazing product. It is called the PNC1200M mono blocks. PNC stands for Premium Ncore. These mono blocks are based around the NC1200 modules. We use Weiss OP2-BP op amps for the input buffer and a linear power supply for the input buffer stage and modulator stage.

The enclosure is made in house from 20mm and 10mm very thick aluminium. The NC1200 modules are mounted on a big heatsink so that all heat dissipates out of the enclosure and the NC1200 modules can achieve maximum power ratings possible this way.

The sonic performance is simply amazing. We also have the same version with the all mighty NC2K module (PNC2K) for very very power hungry speakers. I'm very curious on what do you think about our new product. ]


The product is already on sale but does not have a specific page yet, so ASR forums is offering a scoop.
Btw, https://www.google.com/search?&q=Weiss+OP2-BP nothing, only the OP1-BP:

-> https://www.diyaudio.com/forums/class-d/190434-hypex-ncore-post4905193.html

bavmike, 3rd December 2016

[ The improvements of the OP2-BP over the OP1-BP are:

- Emitter follower to drive bootstrapped cascode of input differential pair omitted; instead current source with emitter-referenced used.

- Trim range of DC offset adjustment reduced; drift improved by use of precision resistors in the active load.

- Improved bias line (frontend, output stage).

- Use of 68 pF capacitors instead of 47 pF for emitter follower feed-forward.

- Improved thermal coupling of output stage transistors by use of a common heatsink for all four emitter follower transistors.

- Use of SMD parts for the power transistors.

- RLC decoupling for frontend to improve PSRR.

- Differential decoupling capacitor for output stage to reduce harmonic distortion content in supply current. ]

[PDF] http://www.weiss.ch/files/downloads/op1-bp/OP1-BP-Datasheet-R1.pdf

https://www.weiss.ch/products/op1-bp


Three pictures optimized to see the details. On the page there will be more photos (and info) but much darker.

 

[NielsMayer]

The pin 1 issue is obvious -- where is the short pin 1 wire to ground? this is different than the "electrician"/UL/etc case ground near the IEC power receptacle.

The Hypex diagram shown in the initial screenshots shows exactly how it is supposed to be wired. Note the pin-1 connection to chassis and shield.
Note the non-crossing and lack of proximity of the input, power supply and output connections.

(diagram taken from https://www.audiocircle.com/index.p...dul1c69g07&topic=124615.msg1365390#msg1365390 )

See also the spec sheet:

9.1 Cable dressing
The NC400 module has exceedingly low distortion. This makes it very easy for extraneous causes to add
much more distortion and colouration than the amplifier itself. The first major cause of such distortion is
direct magnetic crosstalk from the supply cable into the audio input or the loudspeaker output. This is
minimized in several ways:
 Run the audio and power supply cables away from each other.
 Tie-wrap the supply cable to form a tight bunch.
 Tightly twist all loudspeaker cabling inside the chassis.
9.2 Input configuration
The second major cause of extraneous noise and distortion is common-impedance coupling between power
wiring and signal connections. This is caused by the use of ground-referenced signalling (aka single-ended or
unbalanced transmission), which unfortunately is the predominant method of interfacing consumer-grade
audio equipment. As a result the ground circuit becomes an inseparable part of the signal path and any
currents flowing through the ground circuit affect the audio signal.
Ground loops cannot fundamentally be avoided. Star grounding only works at low frequencies. The longer the
wires to the “star”, the lower the frequency at which supply decoupling becomes ineffective. The maximum
permissible trace length of decoupling capacitors in class D amplifiers is measured in millimetres and the
value of the decoupling capacitances is large. To make a long story short: you cannot connect the audio
signal using a single wire and hope to solve the ensuing drama using star grounding. It won’t work.

Note: the output impedance of the NC400
is very low, allowing you to maximize the benefit of biwired configurations by starting both cable runs from
the screw tags. It is very important to use twisted pairs for the output cabling, at the very least anywhere
near the PSU cabling. The distortion of the NC400 is so low that it is easily exceeded by magnetic coupling
between the supply wiring and the audio wiring.

I can not see if there are or not pin1 issue in the previous picture:

It is connected according to the Hypex recommendations for balanced connections. The drawing shows how it is made. Therefore, this problem is non-existent.

He tells me even the length of the wiring used in the Mola Mola and in the Apollon.

My words: In short, if the Apollon is wrong Mola Mola too. And Bruno Putzeys has no idea about anything!

 

[Ron Texas]

@maty does it have a ludicrous mode?

 

[NielsMayer]

The pin 1 connection to ground should happen between pin-1 and the ground-pin that is solderable and visible in the image below as the gold metal loop on right hand side at bottom.

 

[Matias]

@maty does it have a ludicrous mode?

That would be the NC2k, 2,000W @ 4 ohms!

 

[maty]

"The sonic performance is simply amazing. We also have the same version with the all mighty NC2K module (PNC2K) for very very power hungry speakers. I'm very curious on what do you think about our new product."


Well I guess the Mahler Symphony No. 5 that I am listening to right now would sound even better, incredibly fine for 5.25" coaxial speakers (KEF Q100 tweaked and modded). I still marvel at how they can handle an orchestral mass. Better not think about your amplifiers that would surely unveil me tonight!

-> https://www.diyaudio.com/forums/music/6958-playing-listening-post5810518.html

Bernard Haitink, Concertgebouw Orchestra - Gustav Mahler - Symphony No. 5 / Adagio (Symphony No. 10) (1971), Vinyl x2, Philips, Netherlands

Gustav Mahler - Concertgebouworkest Conducted By Bernard Haitink - Symphony No. 5 / Adagio (Symphony No. 10) (Vinyl, LP) | Discogs

DR Peak RMS Filename
----------------------------------------------------------------------------------------------

DR15 -0.86 dB -21.43 dB A1 Sinfonie Nr. 5 Cis-Moll - 1. Trauermarsch (In Gemessenem Schritt. Streng. Wie Ein Kondukt - Ploetzlich Schneller. Leidenschaftlich. Wild - Tempo I)
DR14 -0.28 dB -18.94 dB A2 Sinfonie Nr. 5 Cis-Moll - 2. Stuermisch Bewegt. Mit Groesster Vehemenz - Bedeutend Langsamer - Tempo I Subito
DR14 -1.78 dB -21.69 dB B Sinfonie Nr. 5 Cis-Moll - 3. Scherzo (Kraeftig, Nicht Zu Schnell)
DR13 -8.55 dB -28.44 dB C1 Sinfonie Nr. 5 Cis-Moll - 4. Adagietto (Sehr Langsam)
DR14 -0.39 dB -19.76 dB C2 Sinfonie Nr. 5 Cis-Moll - 5. Rondo-Finale (Allegro)
DR15 -0.41 dB -21.23 dB D Sinfonie Nr. 10 Fis-Dur (Unvollendet) - Andante - Adagio
----------------------------------------------------------------------------------------------

Number of files: 6
Official DR value: DR14


CD, 2018

Mahler: Symphony No. 5 by Bernard Haitink and Royal Concertgebouw Orchestra on Amazon Music - Amazon.com


Bernard Haitink - Wikipedia

Royal Concertgebouworchestra, Amsterdam – RCO

Royal Concertgebouw Orchestra - Wikipedia

 

[Apollon Audio]

We use a Neutrik XLR connector that has an additional optional connection to easily join pin 1 to chassis ground. The pin1 is only connected to the chassis ground and input wire shield. It is not connected to the audio circuit ground. (AES48 practice)

 

[Apollon Audio]

The pin 1 issue is obvious -- where is the short pin 1 wire to ground? this is different than the "electrician"/UL/etc case ground near the IEC power receptacle.

The Hypex diagram shown in the initial screenshots shows exactly how it is supposed to be wired. Note the pin-1 connection to chassis and shield.
Note the non-crossing and lack of proximity of the input, power supply and output connections.

(diagram taken from https://www.audiocircle.com/index.p...dul1c69g07&topic=124615.msg1365390#msg1365390 )

See also the spec sheet:

We use a Neutrik XLR connector that has an additional optional connection to easily join pin 1 to chassis ground. The pin1 is only connected to the chassis ground and input wire shield. It is not connected to the audio circuit ground. (AES48 practice)

 

[Apollon Audio]

The pin 1 connection to ground should happen between pin-1 and the ground-pin that is solderable and visible in the image below as the gold metal loop on right hand side at bottom.

The pin1 soldered to the ground pin is pretty obvious. Please see attached picture.

 

[NielsMayer]

The pin1 soldered to the ground pin is pretty obvious. Please see attached picture.

it is obvious in that picture, but that is a completely different amp than the initial interior picture of the appolon stereo unit, with a very clean and nicely dressed appearance, but issues with asymetrical layout causing unecessary crossing of input and output signals, especially on the right channel.

The other high-end Apollon units pictured as well as the Mola Mola example appear to be correct. Although at least one unit had the output wires not well twisted at their ends -- significant wire separation making them nice little AM radio transmitters inside the case -- and these output wires spanned nearly the entire length of the chassis (why not put the output board right next to the outputs like in Bruno's "preferred example" case that I included in my previous posts??)

The Mola Mola looks very nice and correctly engineered. But then again, you can buy a car for that kind of money, making it quite ridiculous IMHO.

 

[Apollon Audio]

it is obvious in that picture, but that is a completely different amp than the initial interior picture of the appolon stereo unit, with a very clean and nicely dressed appearance, but issues with asymetrical layout causing unecessary crossing of input and output signals, especially on the right channel.

The other high-end Apollon units pictured as well as the Mola Mola example appear to be correct. Although at least one unit had the output wires not well twisted at their ends -- significant wire separation making them nice little AM radio transmitters inside the case -- and these output wires spanned nearly the entire length of the chassis (why not put the output board right next to the outputs like in Bruno's "preferred example" case that I included in my previous posts??)

The Mola Mola looks very nice and correctly engineered. But then again, you can buy a car for that kind of money, making it quite ridiculous IMHO.

I zoomed in our NC800SL stereo unit. Please see photo attached.