Gryphon Antileon Signature: Clone and Build

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The Basic Law of Gryphon's Design Topology

• Non-GFB
• Fully DC-Coupled
• Class A output
• Ultra-wide Bandwidth. 

The Gryphon Antileon Signature

• Power: 150W+150W@8 ohm Class A without output relays
• Year of Production: 2001
• Output Stage: 20 pairs of BJT
• Filter Cap: 440,000 µF
• Bandwidth:  (0.5 – 350,000 Hz, (+0 dB, -3 dB)
• Fully balanced circuit, 
• Automatic Green Class A bias setting or manual Low/High bias (See scheme)
• PCB with 105 µm copper

Gryphon Antileon Signature doubles power output to 300 W into 4 Ohms,  doubling again to 600 W into 2 Ohms,  it is even able to deliver a stunning 1100 W into a 1 Ohm load (!!!)  for superb stability with any speaker.

The Philosophy of Topology Designing

OK, this is a Gryphon Antileon Signature Power Amplifier, only driver section shown, but that's fine, just use Goldmund's output stage will work just fine (actually, the genuine uses 20 pairs BJT!). The design is kind of similar to Goldmund, some diff though: MAT02 BJT as input pair (JFET 2N5564 in Goldmund).

I was told that this is a NGFB design. Indeed, the design is dedicated; there is feedback, but not directly from output of power amplifier. The feedback originates from driver's output, so yes, this is NON-GFB with FB partially though :)

This kind of topology makes it a smarter choice, NGFB amplifier has its unique sound stage, but DC offset is a huge concern. Yet Global-FeedBack, or GFB just makes nothing new from engineering point of view.

Therefore, someone in someday just said, hey! why don't we connect the feedback from driver stage?!

This is brilliant anyway. Partial feedback from driver stage improves DC offset issue with no traditional GFB. Surely this makes sound stage difference with more stable DC offset!

Feedback from driver stage output is a topology between totally FB and totally NON-FB, and we can expect it has sound stage like NON-FB but also stable DC offset like FB.

Apparently, this is a trade-off of engineering, and why not give it a try!

In this case, the Grypho Antileon, a DC servo OP was implemented even to achieve more better DC stability.

Gryphon Antileon Signature

一位越南朋友傳給我的Project，他們正在弄這套後級，屬於NGFB但是有從驅動級拉FB跟DC Servo回去；我忘記在哪裡讀到相關的資料，說這是一種蠻巧妙的做法，因為全無回授要煩惱DC穩定的問題，但又想要有無回授的聲音/體驗，那就折衷，從驅動級拉FB回去，而不從輸出端拉FB回授。 這便可達成NGFB的設計，但又能得到較為穩定的輸出DC偏壓，一石二鳥，因此本機甚至沒有輸出繼電器，顯示設計者十足有把握。

* Gryphon據說設計哲學大概有四點: 1. Non-GFB

2. 全 DC-Coupled

3. A類輸出(自動A類，見下文) 4. 高頻寬(此機為350KHz)

*

從線路圖上面我們可以看到設定靜態電流的地方，有繼電器跟可調電阻來設定電流，繼電器部分往外連接的部分應該是MCU，由MCU來開關繼電器，所以可以得到三種偏流狀態: 待機20mV、低偏流290mV、高偏流435mV，這是指射極電阻的跨壓，因此可換算出成正比的電流。真是很聰明的設計，而這個設定很可能是可以給使用者自行選擇的，例如面板設定高低偏流，那MCU偵測到訊號之後自動從待機時的20mV切換到高或低偏流，體驗兩種不同的聲音。

* 本圖只有涵蓋到驅動級，採全平衡輸入，全平衡電路，而輸出級其實也不難想像，就是一般上下NPN+PNP+射極電阻這樣的配置。根據資料，此機型採用20對、40只BJT電晶體功率級，可以想像是個大怪獸。 另外也因為這樣的設計，此機的負載能力超級強悍，(以下皆為單通道瓦數)8歐姆下150W，4歐姆300W，2歐姆600瓦，甚至可以低到1歐姆輸出1100W!

* 如果是以機器本身的視角來看，那等於是負載1歐姆下總共輸出2200W A類! 為此濾波電容總共用了四十四萬uF，實乃猛獸也。