giesemann reference sfp optical isolator pa1 on sale

AfterDark. Constellation Giesemann SFP Optical Network Enhancer PA5

10M Master Clock
12V DC Socket Option

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AfterDark. Constellation Giesemann SFP Optical Network Enhancer PA5

The very first SFP Network Enhancer which build in 10M Master Clock Sync Module for Audiophile.

We performed real listening test and music playback is approaching perfection, it is so much refine and organic with S1 and Giesemann EVA OCXO Reference Master Clock.  

The design is based on the unique material on shielding layer, selection on Carbon Fiber, the product research and development on Giesemann OCXO product since 2021. AfterDark. take a further step to design the world's first audiophile network card which can accepting 10M Master Clock input for Audiophiles who would like to paid extraordinary attention to the master clock arrangements (as well as providing developed clocksync and external reference clock options for EtherREGEN) to minimize timing error to unprecedented levels. 


The AfterDark. Constellation Giesemann SFP Optical Network Enhancer is designed for Audiophile using MAC or Intel PC Music Server, equiped with external Thunderbolt 3 or 4 connections.

The SFP Optical Network Enhancer will make use of the new technology made by Intel Thunderbolt4 Chipset to provide the streaming fast, simple and most reliable connection for Audiophile application. For example, the SFP Network Enhancer can utilise the Thunderbolt 4 port in MAC mini to extend the possibilities to use Intel I350 S1 DUAL SFP Ethernet Server Adapter with external connection via single Thunderbolt cable. 


What is Thunderbolt 4 Technology?


Get the most from Thunderbolt 4 Technology?


The SFP Optical Enhancer will transform the Mac Mini to use SFP optical fiber connection for sound optimisation.

The quality of the Network Card is crucial to deliver the optimal sounding for Music Server, which ensure the smoothness of music data at the very first transfer via Network. The Constellation Giesemann is designed along with the mind that temperature perturbation, vibration shock, and electromagnetic interference (EMI) may cause some effect on high precision OCXO inside a Music Servers. The chassis inside the Music Server is heavily polluted by EMI noises from CPU, RAM, SSD. So the ultimate or ideal solution is to separate the OCXO physically in a separate chassis if possible. 

The Giesemann Clock Sync motherboard is located at the middle and mounted on Carbon Fiber audiophileMAT to maximise the performance for Giesemann Clock Sync Module (GCSM) for Constellation Giesemann Network Card. The grounding arrangement and 5V DC port slot is located on the bottom of the PCIe card to provide the best electronic contact for the clock module. 

The Constellation Giesemann SFP Optical Network Enhancer is balance in sounding, no excessive mid and bass. The mid-range is sweet and background is full of darkness with trace of micro details. Soundstage is deep and instrument opened up nicely on music, the bass is just right. Overall Constellation Giesemann Network Card is very musical, airly and provide the state of art resolution in music. 

What is special about SFP Optical Network Enhancer?

  • The SFP Optical Network Enhancer make use of the optical transfer and physically blocking the electrical noise from network switch that distorts the audio signal from your network and reduce noise floor and interference. 

  • It is pefect for you if you are using a wired connection and want to change to SFP fiber connection to reduce / minimise networ noise or reduce jitter over long distance data transfer with use of optical fiber. 

  • The SFP Optical Network Enhancerhas a zero-noise design and galvanically-isolated inputs to reduce digitial jitter and overall system noise. 

  • Galvanic Isolation optimised, where electrical circuits are saparated to eliminated stray currents. Audio signal can pass between galvanically isolated circuits to block differences in ground potential or currents induced by AC power. 

  • The SFP Optical Network Enhancer is tailor made to use 10M Master Clock to optimise sounding.  Audiophile can make use of their 10M Master Clock to provide the master sync for the audiophile system. Using the single Master Clocking system can achieve the best possible sound quality for both Roon Server on NIC and Switches and Network Player. Improves music playback from Roon (Tidal, Qobuz) and files on local network. 

  • 10M Master Clock Signal can be either Square Wave or Sine Wave
    • Full supports for all AfterDark. Giesemann Master Clock, Mutec Master Clock and Cybershaft Master Clock 
    • 50 ohms or 75 ohms input version can be choose when order.  

  • The Standard Version of BNC port is used to input external 10M Master Clock. This arrangement and design would ensure Audiophile can use their very best exotic BNC Clock cable without any BNC to SMA adaptor which may caused loss of information in clock signals. Incredible sound quality improvements for any music server.  

  • The Enterprise level high quality Intel I350 Ethernet Controller is used. The chipset is the new generations of I350, the heat is much lower and lower powered. Lower heat means lower noise floor and smoother sounding. The hardware of Intel i350 is well known to provide much better stability and this can provide the best support for operating system: Windows (all editions and Linux of UBuntu, Snakeoil). Plug and Play of any PC with PCIe slot. 

  • Audio Grade Electrolytic, aluminum electrolytic is used for sound tuning 


The S1 Dual SFP NIC is build in the Carbon Fiber Chassis  

  • The power section of Gisemann Clock Sync Module (GCSM) is separated power by external LPS at 12V 3A. It eliminates computer as source of powers. For lowest noise and best sounding using Farad Super 3 power supplies. 
  • Two audiophile grade SFP network ports support 1G SFP connection speed.  Audiophile can make use of software network bridge function to connect one port for incoming data from router and other port to connect the music streamer directly. The noise floor will be much quieter and details on background will improves. 


The Giesemann OCXO Master Clock ensure best performance for sound optimisation.

Why use OCXO Master Clock? 

You will get an improvement in dynamic's, a lower noise floor and more natural flow in the sound.

  • For us a OCXO Master Clock is one of the most important factor's in ensuring the best possible sonic platform for any hifi system!

  • The Giesemann Master Clock is designed for high precision audio equipment to enhance the integrity of the signal, the top of the line Giesemann OCXO ensure the accuracy of the master clock prodvide a time domain reference for reading data, its transfer and decoding. As a result, the Master Clock could minimize jitter and ensure the improvement on sounding.

  • The Giesemann EVA OCXO Master Clock is designed to generate a very accurate, ultra low phase noise 10M Master Clock signal that delivers more accurate transfer and conversion of digital signals.

  • The addition of the external 10M Master Clock can improve the soundstage and details of the Music Server, the extraction of details from the background is just amazing and help to achieve optimal music playback with enhanced timbre, full tone, and escpecially pace, rhythm and timing. 


The Thunderbolt 4 cable in black is connected to a Intel Laptop to make use of Cisco AOC SFP fiber cable to audiophile switch for sound enhancement.  

Purchase Link for S1 Dual SFP Optical Network Enhancer

Technical Specification:

  • Ultra - Low Noise Linear LT3042 Regulators and filters eliminate the noise interferences from a PC
  • Duelund Silver Cable is used to connecting the DC power to Giesemann Clock Sync Module (GCSM)  
  • DC Port at 2.5mm 
  • Required to power with external LPS rated at 12V 3A
  • Audio Grade Electrolytic, aluminum electrolytic is used for sound tuning 
  • 10M Master Clock input of BNC is required to connect to the board for full operation. 
  • Master Clock accepts either Square Wave or Sine Wave 
  • Choice of impedance of 75 ohms or 50 ohms to choose for 10M input 
  • Superior OCXO signal isolation, industrial grade IPEX cable for signal transmittion to motherboard. 1st Layer of aluminum foils for High Frequency (HF) Effective shielding. SFS-PE (Foam-Skin Polyethylene) insulated and 2nd layer of copper wire braiding. This will prevent external noise from getting to the signal conductors, shields the shield of the cable to further prevent the ingress of noise (RFI, etc.) into the signal wires.
  • Layer of Carbon Fiber Shielding (CFS) for EMI shielding, Carbon Fiber protection provide the highest standard of shielding material which mainly used for industrial and most demanding engineer on special project.  
  • “Extra Arrangement on Grounding Wire” the grounding braid outside of the 10M cable was connected by IPEX connector for best connectivity on clock signal witin industrial standard. 
  • Industrial Version of Intel i350 SFP Ethernet Controller 
  • Highest Industrial Grade with wide range of extreme operating temperature -40C to +85C.  
  • All Windows editions, MAC and Linux OS Supports 
  • All Thunderbolt 3 or 4 supported
  • All modification hand made in Hong Kong by AfterDark.

For Audiophiles who like to optimise the sound on software levels, the Tips and Tweaks is attached for audiophilestyle's members:


Type: OCXO Clock

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AfterDark. is delighted to have successful shows at HighEnd Munich 2024.🙂

Please feel free to share the discount code with friends.We love to hear more music lover to enjoy this great product. 

Discount code: PA1