giesemann reference sfp optical isolator pa1 on sale

AfterDark. Constellation Giesemann S2 Reference SFP Network Card

10M Master Clock
5V DC Socket Option
Backplate Style

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AfterDark. Constellation Giesemann S2 Reference SFP Network Card 


The S2 is designed along with one Audiophile which he highly recommended to AfterDark. to use in their Music Server. As you may know, we continues keep on testing the different brand of SFP, USB, Network card in the market and we modified and perform testing with our reference audiophile system. The Giesemann S2 Reference SFP Network card is highly recommended and AfterDark. are uisng this SFP card as a references sound.

The S2 Reference SFP card can made to order for external 10M Master Clock input or build in OCXO Master Clock. 


The magic behind this SFP card is that the music playback from S2 SFP Card is very smooth and analog sounding and transparent with high resolutions. Not much SFP card can sounds so natural. 






When we choose the SFP card, we usually take compatiabilty on both Linux, Windows, and MAC OS. This card will work plug and play for any system. 


We modify them with Gisesemann Clock Sync Module (GCSM) and we use the same design is with the unique carbon fiber material at 3mm on shielding layer with repect to 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 arragements (as well as providing developed clocksync and external reference clock options for EtherREGEN) to minimize timing error to unprecedented levels. 



The S2 Reference SFP NIC is very high quality with two indvidual clocks for CPU and SFP chips. The Giesemann Clock Sync Module (GCSM) will genrate the re-clock signal from OCXO Master Clock. 



The quality of the Network Card is crucial to deliver the optimal sounding for Music Server, which ensure the intergrity 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). 





The Giesemann Clock Sync motherboard is located at the back end 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 S2 Network Card is balance and lush in sounding, very airly and resolving. 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. Highly recommended. 




What is special about S2?


  • The S2 SFP Netword Card 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.  


  • Dual Core Realtek chips for dual re-clocking via Giesemann 
    • Since there is two independent ASMedia ASM3142 Controllers with two independent clock near each chips. The modification is required to perform in high precision within 1mm to bypass two of the clock on the motherboard. 
    • The Giesemann Clock Sync Module (GCSM) will be output two independent clock signal to each chip to operated. 





  • The silim 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 Grade Realtek Chips is used. The chipset is the new generations of Realtek, the heat is much lower and lower powered. Lower heat means lower noise floor, lower latency with smoother sounding. The hardware of Realtek 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 power section of Gisemann Clock Sync Module (GCSM) is separated power by external LPS at 5V 2A. It eliminates computer as source of powers. For lowest noise and best sounding using Farad Super 3 power supplies. 


  • Single 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. 


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. 



Technical Specification:


  • Ultra - Low Noise Linear LT3042 Regulators and filters eliminate the noise interferences from a PC
  • Duelund Cable is used to connecting the DC power to Giesemann Clock Sync Module (GCSM)  
  • DC Port at 2.1mm (Gold Plated DC port) 
  • Required to power with external LPS rated at 5V 2A
  • 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 Realtek Ethernet Controller 
  • Highest Industrial Grade with wide range of extreme operating temperature -40C to +85C.  
  • All Windows editions and Linux OS Supports 
  • All x1 - x16 lane PCIe 2.0 to 4.0 slots supported
  • All modification hand made in Hong Kong by AfterDark.




Type: OCXO Clock

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Discount code: PA1