giesemann reference sfp optical isolator pa1 on sale

AfterDark. Giesemann Reference SFP Optical Isolator PA1

OCXO Version
DC PLUG Version

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AfterDark. Giesemann Reference SFP Optical Isolator PA1 

A mini SFP Optical Isolator produced by AfterDark. 
gives a significant improvement on sounding
designed based on Project ALPHA program 
with one well respected member in Audiophilestyle.
To honor that moment, we invite all 
Audiophiles to share the happyiness 
 with friends 

The one-of-a-kind creation was designed especially for one serious audiophiles in to connect the AfterDark. Trifecta Extreme Giesemann Clock on the audiophile system. The device is made by two motherboards inside that were individaully working and sepeated in two seapated layer on Carbon Fiber AudiophileMAT at 3mm and 1mm thickness for best isolation. These existing arrangement are reconstituted as parts to bring the whole system to another levels.    

The Giesemann Clock Sync Module (GCSM) will either accepts external inputs of 10M Reference Master Clock Signal or  works with internal OCXO. Two versions would be made to orders. 


The SFP Optical Isolator or Media Convertor will re-clock by GCSM to provide the best SFP to LAN signal to Music Server or Network Endpoint. The SFP Isolator PA1 not only changes in the overall sounding but brings all micro details and extracted them in precise timing with lowest possible jitter.  

Audio is very vulnerable to noise. There are many types of noise that can negatively affect audio quality, but the noise that has the biggest impact on computer streaming is EMI, RFI, and impulse noise .

The main role of SFP Isolator PA1 is to block EMI noise coming from the lan cable of Router and Music Server. RFI noise that
enters beyond the sheath is a problem at the cable end, so it can be solved with a optical fiber cable. However, no matter how well shielded a lan cable is, it cannot completely block out RFI noise. 

Giesemann Reference SFP Isolator PA1 is a device that uses Optical Fiber with Giesemann OCXO precision clocking  technology to remove RFI noise and impulse noise coming in from cables, and revive or reclocking the LAN signal for Audiophiles system.

The advantage:

  • The density in the sound image is increased, the color of the sound is revived, the sound of the singer's breathing, and the lingering sound that lasts until the end improves the sense of space and air, and the tone becomes more vivid and dense, allowing for musical nuances even in digital. Your sensibilities will be revived, and your music will start to sound more musical.
  • The sound stage is much wider and opened up with 3D and improved focusing, quietness, clarity, purity, detail, and precision , while OCXO increase the precision and microdetail extraction with more refine backgrounds, the smoothness and microdynamics will be much better represented and created spatial region. 

Connection matrix:

Method 1: Connect the SFP Isolator PA1 to the Lan port of the upstream devices. E.g. Music Server , Internet Router 


Method 2: Connect a SFP Isolator PA1 to the LAN port of the DAC.image.thumb.png.8741e7cc6a8d6c68542e65d13e505d84.png

Method 3: Dual SFP Isolator PA1

  • Connect one SFP Isolator PA1 to the upstream LAN port.
    Then connect another SFP Isolator PA1 to the DAC's LAN port.
    Although the installation cost will increase, the performance of the SFP Isolator will give you the best effect.


Behind the minimise design of the mini SFP Optical Isolator, the internal components and parts is precision apply during the assembly process by soldering the chips with industrial graded signal cable to nearest 1mm, the process illustrating the hand craftsmanship that went into creating this entirely unique devices, which is highly skill intensive and cannot be made in today commercial standand procedure.   

Compataible to most SFP modules including Cisco, Finisar SFPs and UpTone EtherREGEN  

 Giesemann Reference SFP Optical Isolator
 Compatible optical fiber

 Multimode (2 cores) or Single Mode

 Terminal shape

 UTP side

 RJ-45 type

 optical fiber side

 2-core LC terminal

 Transmission speed  UTP side


 optical fiber side


 External 10M Reference Master Clock OCXO Impendance 

 50ohms or 75ohms 

 Power-supply voltage  5V DC  2A (Gold Plated DC Socket) 
 Maximum power consumption  2.8W
 Size (width x height x depth)  15×12×7cm
 weight  638g (body only)

 Cisco AOC Cable (Optional) 

 Cisco AOC SFP optical transceiver (Optional) 
 Terminal shape   2-core LC terminal
 Transmission speed   1000Mbps
 Size (width x height x depth)   W13.4×H8.5×D56.5 mm
 weight   25g





Type: OCXO Clock

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Let's celebrate!

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