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919.00 PLN

Weight: 1.6 kg

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Fully automatic SCART switch with full galvanic inputs separation.

  • 16 scart inputs ( RGB, s-video, composite)
  • 1 scart ouput
  • "Knight rider" style active scart detection
  • full ROHS
  • AVR controller with firmware future updates
  • HQ plexi transparent ( made by me ;-) at my laser machine)
  • MICRO USB power supply (regular mobile phone charger 5V will do the job - please, use sth decent - approx 1A)


How doees it work ?

      Imagine, You have many retro system in use. Amiga, Atari ST, ZX spectrum, etc... And You have only one classical TV/Monitor with one SCART INPUT. Each time, You want to switch system, You have to connect Your machine to Your monitor. Everytime, You do it - You damage scart socket inside. Those days are over. Connect up to 8 computers/consoles to HYDRA, then connect HYDRA to Your TV/Monitor and power on hydra with You mobile phone charger with MICRO USB plug. Since now, HYDRA will detect active scart input and forward all signals to Your monitor. Simple and efficent.





  • left - scan for active source to the left from active one (if active is far left, no action)
  • right - scan for active source to the right from active one (if active is far right, no action)
  • middle - HD/LOW PASS filter (led on/off) - default ON
  • left+right pressed - disables "knight rider led effect"


Changes in  firmware 20180220. Now, all setiings are stored in avr flash:

  • left - scan left in auto mode / next scart in manual mode
  • middle - HD/SD filter 
  • right - scan right in auto mode / previous scart in manual mode
  • left + right - DISABLES/ENABLE leds
  • middle + right - Automatic/manual mode





Product gallery




  • 20180220 firmware
    • left - scan left in auto mode / next scart in manual mode
    • middle - HD/SD filter
    • right - scan right  in auto mode / previous scart in manual mode
    • left + right - DISABLES/ENABLES leds
    • middle + right - Automatic/manual mode switch




Q: I have a PlayStation 1  have hooked up to it and it does not seem to work.I am using a very high performance scart cord from the hydra to the adapter and all of my scart cables are from retro gaming cables in the UK or retro gaming accessories from ebay.

A:  You have sync stripper installed and Your RGB cable outputs  "composite sync" signal that exceeds voltage level definied by scart signal standart ( please, have a look at table below - source: Instead of desired 0.7 Vpp (on 0.3V) You get 4Vpp.  As Your TV may not care, Hydra may not detect Your signal.

What Can You do:

  • Feed composite video (or best luma) to scart pin 20 directly, avoiding elements on the way. 
  • Use orginal cable 

"Be aware that in the context of retro gaming, there are two types of csync signals:  TTL and 75 Ohm.  Most displays and processors will require 75 Ohm csync, but some can accept TTL.  As a general rule, unless your setup specifically requires otherwise, your target goal is that the cables you use with your consoles will all be outputting a 75 Ohm signal and the target device will also be receiving a 75 Ohm signal."


Please, remeber and keep in mind, that HYDRA may

not lock on scanning on input with composite sync of TTL LEVEL (4Vpp),

as SCART STANDART ASSUMES 1Vpp including sync



Pin      Signal    Level     Impedance   
1 Audio Out Right 0.5 V rms <1k ohm
2 Audio In Right 0.5 V rms >10k ohm
3 Audio Out Left + Mono 0.5 V rms <1k ohm
4 Ground Audio    
5 RGB Ground Blue    
6 Audio In Left + Mono 0.5 V rms >10k ohm
7 RGB Blue In 0.7 V 75 ohm
8 Audio/RGB switch / 16:9 High (9.5-12V) AVmode
Low (0-2V) TVmode
9 RGB Ground Green    
10 Comms Data 2         
11 RGB Green In 0.7 V 75 ohm
12 Comms Data 1    
13 RGB Ground Red    
14 Ground Data    
15 RGB Red In / Chrominance 0.7 V (Chrom.: 0.3 V burst) 75 ohm
16 Blanking Signal High (1-3V) RGB
Low (0-0.4V) Composite
75 ohm
17 Ground Composite Video    
18 Ground Blanking Signal    
19 Composite Video Out 1V including sync 75 ohm
20 Composite Video In 1V including sync 75 ohm
21 Ground/Shield (Chassis)    




Q: Hydra makes "click sounds" when scanning. is that normal ?

A: Yes, all hydras when scanning for ative input behave the same. For short perios of time main cpu connects output with underlighted input. There is no easy way to eliminate this, but adding few ms delay when  active scart is detected and connection input <=> output established. It is subject of next ver HYDRA being designed.


Q: Hydra acts strange. doesn`t detect inputs, sound is disturbed, video blurry...etc

A: Two words: POWER SUPPLY. Please, use decent one.


Q: Hydra gives "jumpy" picture. I have SNES and my cable is pal one.

A:  HYDRA has built in signal termination - 75ohm resistors to gnd. If Your cable has this feature, picture will be darker and may be jumpy. Remove passive elements on RGB lines.  please, read next one answer


Q: Hydra is very problematic with my systems.

A: No. it is not. problematic are Your cables. Please, keep in mind, that hydra has built in many features, like sync stripper for signal detection on scart, signal termination, low/high pass filters. Please, use regular and simple cables to connect Your systems.  For best effects, please considering direct RGB connection, composite video connection and sound to scart socket. ONLY EXCEPTION is RGB switch - 16pin of scart input. it must be pulled high by resistor from 5V to make hydra switch into RGB MODE. How to get proper signal from You system -


FIRMWARE UPDATE PROCEDURE: (thanks to Frank Skilton for debugging)

  • download last firmware from download section
  • connect usbasp (or any avr programmer) to KANDA connector of HYDRA (PINOUT)
  • run Your AVR programming software
  • flash it