Mosfet Relay as a replacement of small Finder relays

[DJRix]

Mosfet Relay for speaker protection in Audio Amplifiers

As a result based on my experience as a serviceman of audio amplifiers,I have developed direct replacement of a standard mechanical relays Finder type 40.61.


This "relay" has parameters:
On-State resistance: 9mR
Maximum continous current 16A
Maximum voltage accros open relay 64V DC


Used mosfets has maximum continous current over 150A and peak current over 600A 🙂



It´s easy to use, just desolder old mechanical relay and solder new "SSR" 🙂



For anyone interrested, it would be possible to sell these relays. The price is 22 Eur/pc , approx 7 Eur shipping



Below you can find pictures.

 

[Mooly]

Moved to Vendor forums.

 

[sg2]

Beware of safety, as you loose galvanic isolation.

 

[DJRix]

This SSR relay is ofcourse galvanicaly isolated 🙂 I used Vishay photocell. Tested on my 500V tester without any problems. Photocell is rated for 4,5kV but because of PCB spacing i do not recommend more than 500V between "contact" and "coil".

 

[DJRix]

Toff measurement. No problem with iductive load.
Toff 250ns for resistive load.

 

[nigelwright7557]

There is a need for a low cost solution as some of the SSR's that RS Components sell are silly money.

 

[DJRix]

Thats absolutely true. This relay is unique for audio application - conventional mechanical relays are often cause of problems with sound dropouts in audio amplifiers becasuse of transition resistance on contacts after years...



Attached simplified schematics.

 

[doctordata]

Thats absolutely true. This relay is unique for audio application - conventional mechanical relays are often cause of problems with sound dropouts in audio amplifiers becasuse of transition resistance on contacts after years...



Attached simplified schematics.

I made a similar relay drop in for the Songle SLA relay some 5 years ago for my 5 channel HT amp . still working fine !
LJM L250 or Arjen Helder 2050


Cheers ,



Rens

 

[meanman1964]

As a result based on my experience as a serviceman of audio amplifiers,I have developed direct replacement of a standard mechanical relays Finder type 40.61.


This "relay" has parameters:
On-State resistance: 9mR
Maximum continous current 16A
Maximum voltage accros open relay 64V DC


Used mosfets has maximum continous current over 150A and peak current over 600A 🙂



It´s easy to use, just desolder old mechanical relay and solder new "SSR" 🙂



For anyone interrested, it would be possible to sell these relays.



Below you can find pictures.

Can you send me a mail regarding the price

 

[Tromperie]

Could you post the prices here, please?

 

[DJRix]

Sure, the price is 22 Eur/pc , approx 7 Eur shipping.