relay question

[mkruger]

12v power relay in a tube mic pre. can i connect the 12v relay directly to the 12v transformer? or does it need to go through the filtering, regulator, etc...?

the reason i ask is because it's not like it's being used in the actual preamp stage or anything. you see this way i can use 12v to turn on the 12v regulated.

-mike

 

[SSLtech]

check the relay markings to see if it has any admonitions about AC or DC. I've used a few DC-only relays of late...

Keith

 

[mkruger]

i will check but i guess if it were DC only I could connect it on the DC side of the rectifier but before the regulation and filter stage... does this sound like it would work? or will the 12v be too unstable and "dirty" before the regulation and filtering?

 

[owel]

The 12V is just powering the coil. So even if its unregulated, it will work.

However, if you're passing audio thru that relay, I don't know if it might pick up the hum from an unregulated DC powering the coil. Maybe yes, maybe no.... Just to be safe, a regulated DC may not be a bad idea anyways.

 

[mkruger]

no i'm not passing any audio, but that was my point of asking. I was wondering if the unregulated 12v might pass unwanted stuff into the power supplies being swithced? can this happen in a relay?

 

[SSLtech]

No conduction from primary to secondary, BUT.....

12V RMS AC after rectification and smoothing gives you almost 16Volts... Your relay might object a little...

12 x 1.414 (square root of two) = fractionally under 17Volts. minus a volt or so for rectifier tax gives about 16V. Off-load transformer secondary rise will raise this number.

You can do it, but the relay's probably out of its comfort zone. Either use the AC or the regulated DC. otherwise, use a 16V relay... failing that... use the Force, luke!

Keef

 

[mkruger]

ah, excelent advice, will use regulated