Zeners For Input Question

[vdi_nenna]

What is a good voltage and current rating for back to back zeners protecting the input of a balanced amp? 9.1v, 10v, 20v?

I'm trying to protect the input of the Hoffman 2 stage SE amp. Any suggestions?

thanks,

Vince

 

[Eric]

Zener Values for Input Protection

Hi Vince: A short while ago I posted the same question. The answer I received (I think it was from Robert Pear?) was back to back 5v 500mw zener diodes. I was asking about unbalanced RCA inputs, but I can't imagine that the requirements for unbalanced input would be much different.

Anyone know otherwise?

 

[vdi_nenna]

Zener Values

I know that it's need to protect the gate, because it can't exceed a gate voltage of 20v. I don't know if it's suppose to be close to that value or less, so it never reaches 20v.

Thanks for the response Eric.

 

[Petter]

If you go to http://www.passlabs.com and check out the schematics of preamps/poweramps (service manuals), you will find a sutiable value and probably industry part number as well. Typically, such diodes are 9.1V, but it would depend on the application and also how they are connected.

 

[vdi_nenna]

Yeah, I have a few of the manuals. What confused me was that the input for the Zen amp was 9.1v then changed to 20v for protection. The Aleph 4 is 9.1v. I guess I'll go w/ the 9.1v because I'm working on a 2 stage, like the Aleph.
I guess I'm looking for the voltage to start protecting. Like you said, the application.

Thanks Petter