Low End Preamp to Medium End :D

[RuudNL]

I think a 'millivolts generator' would be closer to reality...

(Anyway: under normal circumstances a 4.7 or 5.6 V zener won't conduct because of the microphone output.)

 

[sahib]

You would be surprised. I would not like to take the signal level coming from a kick drum lightly.

See the maximum output at below link;

http://www.microtechgefell.com/index.php/en/microphones/studio-a-recording/small-membrane-transistor-mics/429-m-221

 

[JohnRoberts]

THAT corp wrote a pretty good AES paper about input protection. Yes you want to prevent the input devices from zenering (<<7V), but transients from shorted, charged up, phantom supply blocking caps can drive the inputs negative a few tens of volts. Oversized input caps means lots of current must be clamped, too.

JR

 

[rıdvan]

So what about my schema?

 

[rıdvan]

OK!

I started to draw power supply.I did Preamp and Phantom Power Supply for now.Please look and tell me if it's wrong.

http://dl.dropbox.com/u/91809016/preamp.psu.bmp

Thanks!

 

[Meathands]

THAT corp wrote a pretty good AES paper about input protection.

I believe you mean "More Analog Secrets Your Mother Never Told You"? http://www.thatcorp.com/datashts/More_Analog_Secrets.pdf

 

[JohnRoberts]

My recollection was a separate paper just about input protection, but that paper gives it a good treatment, and looks like it has some other useful information worth reading.

Back in the day I learned a lot from the national audio applications manuals. While they always pimp their own products you can still learn a lot of the basics from such sources.

I suspect THAT engineers were forced to rapidly develop expertise about input protection from trying to keep their chips alive inside customer applications. On-chip clamps can rarely handle a full dump from an oversized input cap... bigger must be better right? 

JR

 

[rıdvan]

Why no one talks about my schma?

 

[rıdvan]

Ok,i did psu of preamp.It's working perfectly!Now i'm working on Phantom power.

 

[DLJ]

Why no one talks about my schma?

No one talks about your schema because you need to work on it some more. The power supply will not produce + and - voltages as you have it drawn. Try running a full wave bridge (4 diodes) from each of the 12 volt windings, to make two separate 18 volt supplies if that's what you want. The phantom supply is somewhat complicated, a full wave bridge and a 48 volt zener is enough for the regulator, at this point.