Electronics > Projects, Designs, and Technical Stuff
Basic inline preamp diagram required.
(1/1)
drummerdimitri:
I watch movies on a projector but the 3.5 mm output signal is too low so even when I turn the volume to the max on my sound system, the loudness is not satisfactory.

Would like to assemble a basic preamp to double the output voltage of the signal. Does anyone have a circuit diagram I can use to assemble this device?
Tek Tech:
A simple one-transistor amp should work. One for each channel.
They can be cascaded if you need greater amplification.

[Edited from emitter follower. Thanks to Benta's observation one post below]
Benta:

--- Quote from: Tek Tech on April 26, 2019, 04:34:23 pm ---A simple emitter follower should work. One for each channel.
They can be cascaded if you need greater amplification.



--- End quote ---

Just a little problem: emitter followers have a voltage gain of less than 1. Not the right solution.
moffy:
Attached is a possible solution. Use an LM833 dual, you get 2 opamps therefore stereo. Has a gain of 2.2 but you need a +/-12v supply as well.
Caps should be non polar (not electrolytics) and avoid ceramics for the 1u.
MarkF:
Here is a pre-amp for a condenser mic.  Maybe you can tweak the gain for your case.

   
Navigation
Message Index
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod