"A Simple, HIGH QUALITY Transistor Preamp"
Draws very little current.
Works over a Wide Range of Supply voltages.
Transistor Construction, for a Very Low Cost and HIGH QUALITY Preamp.
Build one or more For Microphones, or Two for a Stereo Cartridge.
I did Not create a Stereo PCB, as Two seperate boards can be better.
(You can Stack them to use less Space.)
Ideally the Voltage at the TP. should be set to: ((Supply Voltage/2) - 0.6 volts)
But just 1/2 Supply voltage is OK.
Revised "NOV 12 2009"
R1/R2 sets Gain, typical 680K/470 ohms.
Open Loop Gain = 1446 @ 1000 Hz. 1.6 mv in = 2 volts out if supply voltage is 15 volts.
Frequency Response 10 Hz to 50 Khz. if supply voltage is 40 volts.
With a 40 Volt Supply, Distortion = less than 0.03% at 4 volts output, Increases to 0.2% at 10 volts output.
I show a Trimpot on the PCB for the Volume Control. You will probably use a Convention Mount, LOG Taper Pot for Volume.
This is a Very Versatile Preamp and other than the two compensation networks that are shown, you can create Many Others.
For Example: NATB which is a Tape Compensation, Or create Greatly Emphanzied Low or High Frequency output, Or Reverse RIAA Compensation.
The Etched and drilled PCB is available,
And all the other parts also, If Needed.
Picture Overlay, Flat Response
All Imformation in this Article is "Copyright protected".
Chemelec
*Copyright © 2004 & 2009*
