- Simple two transistor stage pre-amplifier circuit, with a high impedance input stage suitable for musical instruments with passive pick-ups and an output stage with enough signal level to feed AV equipment.
- A brief description of the processes I used to fabricate the clear acrylic case I made.
Step 1: Make the Circuit
I used point-to-point construction for this circuit, however it could be built on a PC board if desired. I used aluminum duct tape to form power rails on the inside of the acrylic case. Since the tape can't be soldered I used small pieces of tape to fasten the connection points to the components. It was challenging to make reliable connections with this method. Alternatively copper tape, or wire could be used.
- Q1, Q2 = 2N3904 (most general purpose transistors could be substituted)
- R1, R2, E3 = 10K
- R4 = 22ohm
- C1, C2, C3 = 35v 10uf
- 1/4" Mono Input Jack
- 2 RCA Phono Plugs (I cut the thread on back shell to form nuts for panel mounting)
- 2 AAA Battery Holder
- Project Box (this is an alternative to the custom case I made)
Standard AV RCA phono plug on center spacing is 13mm with a 10mm panel mount hole.