A little background, I've been messing around with building chip amps for a few years now. (Guitar amps) Mostly battery powered lm386 amps and a couple tda 2030 amps from kits. I did take a 2 year electronics course about 30 years ago and do remember bits and pieces of what was taught.
Over the last few years I have wanted to build an amp of my own. Nothing outrageous just a simple 20 watt amp. After a couple false starts and becoming overwelmed because I bit off more than I can chew I have a new plan.
I have a TDA 2030 power amp built from a kit that works now I want to put a pre amp in front of it. I have a simple 2 transistor preamp built and according to LTSpice it works.
When I wired it up on the breadboard it does indead work but I get alot of what sounds like 60 cycle hum. The power amp is dead quiet until I put the preamp output into it. I added 2 2200uf caps across the power rails on the breadboard and it does get quieter but is still too noisy.
I scaned a copy of the circuit and attached it since I couldn't figure out how to attach a file from LTSpice.
edit; the resistor values are as calculated in spice, I used the closest values I could.
This is not the finished preamp, just the starting block to build on. I am curious as to why it is so noisy. I'm looking for input on what changes to make and where to go from here.
Over the last few years I have wanted to build an amp of my own. Nothing outrageous just a simple 20 watt amp. After a couple false starts and becoming overwelmed because I bit off more than I can chew I have a new plan.
I have a TDA 2030 power amp built from a kit that works now I want to put a pre amp in front of it. I have a simple 2 transistor preamp built and according to LTSpice it works.
When I wired it up on the breadboard it does indead work but I get alot of what sounds like 60 cycle hum. The power amp is dead quiet until I put the preamp output into it. I added 2 2200uf caps across the power rails on the breadboard and it does get quieter but is still too noisy.
I scaned a copy of the circuit and attached it since I couldn't figure out how to attach a file from LTSpice.
edit; the resistor values are as calculated in spice, I used the closest values I could.
This is not the finished preamp, just the starting block to build on. I am curious as to why it is so noisy. I'm looking for input on what changes to make and where to go from here.