this is what I get from my amp. ear.

[Johan Wagener]

All connections double checked. All transistors checked and the all
have 0.8V on BE. Except for transistor 2 which has 1V over its BE?

Mic is a brand new miniature electret microphone which runs on 1V-10V
with 2Vnom

I don't even pick up the mains hum when I touch the input. I do
however get a small amplification of the microphone and when I connect
a 3V supply to the circuit I can hear sounds picked up by the mic, but
it is very faint.

Should I perhaps try using a LM741 as a preamp for the mic and then
send this signal into the Amplified Ear?

BTW, the circuit can be found at
http://www.electronics-lab.com/projects/audio/023/

Please send your suggestions

 

[Graham Knott]

All connections double checked. All transistors checked and the all
have 0.8V on BE. Except for transistor 2 which has 1V over its BE?

Mic is a brand new miniature electret microphone which runs on 1V-10V
with 2Vnom

I don't even pick up the mains hum when I touch the input. I do
however get a small amplification of the microphone and when I connect
a 3V supply to the circuit I can hear sounds picked up by the mic, but
it is very faint.

Should I perhaps try using a LM741 as a preamp for the mic and then
send this signal into the Amplified Ear?

BTW, the circuit can be found at
http://www.electronics-lab.com/projects/audio/023/

Please send your suggestions

--
Measure emitter, base and collector voltages with respect to the negative
supply for all transistors and post them here (unless you've already done
so)
..
My most up-to-date website
Electronics for Beginners & Intermediate Electronics
http://homepage.ntlworld.com/g.knott/index.htm