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

 

[Watson A.Name - \"Watt Su]

"Johan Wagener" <johanwagener@webmail.co.za> wrote in message
news:c86a2c09.0408110333.3b889aa4@posting.google.com...

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?

This circuit has plenty of gain if it is working right. The 1V on Q2
seems a bit off. I would remove the transistor and replace it with
another one.
Also check to make sure your capacitors are installed in the correct
polarity.

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

Please send your suggestions