1. Home
  2. General Electronics
  3. this is what I get from my amp. ear.

this is what I get from my amp. ear.

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

formatting link

Please send your suggestions

Reply to
Johan Wagener
Loading thread data ...

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

formatting link

Please send your suggestions

Reply to
Johan Wagener 

--
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
Reply to
Graham Knott

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.

Reply to
Watson A.Name - "Watt Sun, th

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.