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Author Topic: Distortion on this circuit  (Read 1196 times)

Fossilshark

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Distortion on this circuit
« on: June 12, 2016, 12:46:36 PM »
Im using the single transistor preamp with this 3 transistor amp circuit as a power amp. It works but its not good, im hearing radio signals, and alot of distortion. Whats wrong?
« Last Edit: June 12, 2016, 01:17:20 PM by Fossilshark »

Fossilshark

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Re: Distortion on this circuit
« Reply #1 on: June 12, 2016, 04:01:57 PM »
Update: amplifier very quiet, transistors heating up, and distortion only at high volumes.

Loudthud

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Re: Distortion on this circuit
« Reply #2 on: June 12, 2016, 09:44:58 PM »
The Voltage at the minus side of C1 should be half the 9V battery Voltage. If the Voltage there is too low, increase the resistance of R2. If the Voltage there is too high, decrease the resistance of R2.

If Q1 and Q2 are too hot, install a resistor across one of the diodes, D1 or D2. Try a 1K or 470 Ohm or go lower until Q1 and Q2 cool off.

This circuit is too simple. It won't work at all 99% of the time. If it does work, performance will not be very good. An LM386 is easier to use and will work most of the time without adjusting any resistors.

The preamp is another crappy circuit. Find something else.
« Last Edit: June 12, 2016, 09:51:27 PM by Loudthud »

Fossilshark

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Re: Distortion on this circuit
« Reply #3 on: June 12, 2016, 11:19:30 PM »
Haha i kind of figured as much. Im actually trying to find a simple transistor circuit to replace an lm386 i have. I need something with a little more power then the 386 puts out, mabey 2 watts. Is this achievable with 3904/3906 (all i have on hand) or will i have to bite the bullet and invest in some more powerful trannies.