i wanted to make a preamp for guitar with TL072 ic . so i looked around the web and found this schematics , which looked promising ( Guitar Preamp with Tone Controls )
so , i got some new parts and started building . i tried building it on breadboard , prefboard and lastly on veroboard . though it worked okay , bt there was a whole lotta noise to it . (i think it has to do something with grounding , because ,if i touched the strings of the guitar , the sound would become less and if i let go it would just scream )
so , can anyone help me how to deal with this problem ?
ps: im using 35 watt desktop amp as an power amp (cause ,im planing to make a 100 watt power amp with tda 7293 ) and the circuit is unshielded and i dont have much knowledge in electronics , just trying to make an amp for my big brother )
so , i got some new parts and started building . i tried building it on breadboard , prefboard and lastly on veroboard . though it worked okay , bt there was a whole lotta noise to it . (i think it has to do something with grounding , because ,if i touched the strings of the guitar , the sound would become less and if i let go it would just scream )
so , can anyone help me how to deal with this problem ?
ps: im using 35 watt desktop amp as an power amp (cause ,im planing to make a 100 watt power amp with tda 7293 ) and the circuit is unshielded and i dont have much knowledge in electronics , just trying to make an amp for my big brother )
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The charger may put out pulses instead of clean DC. That would cause noise.
Also, that circuit needs a bipolar supply. With one polarity of DC., it wouldn't work right.
Can you try a couple of 9V batteries instead, like on your schematic?
Then the noise should be gone.
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thank you .
it worked . i made a dual power supply with a step down transformer . tho there was a slight noise , i dont think it would matter much after i use some distortion pedal.
You may have to do Noise Analysis ...... this way you can see if it is "design" related or part quality...
Look at Broadband Voltage Noise, Current Noise, Flicker Noise.. Resistor noise aka Johnson Noise.....
I see some 10M resistors !!
You can set up a Spread sheet to summarize all the noises... or I belive there are free spread-sheets on the Internet that are all ready to use..just drop in the numbers from your data sheets..
Look at Broadband Voltage Noise, Current Noise, Flicker Noise.. Resistor noise aka Johnson Noise.....
I see some 10M resistors !!
You can set up a Spread sheet to summarize all the noises... or I belive there are free spread-sheets on the Internet that are all ready to use..just drop in the numbers from your data sheets..
Here a couple of links. Could not get THD down and was puzzled.
http://www.diyaudio.com/forums/analog-line-level/320015-doa-discrete-op-amps-2.html#post5378331
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http://www.diyaudio.com/forums/analog-line-level/320015-doa-discrete-op-amps-2.html#post5378331
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What is "noise"? Hum? Buzz? Hisss? Creaking? Radio stations?
A high-gain amplifier out in the open WILL pick-up all the electrical signals in the room. Inside a wired house there will be both hum and incidental garbage from appliances. Out in a field you still get far-away lighting static.
Your body also picks-up all this interference. Connecting body to amplifier (through string ground) at least keeps your body-noise and amplifier-noise the-same so less audible.
Try it in a metal box. For a prototype, you can put a newspaper in a large cookie-tin, set the breadboard inside, and bring connectors out through small holes. Use a clip-lead to bond the box to the circuit ground.
In case you can live with CMOS-inputs the OPA1678 offers similar performance at a fraction of the price.
thank you . i just needed a suggestion like this .
can u give me link to its preamp and power amp schematics that only uses the best component
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