Power amplifiers that we sometimes raises a raft of small drone as groundingless than perfect.The following are some ways to cope with the hum of the power amplifier:
1. Keep sensitive circuits of the transformer, casing dimensions are not too small.One blog even suggested to use two-bok, bok special one for the transformer. For the toroid transformer or amplifier with a large transformer, should only contain a series of power amps, with no tone control.
2. Change the position of the transformer, side by side into the lower side (the transformer is high) withfacing a series of sensitive posts
3. Use a spacer on each PCB board as high as half the height of the transformer, eg as high as 2.5 cm or more so that the PCB board parallel to the core / center of the transformer, here the effect of the weakest fields.
4. We recommend using a stereo module instead of two mono modulesThis avoids wiring errors. If forced to, try to sizecable between the right and left modules as long and as short as possible.
5. Should take the ground path for the speaker of ct ct elco instead of the transformer,if the board pcb mounted two big elco (like elco power supply), takeground path of the speakers here, and check to hear!
6. Power supply for radio (TX or RX) is very sensitive, use a capacitor4x100nf, 4 pairs of these capacitors in parallel to each mem-diode (bridge).
7. At the tone control circuit IC op-amp that uses a symmetric power supply,sufficient ground wiring is taken from the signal ground wires only. shouldIC power supply (7812) installed near the main power supply, notmounted near the tone control.
8. Always use a stereo cable shrouded perfect (color stereo cablered-white-covered ground and wrapped in transparent skin.
9. For power supply, use capacitors of 2200uF per ampere elco
10. Zoom and ground wires as short as possible, especially a pair of elco (ct line between elco) power supply (can be tried for the amplifier blazer)
11. For the amplifier should be mounted to the computer casing when not in the ground soil is diground PC casing soil
12. Pairs of each kit to the circuit without passing groundnya nut / baud / spacer. Do not let the existing ground line at the hole pcb connected to the casing / box. Do not follow this ground. ground attached to the casing should have one. if necessary use a plastic spacerovercome the noise:
1. Use the active component (IC) that qualified as TL084, TL074, notLM324. LM324 any brand of noise. TL084 is more guaranteed authentic yellow (ST), not white. For now, the IC TL084 is printed white-work unstable frequencyhigh (treble breaks and more noise). For IC 4558 (NE5532) use plain white silk screening JRC4558D or TL072 - TL082 yellow, LF353 noise. LM741 (NE5534) can be replaced with the Hitachi HA17741, LF351 noise may also, has never been tried.we do not have to look for the brand and the price is more expensive because it is the most low noise.
2. If necessary, the circuit power amplifier OCL, lowering its gain by lowering the value ofresistor in the path gain from 33k to 22k speaker, mimics the gain-clone lower amplifier noise.
3. Should simplify the circuit, the circuit is too complex is more susceptible to noise and interference.
4. Should then potentio / volume mounted on the input-power amplifier, such as professional amplifier without tone control.