falken1208
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no I tried 12v car battery and 9v dry battery, cannot compete with good ac power. but offen in resident area power quality is not as good as mixed used place for some reason(chinese people live in apartment not house so we use large transformer for whole community,Simple check - use a 12V battery (car battery for example) instead of your power supply. It would take an extraordinary change in load to make the voltage change. Let us know if it fixes the problem, even if it isn't a permanent solution.
Brian.
i ab tested 48v to 12v dc-dc vs. 12v battery straight in. the result is amazing. it is as the same as this picture says. 48 to 12v is faster than native 12v. which leads to better recording performanceI agree Klaus.
We are absolutely sympathetic to your problem falken1208 but if wired correctly the power source should have no noticeable effect on the sound quality. It WOULD have an effect if you were driving high power through loudspeakers because most power amplifiers use class AB where the current consumption increases with loudness but you are referring to a recording amplifier where the power will be a few thousands of one Watt at most. If the power source is varying randomly, not in time with your guitar sounds, it would imply the power supply was not regulated properly. That is why I suggested trying it with a car battery which should have rock steady voltage under such a small load.
Can you sketch a diagram of exactly how you have the guitar, amplifier and power supply connected please, it will help us diagnose the problem.
Brian.
diagram attached. after 5 years test. I promise the final sound quality is only based on the power source no matter ac or dc. The best power would be 220v generator direct to my house. But I don't know what compensation they have done after transform 10kva to 220v over there on street.I agree Klaus.
We are absolutely sympathetic to your problem falken1208 but if wired correctly the power source should have no noticeable effect on the sound quality. It WOULD have an effect if you were driving high power through loudspeakers because most power amplifiers use class AB where the current consumption increases with loudness but you are referring to a recording amplifier where the power will be a few thousands of one Watt at most. If the power source is varying randomly, not in time with your guitar sounds, it would imply the power supply was not regulated properly. That is why I suggested trying it with a car battery which should have rock steady voltage under such a small load.
Can you sketch a diagram of exactly how you have the guitar, amplifier and power supply connected please, it will help us diagnose the problem.
Brian.
Because i use active pickup with 9v battery it clips inside the pickup. All recordings with that pickup have the same cliping waveform.some amplifier in the chain from the guitar pickup to the PC is clipping - that much is clear from the pictures
all else from the OP holds little meaning.
Because i use active pickup with 9v battery it clips inside the pickup. All recordings with that pickup have the same cliping waveform.some amplifier in the chain from the guitar pickup to the PC is clipping - that much is clear from the pictures
all else from the OP holds little meaning.
I could only draw this diagram. no computer I could hear its not correctThis looks like you do not have a good explanation for your symptoms. If you can show a block diagram with all the power , signal and ground connections. i suspect you have common mode ground noise that needs to be bypassed or balanced out. Can you sketch and post it?
I could only draw this diagram. no computer I could hear its not correctThis looks like you do not have a good explanation for your symptoms. If you can show a block diagram with all the power , signal and ground connections. i suspect you have common mode ground noise that needs to be bypassed or balanced out. Can you sketch and post it?
1.guitar signal is unbalanced and you are talking about DI box to make it balanced signal, I tried , useless. the high-z input on interface are designed with 1m ohm impedance spacially for guitar. but you said wireless interference, I would say maybe, but it seem not change a little alone with where I recorded, even I go cross the cities and moved 500 miles away. I thinik if its wireless noise, it could at least change when I start to move. and every people record guitar by guitar cable. I have tried different cables. not the problem.Are all wires in pairs like this or shielded? Where is your 0V reference?
I see all wires as antennae. So to make "poor" reception on these "antennae, requires care. (Shields, shunt filters, guitar balun to balance it etc.)
If signal impedance is higher than return then it is called "unbalanced", then a common-mode interference can create a differential signal from your wire pair induces by outside interference like line transients. Meanwhile you show no direct connections to the line or Protective Earth (PE);ground.
If you are not near AC Protective earth, you may need to shield everything and make the battery -ve your ground. You may also need a 1:1 transformer for the guitar.
I assume your amplifier is a commercial product and not a DIY problem missing something fundamental.
For experiments, connect your hand to an earth ground ( electric stovetop or similar ) and use other hand to make your battery powered guitar amp pickup the problem to make it worse and/or better. This tells me where it is sensitive.
Then report results.
people told me high impedance signal is sensitive to wireless noise, it is like antenna. if there is no signal on guitar cable. there is no noise at all. if guitar produced a little voltage. what wireless noise could go with that little voltage?Are all wires in pairs like this or shielded? Where is your 0V reference?
I see all wires as antennae. So to make "poor" reception on these "antennae, requires care. (Shields, shunt filters, guitar balun to balance it etc.)
If signal impedance is higher than return then it is called "unbalanced", then a common-mode interference can create a differential signal from your wire pair induces by outside interference like line transients. Meanwhile you show no direct connections to the line or Protective Earth (PE);ground.
If you are not near AC Protective earth, you may need to shield everything and make the battery -ve your ground. You may also need a 1:1 transformer for the guitar.
I assume your amplifier is a commercial product and not a DIY problem missing something fundamental.
For experiments, connect your hand or finger tip to an earth ground ( PE grounded electric stovetop or similar ) and use other hand to make your battery powered guitar amp pickup the problem to make it worse and/or better. This tells me where it is sensitive and suppresses CM noise.
Then report results.
I don't play guitar but if I did and it swallowed 50A ( = 600Watts) I would have to strum with asbestos gloves.
Brian.
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