I have done some messuring on my Brute force (Glass Audio) headphone amp and as I can see there is something with 50 and
100hz that I don´t like.It must be something whit the power feeding or?I do not use any stabilizator in the power,but I am planing to use one will it help for this?I am messuring through my souncard,and when I messure only the soundcard there´s almost a straight line even at 50 and 100Hz.But when I listen with headphones (No signal) I hear hum,then I disconnect the line in to the headamp.the hum dissapears,what´s this hum from the computer?Is it some grounding problem how to solve this?
100hz that I don´t like.It must be something whit the power feeding or?I do not use any stabilizator in the power,but I am planing to use one will it help for this?I am messuring through my souncard,and when I messure only the soundcard there´s almost a straight line even at 50 and 100Hz.But when I listen with headphones (No signal) I hear hum,then I disconnect the line in to the headamp.the hum dissapears,what´s this hum from the computer?Is it some grounding problem how to solve this?
Hi,
The PC PSU is a switched mode supply rectifying at HF so 50/60 or 100/120Hz shouldn't originate from that one.
It sounds as if you have a groundloop somewhere.
Cheers,😉
The PC PSU is a switched mode supply rectifying at HF so 50/60 or 100/120Hz shouldn't originate from that one.
It sounds as if you have a groundloop somewhere.
Cheers,😉
A tips and a question.I have made some changes on my brute force,I have added a ground loop breaker: http://headwize2.powerpill.org/projects/meier_prj.htm
and an extra ground wire to from the amp to the coumputer chassie,so now it is a little bit better,but I am wondering about the thing from ca 40-500hz it´s a little bit higher than the rest.I have tried to change the capacistors in the signal path to different values,but there was no difference.When I mesaure just with the soundcard it is a flat line,so it must be the brute force.Any suggestions?
and an extra ground wire to from the amp to the coumputer chassie,so now it is a little bit better,but I am wondering about the thing from ca 40-500hz it´s a little bit higher than the rest.I have tried to change the capacistors in the signal path to different values,but there was no difference.When I mesaure just with the soundcard it is a flat line,so it must be the brute force.Any suggestions?
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I think you still have a ground loop, but inside the amp. Are you returning all grounds to a single point?
Yes,from the input and output RCA´s,they are isolated from the chassis,I have thick solid wire,where the cathode resitors are soldered to,and from that solid wire another solid wire to the first
e-lyt in the power supply where all other grounds meet,eccept for mains ground wich is connected to chassis.and between chassis and the solid wire is the ground loop breaker.
e-lyt in the power supply where all other grounds meet,eccept for mains ground wich is connected to chassis.and between chassis and the solid wire is the ground loop breaker.
I have now moved around the grounds in the amp and now I cannot hear any hum at all,I coul´d even remove the extra wires to the PC chassis,in fact I got more hum if they where there.But the peak in the frekv.response is stil there.The frekv.rexponse is from +1.6db-0,75db,what is good ,(acceptable)?The next step is to try Regulated supply.
Thank´s for the answers.
Thank´s for the answers.
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