Max,
does it hum with one channel powered ON and the inputs shorted?
What does H+N measure at the output, in 0.1mVac units?
does it hum with one channel powered ON and the inputs shorted?
What does H+N measure at the output, in 0.1mVac units?
I will make some detailed investigation today... what i found, that when i grounded chassis hum disappear.. 🙂
grounding, or earthing, of the chassis should not affect the audio.
The chassis is NOT part of the audio circuit.
The chassis is NOT part of the audio circuit.
of course.. my chassis isn't connected with earth and when I used crocks and connect PSU ground wire to chassis, preamp stop humming...it was just quick idea... as I said, I have to change something in groundin
Hi maxwell007,
your preamp must be divided in two parts - one with transformer and power supply PCB, and another with preamp PCB.
If you made power inlet at left side of enclosure, it means that transformer, PSU PCB and power switch must be also at left side.
Right side of enslosure should be for preamp PCB and input/output jacks.
With such organization of preamp you will avoid 230V leads next to input jacks or transformer next to output jacks.
Look at post #4969. I made simple and cheap twisted pairs wiring and have no hum at all.
Best regards
your preamp must be divided in two parts - one with transformer and power supply PCB, and another with preamp PCB.
If you made power inlet at left side of enclosure, it means that transformer, PSU PCB and power switch must be also at left side.
Right side of enslosure should be for preamp PCB and input/output jacks.
With such organization of preamp you will avoid 230V leads next to input jacks or transformer next to output jacks.
Look at post #4969. I made simple and cheap twisted pairs wiring and have no hum at all.
Best regards
Hello Dobrivoje,
yes I know, I just used holes from original rear panel... I will made new one with 230v on PSU site...
yes I know, I just used holes from original rear panel... I will made new one with 230v on PSU site...
I have been playing around trying to learn how to do layouts. Please take a look and see if this will work for the A2. I designed it for the TL072.
Thanks, Terry
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Terry that look good man only just make the annular ring outer diameter a bit larger if you can try 2.5 mm if possible, the hole inner diameter about 0.70 mm see image example
🙂 nice man ! I'm glad you are put hand on layouts it is my favorite hobby of all
Regards
Juanhttp://www.diyaudio.com//www.pinterest.com/pin/create/extension/
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Terry that look good man only just make the annular ring outer diameter a bit larger if you can try 2.5 mm if possible, the hole inner diameter about 0.70 mm see image example
🙂 nice man ! I'm glad you are put hand on layouts it is my favorite hobby of all
Regards
Juanhttp://www.diyaudio.com//www.pinterest.com/pin/create/extension/
Done.
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it is my favorite hobby of allTerry that look good man only just make the annular ring outer diameter a bit larger if you can try 2.5 mm if possible, the hole inner diameter about 0.70 mm see image example
🙂 nice man ! I'm glad you are put hand on layouts it is my favorite hobby of all
Regards
Juanhttp://www.diyaudio.com//www.pinterest.com/pin/create/extension/
If it is so,make a pcb for this amplifier protection🙂
If you flip R11 by 90 degrees and shuffle the tracks a bit you'll be able to remove the wire link.
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Terry, The layout has issues. Whilst I probably won't make one, what grabbed my attention are several long parallel tracks. I hate them for a number of reasons.
But you have the two zener diodes D4 & D5 shorting out each other.
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But you have the two zener diodes D4 & D5 shorting out each other.
Sent from my HUAWEI MT7-L09 using Tapatalk
Thanks for looking it over. I see the short and will fix it. I can probably slide the IC to the right some and shorten the parallel traces. I don't see how rotating R11 will remove the wire link.
Which resistor are you talking about? Part number please?
Thanks, Terry