Search results

  1. F

    Guitar Aplifier

    Why it worked then? I mean with LC filter. It reduced oscilating and noice brum..What is wrong with that connection?
  2. F

    Guitar Aplifier

    I connected it like this:
  3. F

    Guitar Aplifier

    I repaired this trace. I soldered 1mm wire instead of pcb trace on it..I will get new parts tommorow maybe. Or else latest in monday. I will report. But I am also afraid, that when I will play on full volume for too long, something will die..Even heatsink won't help. Oh, and about oscilations...
  4. F

    Guitar Aplifier

    Just to report, I made an LC filter to reduce oscilating and brum..I connected it in series with C13 and to power amplifier...It works great, but I burned everything ;D I turned Volume potentiometer to full and played for 2 minutes really hard, when suddenly everything shuted. I checked PCB and...
  5. F

    Guitar Aplifier

    But in this contribution it says, not to connect them together...Can you draw me, how to connect grounds with use of star grounding..I would very appreciate that. Thank you
  6. F

    Guitar Aplifier

    Yes I know what star grounding do, but I don't know if I can use it with my PCB. I should separate grounds of preamplifier from grounds of power amplifier, am I right? In that case, I must make new PCB.
  7. F

    Guitar Aplifier

    Can you tell me something..How can I use star grounding with my PCB. I think, i can't, becouse I used a copper ground...I can't wire every ground to the star connection with different wire. I am confused now.
  8. F

    Guitar Aplifier

    Yes I will shield everything when I make case from aluminium and put everything in. I will then make grounding on the case and I will insulate case to prevent it to electricute me. So you thing shielding will make this oscilating go?
  9. F

    Guitar Aplifier

    I disconected preamplifier and power amplifier still oscilated. I connected 1k resistor in series with C9, like you said and oscilation stoped. I hear very quiet hum in speaker, with volume potentiometer set to 0. I must try connect preamplifier back and try put some signal on. I will report...
  10. F

    Guitar Aplifier

    i did that. I connected 0V rail to radiator. What is screened cabe? In Slovenian forum, I got advice, to remove C10, becouse this capacitor causes many unwanted effects. It drives signal from power amplifier back to preamp and cause oscilating. Amplification without this capacitor is much lower...
  11. F

    Guitar Aplifier

    I am saying, that I don't know, how to connect everything with the chassis. I also don't know, how to shield inputs. Can you tell me that? Beside that, I have power supply circuit on the same PCB than preamplifier and power amplifier
  12. F

    Guitar Aplifier

    But how do I have to connect things? And for connection like this I would aquire supply circuit by itself, not togheter with preamp and power amp...
  13. F

    Guitar Aplifier

    What if I should put this thing in iron case and ground everything and use shielding like this guy
  14. F

    Guitar Aplifier

    I used same transistors. Which one should I suspect? Hehe I am quite young..I was born, when yugoslavia died :)..Then we got Slovenia :)
  15. F

    Guitar Aplifier

    I forgot to say, that it's only oscillating, when I power on circuit and have volume potentiometer set to minimum resistance..If I turn it to something bigger than 0Ohms it's cool to turn it back to 0Ohm when I power the circuit on. I am now reading current drawing from fuse of 25mA (I turned R9...
  16. F

    Guitar Aplifier

    I made new differend and better PCB, but circuit is still oscilating...only change, I made from original schematic was n-fet transistors Q1 and Q2. I used BF244A It is kind of a inposible to make new PCB and connect transistors wrong again to make circuit oscillate...I checked them again and I...
  17. F

    Guitar Aplifier

    These voltages are just betwen mouse pointer and 0V. But how can I messure VBE of some transistor for example?
  18. F

    Guitar Aplifier

    How can I see voltage betwen ground and some element. C13 for example...There should be higher voltage then 24V. And how can I turn trimmer? I don't  know this program much.
  19. F

    Guitar Aplifier

    I checked them all. They are all correct soldered. Only option left, I think is poor solder joint somewhere in the PCB. I am now making new PCB with differend software to make more mechanical compact pads. I will report.
  20. F

    Guitar Aplifier

    But why is oscilating? It is also oscilating with speaker. How can I stop that?
Top