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  1. WHONOES

    Stage Line 500W amp repair project

    Do you have any info on the devices you have bought?
  2. WHONOES

    How to limit amplifier output power

    If you use a series resistor to limit the power your speaker receives, assuming it has a crossover in it, it is going to sound fairly different. This is because the crossover was designed to operate from a source impedance close to 0Ω. Realistically your amp's output impedance is going to be in...
  3. WHONOES

    synchonizing speeds of two dc motors.

    Having thought about this a bit more, it is not necessary to use either a Tacho or an optical encoder. If the motors are driven using using PWM, it is possible to sample the back emf of the motors during the PWM off period and use this to gauge any difference in motor speed. It would then be...
  4. WHONOES

    synchonizing speeds of two dc motors.

    I was under the impression that the two motors were independent. If not, there would be no need to control them independently.
  5. WHONOES

    synchonizing speeds of two dc motors.

    You could use two smaller motors attached to the shafts of you drive motors. These can then be used as Tacho's. They will output a voltage that is proportional to speed and can then be used to balance the speed of you drive motors via your control circuits.
  6. WHONOES

    Why is it PNP instead of PPN for transistors

    No I don't have the schematic. It is the property of the company I worked for at the time.
  7. WHONOES

    Solar/ Battery cable (to sockets) specification please.

    An ordinary 12V car battery is capable of delivering close to a 1000A into a load. They need to as starter motors typically run at several hundred amps. Your 225AH battery is probably 3 times what you would encounter in a car an will deliver a proportionately larger current. If you are using...
  8. WHONOES

    Solar/ Battery cable (to sockets) specification please.

    Before anything else is discussed, you absolutely must without fail put a fuse or fast circuit breaker at the battery end of your wiring. The reason being the batteries you are proposing to use will quite literally deliver thousands of amps into your wiring. If your wiring should encounter a...
  9. WHONOES

    Stage Line 500W amp repair project

    Can you determine the maker of the sound card in your computer. If so we may be able to get some info on it and see where the hiatus is.
  10. WHONOES

    Stage Line 500W amp repair project

    Ok. That's all reasonable. Your box seems to be working. Have you tried it with you virtual scope recently?
  11. WHONOES

    Why is it PNP instead of PPN for transistors

    I designed a patient support monitor to detect if it had started going in the wrong direction and if so, to stop the motion. The limit was 3mm travel. That was all designed using CMOS logic I think there was about 25+ IC's on a eurocard. That was in the late 1980's. I am / was an analogue...
  12. WHONOES

    QSC Power Amp gets hot

    Is the channel that gets hot the one that measures .706 DCV and -.645 DCV?
  13. WHONOES

    Stage Line 500W amp repair project

    What does the battery measure on its own?
  14. WHONOES

    Stage Line 500W amp repair project

    O.K. You should still be able to carry out the battery check I suggested. You can, as you suggested, measure the output at the headphone jack using your DMM.
  15. WHONOES

    QSC Power Amp gets hot

    The output voltages look ok. Can you do the transistor voltage tests directly across the base and emitter pins. I'm not interested in the power supply voltages in this instance, just the Base Emitter voltage. Both output transistors on both channels.
  16. WHONOES

    Stage Line 500W amp repair project

    Personally, I use flying lead a lot. I have many of them in various forms and would find developing circuits difficult in the extreme without them.
  17. WHONOES

    Stage Line 500W amp repair project

    Yes. A flying lead is one that is connected at one end whilst the other can be moved around to various points. Example, Your lead with a BNC on one end and croc clips on the other. With the BNC plugged in, the croc clip end becomes the flying end hence flying lead.
  18. WHONOES

    QSC Power Amp gets hot

    Can you measure voltages as requested.
  19. WHONOES

    VDO Voltmeter

    68.1Ω @ ±2% seems a bit odd. It could be anywhere in the range of 66.8Ω to 69.2Ω so the 0.1Ω bit would be a bit superfluous not only that but 68.1Ω seems quite low as well. If you have a DMM, could you measure the actual value of the resistor?
  20. WHONOES

    Stage Line 500W amp repair project

    If yo have a single AA or AAA battery to hand, you could use it to test your box. Call the AA battery "Test Battery" Connect your scope lead to the input of the box. Connect a flying lead with croc clips to the output. Connect your DMM to the flying lead. Set DMM to 2V range. Switch on you...
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