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  1. bertus

    Speakers in series - capacitor

    Hello, When the Z2300 has active filters, you do not need external filters. Can you post a picture of the Z2300 board, top and bottom? Bertus
  2. bertus

    Speakers in series - capacitor

    Hello, Here is an article from ESP for the calculation needed for passive cross over filters: https://sound-au.com/lr-passive.htm Bertus
  3. bertus

    Sansui 7000 Receiver with weak FM

    Hello, The dual gate mosfet 3SK39 would be the prime suspect for the low sensitivity. In a cross reference I found that it may be replaced with a BF960. Bertus
  4. bertus

    Sansui 7000 Receiver with weak FM

    Hello, Could you post the schematic of the antenna input section with the first transistor/fet ? (you could print the page to a new PDF). Bertus
  5. bertus

    Alternative long time 555 monostable

    Hello, I got an article in Funk Amateur , a german magazine about a long time 555 monostable. It uses the discharge transistor to charge the capacitor and a parallel resistor on the capacitor to perform the timing. In this way you can even make long times upto 0.5 hours: Sorry for the...
  6. bertus

    Fairy light Timer

    Hello, You could use the nano to make the 6 / 18 sequecence on one of the pins. A transistor or better a logic level mosfet could be used to switch the box on and off. The nano will not have enough power to do the switching alone. Bertus
  7. bertus

    Speakers in series - capacitor

    Hello, C1, C2 and L1 make the highpass filter for the tweeters. L2 and C3 make a low pass filter for the low range speaker. Rp1 and Rp2 make an attenuator to balance the volume between low and high. Req en Ce make a correction for the impedance of the low speaker. Bertus
  8. bertus

    Speakers in series - capacitor

    Hello, This project uses a 4000 Hz cross over, with two tweeters and 4 bass speakers: https://diyaudioprojects.com/Speakers/HiVi-Center-Channel/ Bertus
  9. bertus

    Nixie Tube Clock- Switching Adapter Help

    Hello, Any adapter of the correct voltage and with a current equal or higher as the origenal will work. Take care that the plug has the positive in the middle contact. The shown adapter from Amazon seems to be OK. Bertus
  10. bertus

    Speakers in series - capacitor

    Hello, You may find this site interesting for building speakers: https://diyaudioprojects.com/Speakers/speakers.htm Bertus
  11. bertus

    SW radio using OP amplifier

    Hello, Do you see the point Vcc/2 ? That is on half the supply voltage. It can be done using two equal resistors with a capacitor of 10 uF from the middle to ground. Bertus
  12. bertus

    Book Reviews

    Hello, Here I have a collection of general electronics and amateurradio PDF's: http://n5dux.com/ham/files/pdf/ Bertus
  13. bertus

    SW radio using OP amplifier

    Hello, If you want to bias the opamp correctly, have a look at fig 3 of the attached PDF. Bertus
  14. bertus

    SW radio using OP amplifier

    Hello, The shown schematic has no bias for the opamp. Also there is no detector. It probably uses the opamp itself as detector. Bertus
  15. bertus

    COVID-19

    There is a small child praying to God. Dear Lord can you delete and reinstall 2020. There is a virus in this one.
  16. bertus

    SW radio using OP amplifier

    Hello, That 741 amplifier circuit will not work. The negative going signals will be cut. Also the 741 will not be able to drive a speaker. Bertus
  17. bertus

    COVID-19

    Found at AAC:
  18. bertus

    Gulbransen Power Supply Redux

    Hello, You could replace the transformer with 3 smaller ones: Assumed the electronics is still fully functional. Bertus
  19. bertus

    Help required on Logitech Z-2300 toroidal transformer #2

    Hello, I would disconnect the two battery packs: When the step up converters are not isolated you would get into trouble with your setup, as @Harald Kapp explained. Bertus
  20. bertus

    microsoft surface pro 4 repair

    Hello, It could be an OEM product, so you will not find any data on the internet. Bertus
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