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  1. CDRIVE

    Clap clap switch

    By this definition, including Steve's comments about time between claps, I think we can do this by rectifying the mic audio and adding an RC time constant to the base of the mic amplifier transistor. The cap would have to receive another clap within X period of time to produce enough forward...
  2. CDRIVE

    Isolation b/w DAC & Power amplifier

    I don't get any of this. If the input Z of your amp is 10KΩ it would require an input voltage of 100V to draw 10mA! :eek:
  3. CDRIVE

    Isolation b/w DAC & Power amplifier

    I just gotta know! What will you be doing with a 2KW sinewave?
  4. CDRIVE

    Valve (tube) amplifier schematic help

    Here's an update to the PSU with an RC PI filter. It should provide ripple free B+ and decoupling between the stages. Back in the my day 100uF caps were physically very large because we were working with much higher voltages. You could probably get by with much smaller filter caps, like 25uF to...
  5. CDRIVE

    Valve (tube) amplifier schematic help

    Here's the power supply schematic
  6. CDRIVE

    Valve (tube) amplifier schematic help

    To power the heater directly from the transformer none of the heater pins can be referenced to ground. You must lift pin 4 off ground. I just wanted to make sure you understood this. Also, a 12V transformer when rectified and filtered will produce B+ of about 16V.
  7. CDRIVE

    Valve (tube) amplifier schematic help

    No, it wouldn't. Use your original (450mA) transformer or the 1A model.
  8. CDRIVE

    Valve (tube) amplifier schematic help

    Yes it would work but so would the 12V @ 450mA model this topic is about. If you power the heater directly off the transformer secondary you'll be able to get by with a 100uF filter cap for the B+. On the other hand, if you power the heater off the DC B+ you'll need about 2000uF filter cap...
  9. CDRIVE

    Valve (tube) amplifier schematic help

    Heater @ 12V: Heater wired in series. Heater current = 150mA Heater @ 6V: Heater wired in parallel. Heater current = 300mA What do you think?
  10. CDRIVE

    12v Switch Mod

    Are you saying that this switch doesn't mechanically latch? In other words is the Left - Off - Right are momentary switch contacts? If so, using the existing switch might be doable. if the switch mechanically latches then I don't think it's doable using the existing switch..
  11. CDRIVE

    12v Switch Mod

    I thought the issue was how to use your existing switch to produce an emergency flash. Is your turn signal flasher a hot element type or electronic?
  12. CDRIVE

    Valve (tube) amplifier schematic help

    You can run this on 12V but it will require a bit more input drive (about 5mV increase) to make it clip when you want it too. With VR1 set to minimum she starts to clip @ 20mVpp input. Increasing B+ to 12V required an input of 25mVpp to produce the same amount of clipping. Actually, not...
  13. CDRIVE

    tv power cable

    Absolutely, undoubtedly, inarguably, definitely and positively true. During my many years in Marine Electronics service I replaced countless mic cables. So much so that I ran out of stock many times. Yes, I wasn't the best bookkeeper. Fact is, I wasn't the best shop keeper either. I had three...
  14. CDRIVE

    12v Switch Mod

    Please post a photo of the switch.
  15. CDRIVE

    ASAP HELP.. guitar preamp

    Would this interest you? https://www.electronicspoint.com/valve-tube-amplifier-schematic-help-t251475.html
  16. CDRIVE

    Valve (tube) amplifier schematic help

    Why not power it from a 9VDC wallwart rated >=1A?
  17. CDRIVE

    VHF booster

    Most U.S. grown sugar is grown here in Florida and Hawaii. The price is high because of the EPA. No matter how you slice it, it isn't easy to get a lot of common things in Cuba and I don't think the US embargo has much to do with it. Hell, we don't make anything here anymore!
  18. CDRIVE

    Valve (tube) amplifier schematic help

    Yes, that's why. If you want to keep the filter cap small you can float the filament above ground by tying it across the transformer secondary. This will reduce the draw on the filter cap because it only needs to filter the plate supply. Chris
  19. CDRIVE

    VHF booster

    I wasn't kidding about the 57 Chevy. ;) Isn't Communism wonderful? :rolleyes: Chris
  20. CDRIVE

    VHF booster

    You were too fast on the trigger. Go back and read my edit. BTW, Little Havana in Miami has lots of them. . :D
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