Main amp for car coil preamp project

Discussion in 'The Projects Forum' started by qlocs, Jan 27, 2013.

  1. qlocs

    Thread Starter New Member

    Jan 27, 2013
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    Dear Members, I've successfully completed the audio amp project (http://www.allaboutcircuits.com/vol...I'm really into the primitive side of things.
     
  2. Audioguru

    New Member

    Dec 20, 2007
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    The vacuum tube amplifier has very low output power.
    Why bother with high voltages, a huge transformer and a vacuum tube? Use a little low voltage IC amplifier instead.
     
  3. qlocs

    Thread Starter New Member

    Jan 27, 2013
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    As I stated at the end of the message, I want to stay on the primitive side to demonstrate how basic this thing can be. I don't want to use any solid state devices.
     
  4. tshuck

    Well-Known Member

    Oct 18, 2012
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    I'm not sure I'd call a controlled stream of electrons moving through a vacuum primitive;)

    Archaic, perhaps, but certainly not primitive...
     
  5. qlocs

    Thread Starter New Member

    Jan 27, 2013
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    Ok then, If you prefer, I will use the term archaic... BTW do you know of any links where I might find a single tube high gain pre-pre amp(new term) that could take the weak output of a crystal set and feed it to the input of the weird car coil amp?
     
  6. Audioguru

    New Member

    Dec 20, 2007
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    A crystal set was an old AM radio. It used a very long antenna and an earth ground to pickup only strong local stations and lots of static.
    In those days there were few stations so its lack of sharp tuning did not cause the problems of interference from the many more stations today.

    Good grief!!
    An AM radio sounds awful. A home-made "foam plate speaker" also sounds awful.
    Most Instructables are designed by little 10 years old kids who don't know nuttin'.
     
    jaygatsby likes this.
  7. qlocs

    Thread Starter New Member

    Jan 27, 2013
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    I am well aware of the limitations of crude radios and speakers but I am fascinated by the origins of the polished and efficient gadgets we have now. I like getting to the roots of these things and by constructing them get a feeling of discovery and satisfaction that the originators had. As for 10 year olds posting on instructables, that is the exception rather than the rule. The site is rife with things of amazing complexity. As for the foam plate speaker, it sounds pretty good! There is a video & audio of it w/ Kip Kay on Instructables.
     
  8. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    Congrats on your success!

    Just wanted to step in and say that you were lucky this time--usually electronics problems on the instructables site are complete garbage. AG is right--they're made by people who have no idea what they're doing. Sometimes you get lucky and find one that works, but I just wanted to let you know not to trust much that comes from that site.

    The same goes for Kipkay. I've seen some of his youtube videos, and to be perfectly honest, he's an idiot :D He often puts together electronics projects, but he has absolutely no clue what he's doing. My point: don't trust him unless you've checked the circuit/project with experienced electronics designers/builders.

    That's my personal view, anyway.

    But again, congrats on the build :) Do you have any videos of it working?

    regards,
    matt
     
  9. qlocs

    Thread Starter New Member

    Jan 27, 2013
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    Matt,

    Thanks for the reply. I don't have a video of this thing working but I think I'll do one. I found it strange that I didn't get the expected high voltage at the speaker wires. When I do the video, I'll also demonstrate that anomaly. I'll need to research how to post videos on this site.
    Since you seem very knowledgeable about this subject, do you have any recommendations for building another stage of amplification(with a tube) to allow the feeble output of a crystal set to increase with enough (undistorted) gain to drive the input of this rather bizarre amp to a level that can be heard without difficulty?
     
  10. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    I'm not experienced at all with most types of amplifiers. I do more work with digital systems than analog ones. I know my basic op-amp circuit, but that's about it. But I'm sure the guys here can help you ;)

    Best wishes,
    Matt
     
  11. Audioguru

    New Member

    Dec 20, 2007
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    Your weird amplifier with the wrong high voltage supply and the wrong output transformer has a very low maximum output power. Increasing its input with more voltage gain simply increases its distortion without making it louder.

    You need a real amplifier driving a real speaker.
     
    jaygatsby likes this.
  12. DerStrom8

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    Feb 20, 2011
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    AG, I think you misunderstand the idea of this project. It's not supposed to make a nice, clean, clear output. It's just supposed to be a fun thing to do with unorthodox parts. It's more of a novelty sort of thing. It's much like my tesla coil, which I built out of garbage. It's not supposed to work as well as a tesla coil with brand new parts, calculated sizes, shapes, voltages, currents, etc. It's just fun to make something with stuff that nobody else would think would work :D

    Matt
     
  13. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Last edited: Jan 28, 2013
  14. Audioguru

    New Member

    Dec 20, 2007
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    No bass. Bass is very low audio frequencies. A speaker without an enclosure has the low frequencies from the rear come around the speaker and cancel low frequencies from the front. The foam speaker is garbage.
     
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  15. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    That's my point exactly! It's garbage. Nobody would expect ANYTHING pulled out of a trash can to play ANY sounds at all ;):D
     
  16. qlocs

    Thread Starter New Member

    Jan 27, 2013
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    Thanks to all who replied. Yes this is just a fun project to see what can be done with a bunch of crude and unconventional parts. I'm well aware of what needs to be done to produce 21st century sound, but all that stuff is conventional, everyday, boring stuff. To make an analogy, I want to start a fire caveman style. I know I can whip out my aim and flame or blue laser and do it, but I get much more satisfaction (and fatigue) from using iron pyrites or a bow and drill. Of course I don't do this everytime!
     
    DerStrom8 likes this.
  17. wayneh

    Expert

    Sep 9, 2010
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    Just my 2¢.

    I share a fascination with making stuff out of "nothing". I mean, imagine being transported back in time a couple hundred years. How would you teach others make a rifle barrel, for instance? Or a light bulb or a telephone. Even knowing how it turns out wouldn't guarantee success.

    But this nostalgia is, in many ways, a nasty human trait that distracts us from making progress. Steve Jobs famously said it well by not allowing a museum of past Apple products to be housed on site at Apple (nearby Stanford took up the chore). His reasoning was that the success at Apple depended on looking as far ahead as possible, not back. Duh.

    It's agonizing how much time and effort is devoted to, for instance, over-unity and all manner of other wheel-spinning projects. Perhaps these folks are not the same people who might design the next generation of smartphones, but surely they have better things to do.

    That all said, if it's fun, maybe that's enough. It has to be better than eating chips on the couch and watching "reality" TV.
     
  18. Audioguru

    New Member

    Dec 20, 2007
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    I never made anything out of garbage that was crude and primitive with horrible performance.
    Everything I made with normal parts performed very well.
     
  19. DerStrom8

    Well-Known Member

    Feb 20, 2011
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    Good for you. But you're still missing the point.
     
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