Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com
Asher Guitars WD Music Products Amplified Parts Mod Kits DIY Nordstarnd Pickups Warmoth.com

The Ultimate Light Bulb Limiter

Discussion in 'Amp Tech Center' started by Phrygian77, Nov 7, 2017.

  1. Phrygian77

    Phrygian77 Tele-Holic

    639
    Apr 30, 2016
    Crawfordville, FL
    Parts to built the ultimate light bulb limiter...

    1510094482184.jpg
     

  2. robrob

    robrob Poster Extraordinaire Ad Free Member

    Dec 29, 2012
    United States
    I like it.
     
    Phrygian77 likes this.

  3. Bill Moore

    Bill Moore Tele-Holic

    I'm waiting to see the result! I'm surprised you could shoehorn an ammeter in there also!
    (Mine is the minimalist design).
    BL2.jpg
     

  4. rickmurphy

    rickmurphy TDPRI Member

    Age:
    60
    8
    Sep 1, 2017
    Naples, FL
    Could you please provide a parts list?
     

  5. D'tar

    D'tar Tele-Holic

    946
    Jan 11, 2013
    WNY
    Cool Phryg!

    Is this a build thread? I like toys...
     
    Bill Moore likes this.

  6. Phrygian77

    Phrygian77 Tele-Holic

    639
    Apr 30, 2016
    Crawfordville, FL
    Well, I should have done my homework better. The big rocker switch is about 2 inches deep with the 1/4" blade terminals. The box is 2" in height inside, so I'm going to have to mount the switch on the side. That obviously wasn't the plan. Also, cutting the hole for the volt/ammeter, I gouged the box with the Dremel.
     

  7. Bill Moore

    Bill Moore Tele-Holic

    Hey, if it doesn't have a little "character", folks would think we paid somebody else to do it!
     

  8. Old Tele man

    Old Tele man Tele-Afflicted

    May 10, 2017
    Tucson, AZ
    If you don't use an incandescent lamp, would that make it a solid-state limiter (wink,wink)?




    I know, I know...it's all about the positive temperature coefficient of the tungsten filament.
     
    Last edited: Nov 10, 2017

  9. Phrygian77

    Phrygian77 Tele-Holic

    639
    Apr 30, 2016
    Crawfordville, FL
    It's ugly, but it works perfectly...

    1510623455171.jpg
    1510623466404.jpg
    1510623484406.jpg
     

  10. corliss1

    corliss1 Tele-Afflicted Gold Supporter

    Sep 13, 2008
    Lansing, MI

  11. robrob

    robrob Poster Extraordinaire Ad Free Member

    Dec 29, 2012
    United States
    Very cool and nicely done. I like the character scar.
     

  12. D'tar

    D'tar Tele-Holic

    946
    Jan 11, 2013
    WNY
    Sweet! Would be cool to incorporate a switchable bucking transformer in there as well.
     

  13. jhundt

    jhundt Poster Extraordinaire

    Age:
    63
    Mar 23, 2003
    Netherlands
    this thing is a test instrument when trying out a new build/repair, or when troubleshooting an amp that is blowing fuses. You can't really play the amp with this thing in line - it will sound all wrong. And you can't even take voltage readings inside the amp because they, too, will be all wrong.

    It is a device that will show you very quickly when something is wrong, and with proper use, can help you to localize the problem. It should be taken out of the circuit as soon as possible, lest you forget that it is in place and start taking incorrect voltage measurements and trying to 'fix' problems that don't exist. I know, because I have done it more than once.

    Knowing the AC voltage might be useful, a little bit. Knowing the current is not really necessary. Can anyone tell me what the current should be for their Fender amp when it is operating correctly? When the light bulb shines brightly, something is wrong. When the lamp is dim, things are OK. It isn't really useful or helpful to have the meters.

    But they do LOOK cool, and I will probably put some on next time I build a light-bulb limiter!
     
    xafinity likes this.

  14. archetype

    archetype More tone than talent Ad Free + Supporter

    681
    Jun 4, 2005
    Williamsville NY
    I've used all my psychic powers, but I can't come up with a bill of materials and a schematic. Could you please provide these?
     
    Phrygian77 likes this.

  15. D'tar

    D'tar Tele-Holic

    946
    Jan 11, 2013
    WNY
    Depending on how this thing is wired and or switched, I bet Phrygian can tell us.

    I know its a tool that has valuable however limited use. But its cool as ever:)
     
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  16. Phrygian77

    Phrygian77 Tele-Holic

    639
    Apr 30, 2016
    Crawfordville, FL
    This is exactly why you shouldn't Dremel and drive, or drink and Dremel. I don't advise trying either. Although, a drink or two can certainly help with soldering, like any old school marksman or surgeon might tell you ... wink wink.

    I didn't really want to post pics of the exterior, but it does what it's supposed to so well, I thought, "why not."

    The ammeter is a nice useful feature. There's not a lot of resolution though, and it seems to round up 100mA, but it works.

    I wired the limiter with an on-off-on switch. It's a big DPDT rocker, but I only used one pole. One side puts the hot lead in series with the bulb, and the other is full on. The big rocker is nice because you can quickly and easy flip the positions.

    I'll put the parts list up tomorrow, and draw up a layout/schematic. Most of it came from Mouser except the the volt/ammeter, which I got from amazon.
     

  17. Phrygian77

    Phrygian77 Tele-Holic

    639
    Apr 30, 2016
    Crawfordville, FL
    The Princeton Reverb I just built is pulling .4-.5A at 124VAC, or around 60 watts. That's idling with 422 on the plates and 22.5mA on the cathodes. That should be about right because of the inefficiency of a tube amp.
     

  18. jhundt

    jhundt Poster Extraordinaire

    Age:
    63
    Mar 23, 2003
    Netherlands
    can you read the ammeter with the limiter out of circuit? I wonder what happens when you really crank the amp..
     

  19. Phrygian77

    Phrygian77 Tele-Holic

    639
    Apr 30, 2016
    Crawfordville, FL
    Yes, because the hot lead from the IEC inlet runs through the current transformer. The voltmeter is also wired to the inlet.

    My guess is, at full output, it'll draw 800-900mA. I can tell you when I do my output power test.

    My BF Bassman build puts out 45 watts clean. I had inadvertently put a 1 amp slow blow fuse in it instead of a 2 amp. It blew the fuse when I dimed it at the end of a 3 hour practice. So, it was obviously drawing well over 120 watts. Again, it just shows you how inefficient a tube amp is.
     

  20. jhundt

    jhundt Poster Extraordinaire

    Age:
    63
    Mar 23, 2003
    Netherlands
    what is the 'current transformer'? Is that part of the ammeter?
     

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