The Amp Garage Light Bulb Current Limiter

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Masco
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Re: The Amp Garage Light Bulb Current Limiter

Post by Masco »

No bypass switch? I use a second bypass switch on my limitter to bypass the bulb when everything is hunky dory. It's a good thing.
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martin manning
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Re: The Amp Garage Light Bulb Current Limiter

Post by martin manning »

Masco wrote:No bypass switch? I use a second bypass switch on my limitter to bypass the bulb when everything is hunky dory. It's a good thing.
That can be done in the same box with an SPDT switch and one more wire. New .pdf posted here with alternate schematic on pg. 2: http://ampgarage.com/forum/viewtopic.ph ... 430#237430 Can't update the posting above since I don't "own" it.
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Cygnus X1
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Re: The Amp Garage Light Bulb Current Limiter

Post by Cygnus X1 »

A bypass would be good.

That transformer was under test.
It ended up being "recycled".

I built the rig on a board big enough to mount more barrier strips to test circuits and components.
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ToneMerc
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Re: The Amp Garage Light Bulb Current Limiter

Post by ToneMerc »

I whipped one up with a bypass, gotta love cheap and easy.

Thanks guys

TM
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boots
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Re: The Amp Garage Light Bulb Current Limiter

Post by boots »

Here's mine. Cheap and dirty.
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Don't you boys know any NICE songs?
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Colossal
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Re: The Amp Garage Light Bulb Current Limiter

Post by Colossal »

boots wrote:Here's mine. Cheap and dirty.
Wow! Nice mod! I've got a standby on mine :roll: :lol:
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Structo
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Re: The Amp Garage Light Bulb Current Limiter

Post by Structo »

Wow Boots, you even used conduit!

Nice limiters guys.
Tom

Don't let that smoke out!
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cbass
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Re: The Amp Garage Light Bulb Current Limiter

Post by cbass »

Your guys limiters look nicer than my amps. :oops:
DLR is a Captain beefheart wannabe
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Structo
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Re: The Amp Garage Light Bulb Current Limiter

Post by Structo »

If any of you guys have questions about the construction or use of a light bulb current limiter, please ask questions in the Technical section.

Thank you.
Tom

Don't let that smoke out!
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Structo
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Re: The Amp Garage Light Bulb Current Limiter

Post by Structo »

This is the document I built my current limiter from.

Remember as you increase the wattage of the light bulb, you are allowing more current to flow.

If you start with a 25 watt bulb you are limiting the current to your amp to around 250ma.

With a new build I always start with no tubes and the current limiter set with a 25w bulb.

You will instantly know if there is a problem or short circuit with this setup.

If no problem, step up the wattage to 40w or 60w.

No problem?
Install tubes and try it again.

Better safe than sorry $$$$$.

Enjoy!
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Tom

Don't let that smoke out!
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martin manning
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Lightbulb limiter II

Post by martin manning »

The new (actually rebuilt) model uses combination switch/socket units to select one or two bulbs and bypass. Short male/female cords keep things neat and allow easy use of the Kill-A-Watt thingy for monitoring voltage and current. Incandescent bulbs are getting scarce, but specialty types are still around. The ones in the photo are 60W vibration resistant types designed for use in ceiling fans. I've had them for a while, and they will probably last forever given the limited use and low voltage. Here both bulbs are on (120W equivalent), and the load is a 2x EL34 TW Express clone. The amp is seeing ~100VAC.
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drew
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Re: Lightbulb limiter II

Post by drew »

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ChopSauce
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Re: Lightbulb limiter II

Post by ChopSauce »

You guys make me feel so cheap ... :wink:
(thx for sharing!)
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roberto
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Re: Lightbulb limiter II

Post by roberto »

Thanks Martin!
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martin manning
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Re: Lightbulb limiter II

Post by martin manning »

ChopSauce wrote: Thu Mar 11, 2021 7:49 amYou guys make me feel so cheap ... :wink:
I'll admit this is a deluxe model, but it was entertaining to build and a pleasure to use.

BTW, the 2x EL34 amp draws 720 mA at 120V (no limiter, no signal), 430 mA at 99.8V with both 60W bulbs on, and 290 mA at 77.8V with one. By comparison, a 100W 4x 6L6 D-clone amp draws 1260 mA at 120V, 550 mA at 83.1V with both bulbs on, 340 mA at 60.8V with one (glowing quite brightly operating on 59 VAC). I highly recommend the power meter, which can be had for $25 or less. It comes alive at around 42 VAC, so it's working fine for the 100W amp/60W bulb case.
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