Question on current limiter

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Question on current limiter

Postby Gregt01 » Fri Mar 23, 2007 4:42 am

Hi guys, I’ve got another quick one.
I’m working on another amp that is using a KC012L (1,7A 10 Ohms) inrush current limiter on a 115vac primary circuit, I am using a 220vac-240vac primary. Do I use a CL120 that has the same specs or do I use something else?
Also there is a V230LA10 varistor (max 230vac 2500A) do I need to use it and if I do where the ….. do I find one?


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Postby mesherm » Fri Mar 23, 2007 5:10 am

Your dealing with twice the voltage and half the amps so pick one around 1 amp 20 ohms or maybe wire two KC012L in series.
The varistor usually is wired across the PT primary to protect against spikes and surges. Think of it as kind of like a zener diode for AC. Most electronic supply places have them but unless you have frequent lightning storms or bad power lines I would think you could do without it. Just plug the amp into a surge protected power strip.
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Postby Gregt01 » Fri Mar 23, 2007 6:40 am

Thanks for that I'll jump to it.
Also whill I've got you the circuit has 8 X 0.25 600v paper oil caps. I have some new mil units should I use them or use new ones?

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Postby mesherm » Fri Mar 23, 2007 9:13 am

I sure any quality cap will do fine. I have not used any PIO caps yet although I have some on order. I usually use either Orange Drops or Dayton Film/Foil for coupling duties. I recently tried some Nichicon Muse electrolytic caps for bypass duty and was impressed with the change.
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Postby Gregt01 » Fri Mar 23, 2007 3:23 pm

Thanks again I've added a new gallery with the new amp I am working on.
I have looked for a limiter and there is no 1A 20 Ohm so I will do as you said, use two. That will bring it down from 1.7A to 0.85 mA, will that be ok?

http://gregt01.gallery.netspace.net.au/6A3

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Postby Gregt01 » Tue Apr 10, 2007 3:45 am

What can I tell you? The new amp is finished. What a sound!!!!!! I thought that the KT88's sound great but the 6A3's at 6 watts what a mind blow. I eventually changed the caps, not due to being unhappy but room was getting tight, and I also said that since I'm going to build this “I'll go the whole hog” and put better caps so I used M-caps. I don’t know if that would change anything but I can truly say now I’m starting to see and hear the true tube dream. I don’t think I could ever go back to solid state. Guys keep going with it, this is the only way to be, manipulating the electrons at there core.

http://gregt01.gallery.netspace.net.au/Finished-6A3
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Postby TomMcNally » Tue Apr 10, 2007 7:52 am

Wow - that's a monster Greg ! Very nice - congrats on the nice layout and build.
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Postby Gregt01 » Tue Apr 10, 2007 2:42 pm

Thank you Tom, let me say that you and Shannon have been an inspiration and a great help in showing me the way of the valve, “may the valve be with you” LOL.
Tom how do you find the sound of the 6B4G? It must be simular to the 6A3’s and the 2A3’s.

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Postby TomMcNally » Tue Apr 10, 2007 4:30 pm

Yep - the 6B4G really is a 2A3 with a different base and a 6 volt filament. The get*set*go amps sound really nice, I would say better than my 2A3 and on par with the 300B. It's a combination of good design, and the James transformers.
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