G'day Guys,
I've had a few thoughts on the recent thread about filament inrush. People
were suggesting all sorts of methods including inductors, specially wound
transformers etc.
Nobody seemed to pick up on the most glaringly obvious method that has been
around for quite some time and has proved to be the most effective method
of filament and ht supply startup.
Those of you with an Emtron amplifier in the shack will know what I mean.
It has been used in power rectification equipment. and even washing
machines with great success.
I am referring of course to the use of triac control start up circuits.
For a few bucks worth of components you get the best soft start for both
the filament and your ht supply.
At switch on, my Emtron DX-2 takes around 4 seconds to start up the power
supply. Now you try to tell me that this is not better than all the ideas
we've seen on the subject in recent times. It just has to be better than
the old resistor and relay and your super wound trannies and AC analysed
inductors and all that stuff.
I don't claim to be very clever in this area myself. I'm just a lowly
telecom technician with a Diploma in Electronic Engineering. I'm not a
power or rf engineer and all I ever knew about AC analysis etc is long gone
from my brain. I just know that when I switch my amplifier on each day when
I enter the shack, that all the expensive bits inside it are well protected
from any sort of stress.
Next time you are at Dayton, have a look at the Emtron gear. Take off the
cover. Lift the thing up. See how solidly it is built. It's shipped with
the transformer installed you know. Ask about the ramp function slow start.
Ask about the screen regulation. Ask about the tube protection. Take a good
long look and then go and take a look at the new Ten Tec and all the other
amps. Make your comparisons.
There's more info available at http://www.emtron.com.au/
73, Alek.
VK6APK
ps: I have no interest, pecuniary or otherwise in Emtron. Just a happy user.
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