[AMPS] re: Dayton and Emtron

nospam4me@juno.com nospam4me@juno.com
Wed, 23 May 2001 22:42:26 -0700

: From: "vk4sx" <vk4sx@dingoblue.net.au>
: any comments from the Dayton visitors in rgds the 
: new range of EMTRON amps?      rgds Dennis
Hi Dennis and the group,  
I actually took a camera full of pictures of the different amplifier 
mfgr's products and display booths.  I used the "analog method" 
so it will be a few days before the pics are available for amps 
member viewing. 
Emtron was one of the mfgrs I spent a bit of time looking 
at.  Significant items of interest were the models with the 
4CX1600 tube which the rep mentioned would be phased 
out as the tube is getting rather hard to obtain in long term 
stable amounts.  Not the first or only person I've heard 
that from...
They also had other nice looking amplifier models with the ever 
present  Eimac 3cx800a7 tube(s) on board.    The current "major 
valve" of choice seems to be the Eimac 3cx800a7, used by most 
mfgrs as the most popular amplifier work horse tube.  The 
3-500z is no longer in the "sweet spot" although Ten Tec and 
Ameritron had glass valve circuits on Display. 
It might be more practical to just mention some of the things that 
I noticed right away about the Emtron. 
Some of the power supplies of the models I could inspect 
(covers off) had series banks of 85c filter caps. But potential 
trouble might not be too far off.   
The radial lead capacitors are mounted horizontal and the 
"top" of the individual capacitors are very near the side bare 
chassis.   I mean real close with no insulation other than the 
actual cap factory shrink skin.  
The cap to chassis distance appeared less than 1/2 inch... 
and at 3kv plus potentials, that would worry me a great deal. 
There was no obvious side mounted insulator between the 
capacitor bank (cap tops) and the bare chassis. 
The capacitors were also mounted right next to each other.  
Cap cooling is something less than desired. In my opinion, 
an issue that should be looked at.  Although I wasn't able 
to check the values, the capacitor bank looked "rather light 
duty" for the power supply level so these close spaced caps 
will get at least very warm with significant ripple current. 
The plate blocking caps appeared to be low current "disc 
style" units.  In my recent (less than a year ago) tests I've 
found these units don't handle high power (current) as well 
is I had hoped and quickly get hot and fail/change value 
in key down (continuos) conditions.   
For SSB and other low duty cycle operation, they  
will probably "hold up." 
Most all the amplifier models I saw had healthy pi-tank 
circuits, caps and coils although everyone pretty much 
is still using air variables. 
The rep spent a lot of time talking about the hefty power 
transformers.  The physical layout was traditional and 
the cosmetics pretty good.  Your results may vary... 

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