long, scott a. wrote:
>
> I have a Dentron MLA-2500 (pair of 8875's) and I am seeing approx
> 600-650w out with 100w drive. I am running it on 110v at the present
> time. I know this amp was not designed to put out -big- power on 160,
> but how much difference would I see if I put it on 220v? I havn't done
> any modifications to it or anything, its stock. Anyone have
> modifications or tips for this amp?
>
> 160 600-650W
> 80 750-800W
> 40 850-900W
> 20 1 KW
> 17 1 KW
> 15 1 KW
> 12 800-900W
> 10 800-900W
>
> I listed the other bands for reference points only. I am only
> interested in increasing the power on 160.
>
> Thanks for taking the time to read this.
>
> Scott K8SM (ex-AA8SM)
>
Scott
The Dentron's were famous for their "low Q" tank circuits on 160M (which
is where most of your missing 300 watts is going). I modified one in the
past (which I no longer have) by adding in C and taking out some of the
L in the tank circuit. Unfortuantely I dont remember the exact values.
Since I was only using it as a 160M amp at the time it was no big deal
to change things around a bit. If you still want all band capability
then you will have to do some pretty extensive mods like adding another
waffer to the band switch to switch in the xtra C on 160.
Later I got a much better all band amp (TL-922a) and dumped the Dentron.
There were a number of detailed design articles in the ham rags back in
the mid 80's on designing PI Network tanks for better effeciency. I used
them as the basis for picking new L and C values. The short of it was
that I was able to get close to 950W out on 160 after the mods. I was
really amazed at the improvement. I doubt the change to 220v will do
much for you since you are getting out close to a KW on the other bands.
If you get into the tank circuits I still have the articles in the files
somewhere but it may take a day or two to find them. I do remember that
you will need a set of characteristic curves for your tube if you go
this way, so start looking for that now as well.
--
Dave Henderson
N7EX ( EX....N0DH that is!)
Spokane, WA (one of the great radio black holes)
"The bad news....Life is hard"
"The good news...Life is short"
"The Moral...Eat Dessert first, chase DX and Contest often"
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