[AMRadio] Re: Ranger... good news, bad news


ne1s ne1s at neandertech.com
Thu Nov 9 13:18:35 EST 2006


Jack Schmidling writes:
> Gary Schafer wrote: 
> 
>> So unless you have some higher gain tubes in the amp 12 to 15 watts drive
>> will not be enough drive.

 -SNIP- 

> I have contended all along that it takes about 20w drive.  Everything 
> seems to work well including 100% mod when I drive with 20w.  Only >problem being that the tubes redden. 
> 

The low-voltage B+ modification may not be practical for you, Jack. Any 
class AB2 grounded-grid linear I've ever played with (and I've designed and 
built two) had a power gain between 10 - 15. Someone said the power gain of 
you amp was only around 6. So after reducing the Ranger power to 12W and 
feeding the amp, you'll only be getting ~70W carrier out, not quite double 
what the unmodified Ranger puts out (~40W). Hardly worthwhile. 

> As a point of interest, I am using 6L6's in the modulator but assume they 
> just won't last as long and not effect the amount of modulation. Is this > a good assumption? 
> 
Kinda depends. From memory the original metal 6L6 only had a maximum plate 
voltage rating of 350V, so voltage breakdown at the socket may be a problem. 
The maximum plate voltage of the 6L6GC was 400 or 450V. I can't remember if 
there was a difference in the maximum plate dissipation. Anecdotally, I am 
running 5881s in my Ranger that gets used reqularly, and they've been in 
there at least 10 years. They may be a bit soft by now but still give me 
nice sharp peaks in excess of 100%. As long as the tubes survive, though, 
they should be equivalent to the 1614 electrically, and thus in terms of 
their ability to modulate. 

73/GL,
 -Larry/NE1S



More information about the AMRadio mailing list

This page last updated 20 Oct 2017.