[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.


> 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. 


More information about the AMRadio mailing list

This page last updated 17 Dec 2017.