Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: jjjtttggg on December 21, 2016, 11:37:24 am

Title: anybody know how 5w and 10w settings work in Mesa Lone Star / Lone Star Special?
Post by: jjjtttggg on December 21, 2016, 11:37:24 am
I've seen studied the available schematic for the Mesa Boogie Lone Star, but it seems the Lone Star Special schematic is not public.  On the Lone Star, I see where they get 100w/50w switching just by shutting off two of the output tubes. I assume this is the same in the Lone Star Special for the 30w/15w switching. What I'm interested in, though is how they get to the 10w and 5w levels. In the owners manual for the Special, it says the 5w setting switches the amp to a Single Ended output stage. 

Anybody know what they're doing here?

Thanks,
-J
Title: Re: anybody know how 5w and 10w settings work in Mesa Lone Star / Lone Star Special?
Post by: kagliostro on December 21, 2016, 11:46:08 am
Quote
Anybody know what they're doing here?

Not for sure

May be they use a pot on one side of the PP between the PI and the grid of one Power Tube like in the Soma 84

(http://el34world.com/Forum/index.php?action=dlattach;topic=11667.0;attach=23719;image)

Franco
Title: Re: anybody know how 5w and 10w settings work in Mesa Lone Star / Lone Star Special?
Post by: BetterOffShred on December 21, 2016, 12:15:28 pm
The Orange Tiny Terror has a similar setup, where it's switchable from 7 or 15 watts, and from looking at the schematic it looks like they have a selectable coil on the power transformer.   Not sure that's what is happening there, but the best I can tell that's the selectable power switch.   You might want to take a peek at that Schematic (which I found with a google search).  Looks interesting!  I could also be totally wrong.

It also features one of Merlin's accepted standby switch configurations! 

-Brett