[AMPS] filament rheostats

[MM@plextek.co.uk (Mark Marsden)]

>
>Rich says:
>
>>So when are amplifier manufacturers going to get off of their lazy
butts 
>>and start building amplifiers. with a filament adj. rheostat and a
means 
>>of measuring filament potential?
>
>I guess they don't because of number 1, cost, and number 2, the
capability
>of allowing people to wind up the volts - 'gee, Wilma, you get more
output'.
>
>Better, but even more expensive, is a regulated filament supply that is
>current limited so the inrush current can't exceed twice the normal
current,
>and doesn't vary with line volts. You can afford to build that sort of
thing
>into a home brew amp.......but commercially it's a no-no.
>
>73
>
>Peter G3RZP
>
Heaters are soft-started with a motor-diriven variac, or
get a step-start supply, but has anybody seen or tried
slow starting a heater using a triac and PWM control?

Mark G4AXX 

                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                        
                                                                     

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