Tube Amps / Music Electronics
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|previous: J.D Curious if anyone have had any expe... -- 4/25/2000 1:10 AM||View Thread|
|4/25/2000 9:17 AM|
|Rick Erickson||Re: Sundown GOV and RMS functions|
The Sundown is a class AB amp. The Guvnor control is a 500K pot wired across the p/i as a "choke" or "strangler" type mv. It pulls the signals from the p/i together and they cancel out since they are 180 deg. out of phase. Shorting across the tone-cut cap in a Vox AC-30 will produce the same MV effect, Matchless used a similar circuit in their DC-30. The RMS control is a 200 ohm 5W wire-wound pot. It is indeed a variable cathode resistor. At its full power setting it connects the cathodes directly to ground. At the lowest power setting it places a 200 ohm resistance in the cathode circuit. The amp has a fixed bias supply as well as the variable cathode resistance which will bias the amp a bit colder in the lower power settings, creating a bit more distortion.
I have seen this control burn out in Sundowns. If a tube shorts to cathode it will often take the pot with it. Hope this helps.
|J.D Thanks Rick!|