Dirty Shirley default Supply Sag value?

M

marshall2553

Power User
I noticed the Dirty Shirley model has a default Supply Sag value of 1.15. The real amp has a tube rectifier but that sag value is lower than a lot of SS rectifier amp models. Obviously I can raise it if I want more sag, I was just wondering if that value is accurate.
 
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Supply sag was recently updated, you can now get twice as much and as a result all older values were halved to stay consistent
 
Brownmatthall said:
Supply sag was recently updated, you can now get twice as much and as a result all older values were halved to stay consistent
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Yes, but the default value is still lower than the default for a lot of amps that have a solid state rectifier. That strikes me as odd as I would expect an amp with a tube rectifier to sag more.
 
The power transformer and filter capacitors of the amp also affect the amount of sag, so the Dirty Shirley might have a beefier power section that is more resistant to sag.
 
mr_fender said:
The power transformer and filter capacitors of the amp also affect the amount of sag, so the Dirty Shirley might have a beefier power section that is more resistant to sag.
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You're probably right. It's marketed as having a JTM-45 inspired power section and the Supply Sag for the Brit 45 model is only slightly higher (1.30). I still think it's weird, I just assumed the tube rectified amps would have sag values significantly higher than the SS rectified amps.
 
The power transformer is equally responsible for sag. Some power transformers (i.e. old Plexis) have a lot of winding resistance. Even though these amps have SS rectifiers they sag like crazy due to the power transformer. My 100W Plexi is the saggiest amp I own and it doesn't have a tube rectifier.
 
FractalAudio said:
The power transformer is equally responsible for sag. Some power transformers (i.e. old Plexis) have a lot of winding resistance. Even though these amps have SS rectifiers they sag like crazy due to the power transformer. My 100W Plexi is the saggiest amp I own and it doesn't have a tube rectifier.
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Would be worth a short Tech Note on Sag/ DC Supply Voltage drop, though.

Btw is an increase in Sag/DC Supply Voltage part of the intended concept when looking at the Mesa Boogie rectifier series? They seem to be known as modern preamp based amplifiers. Whereas sagging as part of the amp behaviour seems to be dominated usually more by older or vintage type guitar amplifiers, especially with rectifier tubes e.g. JTM-45, Fender, Dirty Shirley.
 
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