Possible Bug? No Master Volume on some models with Power Amp off?

Sonofiam

Sonofiam

Power User
According to the manual:
"Turning SUPPLY SAG fully counterclockwise defeats power amp simulation, allowing one preset to be used into a real (presumably tube) power amp without globally disabling power amp simulation. (See “Global: Settings Page” on p. 79 for more on this.) In this mode, MASTER works as a simple volume, DEPTH is deactivated, and PRESENCE turns into a simple shelving filter."

I was messing around with a few amps and found the Master Volume (on the 'Basic' page of the amp block) did not work on a couple of them when the Power Supply - Supply Sag was set to zero. I went through the amp "brands", not every model though, and found the following were affected:

AC20
Boutique
Citrus
Class-A (the FAS Class-A was not affected)
Div/13
Matchbox D-30
Ruby Rocket

Not all of these amps are non master volume, that was my first thought. Other non master volume amps are unaffected.

EDIT: Firmware Version 7.01
 
Last edited:
Sonofiam said:
According to the manual:
"Turning SUPPLY SAG fully counterclockwise defeats power amp simulation, allowing one preset to be used into a real (presumably tube) power amp without globally disabling power amp simulation. (See “Global: Settings Page” on p. 79 for more on this.) In this mode, MASTER works as a simple volume, DEPTH is deactivated, and PRESENCE turns into a simple shelving filter."

I was messing around with a few amps and found the Master Volume (on the 'Basic' page of the amp block) did not work on a couple of them when the Power Supply - Supply Sag was set to zero. I went through the amp "brands", not every model though, and found the following were affected:

AC20
Boutique
Citrus
Class-A (the FAS Class-A was not affected)
Div/13
Matchbox D-30
Ruby Rocket

Not all of these amps are non master volume, that was my first thought. Other non master volume amps are unaffected.
Click to expand...
Probably useful to post which firmware version. Did you try a different version?

My first thought was also NMV amps...
 
Update: Just rolled back to Firmware 6.02 to check and had the same results. With the Power Amp Sim off, the Master Volume doesn't do anything on the amps in the original post. The other amps I checked worked fine but I didn't go through them all.
 
They're all amps that have zero negative feedback, mostly all Class A (although you aren't specific about which Citrus, and which Div/13). That may or may not have something to do with it.

Either way, when the power amp isn't functioning and the MV is a simple level control, it's redundant to the Amp Level control.
 
There are amps that have zero negative feedback and operate the way the manual states. Here's a few that the Master Volume works fine with Power Amp Sim disabled:

Buttery
Deluxe Tweed
Div/13 FT37
FAS - Class A

This isn't an exhaustive list, I stopped after the Div/13. I had originally checked the FAS-Class A since there seemed to be mostly Class A amps affected..
 
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