" The PRESENCE control is a high frequency attentuator that is placed at the end of each channels pre-amp stage and affects frequencies higher than.. (etc.)"
Is this otherwise done as a neg feedback loop in the output tubes? (or 'around- not sure of the terminology
Try alternating the presence and treble knob. Cut the treble off and use the presence as your "highs". See what that does.Thanks, yeah that's kind of what I was wondering. I never paid all that much attention as to what or how stuff goes on in amps, butI've been trying to get some insights as to how this stuff works -the tone stacks', inter stage gains etc.
One thing that's caught my eye', is I basically (almost always) hate fizz on top. And it occured that as I'm currently running that control' at 'full cut' and still hearing it.. if it were in the output tube loop.. I might be liking the tones better?
BTW, i've been comparing the 'Rectifier, and a few others manuals to the Lonestars (I have the lower power 'special) just to see, and they all pretty much say similar things with regard to this, and the tone controls etc.
On my Marshall JCM 800 2203 and 2204, they both have the least negative feedback of the entire Marshall lineup. They can start to get bottom heavy as the volume goes up. The louder you turn them up, the less "bass" setting you actually need.I recently revisited the excellent owner's manual for my Lonestar Special and read that same bit about the presence control. It's such a dark-voiced amp, I was looking for ways to brighten it up without it getting fizzy. I didn't have much success. I did get some better results after realizing that I should dial the bass way down when I have the gain control turned up. That did help the dark voicing a bit...I had just assumed it was so bassy because of my crappy room. 12:00 didn't seem out of the ordinary for the bass setting, but it turns out that was way too high when the gain was up past 2:00.
But yeah, the presence is basically a super-treble on the Lonestar that controls frequencies higher than what the treble knob controls. The tone stack on this thing is like a freaking combination lock. Turn one knob and it affects how all of the subsequent knobs behave. I usually have the presence knob either all the way down, although recently I've started notching it up to about 8:00 or 9:00, in an attempt to help the amp shine through a mix more clearly.
On my Marshall JCM 800 2203 and 2204, they both have the least negative feedback of the entire Marshall lineup. They can start to get bottom heavy as the volume goes up. The louder you turn them up, the less "bass" setting you actually need.
And I should have known that. That's kind of a rule of thumb with amplifiers...I've had a few hi-fi systems that had the "groove" or "max bass" button that's intended to enhance the bass when listening at low levels. But above a certain volume, they aren't needed because the amplifier/speakers produce plenty of bass. It seems like the same principal at work here.
Greg, are you referring to neg. feedback for their presence controls, or more the fixed types in part of the amp's designs?Mesas, Vox, and the two Marshalls I mentioned are pretty loose with a less restrictive negative feedback loop. Vox and Marshall counters this with top boosts and bright caps. Mesas just stay fat and blubbery. My JVM and Plexi are "tight" though with a lot of negative feedback and they stay tight and articulate pretty much no matter what the volume does. ..
Greg, are you referring to neg. feedback for their presence controls, or more the fixed types in part of the amp's designs?