[NOT A BUG] Q. 4.01b - Strange behaviour of Plexi 100W 1970

GitarKnut

Member
I have a XL and noticed that when attaching an external controller to the Treble Drive on the Plexi 100w 1970 the CPU-usage increases with 10% or more. I have an Ext.ctrl. on the Drive (or Treble Drive) on several other amps/presets and the CPU usage is fairly stable when attaching and using the Ext.ctrl.. I use the same expression pedal (Roland EV5) connected to Ext. 2 on all the presets. I have also tried with/without using Axe Edit and have also inserted the Plexi 100W 1970 into other presets. The CPU increase is consistent across the presets and w/wo using Axe Edit (i.e. front panel or AE). I have attached the preset where I use the Plexi 100W 1970 (no ext.ctrl.) and also a csv-file from the preset with the Ext.ctrl. attached.

I have had the preset for quite some time (i.e. across several FW-versions) and have never observed this before. The only change I have made to the preset from Q4.0 to Q4.01b is introducing the Capt.Hook rhy amp as Amp 1 Y (The Plexi 100W 1970 is Amp 1 X).

Edit; I have the Input 1 Left select set to "Front" and Input 1 Mode set to "Stereo" as I also use the Rear R Input for a piezo-equipped guitar (PRS P22) on some presets. Hence the Input Select on my amps are set to "Left".
 

Attachments

  • Marshall Rig.csv
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  • Marshall Rig.syx
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Last edited:
It's always been like that. Requires lots of double-precision math.
First, I will use the opportunity to thank you for creating the best "guitar multi tool" ever made. I have been playing guitar for over 40 years and I have never enjoyed playing as much as I do now with the Axe Fx with its endless possibilities and the best guitar sound I've ever had (having owned and played a lot of good tube amps). Also thanks for taking time to answer my question! One important thing I forgot to include in my first post was that I recently switched from having the Ext.ctrl. connected to the input trim to connecting it to the Input drive and that is possibly the cause of noticing the CPU-jump on this FW-version.


I am not expecting any reply to this, but I still wonder why it is only (at lease on the amps I have in my presets) the mentioned Marshall that exhibit this behavior. Thanks again :).
 
different amps use different amounts of maths to calculate things like drive. i don't really understand it, but i'm just going on what cliff has said in the past. if you want to change gain with a controller, you're better off using the input trim parameter
 
different amps use different amounts of maths to calculate things like drive. i don't really understand it, but i'm just going on what cliff has said in the past. if you want to change gain with a controller, you're better off using the input trim parameter

Thanks Simeon.
In my presets I use either the Input Trim, the Input Drive or an Eq (graphic or parametric) connected to an External Controller. (Filter or Volume blocks are other nice options). Which method I use depends on available CPU and what I want to achieve with the extra gain hitting the front of the amp. A slight mid-boost on the lead Scenes is a keeper. I have not been using the drives very much but after installing Q5b I might have to reconsider this......

I ran out of words (even in my native language) describing how good the Axe Fx sounds some FW's ago and now it is simply jaw-dropping and highly addictive.

And by the way; as the issue with the CPU increase is not a bug - do you know how to change the heading to indicate/state that it's not a bug?
 
don't worry, one of the mods will do it

yes, there's lots of ways to achieve an increase in gain. if adjusting the input gain causes a jump in cpu, then you have lots of other options.
 
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