Modeling Questions

James Freeman

James Freeman

Inspired
Is the impedance curve fed back to the phase inverter like in a real amp?
Are the presence and depth controls in the NFB loop and are they affected by the NFB gain?
Is the NFB filtering component based (RLC) and is the passive component math resolved on-the-fly?
Are all the above measured form the actual reference amps when creating the models?
Are non-adjustable filters added to the models internally to match the reference amp?
Are things like B+ and power transformer sag (series resistance) measured form the reference amps?
Why cathode bypass caps necessitate a separate model?

Thanks in advance Cliff. :kissingheart:
 
James Freeman said:
Is the impedance curve fed back to the phase inverter like in a real amp?
Are the presence and depth controls in the NFB loop and are they affected by the NFB gain?
Is the NFB filtering component based (RLC) and is the passive component math resolved on-the-fly?
Are all the above measured form the actual reference amps when creating the models?
Are non-adjustable filters added to the models internally to match the reference amp?
Are things like B+ and power transformer sag (series resistance) measured form the reference amps?
Why cathode bypass caps necessitate a separate model?

Thanks in advance Cliff. :kissingheart:
Click to expand...
I can't answer these questions, but I can tell you that adjusting negative feedback seems to me to be one of the most important tweaks. I actually think it should be on the simple tone page.
 
James Freeman said:
Is the impedance curve fed back to the phase inverter like in a real amp? Yes
Are the presence and depth controls in the NFB loop and are they affected by the NFB gain? Yes
Is the NFB filtering component based (RLC) and is the passive component math resolved on-the-fly? Yes
Are all the above measured form the actual reference amps when creating the models? Yes
Are non-adjustable filters added to the models internally to match the reference amp? Rarely. Sometimes there are parasitics that require "tweaks" to the model.
Are things like B+ and power transformer sag (series resistance) measured form the reference amps? Yes
Why cathode bypass caps necessitate a separate model? Don't understand the question.

Thanks in advance Cliff. :kissingheart:
Click to expand...
 
Orvillain said:
I can't answer these questions, but I can tell you that adjusting negative feedback seems to me to be one of the most important tweaks. I actually think it should be on the simple tone page.
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It’s a good control to throw on an amp-centric performance page. My Ceriatone AH50 Deluxe has a NFB control and it adds so much to the amp’s tonal palette.
 
As far as I know, KSR amps are the only ones building amps with an nfb knob. That alone made me briefly consider one. Such a great tone tool.

Check the amp page to see what I ended up with though..
 
James Freeman said:
Thanks Cliff!


When there is a switch that adds a cathode bypass cap in the schematic, there are separate models ie. Deep, Bright in the Mark amps.
The cap changes the response of the 12ax7 gain stage, why does it require separate preamp models, can't that be modeled on-the-fly?
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Cliff has stated in the past that currently it's just easier/faster to add a separate amp model with regards to various manufacturer's circuit options like the ones you mentioned, though it's possible that might change going forward at some point.

Remember that you get 4 amp channels per amp block, and now gap-less switching, so it's not hard to set up those kind of options for performance use if need be (which most real amps don't allow aside from the front panel etc).

Surrender to "THE FORCE", and save yourself from the "Dark Side"!
 
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James Freeman said:
Lol, yup.
Cliff's answers are exactly what I wanted to read, I don't think I can dodge this time. :grimacing:
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You won’t regret it James.

There will be some initial frustration with your Helix muscle-memory that will cause wrong button presses (and also just learning how the Fractal architecture is constructed vs Helix), but once you learn your way around it, it’s not bad at all.

Biggest tip for a Helix user: to get to the layout view, which is like the Helix’s normal signal path view, press the big knob once, or double-tap the HOME button. From there it’s just a matter of placing blocks, editing them, and learning how to navigate through their pages for various settings. The Home view for Fractal just shows the preset name and its scenes (akin to Helix snapshots). (Or just install FM9 Edit and dig in.)

The tones and modeling quality are there, 100%. It sounds and responds as well as the best Tonex & NAM captures I’ve tried, except it’s fully modeled and tweakable.
 
DJD100 said:
Remember that you get 4 amp channels per amp block, and now gap-less switching, so it's not hard to set up those kind of options for performance use if need be (which most real amps don't allow aside from the front panel etc).
Click to expand...
Channels are definitely a nice convenience. I find myself using them a lot just to quickly A/B different settings of the same block type without losing settings on the original.
 
Start with the software Editor, makes everything super easy, and then learn what you need to get by with via the Front Panel for gigs etc. The Fractal Editor is for the most part self-explanatory (for a guy with amp building and audio production experience anyways!).

Note that also get an easily assessable Performance Screen that can hold up to 16 of your most used parameters, all in one place sans deep diving through menus.
 
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When I turn off power amp modeling in the amp block, where does the signal is taken from, before the phase inverter or after?
"Master Volume becomes a simple volume" that implies that the PI is also removed but it could still have an effect?
Also, where is the 0.0dB position of the Presence knob when it is in shelving mode?
 
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