Schmalle

If you get a sound you like from one of the Vox amps and want a preamp to do that sound: You could try to match it with the Cali Texas Ch2 as an exercise / experiment. It's my fav preamp and very versatile. Try to get the sponginess / sagging right first by tweaking the master.

The character and overdrive of those amps comes mainly from the phase inverter and the power tubes which are not part of the preamp. Their preamps themselves are relatively weak and clean.

Sure; Less input impedance means more of the guitar's signal escapes through said impedance to ground. The input impedance is in parallel with the volume knob on the guitar. Lowering it has the same effect. (EDIT: This is a simplification - the volume pot is also in series at the same time). A pickup is a coil of copper wire with a magnetized core. It has resistance, capacitance and inductance that together act a resonant circuit which means at a certain frequency (1.5kHz to 4kHz) it "rings". This is often called the resonant peak. It is tamed when you decrease the input impedance. The sound looses character / attack / aggression / harshness depending on how much this peak sticks out in the frequency spectrum. It's like mustard - very nice on a Bratwurst, very annoying in a milk shake.

When you jumper channels the amp's input impedance is lowered, too. Try 230kOhm input impedance so that your guitar's electrics "see" the about the same load as if you'd plug into the amp directly. That will reduce "harshness" a little.

The 70's chorus actually is the low impedance exception in the modulation category.

The 70s chorus uses 22kOhm, because the real Boss CE-1 does. It is a line input device. You can set the input impedance to 1MOhm or put a neutral gain block as first "dummy" block. Or mess with the global settings.

If you use input 2 of either channel of your Bassman and want the same more mellow sound set the input impedance in the input block to 136kOhm.

But the schematic states 10KB aka 10kiloByte. I have a 2GB USB stick - will it work, too? But more seriously: stick to 10kOhm linear pots - at higher values only part of the control path of the pedal is recognized.

Correct. The pedals use TRS - tip, ring, sleeve. What needs to be done is to remove the ring signal. You can use a TRS cable where you open up one of the plugs and cut the ring conductor. Or modify the pedals and open up the ring signal path somewhere. Often people pull the pedal's TRS jack's middle connector so that it won't make contact when a cable is plugged in.

Where do I get those 10kB pots? In an app store?

Your amp / cab levels are too high as you found out yourself. Yes, the delays and reverbs have upper limits (fixed headroom) like real hardware reverbs and delays. Deal with it and lower the block's input signal level.

Already suggested before i.e.: EQ Cut filters FULL frequency spectrum AND adjustable db/8va Adjustable high and low pass slopes for cabs and ir's

Formants! Pitch shifting something characterful as a cab will put it's eq bumps and dents in unusual places in the spectrum and shift the resonance frequencies of the cab.

Vox normal channel or Matchless channel 1 with zero bass would be my intuition as a starting point.

Now add the memory footprint to it. The difference in file size of FW 3.15 and 3.5 divided by the number of IR files you computed. Some heavy black magic compression going on there.

True. And the reason why the new cabs and IR's use less "DSP" is because the IR convolution stuff is now computed with the DSP's hardware accelerator which works in parallel with the normal computation.

A high cut that only really does stuff in the last quarter of it's control range.

This is no speculation. The amp models replicate the speaker out signal of an amp. It matters what load / cab is connected when modeling. How much depends on how much current feedback the amp has. The impedance curve is an electrical frequency response of a speaker and it is indeed imprinted in the model. IRs on the other hand only contain an acoustic frequency response.

What's the recipe for a McDonalds burger? Tip no. 1: specify the target tone. Edit: Tip no. 2: for OD1 channel sound the Badonk is closest.

Amp blocks because the Catalyst has a neutral class D power amp. Preamps are more for coloring (tube) power amps. That's just a general rule of thumb though - there are preamps that are designed for flat or flat-ish power amps.

For me a big step was to use the York Audio Marshall V30A Mix1 as a reference point. It is the filter that connects my amp's speaker out or amp sims with a flat speaker (studio monitors) and sounds like the cab I love. It feels like being able to virtually go into the recording room and play through a real cab. Most amps sound great through it. That said I use the Helix cabs quite a lot as a tone shaping tool - really fun stuff. And if you're after some recorded / in the mix tones that's a great way to get there.

As far as real amp vs modeler I A/B'ed my Laney AOR tube amp against the HX's Brit2204 + class D amp into the same cab. I could make them sound and feel almost identical to me in that experiment. I noticed that on several models the default sag is quite low when compared to the real deal or my AxeFxII. This can result in a too stiff or harsh sound. Some models are great on default settings, most can be tweaked to sound and feel right and some just are just bad amps IMHO. The whole FRFR thing has more parameters to it when compared to a powered cab. Basically what you want your FRFR to be is a good representation of the PA. And you want to find a filter (cab sim / IR / eq ) that makes it (and therefore the PA) sound like a cab you like.

Warwick Gnome and TC Electronic BAM200 are popular. class-d bass-head discussion I would not recommend the popular and cheap Harley Benton GTA-100 for bass because it cuts lows with higher volume.

A thing to notice it that there are two Brit P75 + cab blocks - one with a new cab and one with the legacy cab. I like the old one better (the one in the video) in this case. To match the new one with the legacy one I suggest to change the cab settings: 4x12 Blackback30, 57Dyn, 4.0, 2.00", 45°, 80Hz, 5.7kHz I saved this as user default settings for this amp.