IRs made with SS amps or Tube amps?

[Michael R]

I did try one of these IR's against my regular IR. Elements of the tube distortion were there. And the chug was definitely nicer and more pronounced. I am all for for adding harmonic complexity. But, the loss of clarity and definition was too much for me. It also seemed less organic and displaced. Perhaps, because it was used in a different evvironment than it was generated in.

My experience is that it isn't easy to add complexity with a general strategy that feels organic and has a sense that it was "meant to be." I feel the same way about Room IR's. There are elements I like. And yet, it feels foreign and out of place in other environments,

I remember when everybody said a post-PI master volume would never work because a dual pot would not have a matched resistance that was close enough.for a push-pull power amp.

Collective blind spots are all-around us and untouched,

An interesting experiment I tried was taking one of the tube variation IRs and loading it in to Cab lab. Then take the same IR that is the SS version and load it in to the right side of Cab Lab ( where you would add the "amp part" to remove from the IR). This creates a different sounding IR that is somewhere in between the full tube version and the SS version.

 

[MirrorProfiles]

In my opinion, it’s best to cancel out any power amp interactions and colouration and have the cleanest IR possible. There’s enough software now (like what Fractal do) that allow you to load in an appropriate impedance curve to get the poweramp interaction.

I honestly prefer using valve power amps to make IR’s - you can capture the IR’s with the colouration and then easily account for it and remove it from the IR’s (or compensate for different interactions). Personal opinion of course, but this approach has made the most accurate IR’s in my tests.

 

[Postretro]

In my opinion, it’s best to cancel out any power amp interactions and colouration and have the cleanest IR possible. There’s enough software now (like what Fractal do) that allow you to load in an appropriate impedance curve to get the poweramp interaction.

I honestly prefer using valve power amps to make IR’s - you can capture the IR’s with the colouration and then easily account for it and remove it from the IR’s (or compensate for different interactions). Personal opinion of course, but this approach has made the most accurate IR’s in my tests.

@easstudios, what I found, while seeking to reduce IM in a bass amp signal, was that the flatter the Speaker Impedance Curve is, on either end, the less IM distortion there will be. This was particularly noticeable with low frequency signals. I don’t know enough to say how that might affect the production of an IR.

A flat IR may be colorless and have no character. But, having a perfect impedance match at every frequency makes a big difference in how accurately the signal will be amplified.

I have noticed that some IR’s, particularly bass IR’s, will bring various levels of IM or Phase interference. Generally, multiple speakers in a single cab will be worse. And even single speakers might have a noticeable amount. This intermodulation isn’t as noticeable with a distorted guitar signal. But, it becomes very noticeable with a clean bass signal. I have begun to wonder if this is the reason many players prefer to record bass with an EQ instead of an IR.

It might be worthwhile to see if two low frequency signals, or bass notes, reveal anything in comparisons.