After building the Princeton Reverb kit (PR) and using it every day, my ear has been trained to like its tone and overdrive. My UA Dream 65 couldn't get me there and it left via eBay.
I then tried to get my Positive Grid Spark Mini and Go to sound as close to the PR as possible. I settled on the Tweed 4x10" Bassman model plus hall reverb.
Then the Boss IR-2 arrived. It weighs 15 oz. and draws 98 mA at 9 volts. It is not quite as light and battery friendly as I might like. Again my PR targeted setting is a tweed 4x10 Bassman model plus hall reverb.
The IR-2 has several useful power-on settable configurations:
- Amp or cabinet models on/off
- Hall/Plate/Room reverb
- Output options to optimally drive an FRFR or to compensate for the model stacking on a real speaker or amp.
You can load an IR into any of the amp slots which means you could use this pedal to host one of my IRs. Either turn the amp models off or use the clean slot where the amp model is very modestly impactful. The hall reverb it is not as good as my PR kit's spring, but it is dead silent. All reverb springs pick up some 60 Hz power transformer hum. I'm not sure why they never went humbucking.
I like the IR-2 knob UI and the tones are overall excellent. There are two modeling camps, black box, and white box. In black box you set the amp controls and measure its characteristics. In white box you look at the schematic and attempt to build a computer model that runs sufficiently fast to be usable for audio. I'm not sure if Roland/Boss specifies black or white. I suspect most modeling is black box and the EQ is post processing with maybe some concession to the amp being modeled's tone stack.
IK MM has the older Amplitude White Box software, and the newer Tonex Black Box software and hardware. Black box might seem more limiting as you are stuck with the control settings when the amp was measured. I don't think that is important, at least for the clean and light overdrive I prefer (set all the amp's knobs to 5 and I'm good to go). It certainly generates a larger market for models (one per amp setting, instead of one per amp). For high gain amps with cascaded gain stages, black box must be a model seller's bonanza...
I am looking forward to the arrival of the Tonex One as it is lighter, smaller, draws less power, and I can download a model of my now favorite PR. Physically it is the perfect guitar gig bag pocket companion. Even the "recording studio" YouTube reviews are stellar for tone. I'll use my Mac to set the three foot switch accessible models (A/B mode, C On/Off mode). There are knobs for the important real time stuff that is not part of the amp model (pre-gain, EQ, reverb, master volume, plus compression and noise gate). The UI is crazy complicated if you want to dive deeper without a computer and there is no Bluetooth phone app (Positive Grid has this mastered).
In Summary, given they all have very nice sounding amp models:
- Positive Grid Spark Mini/Go - almost no useful knobs, good iPhone app, battery, not stomp box sturdy.
- Boss IR-2 - a stomp box! knobs! no model download, no tuner.
- Tonex One - knobs, complicated pedal UI for deeper dive, Mac/PC for ultimate flexibility.