Boss Tube Amp Expander Core

Offering all the essential facilities at a lower price point, could the new Core version of the Tube Amp Expander be a serious competitor to the original flagship model?

The Boss division of Roland announced their original flagship Waza Tube Amp Expander at 2019’s Winter NAMM show, putting it head‑to‑head with Universal Audio’s OX tube‑amp load box and speaker simulator, and we reviewed it in SOS September 2019. Five years on, that ‘big box’ version is now joined by the TAE Core, which is half the size and half the price, but offers by no means half the functionality. The TAE Core, like the original TAE, facilitates direct recording of a tube amp without the need for a guitar speaker. The amp feeds the TAE’s dummy load, where a line‑level signal is derived to pass through an A‑D converter. A range of digital effects can then be activated, before the signal is split into two paths: one to feed an impulse‑response host, where you can access both the integral cabs and any other speaker IRs you may choose to load; and the other to feed an internal solid‑state power amp to use with a real speaker.

Overview

The Core’s reactive load is switchable between 4, 8 and 16 Ω, with power‑matching options of 10, 50 and 100 Watts, primarily I’d imagine for internal level optimisation. Maximum power input is stated as 100W, and there is a ‘safety load’ in place if you forget to power up the TAE before switching the amp on. Once you are all hooked up, the Speaker Out socket on the back of the TAE Core, which is fed from the internal 30W power amp, can then be used to hear your safely‑loaded amp at whatever volume setting you like, via a fully variable (not stepped) level control on the front. A pair of balanced XLRs convey the DI path’s speaker‑emulated signal to a PA mixer or recording system.

Apart from the fact that it was possibly the first integrated re‑amping solution, as opposed to an attenuator, the original TAE’s ‘big thing’ was that it offered a user‑adjustable impedance curve, rather than the fixed response offered by most dummy load/attenuator boxes. It offered 16 possible response shapes via its Resonance Z and Presence Z front‑panel switches. In the guitar world, we tend to think of speakers just in terms of 4, 8 or 16 Ω units, but an actual impedance will always vary significantly across the whole frequency range. The significance of this parameter is that the impedance curve determines the power transfer at different frequencies, which, of course, becomes a factor in the actual sound that we hear. The purpose of including the user‑adjustable reactive load is that it allows the user to approximate the impedance curve of a number of different types of speaker, thereby making the connected amp behave more accurately like it would if it were connected to that specific driver.

With a block diagram printed on the top of the TAE Core, you’ll never be in any doubt about the signal flow.

Now, the reason I’m dwelling on these controls on the original model within a review of the new one is that the TAE Core doesn’t have them... But I think it is none the worse for it. The load settings for the Core are just a choice of Combo or Stack, perhaps replicating a single‑driver open‑back cab and a closed‑back 4x12. Whilst the more sophisticated control setup could allow you to fine‑tune an exact the response, it could also allow you to get it a bit wrong. A single, fixed impedance curve is likely to be optimised for just one type or the other, but a choice of the two primary types really has got you covered without having to think too deeply about it. Yes, the impedance curve matters, but so do all the other variables — the virtual mics, the effects and EQ, and the room ambience — as well.

Speaker Emulation

Air Feel is a clever effect that can counter the dryness of close‑miked IRs, leaving you a sound that can make playing feel more comfortable.You can use the TAE Core’s speaker‑emulated outputs straight out of the box without firing up the dedicated software editor — there’s a speaker and effects setup stored in every one of the 10 settings of the front‑panel Rig control — but you’d be missing out on quite a lot. The editor, available now in both desktop and mobile formats, and connecting over USB‑C or (using an optional adaptor) Bluetooth, allows you to store your own Rigs (whole setups of routing, IR, EQ and effects), with 10 of these able to reside within the TAE hardware for instant recall via the front‑panel control, the app, or MIDI, whilst many more can be stored in your library via the app. The editor improves on the original TAE editor in that it now also includes the IR loader, which makes a lot more sense than having separate...