Microphone Preamps

Published September 2024

These classy preamps combine exemplary technical performance with some unusual stompbox‑friendly features.

Grace Design are a long‑established pro audio company known for their high‑end preamps and monitor controllers, and their products are typically targeted very much at the professional studio. The products we have for review here reveal a more playful side, combining a miniature studio channel strip with features and functionality more commonly seen on a guitarist’s pedalboard.

Grace describe the Rex and Roxi as the ‘ultimate solutions’ for performers who like to control their own mic output on stage while adding effects using guitar‑style pedals. Such users can benefit as much as studio engineers from a high‑end preamp and a quality EQ to shape their sound. In further evidence that these products may have been conceived on ‘dress down Friday’ in the Grace office, practical examples given in the product literature include horn players, harmonica shredders or one‑mic bluegrass bands who like to play with their own effects on stage. I think it’s fair to say that these are rather niche applications, though, so I was intrigued to explore what these unusual products could offer in a more general‑purpose studio context.

Roxi Music

The Rex is the little brother of the Roxi, and has a slimmed‑down set of features and a correspondingly lighter price tag. I’ll talk you through the larger Roxi first before explaining what the Rex has and doesn’t have in comparison. The first thing that stuck me when getting my hands on the full‑featured Roxi was just how solid it felt — with its metal casing and ‘roll bars’ it has very much been designed to withstand the demands of the most chaotic of stages. At its heart, this product is a professionally specified mic preamp, and features a full‑fat implementation of one of Grace’s highly respected circuits. It allows for XLR mic or instrument jack input, with 48V available on the mic input courtesy of a small push switch on the back of the unit. There’s 60dB of gain available for mics and 40dB when used with a jack input, with an additional 10dB available from a variable Boost circuit that can be controlled by one of the stompbox‑style footswitches.

Output‑wise, we have a balanced XLR output as well as a jack output. These can operate simultaneously, and the jack output has an independent level control labelled Amp. We also have an output for a tuner, as well as jack inputs and outputs for a dedicated effects loop, which can be used in parallel thanks to the onboard dry/wet control. Alongside this creative functionality, the EQ section on the Roxi is impressive for such a small device, featuring low and high shelving filters alongside a sweepable midrange that can cut or boost from 175Hz up to 4kHz, by up to 10dB. These are the main controls covered but there’s also an additional DIP switch section on the side of the unit, which offers options for engaging a high‑pass filter (at either 75Hz or 150Hz) as well as switching the output of the device between line and mic levels. If that’s not enough, there’s also the option of switching the second footswitch to act as either a boost control or for inserting the effects loop into your chain. Power is supplied either from a standard IEC mains socket or a 9V power supply of the kind more commonly seen on pedalboards. The 9VDC jack on the ROXi is a power output which is provided to supply power to other pedals on your pedal board! (The ROXi can only be powered from its 100-240V AC supply).

[Left: Rex. Right: Roxi.] Aside from their form factor, what sets these mic preamps apart is the presence of a stompbox‑friendly effects loop.

Rex Appeal

The Rex is much smaller than its counterpart but still packs in most of the key features, just with fewer options. The unit can only be powered by a 9V DC power supply, but features the same preamp with the same 10dB boost feature. We also have the effects loop input and output connection, but without the parallel blend control and the footswitch‑controlled insert option. It’s the same deal with the additional amp output, in that you still have the option, just without the separate level control. EQ‑wise there’s a fixed 75Hz high‑pass option as well as the high and low shelving filters, but there’s no mid band as found on the bigger model. It’s not all ‘less’ with the smaller option though: many users, like myself, will prefer having the controls for 48V phantom power, ground lifting and the high‑pass filter available on the main body of the device, rather than having to reach around the back or engage a DIP switch.

In The Studio

I’m predominately a studio engineer, so I was keen to see what these clever boxes could offer me when recording musicians and singers in a studio setting. However, as I had both models for review, I thought I would lend the Rex to a friend who performs live with acoustic instruments using pedal effects on stage, and then collect their thoughts here.

Starting with my own experiences, the thing that struck me first was the quality of the preamp. I’ve used Grace preamps before but I was still taken with how ‘clean’ and vivid my old Neumann U87 sounded on a vocal session. It was a similar story with my Shure SM7 dynamic mic — which needs a lot of gain — in that it seemed to bring the very best out of what can be a fussy mic, without needing a Cloudlifter or other boosting device. The EQ section has more than enough options for tracking sessions, and the low‑ and high‑pass filters worked superbly for adding a touch of weight and fullness or ‘opening up’ the top end. Being able to then also target specific ranges with the mid band seemed like a real bonus.

Putting the extra features to use, I began by connecting my RE‑201 Space Echo to the effects loop, and it was great being able to blend just the desired amount of echo effect using the parallel wet/dry control. I could also choose to send the output of the effects loop to my patchbay, so any effects used could be printed on a separate track, and also sent to a singer’s headphones mix, for example.

I found myself continually surprised by how useful these boxes were in my studio.

I found myself continually surprised by how useful these boxes were in my studio. On one session, in particular, I had both out for tracking a jazz outfit in a live studio session. The double bass player had a fixed pickup in place on his instrument, and using the jack input on the Roxi, I was able to connect his output effortlessly into my setup knowing I had a good preamp taking care of things at source. I also added a touch of EQ, and the performer took advantage of the amp output to feed a tuner. It all worked superbly. In the same session, the trumpet player was keen to hear effects in his cans to get the right feel, so I used the Rex as the preamp for his mic whilst using the effects loop to add some spring reverb to the headphone mix. Again, it all worked perfectly and added both quality and convenience to a busy session.

On The Stage

My friend Rachel from the band Fuzzy Lights was very happy to try out the Rex. She plays violin in the band, using guitar pedals through a less‑than‑ideal setup where various pedals are daisy‑chained into a guitar amp to get sufficient gain. With its wet/dry blend control, the Roxi would really have been perfect for her live setup, but she was still able to plug her violin’s pickup into the Rex’s XLR input and then have her guitar delay pedal connected to the effects loop, with blending taken care of on the delay itself. She was then able to send the signal on to her on‑stage guitar amp using the Amp output, for the distorted amp sound she likes when playing live.

Suitably enthused, Rachel popped into the studio to try out the Roxi, and the sonic improvement compared to her current setup was not subtle; the preamp seemed to bring out much more body from her violin, and the ability to smooth out some harshness with the EQ worked a treat. To quote Rachel herself: “It’s like someone has designed the perfect product for my live setup!”

So much of performing live is about reliability and trust in your gear, and these tools from Grace remove the need for ad hoc setups that can be prone to issues with power supplies and impedance matching.

Final Thoughts

For live musicians who want to have more control over their sonic output on stage, both the Rex and Roxi will have a great deal to offer. It almost feels as if someone in the Grace team who plays live with a mic and pedals has coaxed the rest of the company into designing a product for their live setup! So much of performing live is about reliability and trust in your gear, and these tools from Grace remove the need for ad hoc setups that can be prone to issues with power supplies and impedance matching. In this regard, these are brilliantly designed products, and it’s obvious that a great deal of care has been taken to think of what might be needed in different settings. If this sounds like you and you have the budget you should seriously consider getting one of these options: the Roxi would be great, but if you can only stretch to the Rex, the only thing you should perhaps think about is how you would manage only having an XLR input.

For a studio owner like myself, I was surprised at just how useful these boxes were: using one as an extra little channel strip on one project but then employing the same device to solve an issue on a live tracking session was just great. One of these would be brilliant if you run a small mobile recording setup or are a self‑recording musician who is looking to take a jump in quality.

Pros

Great‑sounding preamps packaged for stage settings.
Simple, good‑sounding EQ.
Well‑thought‑out routing options.
Built like a tank.
Also great as a flexible studio tool.

Cons

Quality comes at a price.
XLR‑only input on the Rex will limit its use for some.

Summary

Grace Design have taken a bold move by releasing unique pedalboard‑style channel strips that pack in a huge amount of flexibility for live performers, home recordists and small studio owners. These are well worth checking out.