I make purchases based on several factors, but often when I'm buying something for the studio it's primarily to fill a hole. I look for pieces that do something different than the gear I already have. In the past, I've had (and used) several inexpensive tube mic preamps and owned one very high-quality tube channel strip. I stopped using the tube channel strip because I didn't really like all of its separate sections, and I've wanted another high-quality tube pre in my tool kit. Those who know me well understand that I'm not the kind of guy that likes a rack full of outboard pres. I'm happiest when using my console's pres, but there's always that pull to have a tube option for vocals or other standout tracks.
I did a fair amount of research, online listening, cost and feature comparisons, and finally decided to buy the stereo Useful Arts SFP-60. I had originally considered the single-channel version (SFP-30) but wanted a stereo option for sources like solo piano, direct keyboards, and small ensemble recordings. Form factor was also important. The SFP-30 is a tabletop model with I/O on the front, while the SFP-60 is a traditional rack unit with I/O on the back plus DIs on the front (making control room overdubs quite simple). There are also the standard feature switches you'd expect on a mic pre; polarity, high-pass filters, phantom power, input pads, and input selectors (rear mic in or front panel DI). These are all controlled with high-quality toggles and include LEDs for each – no signal passes through these switches. The metallic and olive-green faceplate is finished off with a beautiful blue backlit VU that indicates output level.
The SFP-60 is unique in that it has two tube stages: An EF806 pentode tube on the input and an ECC82 triode tube on the final two stages. Each channel offers separate controls for Input, Output, and Color. The second tube stage is shaped by the Color control. It can add up to 10 dB of harmonically enhanced gain to the signal and, unlike most standard tube preamps, allows the operator artistic control of the harmonic distortion. Having an onboard Output control is great for ensuring that you aren't creaming the next input stage (recorder, EQ, compressor, etc.) even if you are creaming the sound. The SFP-60 features Cinemag input and output transformers with Class A circuitry throughout.
I received my unit in January and have been using the SFP-60 on a lot of sources since, to great satisfaction. One of the first things I tried the preamp on was drum overheads with a pair of Octava MC012 mics [Tape Op #25] in ORTF over the house drum set. I made three passes, playing with various feels and dynamics. Pass one with the SFP-60 Color setting at 0; pass two at 5; and pass three set to 10. At 0 on the Color, there was a very transparent, and quite pleasing sound. Cymbals had nice articulation, the stereo spread was clear, the snare was present, and toms spoke well. At 5 things started to get interesting – some saturation made the snare sound more like a finished mix, with added presence and tone, also toms felt bigger. At 10 it became more of an effect. The drums were crunchy and thick.
Shortly after my initial drum testing, I went into song production mode, where I planned to track everything separately, including the drum set. This became a perfect way to use the SFP-60 on every track. We started with acoustic guitar and vocal guide tracks. I recorded Sara Quah playing and singing with two sE Electronics T2 mics in figure-8 patterns. Using the Color and input controls I was able to get a really lovely sound from the acoustic guitar while adding some midrange harmonics. The vocal required less drive but still sounded very nice. I recorded the drums on separate tracks: First two hi-hats, then snare with room mic, then two very openly ringy toms, and finally bass drum. The sounds were all very pleasing, present, and full without being pushed or driven hard. Bass was my first chance to use the SFP-60's DI. The part I recorded was very open, with a lot of long notes. The Fender Precision bass I used always tracks well, and it seemed to love the SFP-60. I put more color on than I had with the drum tracks, resulting in a solid, creamy foundation to the sound. Electric guitar was also DI'd, as the player has some lovely patches ready to go through his Fractal Audio Systems Axe-FX effects processor. Again, I used the input and color controls to get a warm, pillowy sound that suited the song's slow, spacey feel.
I've used the SFP-60 on a few different male singers recently, and it has done exactly what Useful Arts claims – offering a transparent tube or mix-ready sound. If the same singer is tracking melody and harmony vocals, it's worked quite well to simply use two different Color settings to give a different tone to each part. This is particularly wonderful for working quickly as inspiration meets talent. We all know how changing a mic can be a good idea for this but can also kill the flow of the session. A simple adjustment to the Color and Output knobs allows the session to keep moving – the singer doesn't even need to be made aware that you've done anything, just that you're ready for the next part.
I've had the chance to use the SFP-60 on Hammond organ with a Leslie speaker only once since I've bought it, but it sounded stellar. I placed two beyerdynamic M 88s on the Leslie's rotary speaker, at close proximity, while driving both the organ and the SFP-60 for some push. The resultant track sounded almost like you were inside the Leslie! Electric guitars sound thick and very present, with just enough rounding of highs and transients to tame harshness. I'm excited to try this pre on other sources too – specifically on direct keyboards. The SFP-60 delivers a wide variety of tones, with a very simple interface and high build quality.