As well as offering two channels of in‑line gain, Royer’s dBooster2 helpfully has two gain settings.
I have a pair of Royer R10s and a Peluso SR14, all ribbon mics. I primarily record classical and jazz music, and while the output level from the mics is fine for close jazz recordings they’re pretty quiet on classical music, needing the gain on my console preamps to be maxed out, making them a little noisy. So I’d like to purchase an in‑line gain booster and would appreciate your recommendation. Also, is it worth paying extra for a variable impedance feature, such as on the Cloudlifter CL‑Z?
SOS Forum post
SOS Technical Editor Hugh Robjohns replies: The low output level of passive ribbon mics is a well‑known issue and Royer offer several active ribbons that overcome this, but they’ve also designed their own in‑line gain boosters for use with passive ribbons, to help resolve the kinds of issues you’re experiencing.
I’ve reviewed both the single‑channel dBooster and the dual‑channel dBooster2, and found both to be very sophisticated designs that perform superbly well. For me, a really important feature is that the gain is switchable between 12 and 20 dB. Most in‑line gain boosters provide a fixed gain of around 25dB, but I’ve often found that’s too much, risking overload at the console. The dBooster’s 12dB option fits the bill perfectly surprisingly often, boosting the signal enough to reduce the workload on the preamp, while minimising self‑noise and not risking the headroom. It’s true that Royer’s sophisticated dBooster2 is more expensive than many rivals’ products, but I can recommend it wholeheartedly and suggest that it would be the ideal solution for your particular situation: the highest‑quality two‑channel unit, designed with Royer ribbons in mind, and enabling different gain structures for different scenarios. The dBooster2 can also serve as a great stereo recording DI box, too, should that prove useful.
If you want the ability to experiment with different impedance options, the DM2 sounds good and would be worth adding to your shortlist...
As for input impedance options, the sound of passive ribbons (and moving‑coil mics) often changes significantly with different load impedances. Most ribbons deliver their best technical performance when working into higher impedances: over about 3kΩ, and some even prefer loads as high as 18kΩ. For the record, the dBooster presents a fixed input impedance of around 3.6kΩ. Lower impedances act as a kind of dynamic tone control, but it’s impossible to predict the effect of any specific settings. While there are a few brands offering adjustable input impedance, the only model I’ve tested with variable impedance options is the single‑channel sE Electronics DM2 TNT. That particular model also happens to offer switchable 15/30 dB gain options, along with a comprehensive set of switched impedances ranging from 50Ω to 10MΩ. If you want the ability to experiment with different impedance options, the DM2 sounds good and would be worth adding to your shortlist, although I found it had less headroom than the Royer model at the low gain setting.