Radial Engineering SB-6

Sometimes you just need isolation without level attenuation - just easy interfacing between equipment that is suffering from ground loop issues due to being on separate ring mains. I've solved issues with humming monitors, FOH speakers and guitar amps with this. It now lives on my pedalboard, to help run balanced lines from a guitar rig to a rack processor and back, TS->TRS->TS, which reduces unbalanced line interference considerably. I also use it at numerous venues, where lighting desks, dimmer controls and even dishwashers are all spewing noise onto the mains. Some of this is cleared up by RF filters, but used in tandem with the Stagebug, you can eliminate just about anything (excl. single coil noise - nothing can save you from this, except humbuckers!). Another use was to put this between an active acoustic preamp and an A&H desk's Inst input, as I had run out of DI channels but still wanted isolation from the desk. Useful PAD and polarity etc. should you need it. Managed to fit this beneath my pedaltrain so it is out of the way. Very solid and well made, and well worth the money, even if you just keep it in your toolkit until it's needed.

I got the Radial SB-6 to compare with the Palmer PLI-05 and Behringer HD400 for the purpose of removing extra noise from my pedalboard and amp setup. I am using a HX Effects in 4CM which is already notorious for adding some hiss but also ran into an issue of ground loop buzz in the FX loop of my amp (a modded Marshall). The Radial has the best features of all the three options but there was a very noticeable volume drop when routing the signal through the isolator. When used in the FX loop the volume clearly dropped about 6 dB and in front of the amplifier I seemed to lose a lot of gain and low end due to the level drop. So for me it was not working. The HD400 exhibits the same kind of volume drop so Palmer was the keeper here.