Radial Engineering SB-2

Petite, légère et compacte ! Voici en bref les atouts de cette D.I.
Elle peut se ranger partout.
Je l'utilise principalement pour mon clavier lors des Lives. Il n'y a aucune perte du signal. Si les claviers envoient trop de son, trop de puissance, il y a un PAD très utile qui abaisse le niveau sonore de 15dbs. Super efficace !
La Sortie Thrue est tout bonnement géniale.
Et le Ground Lift très utile dans certaines situations, les buzz disparaissent !
Que se soit en studio ou en Live, passer par cette petite boite avec une guitare, électrique ou électro -acoustique, ou une basse vous permet d'optimiser votre son. En gros, vous aurez un son superbe en directe dans la table et votre son repris d'un ampli et/ou d'un baffle.
Enfin, moi, je m'éclate !
Franchement, c'est un matériel super pro !

It is the first time I buy Radial and I believed it would be perfect given the brand reputation...
Turns out it isn't: the output frequency response is simply not consistent depending on the input.
More precisely:
-when plugging an active device (like a buffer or a bass on-board preamp) it produces a resonant peak in the infrabass the frequency and amplitude of which depends on (the quality of) the active device. With my Glockenklang 3 bands 4 poti this is +11dB@55Hz..., +8dB@35Hz with an old Artec SE2... etc... That is precisely why I wanted a good DI suitable for active devices (as advertised!): to get a consistent response whatever an unknown device
-when plugging a passive instrument, it filters the bass depending on the output resistor configuration. If no series resistor or volume at max it is ok almost flat without filtering, but as soon as the volume poti is being decreased, basses and mids are filtered more and more with the volume reduction. And this is rather drastic for -4dB@1kHz (that would be overall level in a normal device) you get -11.5dB@100Hz for instance...

I have already seen these behaviours on cheap devices but not even as pronounced! The Mackie MDP-1P in comparison reproduces perfecly the frequency response whatever the situation, but it is a bit more bulky to handle... I was looking for a smaller equivalent to be able to keep it to the belt for example...

On the other side that is true that the impedance conversion ratio is the highest I have seen so far, we are getting close to a small HiZ regarding a passive pickup resonance peak, where I would argue the Mackie is just enough in comparison; but the Radial has also ~-3dB overall level compared to the Mackie.

So that would work I guess with a passive instrument if you never play with the volume, or with a well-known active device you know is good enough not to be bothered by the infrabass peak... Not suitable for the use I intended, so it goes back.