Happy New Year everyone! Had an interesting question come in from a viewer recently on one of the DI box videos and thought I’d post my response here as well:

G.M.: Hello Bruno. One question that has been on my mind lately is the difference between comparable units in Radial’s DI lineup between their Pro XX and their JXX (e.g. Pro DI vs. JDI) DIs. I believe the main difference is in the transformers with the Pro series containing Eclipse transformers and the J series including the Jensen transformers. First, would you say that is accurate? Second, are there really any other meaningful differences? and third, what really is the difference in those two transformers? I am not sure if this is something you could cover in a comment response or in another video; but, I really value your experience and opinion on these topics!! Thanks for all the great content on your channel.

GLB Productions: Hello GM, thanks for getting in touch. The first thing to understand is that there is a difference between the active and passive DIs in Radial’s lineup: for example, the J48 and Pro48 have exactly the same circuit and sound identical – the differences between them are in the feature set and also more mundane things like the size of the case and the number of colours in the graphic package.
In the case of the passive DIs, you rightly point out that the difference is in the quality of the transformers used. Radial give details about the differences on their FAQ pages e.g. here and here. Basically, the Jensen transformers are the ‘ultimate’ choice for studio use, whereas the Eclipse work fine for live use. I have found this to be true – in live sound, the frequency response of your loudspeakers is the limiting factor rather than the transformers in your DIs.

For live sound, I use the J- and Pro-series DIs interchangeably, and choose more based on the feature set needed. For example the JDI has a merge to mono feature and can also accept a speaker-level input, the ProAV series are specialist DIs with 3.5mm and RCA inputs that can solve a myriad of problems. Hope that helps!

The video that inspired the question:

Hope everyone is doing well – take care and keep sounding good!