Radial JDI issue

[Low Key]

I have owned a JDI for a couple years. Normally, it works like a champ with my Musicman Bongo & Stingray. I only perform 10 – 12 times per year and record 1 or 2 times per year.

However, I have had at least 3 or 4 instances where the sound engineer claims that the signal is weak or not there at all. In these cases, I would pull the JDI out of the chain and use the amp’s DI (which normally has adjustable gain).

Since I use active basses and these are only 200-800 person rooms/gyms/theaters, I assumed that I would have enough signal to push through a passive DI and snake to the board.

So my question is how often I should expect this to happen? Do other people have issues not producing enough signal through a passive DI with active electronics? What have you done?

FYI – I typically don’t use effects or processors before the amp since I like to be as plug-and-play as possible.

[bassman1185]

The engineer may be expecting a line-level signal from the DI. Most amp DI's are line level, and if he's getting a strong signal from that, then he may just need to crank the gain more than he thought.

[bongomania]

I disagree completely about "most amps" putting out line level on their DI out. Yes, a few do, and some (mainly older) heads have a switch to go between mic and line levels. But a DI output is generally supposed to be at mic level, since it is intended to be fed into a mic pre at the desk.

The JDI is funny that way. I have seen many threads describing the exact same problem, and I had the exact same problem myself. AFAICT the problem is that many mixing desks have inadequate gain available in their mic pre's. That's what I ran into- my own mixer's pre's have only about 23dB gain available, and depending on the bass signal and EQ etc., up to 50 or 60db may be needed. With an active bass that has a high output level it's usually not a problem- but not all active basses have particularly high output. I even owned one bass where the active setting was slightly lower output than the passive setting.

I love the sound of the JDI, but if I were gigging in gyms, theaters, and other random venues with questionable PA mixers, I would pack a "preamp" type DI that can actually boost your gain some to compensate for the weak pre in the desk.

[Low Key]

I love the sound of the JDI, but if I were gigging in gyms, theaters, and other random venues with questionable PA mixers, I would pack a "preamp" type DI that can actually boost your gain some to compensate for the weak pre in the desk.

Would an active DI, like a Countryman, put out materially more gain in these cases? I realize this isn't a preamp, but I also know it isn't passive.

BTW - I also have a Demeter Compulator that perhaps can boost the signal. I just wasn't sure how much noise it would add if using to boost.

[bongomania]

The Compulator is relatively quiet for a 9-v pedal boost. I would say go ahead and try that. I don't think the Countryman is intended to add much gain, but I haven't used it to say for sure.

[Munjibunga]

Clean the jacks in your DI with Deoxit. I use a .22 gun cleaning brush for this purpose.

[Mark Reccord]

Originally Posted by bongomania

I disagree completely about "most amps" putting out line level on their DI out. Yes, a few do, and some (mainly older) heads have a switch to go between mic and line levels. But a DI output is generally supposed to be at mic level, since it is intended to be fed into a mic pre at the desk.

The JDI is funny that way. I have seen many threads describing the exact same problem, and I had the exact same problem myself. AFAICT the problem is that many mixing desks have inadequate gain available in their mic pre's. That's what I ran into- my own mixer's pre's have only about 23dB gain available, and depending on the bass signal and EQ etc., up to 50 or 60db may be needed. With an active bass that has a high output level it's usually not a problem- but not all active basses have particularly high output. I even owned one bass where the active setting was slightly lower output than the passive setting.

I love the sound of the JDI, but if I were gigging in gyms, theaters, and other random venues with questionable PA mixers, I would pack a "preamp" type DI that can actually boost your gain some to compensate for the weak pre in the desk.

In order to present a relatively high input impedance, the JDI uses a 12:1 transformer, so the output signal is 12x smaller than the input voltage. That's about -22dB from input to output. It's an inherent issue with passive DIs, though it only creates a problem with very low output instruments or with consoles not having enough input gain.

The Countryman is 12dB better at -10dB from input to output. Some other active boxes do 1:1 input to output ratio. I can't remember if the Radial J48 does or not.

[Low Key]

Originally Posted by Mark Reccord

In order to present a relatively high input impedance, the JDI uses a 12:1 transformer, so the output signal is 12x smaller than the input voltage. That's about -22dB from input to output. It's an inherent issue with passive DIs, though it only creates a problem with very low output instruments or with consoles not having enough input gain.

The Countryman is 12dB better at -10dB from input to output. Some other active boxes do 1:1 input to output ratio. I can't remember if the Radial J48 does or not.

I didn't realize that about the signal drop. That's interesting. I was also thinking about running the DI through the bass amp's effects loop (GK), but - based on some forum searches - that might be too hot of a signal for the board.

[Juniorkimbrough]

I had the same experience with a brand new JDI I owned....I ended up just selling it and using my DI on my RBI.

[bongomania]

Originally Posted by Mark Reccord

In order to present a relatively high input impedance, the JDI uses a 12:1 transformer, so the output signal is 12x smaller than the input voltage. That's about -22dB from input to output.

*smacks forehead* That makes perfect sense, thanks.

[KJung]

Originally Posted by bongomania

*smacks forehead* That makes perfect sense, thanks.

I think the JDI is designed with pro mixing consoles in mind. I haven't used mine that often, and tend to only take it out when I'm in a rare situation of having top of the line front of house (large corporate convention gigs, etc.) With my relatively high output active Sadowsky basses, the sound people have been thrilled with the send from the JDI.

[Nick Kay]

+1 to the high I:O ratio. They're designed with high-gain mic preamps in mind. If you've got less than 40db of gain on tap for your pres, I'd go with a Countryman or something else with less attenuation.

[Low Key]

Thanks for all the information. I'm glad I finally understand the factors here. I will keep the Radial and maybe get a second, active DI to use when the board has the weak preamps.

[TimmyP]

I've never had a problem, even when using crappy mixers. Sounds to me like the Pad was engaged on the DI. (Or there was a bad solder joint in the unit - I encountered this once in a Radial and once in a Whirlwind.)

[Low Key]

I emailed Radial and they are willing to take a look at it. Very responsive to my questions. I just played through the same venue last weekend and this time I didn't have a problem. I believe it was the same board. It is possible that it is bad cabeling or perhaps something glichy on the box itself. I no longer think this has to do with not enough gain, but something cutting in and out. I hope it was cabeling and not the box.

I did check the pad each time and I don't have that engaged. Good to check, though.

I do love when this does work. What great tone this puts through the house!

[TimmyP]

I remove the buttons so that a pen or key is required to activate the switches (except for the ground lift).

[Jazzdogg]

They could have had a pad switch engaged on the FOH console - problems don't always emanate from the stage