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Difference Between DI's

Gearhead17

Gearhead17

Supporting Member
May 4, 2006
5,286
3,629
Mount Prospect, IL
www.afterforeverband.com
#1
Radial JDI
Radial PRO DI
The DI on the back of my Carvin BX1200
The DI on the back of NEARLY ANY BASS HEAD….

What is the difference in tone? In a live setting, can the audience actually hear it? Will the sound guy even notice? I have seen threads about this before, but I have not seen an actual answer to it. The threads generally turn into – “I use this and love it”. Not very technical at all. The other problem being that the majority of bass players (including me) have not had a chance to hear their rig with several different DI’s.

My Radial JDI bit the dust recently and I am currently using the Radial PRO DI. I know about the Jensen transformer, but all I know about it is what Radial tells me. I need to get the facts straight here. From looking at the specs below, there is not a lot of difference.

Any help is appreciated and if these questions were answered best in a previous thread, please let me know and we can close this one down. I have no problem with that. :bassist:

Radial JDI
Dynamic range: 135dB
Signal to noise: 119dB
Maximum input level: +19dB
Frequency range: 10Hz~40kHz
Linearity 20~20kHz: 0.1dB
Phase coherence: 4º at 20Hz
0º at 1kHz
Distortion at 20Hz: 0.006%
CMR rejection 100dB @60Hz
Input impedance: 10kW
Output impedance: 600W
Construction: Welded steel
Finish: Baked enamel
Input connectors: Two 1/4” phone
Output connectors: XLR male

Radial PRO DI

Audio circuit type: Passive, transformer based
Number of channels: Single channel (mono)
Frequency response: 20Hz ~ 18.5KHz (± 0.2dB)
Dynamic range: 128dB
Maximum input: +18dB @ 20Hz
Total harmonic distortion: 0.01% from 20Hz~20kHz @-10dB
Phase deviation: 1° @ 100Hz; 8° @ 20Hz
Input impedance: 140k Ohms, unbalanced
Output impedance: 150 Ohms, balanced
Transformer: Radial RT-DBI, 12:1 ratio
 
#2
the transformers that they use is the major difference here. in the PRO DI is using radial's OEM or generic transformers that they use in their products, where the JDI uses Jensen branded Isolation transformer which is very superior, and the Jensen brand is well known for its build quality.

tone wise im not sure of what if it will be a notable difference of tone, but definitely its effectiveness. also passive verses active will effect the tone, active will brighten up the overall tone.
 
#3
Big_Daws said:
the transformers that they use is the major difference here. in the PRO DI is using radial's OEM or generic transformers that they use in their products, where the JDI uses Jensen branded Isolation transformer which is very superior, and the Jensen brand is well known for its build quality.

tone wise im not sure of what if it will be a notable difference of tone, but definitely its effectiveness. also passive verses active will effect the tone, active will brighten up the overall tone.
Click to expand...

The Jensen will also get you cleaner and quieter over a longer distance if needed, and it also really does superior RF rejection. I use them all the time in pro install work and they are the way to go if you can afford them. I use a Jensen in my own home-built passive DI and never get a hum or a buzz.

Ah yes, the differences. Most bass amps have what is known as an electronically balanced output. This offers no RF rejection and makes you more susceptible to having a hum you can't get rid of at a given gig. Some bass amp DI outs are not more than a pass-through from the input with no available ground lift on it. With a real DI, whether it is a budget beater or a class act like a JDI, you at least get the benefit of transformer isolation between your rig and the front of house. Most live sound men really want to take a bass before the amp, as in straight from your guitar/wireless/pedalboard and avoid having to deal with any unpleasantness your amp may add to the sound of the instrument. I've never like the sound of a bass amp's DI when I can use a JDI or a Sans Amp, or a Whirlwiind or a Countryman, or a ProCo, or a Rapco, or God forbid a B-word. Anything with a transformer is a better shot than using an amp's DI.
 
#5
Hi.

+1 for Jensen transformers being superior by default compared with "house-brand" ones.
The same goes for Lars Lundahl and other "big names" in audio transformers.

A transformer coupled connection doesn't automatically guarantee bliss though, it's very easy, not to mention cheap, to use a regular CT mains transformer to acchieve a balanced out. There was a small thread about it in TB some years ago.

Also +1 for the "servo balanced", or what ever marketing term a manufacturer chooses to call an electronically balanced signal, being an inferior way to do a DI, mainly because of the lack of galvanic isolation.

However, during my days on the console (FOH) I didn't find much difference in the tone of the signal source using DI's of various designs and quality, what ever that signal source may have been, but the noise and hum was everpresent in the lower end of the spectrum devices.
Whether that is of any concern, THAT depends entirely on the situation.

In a studio environment the situation is obviously very different, and there the differences are easier to notice.

Regards
Sam
 

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