Which Radial DI?

[jeffbonny]

Originally Posted by steve_rolfeca

IME, you overstate the case. The JDI's input impedance is only 10K, and you don't have to be a dog to hear what that does.

My active basses sound the same through my JDI, or plugged straight into an amp. But my AV '62 sounded noticeably darker when it was plugged into the JDI. I love my JDI, but I didn't like it with the Fender.

I'm not saying that the rolloff is necessarily a bad thing, but if you can't hear it, you're either running your passive basses with the tone control rolled back, or you've got hearing trouble.

Yeah but the OP is putting a preamp in front of the DI not plugging a passive bass straight into it.

[bongomania]

Originally Posted by steve_rolfeca

IME, you overstate the case. The JDI's input impedance is only 10K, and you don't have to be a dog to hear what that does.

My active basses sound the same through my JDI, or plugged straight into an amp. But my AV '62 sounded noticeably darker when it was plugged into the JDI. I love my JDI, but I didn't like it with the Fender.

I'm not saying that the rolloff is necessarily a bad thing, but if you can't hear it, you're either running your passive basses with the tone control rolled back, or you've got hearing trouble.

+10000

JimmyM rolls off everything above 5 KHz in his rig, so it's no surprise he wouldn't hear any difference.

[JimmyM]

Originally Posted by bongomania

JimmyM rolls off everything above 5 KHz in his rig, so it's no surprise he wouldn't hear any difference.

Doesn't everybody?



I'll admit not being a fan of bright treble past 5k enters into it. But I've used a JDI and a Whirlwind Imp 2 with a passive bass and they still had way more snap than I'd ever need or want. If you want that real high treble, though, get active.

[Passinwind]

Originally Posted by steve_rolfeca

IME, you overstate the case. The JDI's input impedance is only 10K,

Hmm, what impedance mic preamp are you driving yours with Steve? The spec sheet says 140K typical, and Jensen specs the transformer at 200K:1.5K, or 12:1 voltage ratio.

[Mingus Addict]

I own a J48, and have used the Pro48 plenty. They are sonically exactly the same. The J48 simply has more switches for functions you probably will never use as a bass player. I use the J48 for live sound, and sometimes appreciate the the merge function. I would get a Pro48 if it was just for a bass rig.

The Pro48/J48 sounds very good on every type of bass I've put it on (active, passive, upright, pedalboard involved, etc). The Jensen transformer in the JDI can add subtle improvement to the sound as a result of harmonic distortion, and some high end attenuation depending on the set-up.

If you just want a clear clean DI that will always work, and don't want to spend extra money for no good reason, get the Pro48. You may benefit from the character of JDI in certain situations, and it's a quality piece worth it's asking price.

Edit:
One minor advantage of the JDI over any active is that you don't have to worry about battery's or problems with phantom power, but in 10 years I think I may have encountered one mixer that had a single channel where the phantom didn't work. That's not really a problem at all when you consider there were 35 other channels that did work. It's not a likely problem.

[Rip Topaz]

Wow, I went to sleep and this thread exploded!!

With the info here, the Pro48/J48 seems to be the way to go. I'm still confused on the differences between the two.

My main bass is an MIA P-bass (passive). When I play without an amp I use Jamup iOS (iPhone 4S running through Irig (soon to be Apogee Jam), then out of the 1/8" headphone jack into the DI.

There are times where I'll run the bass direct without the amp sims, but mostly I'll be using the iOS rig.

So it IS a passive bass, but I'm not sure if it still would be considered passive after running through the preamp on the iPhone.

And before anyone asks, yes it does sound good.

[Roscoe East]

Originally Posted by steve_rolfeca

The JDI's input impedance is only 10K, and you don't have to be a dog to hear what that does.

Unless Radial has changed something since the JDI was first introduced, its input impedance is 47kΩ.

[Mingus Addict]

Originally Posted by Rip Topaz

With the info here, the Pro48/J48 seems to be the way to go. I'm still confused on the differences between the two.

The Pro48 has the basic functions of a DI you need: Input, Thru, Balanced XLR out, and switchable pad and ground lift.

The J48 takes literally the exact same circuit and audio path and puts it in a larger enclosure with a nicer paint job and adds three more switches. Those switches are polarity reverse, low-cut, and merge. For me the merge function is the most valuable. It turns the Thru into an additional Input and passively sums the two. It's great when you're running low on channels and you have a keyboard player asking for multiple DI's, or if you want to mono sum a DJ or something to one channel.

The JDI btw, has all the same functions. Radials, lower priced equivalent to the JDI is the ProDI. These two do not compare in the same way that the J48 and Pro48 do though because the ProDI has a different transformer from the JDI and sounds different.

[bongomania]

Originally Posted by Roscoe East

Unless Radial has changed something since the JDI was first introduced, its input impedance is 47kΩ.

The website today says 140 K.

That said, the input impedance of a passive DI is dependent on the output impedance of the device you feed into it. So any quoted spec, 10K, 47K, 140K, or whatever, is not an absolute "fact" spec.

[cybersnyder]

Hmmmm.. I was thinking about getting a JDI. If I put my microthumpinator in front of it, it should matter what the input impedance is regardless of using a passive bass or an active bass. Or am I wrong on that?

[BFunk]

Right. If you are using a buffer there is no issue with passive. In my experience as a sound man, passive DI does not work well for live passive basses only if the pickup is weak. Most modern passive pickups have more than enough output to drive a passive DI like the JDI. There may be a little treble roll off, but not enough to notice in a live situation with most pop music styles. Michael Manring would probably disagree.

[Rip Topaz]

Originally Posted by BFunk

Right. If you are using a buffer there is no issue with passive. In my experience as a sound man, passive DI does not work well for live passive basses only if the pickup is weak. Most modern passive pickups have more than enough output to drive a passive DI like the JDI. There may be a little treble roll off, but not enough to notice in a live situation with most pop music styles. Michael Manring would probably disagree.

Tough call. My bass IS modern, but the pickups are aimed at a vintage sound. Treble roll off is fine, I always drop everything above 5k anyway. That knob could be removed from my "amp".

So active is definitely the way to go for the DI. Now to try to convince the wife to double my budget. I can't see that ending without a shoe shopping trip.

I DO think, though, that if I'm gonna spend $400 on a DI box, I'm just gonna hold out for the REDDI.

[Passinwind]

Originally Posted by bongomania

The website today says 140 K.

That said, the input impedance of a passive DI is dependent on the output impedance of the device you feed into it. So any quoted spec, 10K, 47K, 140K, or whatever, is not an absolute "fact" spec.

You've got that transposed slightly. It's the input impedance of the mixer/mic preamp that reflects through the DI transformer back to the DI's input, as the square of the windings ratio in the case of an ideal transformer. Mic preamps can commonly vary from 150 ohms or so to a few Kohms. Radial most likely went from assuming a 600 ohm mic input to assuming ~1.3K, which is a very common figure these days on live sound desks.

[bongomania]

Ah OK. I knew the xfo was transferring an impedance, but (obviously) thought it was the other direction.

[Rip Topaz]

Ok, I'm so totally confused now.

[JimmyM]

Originally Posted by Rip Topaz

I DO think, though, that if I'm gonna spend $400 on a DI box, I'm just gonna hold out for the REDDI.

Wise man!

[phmike]

Radial's web page about selecting a DI
http://www.radialeng.com/r2011/selecting-dis.php

A simple rule of thumb:
If the source is active, use a passive DI box
If the source is passive, use an active DI box

BUT - I want to add a 'but' here - if you put anything between the bass and DI like a tuner or other effect pedal with a buffer then I personally would go with a passive DI. BUT - that's just my opinion. Maybe you could email Radial and ask them for a definitive answer you could go with?

Also see -
http://www.radialeng.com/r2011/di-questions.php

[SteveC]

Originally Posted by phmike

Radial's web page about selecting a DI
http://www.radialeng.com/r2011/selecting-dis.php

A simple rule of thumb:
If the source is active, use a passive DI box
If the source is passive, use an active DI box

BUT - I want to add a 'but' here - if you put anything between the bass and DI like a tuner or other effect pedal with a buffer then I personally would go with a passive DI. BUT - that's just my opinion. Maybe you could email Radial and ask them for a definitive answer you could go with?

I have been using various passive DI's (Radial JDI included) with my Geddy Lee and it has sounded great - live and in studio. I have a tuner/mute pedal so maybe that helps, but I also am not playing venues with long runs to the board/snake.

[Bassist30]

I use the J48 even with an active bass and have not encountered a problem. I do want the get a JDI also.
I do have a 12 ft cable + 15ft +about 3 ft pedal cable. 30 ft of cable I may need the J48 but I would like to get a JDI to compare.

[steve_rolfeca]

This is all really interesting. At the time I bought my JDI, Radial's website said 10K at the input. I've not gone back to the site since then.

Have they changed their specs that much over the years (10K to 47K to 140K), without mentioning it?

This is not a case of me listening with my eyes- I originally went to the website to look at the specs, because I was surprised at how dark my passive P-bass sounded through mine. The specs made sense with what I was hearing, so I've never put a meter on it to check.

No surprise that JimmyM hears things differently. When it comes to P-basses, I like roundwounds and cabs with tweeters, and back when I was using passive basses a lot, I used to disconnect the tone controls, in order to nurse a little more treble out of them.

Anyway, the JDI is a BEAUTIFUL sounding DI.

If you use a Boss tuner, or any other buffer in front of it, it will sound fabulous with your passive basses, and a lot of people seem to like the tone even without a buffer.