Why is a Jensen transformer so important?

[taylor16]

I use my 3Leaf Enabler post-effects as an EQ/pre-amp/DI and really haven't found it to "lack" anything. I have been entertaining the idea of a standalone Radial DI (JDI vs J48) to simple things up if need be.

I keep reading about how a Jensen transformer is some sort of magical component with regards to DI quality. Just wondering what's so great about it and how is it different than other transformers (I'm assuming all DIs have one- I'm not even sure what's in the 3Leaf Enabler).

 

[Geri O]

I was thinking that someone else would come up with a more detailed, more eloquent explanation that I can...

The short and non-technical answer is that it's because of the Jensen's materials and construction. It makes for a "warmer" sound, as well as supposedly being better at handling low bass frequencies than less expensive transformers.

We've all used the Rapco/Livewire/even Radial's Pro series DI with good results. I personally don't know if I could hear a difference in the Jensens and the rest. I just know all the good recording guys I worked with early on were insistent on using DIs with Jensen (or Lundahl, which are highly regarded transformers as well, just not very well known) transformers. One recording truck I worked with had built their own Jensen-equipped DIs. Had about 50 of them. Not sure what they were planning on with that many, but they were certainly equipped for whatever it was! So for me, the Radial is a known factor. Whether or not one wants to make that kind of investment in DIs is a personal decision. THere's not really a right or wrong answer. It's all a means to an end.

I may not be able to hear the difference in a Radial and a Rapco, but I can certainly hear the difference in REDDI tube DI and anything else (and for $700, I would hope so).

I Just looked at the Enabler and that's a pretty sweet looking little box if you are looking for that much processing in your DI (I'm not, but I still like the looks of it). Unless you are having problems with yours, or some golden-eared person you trust thinks otherwise of it, or unless you are looking for a straight DI, no processing situation, I see no need for you to switch from the Enabler.

BTW, the output of the Enabler is most likely electronically balanced, which has its own set of pros and cons, nothing really major or earth-shattering to most people (me included). That's a wild guess, I'm not really sure. It's also a major bummer that it's been discontinued. I was thinking of getting one to play with.

 

[BurningSkies]

Not all transformers are created equal, and much is in the details. There are other great transformer people who will custom wind stuff as well... This is long but probably a great place to start to understanding how the transformer is important in a DI. Seriously, read the whole thing:

Link Removed

 

[seamonkey]

Transformers limit bandwidth as they approach saturation.
As far as I can figure, IMHO, "Warmth" is defined as 1. cut the highs, and 2. add some distortion. That's what a transformer does as it approaches saturation.

This is for an output transformer, but transformers do this in general

The louder you get the more lows and highs are cut.
When you hit tranformer saturation it's good old hard clipping. Saturation means the core can't let any more signal through.

This is how humans on the bell curve hear

When music is quieter, you need more bass and highs for it to sound even.
At louder volumes you need less lows and highs for it to sound even.

So the band limiting effect of transformers fits into how we hear. It cuts the lows and high as the signal gets stronger.

Different transformers, different cores, different windings, behave differently. Some become more "familiar" and thus more popular.

Active DI's use feedback to get around the bandwidth limitations. Much better to actually actively control the bandwidth than rely on trying to hit some passive target perfectly. With active you can get the effect at lower signal levels if you want, or delay it until much higher signal levels.

Still nothing that a little EQ, active or passive, couldn't do in itself. With EQ you can even make the curve more extreme if you want.

Active DI's tube or Solid-State are all about keeping the signal accurate. One's that claim to add "warmth" are taking advantage of the transformer limiting bandwidth. And they are probably adding extra distortion through the active circuit.

 

[N. Kentucky Bass]

Jensen transformers are great. Cinemag also makes excellent transformers. I've used both -- Jensen in my Reiner Studio 1200 amp, and in my Radial JDI and Radial JDV Super Direct Box. And the Cinemag in two REDDIs I owned, a Sonic Farm 2di4 I owned, and a Monique I owned. All wonderful quality. There's a lot of great gear out there. Don't get too hung up on a particular brand.

 

[dheafey]

Here's a pretty good video explaining the Radial JDI and Jensen transformer. Granted, it's from Radial Engineering, but I think it does a good job:



I've been A/B'ing a JDI I just picked up and a $30 Whirlwind IMP 2. This is probably not a fair comparison, but it's all I have on hand. From a sonic perspective, my active MusicMan Bongo 5HH sounds fatter, warmer, and tighter using the JDI. (I've read you want a passive DI with an active instrument and an active DI with a passive instrument.) Another plus is the Polarity Reverse switch which cleaned up some noise problems I was having.

I'm sure I'd never hear the difference between the JDI and a ProDI, but now that I know I have the JDI and a Jensen transformer, I just feel better. That comfort factor was worth it to me.

 

[fokof]

Lundahl trannies are also very good

 

[seamonkey]

For those who may want to build their own passive transformer DI
How to Build a Boutique Passive DI – DIYRE
He seems to mention several brands of transformers.

The Whirlwinds are a very good value, they even make one with a Jensen branded transformer.

If you ever open up a dynamic mic like a SM58 you'll see the mic itself has a transformer in it. A built in DI essentially.
[Invalid or Expired Link Removed]
Old mics could be another source of transformers to experiment with.

 

[taylor16]

Bumping an older thread of mine however I'm curious to know if two different DI boxes from two different companies (hypothetically, of course) both use the same Jensen or xxx transformer, would they necessarily sound the same assuming they were passive?

 

[s0c9]

Bumping an older thread of mine however I'm curious to know if two different DI boxes from two different companies (hypothetically, of course) both use the same Jensen or xxx transformer, would they necessarily sound the same assuming they were passive?

possibly, but not necessarily.. depends on what other pieces-parts are included..

 

[frnjplayer]

A passive DI is usually just a transformer connected directly to all the jacks on the box. Various transformers do have different sounds ans saturation levels as a number of people have explained. It is actually a case of bigger is better with transformers S the amount of metal in the transformer affects the level and frequency ranges that saturation occurs at. As others have mentioned names like cinemag, Jensen, and Lundahl all make transformers that are known and respected in the audio world. Radials lower cost Pro series use a beefy transformer that isn't a Jensen but still sounds decent. As you get into lower cost passive DI's you'll notice them getting much lighter. They tend to put smaller transformers in as the iron and copper cost money.

Once you are into active DI's it's a whole different world. Most have no transformers as they let op amps do the circuit balancing.

 

[seamonkey]

It's popular to talk of transformer saturation as some special magic added to the sound, it's not. It's horrible sounding. It's the rest of the circuit supplying the subtle distortion

 

[walterw]

It's popular to talk of transformer saturation as some special magic added to the sound, it's not. It's horrible sounding.

wow, i really thought transformer saturation was "softer and squishier" than that.

either way, tranny saturation is something that guitar players with small tube amps like, i can't see it as any kind of good thing for full-range instruments like bass or keys.

jensen transformers are just good, beefy transformers, which therefore won't saturate like light, cheap trannys, keeping the headroom and bandwidth.

 

[lokikallas]

I've met Bill from Jensen many times at trade shows and the fact is, there is no BS sales or marketing. It just works.

 

[LUpton]

You can thank the genius of the late Deane Jensen for many of their transformer designs, as well as the design of the 990 large-format opamp, which is the basis of one of the most highly respected mic preamps ever.

 

[Ulf_Hansson]

I might understand why an engineer/producer might want to spend considerable time, effort and cash on the signal chain e.g. for the vox. But, while I care about my instrument and my sound, I really have a hard time understanding where all this "bass magic" is supposed to go in a live setting. I sure couldn't hear any difference FoH..

 

[Geri O]

I might understand why an engineer/producer might want to spend considerable time, effort and cash on the signal chain e.g. for the vox. But, while I care about my instrument and my sound, I really have a hard time understanding where all this "bass magic" is supposed to go in a live setting. I sure couldn't hear any difference FoH..

Part of the reasoning behind the "magic" is "First, do no harm"...

 

[jsbarber]

I seem to recall, perhaps incorrectly, that the transformer on the DI output also protects the circuit from unwanted dc from the recipient device. (I.e. Accidental activation of phantom power on mic preamp) is this correct, or did I imagine this?

 

[walterw]

I seem to recall, perhaps incorrectly, that the transformer on the DI output also protects the circuit from unwanted dc from the recipient device.

yep. transformers won't pass DC.

transformers are essentially two coils right next to each other, and the coil on one side is not physically connected to the coil on the other side; the AC signal induces a moving magnetic field in the one coil that hits the other coil and causes it to produce AC electricity again, but direct current is simply blocked.

 

[seamonkey]

If it's miswired that dc is going add flux saturation on the transformer. DC can be isolated with a couple of caps