DI Boxes: Jensen "JT-DB-E" equivalent?

[danjpiscina]

I second the recommendation of building a tubed preamp stage. An alternative to buffering and sending at line level might be to connect the preamp output to the input of a DI transformer. Okay, yes, you're now spending even more money. But you'll get a really good-sounding DI. Try the tone stack from a Fender Deluxe AB63 -- it does wonders on a bass guitar.

yes. good point. i was thinking about this guy:
http://www.adesignsaudio.com/reddi.html

A UTC A-10 configured as a DI exhibits less than .001% total harmonic distortion over most of the audio range.  Musicality does not imply distortion.

really, musicality almost always implies harmonic distortion. it may be subtle, but when something sounds musical, my bet is that 95% it's distorted. that's just me.

 

[flaheu]

Personnaly, I've built 2 BO hansen's DI, the first with the recommended Lundhal and the other with an OEP 6.50:1.
To my ears the one that sounded best was the one with the OEP, it's got a nice low-mid thickness, not hyper clean of course, but really useable.
I don't like it to be too "clinical" cold sounding, but it must "enough" be clean if you'd like to reamp.

 

[danjpiscina]

Personnaly, I've built 2 BO hansen's DI, the first with the recommended Lundhal and the other with an OEP 6.50:1.
To my ears the one that sounded best was the one with the OEP, it's got a nice low-mid thickness, not hyper clean of course, but really useable.
I don't like it to be too "clinical" cold sounding, but it must "enough" be clean if you'd like to reamp.

Oh cool. Which are the 6.50:1 transformers? I actually just got a Tech 21 Bass Driver/DI, and I've been quite happy with it. It's very flexible. But I'd still like a few more DI boxes, and a reamp box too.

 

[CJ]

the cheap ol banjo center ProCo box used to have a lil jensen  xfmr in there, passive DI, but it did the job nicely for bass.

even into a crappy 1604 i was getting semi good......nah, it was crap.  ;D

 

[flaheu]

danjpiscina,

Sorry, it's not 1:6.50 but 1:6.45, I don't remember the OEP part N°, but this model is very popular here as a mic input TX.
For reamping, search around here you will find a schematic from New York Dave, I've built it with an edcor TX and it works very good.

Cheers 

 

[shabtek]

"
Quote from: gridcurrent on August 31, 2009, 09:53:34 am

A UTC A-10 configured as a DI exhibits less than .001% total harmonic distortion over most of the audio range.  Musicality does not imply distortion.

really, musicality almost always implies harmonic distortion. it may be subtle, but when something sounds musical, my bet is that 95% it's distorted. that's just me."

not only THD:
could be various frequency response anomalies, phase shifts, hi-pass, LC interactions inside transformer and with pickups, not just THD, Could be THC%,

The Dan played Green Earings last night,'twas stellar

 

[danjpiscina]

not only THD:
could be various frequency response anomalies, phase shifts, hi-pass, LC interactions inside transformer and with pickups, not just THD, Could be THC%,

Good point. I did not mean to imply solely THD. Doesn't all that other stuff still fall under the distortion category?

 

[shabtek]

distortion= signal out that differs from what went in-- fundamenal, harmonic, frequency, phase, social, temporal...

 

[CJ]

i can make an A 10 get real ugly, just a few db of 4 hz and away goes the 001.

does anybody remeber the Richard Chycki tube di?

http://www.google.com/url?q=http://www.twin-x.com/groupdiy/albums/userpics/Buffered_Tube_DI_r.pdf&sa=U&ei=aGqfSseTGZngsAPbg6i9Dg&ct=res&cd=1&sig2=bIFnXmWDGwsz-F6Cr1JbJQ&usg=AFQjCNFpuZjIGZOXWPBkPOCrdPqKT19gSw

 

[danjpiscina]

i can make an A 10 get real ugly, just a few db of 4 hz and away goes the 001.

does anybody remeber the Richard Chycki tube di?

http://www.google.com/url?q=http://www.twin-x.com/groupdiy/albums/userpics/Buffered_Tube_DI_r.pdf&sa=U&ei=aGqfSseTGZngsAPbg6i9Dg&ct=res&cd=1&sig2=bIFnXmWDGwsz-F6Cr1JbJQ&usg=AFQjCNFpuZjIGZOXWPBkPOCrdPqKT19gSw

Thanks for this CJ. I had no clue about the tube DI. Awesome! So how do you go about adding 4 Hz to an A 10?

 

[porkyc]

Everybody pfaffs around with transformers, but the best DI box we used in London was the BSS one with the phantom power option. Sorry, blows the transformer ones away.
PC

 

[PRR]

> connect the preamp output to the input of a DI transformer

Generally, tube stages overload at 50V and DI iron at 1V. It's hard to get tube-strain before the iron goes limp. It's a sound, and can be musical.

And money....

> I second the recommendation of building a tubed preamp stage. ... a really good-sounding DI. Try the tone stack from a Fender Deluxe AB63 -- it does wonders on a bass guitar.

I bet you typed AB763. An old reliable workhorse that made a lot of music.

Instead of costly fancy line or DI iron, try the Fender Reverb transformer. The stock reverb channel is short-bass, mostly due to the teeny 500pFd coupling-cap. Fatten that, run the 12AT7 fatter, you should get some bass.

The plan below has gain of about 125, so a 20mV source can put out Line Level. For not-dirty sound, keep the Volume below 10 (you know what to do for dirt). The output stage will clip near 2V, so you can slam it brutally with little fear for your line inputs. The two mike outs clip near 200mV and 20mV, so you can pick how much strain your mike-iron gets.

 

[noulou]

Everybody pfaffs around with transformers, but the best DI box we used in London was the BSS one with the phantom power option. Sorry, blows the transformer ones away.
PC

If you mean the ar-133 which does sound very nice, last time I opened one up there was a transformer in there.

 

[porkyc]

The first and last time I opened the ones we had (BSS that is) was to put the phantom option in!!
But I and others may be missing the point of the /diy/ aspect of all of this. It's very easy to zoom off and say "Buy this, buy that", but the original question was about using the Jensen DI transformers and were they any good.

If you have access to some at a sensible price then you will get a perfectly usable, reliable DI box, one that for a DIY project will do exactly what you want it to. Put it in a die-cast box, not a plastic one, ground the box via the XLR back to the system, put the ground lift switch in, and it'll work a treat.
Is it the best sounding one? No it's not, but for a DIY project that is relatively easy, you get a good return on the time spent, and at that point it's worthwhile; and it's a lot better than no DI at all!
PC

 

[guy_4]

Hi,

I have built tens and tens of DI boxes with Jensen JT-DB-E.

Only great comments, everybody loved them.   

Guy

 

[abbey road d enfer]

I've done several A/B tests between passive and active DI's. Without any exception, when the instrument is passive, the xfmr DI sucks the highs and lows, even with expensive esoteric xfmr's (Jensen, Sowter, Haufe, LL, Melodium...)

 

[danjpiscina]

that's interesting. i tend to prefer the low end on active di's as well. the "REDDI" was exceptional. (http://www.adesignsaudio.com/reddi.html                i like having passive boxes for tube mic pres though.

 

[abbey road d enfer]

I don't get you...What do you mean " i like having passive boxes for tube mic pres though." ?

 

[danjpiscina]

I don't get you...What do you mean " i like having passive boxes for tube mic pres though." ?

bass-->passive direct box-->tube mic pre. the low end on a good tube mic pre is always fun! i love what the ampex 601 does.

 

[clintrubber]

Can imagine that some are fully happy with passive DI's on bass while others can't live with it.
Since at least we need to specify what kind of bass it's about. Like for most sources the differences can be pretty big.

In case of bass (let's for convenience assume electric bass), do we have (#1) some blues bass player who still has the first set of strings on the Fender he bought in 1969 ? Or (#2) some hyper-active guy that likes to swap strings after each two takes and if he was allowed to would actually prefer to re-fresh-cone the full-on tweeters in his bass-cab after ten takes as well ?


While I don't qualify as either of these two extremes, personally I'm not too happy with passive DI directly after bass either.

That's pretty irrelevant actually, since it's just another preference, but passives certainly take away transients etc. While that may not matter at all for #1, it certainly will change the sound for #2.

Cheers,

 Peter