DIY passive direct box

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wannabecomedeat

New member
hey,

I opened a passive DI this weekend. This unit is REALLY basic, 2 phone jacks, 1 xlr plug, one switch one thing I don't know

If someone could tell me what is this item, or refer me a basic schematic, It will cost much less than buy one, and I will be able to reamp

thnx!
 
that is called a transformer. there aren't really any schematics because its really basic like you said. generally its cheaper to just buy the box because the manufacturer gets volume discounts.
 
wannabecomedeat said:
It will cost much less than buy one, and I will be able to reamp

thnx!
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I wouldn't bet on it, like FALKEN said. Building a DI is like many other DIY projects, you shouldn't really be doing it to save money. Radial and Whirlwind both make very good passive DI boxes for under $100. Any DI as good as those that you build as a one-off is gonna be almost that much in parts alone, without your labor cost.
 
The quality of the DI is the quality of the transformer. As you've observed, there's nothing else in there. And good transformers are expensive. So, yes, you could build it yourself, but if you put in a good transformer, you probably won't save any money. In fact, you'll probably pay more.

A Jensen transformer for a direct box costs about $73 (qty:1). A comparable Lundahl is $58. A Cinemag runs about $46. Take your pick.
 
Gilliland said:
The quality of the DI is the quality of the transformer. As you've observed, there's nothing else in there. And good transformers are expensive. So, yes, you could build it yourself, but if you put in a good transformer, you probably won't save any money. In fact, you'll probably pay more.

A Jensen transformer for a direct box costs about $73 (qty:1). A comparable Lundahl is $58. A Cinemag runs about $46. Take your pick.
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Aceept even the $100 Passive DI Boxes still only use a $10 transformer...You will be hard pressed to find a DI box with a Jensen Transformer in it, Or even a Sowter which are cheaper than most of the Big name Transformers (But still good transformers).....

Most Passive DI"s will use a Cheaper audio grade Transformer ,Unless you go for a High end one.....

Cheers
 
uhh I haven't looked inside but I'm pretty sure the $50 whirlwind uses a jensen. no?
 
The Radial JDI with a Jensen transformer is $153 at Full Compass' website. I suspect that if you called, you could get a better price as well. It's a great passive DI box. Actually, you can find GT Dittos on E-Bay for @$150, which is a real bargain if you want a tube active DI.
 
Hum I still think I could save some good money with a 2minutes soldering. I don't really need balanced output, so I don't need the xlr out nor the switch, I then just have to buy 2 phone jacks, which is about 2 dollars. that leaves a big margin for the transformer.

Add to this that a friend of mine works in electronics and can get me parts way cheap. Last week he got me a capacitor for 0,08$ CAN rather then the 1,25$-2,50$US you would pay for one via internet.

I should maibe have said that earlier!
 
wannabecomedeat said:
Hum I still think I could save some good money with a 2minutes soldering. I don't really need balanced output, so I don't need the xlr out nor the switch, I then just have to buy 2 phone jacks, which is about 2 dollars. that leaves a big margin for the transformer.

Add to this that a friend of mine works in electronics and can get me parts way cheap. Last week he got me a capacitor for 0,08$ CAN rather then the 1,25$-2,50$US you would pay for one via internet.

I should maibe have said that earlier!
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I would still use the XLR out. For one thing, it will allow for ground lift if you need it. And an XLR won't be much more expensive than a 1/4" jack.

I guess my point is that yes, you can build a cheap DI with a $5-$10 transformer. But in my way of thinking, if I'm going to build one, I'm going to use a good transformer, because why spend time building something that has lower performance.
 
timboZ said:
Just opened one of my IMP2's and the transtromer is marked with TRHL, Is that a manufacturer ?
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That is a Whirlwind trafo, made by ??? maybe them. TRansformer High to Low, TRHL. They make one with a metal shielding can, TRHLM.
 
so is it just me, or does it seem like it wouldn't take much effort to mod a shitty DI?

if so, i'm going to get a cheap ART DI off of ebay for $20, and throw a higher-end transformer into it
 
Ironklad Audio said:
so is it just me, or does it seem like it wouldn't take much effort to mod a shitty DI?

if so, i'm going to get a cheap ART DI off of ebay for $20, and throw a higher-end transformer into it
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Why get a cheep DI to mod. Just get a 1/4 and an XLR jack and put the transformer between them.
 
wannabecomedeat said:
Hum I still think I could save some good money with a 2minutes soldering. I don't really need balanced output, so I don't need the xlr out nor the switch, I then just have to buy 2 phone jacks, which is about 2 dollars. that leaves a big margin for the transformer.

Add to this that a friend of mine works in electronics and can get me parts way cheap. Last week he got me a capacitor for 0,08$ CAN rather then the 1,25$-2,50$US you would pay for one via internet.

I should maibe have said that earlier!
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Umm..A DI that isn"t ballanced isn"t a DI or at least not a very good one....

One of the Main Uses of a DI is so you can run super long Cables without fear of degradeing the Signal ,That can not be done with a Unballanced DI....
If you just need the DI for Impedance Matching then Unballanced is OK but if you are going to use it to run Long cables then unballanced won"t work.....

Also Ballanced with Guitar sounds SO much better and cleaner than Unballanced.....

Also the best Places to get Electronic Parts for cheap is on line....08c for a Cap might be a Good deal or it might not depending on the Value and Type of Cap it is.....If you paid .08c for say a 10uf Electro or a 0.1uF Ceramic then that isn"t really a very good deal considering I can get 100 good quality 0.1uF Metal films for $3 or Nichicon 1000uF 50v Caps for .11c each on e-bay....E-bay is actually an awesome place to get very inexpensive electronics Parts that are of Fair quality, I have probably saved over $1000 just this year alone with all the electronics Parts I have bought.....


Cheers
 
I have a delta 1010lt sound card, with no balanced output, and I am going to use the direct box as a reamp device, so balanced is useless for me, I already have a balanced active DI to record the guitar +I won'T run through long cables.

The capacitor was .047, and I didn't need 100, just one, :D
your special pack discount doesn't apply
 
Why get a cheep DI to mod. Just get a 1/4 and an XLR jack and put the transformer between them.
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because i'd still rather have something in a decent housing, and with a ground lift and blah blah blah...i'd rather pay $20 + the cost of a transformer and have something decent, rather than spend all the time putting together some little junk box
 
i don't know how you guys work but if I am re-amping something I like to have the amp in another room, to be able to hear it on the monitors exactly how it will sound in the mix. the mic level side of the box is usually balanced and the instrument side is usually unbalanced, i thought.
 
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