n00b build : DI Box

[Joe_caithness]

hey geeks. (this has been crossposted on GS too)

I just enrolled on an audio electronics based course to complete a currently year under degree here in the UK.

We have a task over the year we study to do a major project, with the design, research, testing etc elements.

I am thinking one thing I'd like to do is build a DI, but something with character.

So this is my very first initial braintstorming session, and I'm wondering if anyone would be interested in linking me to useful information?

One of the reasons I'd like to try a DI box, is because I want something I can take round to all the local studios and get them to try out in their rooms, my background is mastering, but I do some tracking occasionally on the side.

Perhaps something to take the edge of brittle sounding acoustic guitar DIs, but also to add some mojo to bass guitars and monosynths, does such a thing exist within the grasps of a first time builder?

thanks for you time.

 

[pucho812]

yes it is totally possible. DI boes come in many flavors and they range from simple to complex. MY first di box was just a transformer wired into proper connectors. I did not put a ground lift, or pad or anything of the sort. Just a box with connectors and a transformer. Still my fave one. If you want my 2 cents, Build/design a tube di that allows you to overdrive the tube to give some character.

 

[Joe_caithness]

yes it is totally possible. DI boes come in many flavors and they range from simple to complex. MY first di box was just a transformer wired into proper connectors. I did not put a ground lift, or pad or anything of the sort. Just a box with connectors and a transformer. Still my fave one. If you want my 2 cents, Build/design a tube di that allows you to overdrive the tube to give some character.

Thanks a lot, sound advice.

Is it possible to build DIs for around 100 GBP or less? I'm not factoring in prototypes and things going wrong here, I'm trying to find a budget/market context to aim the unit at for when I do tests in the real world.

 

[chrispbass]

yes it is totally possible. DI boes come in many flavors and they range from simple to complex. MY first di box was just a transformer wired into proper connectors. I did not put a ground lift, or pad or anything of the sort. Just a box with connectors and a transformer. Still my fave one. If you want my 2 cents, Build/design a tube di that allows you to overdrive the tube to give some character.

Thanks a lot, sound advice.

Is it possible to build DIs for around 100 GBP or less? I'm not factoring in prototypes and things going wrong here, I'm trying to find a budget/market context to aim the unit at for when I do tests in the real world.

Definately, but a tube di will eat alot more money as you'll need to build a high voltage mains power supply, whereas a transisitor/ic design will run off pp3 batteries or phantom power.  Generally, most of the money from a component point of view goes on the audio transformer unless you're using i.c's, but you did say you're looking for mojo!  Good audio transformers such as lundahl, sowter, jensen are not cheap, but there are alternatives such as oep. Anything is possible if you're prepared to shop around and hunt for 2nd hand parts/recycle etc. Might be worth checking out the BO Hansen Di thread in the 'drawing board' for some discrete inspired design.
good luck

 

[Joe_caithness]

totally not against getting old stuff, second hand etc, essentially if I can criticise and compare its all playing into my hands as this is a project after all, not a prototype for a commercial project, but it might lead to something along those lines.

 

[Joe_caithness]

Bit of an idea I had just now, wondered if anyone had tried this?

A block of 3 very simple DIs all with different transformers, so maybe some wacky old vintage ones pulled out of other gear and then a good Cinemag / Jensen to benchmark against? Two different "vibes" and one "control" essentially.

 

[pyjaman]

A good start could be Bo hansen's DI . The design is simple but many transistors combinations could be tried, (perhaps even germanium ones with some tweaks) and more interestingly, many different mic input transformers (pluged backward) can be tested.
Laurent.

 

[okgb]

Check the Jensen app notes , and see what xfmr is available to you cheap or easy ,
but price & performance the Bo , is good .
Start somewhere and then you'll know which direction to go after

 

[shabtek]

When I was in a recording school program some classes built DI boxes wiring up a backwards transformer in a metal box... that is what got me interested in building gear... The instructor claimed a really nice bass DI can be made with a Dynaco output transformer--the A470 or similar part number.