Do I need a DI Box ?

yes, and this is the one you need, use the haufe tranny, it sounds so good you'll laugh, there have been many who've owned some really pricey DI's, that never usem anymore after Bo Hansen showed up.

easiest build in history, sounds extra amazingly good on bass

T

heres my stereo rig

That looks sick !! Stereo DI....I never even see those around . 

So whats the price for all the parts , like $60 ? 

I have to say, I'm not obsessed with di boxes (as opposed to microphones). Most of them seem to work just fine. I tend to mic bass and keyboard amps, so when a di is used it is usually a compliment to the mic signal (and more often than not, more trouble than it is worth imo). Having said that, Emo in the UK sell an affordable passive di. Mine came with a Sowter transformer. The Radial Passive is also a good option. In the active camp, I've had good results with the Little Lab's IBP. It includes a di among it's many functions. I imagine their active di sounds similar if you don't need all the bells and whistles. 

DIY is surely a good choice, specially if you go for the passive type. If I needed a DI I would check out the different diy options.

You can plug your bass into your line in but the impedance won't be correct. If you have a passive bass, it probably expects to see 1M ohm on the other end of the cable. your line-ins will provide something like 10K-47K ohm which will possibly make the bass sound strange. The DI box just does an impedance conversion for you.

I think most of them are just fine to use. don't get wrapped around the axle thinking too hard.

Could that then go the other way? 

Would an active bass be looking for an input impedance of 1M ohm, and misbehave when plugged into a DI with a 10-47kohm input? 

In theory, yes, it's possible, however DI inputs should have high input impedances, which is what makes them different from regular line-ins.

I also have a VP312DI , with no HiZ plugins , just stock .

What about running passive and active basses into the VP312DI ??

yes thats perfectly fine, i imagine a capi di is great, a little portable box DI is great for convenience sake... an active DI suffices for both passive and active instruments, IME the bo hansen(active) seems to have a slight effect on bass that is quite desirable, all of us who'v built them(groupdiy) say the same thing...either we have groupbias confirmed ourselves into believing it, or it's true 8)
my 72 passive jazz bass and bo di remind me of ABBA bass..i likey, no way i'd go direct w/out a di

Don't laugh, I'm still using a Behringer DI...

I really ought to consider something a bit better.

I really like my Little Labs Redeye 3D Phantom. It's great as an active/passive DI, a guitar signal splitter, and it makes re-amping really, really easy. I'm not sure if I'll continue to use it with the Kemper yet, I'll have to play with the Kemper for a while to figure it out.

Thats super cheap ! How well did it stand up to the $200 DI's ??

scumbum,
jazznoise brings it to the point. You can also use any pedal for buffering and go thru a passive (transformer) DI.
But personally i do not like the sound of the cheap chinese transformers you normally get in the cheaper DIs.
And a half way good transformer DI has it's price. Normally overpriced, if you buy a readily built product. Alot...

The Tube MP is a chip amp design with a tube in the signal path to give some nice harmonic overtones, nothing fancy, it just works.
I changed some caps along the signal path, too, but that did not too much to the sound. As with many of these minimalistic cheap mic pre's, the tube and the chosen caps make the character, no transformer involved, so you get no ground isolation...
It had a cheap chinese or russian tube in it, no-name. But the JJ tube is a very nice thing in this circuit. I also read, that the behringer pendant to Tube MP comes to life with Electro Harmonix 12AX7...
There is nothing to gain by using an NOS tubes of whatever fancy flavour. Just find the tube to make the unit sing, in this case the JJ was it.
For the technical background of the JJ ECC803s: It is produced still on the original Telefunken production line for the Tele ECC803s, and it still is a pretty good tube. After 'funken stopped the production, Tesla bought the line and the production process, and transferred it to formerly Czechoslovakia and continued the production, later continued as JJ Electronics since the nineties in todayx Slovakian Republic.
The ECC803s is the latest high end version of the 12ax7/ECC83 tubes because of it's construction (the famous "Spanngitterröhre", you might read up on this, very interesting...). The NOS Telefunken ones are highly sought after and there are many fakes on the market. So you can pay a few hundred bucks and might end up with a JJ one in the end anyways...LOL. I can not think of a way to really distinguish them if you fake the Raute print and production codes in a careful way.....ok, back to topic...
If the pad is engaged, and you dial in some 'sound' in the Tube MP you get a nice little "tubey sounding" DI box from it.

If a DI does, what it is intended for, has a fairly low noise floor (active ones) and a nice flavour sound, that is right to my ears, it is OK.
No matter, how expensive it was.
I liked the Bo H. DI, because it sounds really good compared to any price DIs and the Tube MP especially as bass tube DI, but also for synthesizer DI...
In combination with the right mic, yes, you can use it as a mic pre, too. (You can have a very high priced vocal chain, that sounds NOT good, if the combination of mic and pre sucks. That's nothing, money can buy...)

Well, how good does it compare to high priced units? Not bad, i would say. A lot of bang for the buck.
But sure - you can built or buy great tube DIs racked from classic Telefunken tube line amps, that cost maybe a 20 times more - and you might like the sound better. Sure.
The countryman, mentioned before, e.g. yes a really very good sounding design too, with a nifty little circuit to downtranform the 48V phantom power.
At the low price point i would say - buy the ART box, buy the 10 buck tube and put it in, and judge for yourself. I do not want to say - yes, it beats units ten times the price. Because i think it does not. It would not be fair to say that. It might not be that versatile and i guess the countryman e.g. and others are ground isolating, which might come handy in many situations, and utilize transformers, have more costs in production....
But there is nothing to regret to at least try out the ART MP (or the Bo DI of course), you will find a use for it anyway, it's around 50 bucks alltogether and 5 minutes of work. Give the tube and the circuit some time to break in...

Best regards,
M.