Bo Hansen DI layout

[Bo Hansen]

Scheppart,

It sometimes happens that people who build the DI-box in other ways without using our pc-board, and instead do it with piont-to-point or on vero-board, are unable to get the electronics to work perfectly.

This is usually caused by wrong mounted transistors or reverse LED or that any connection is missed.

Since you have about +45 volts at the junction of the two 6.8 ohm resistors means that the electronics do not work and does not consume any current.

Check your building carefully, look also at our PC layout that you find here or on my tech page, where you can get a good idea of how everything is connected.

Good luck

--Bo

 

[scheppart]

thx for help bo!!!

have you seen my update.

i had one missing connection and one on the wrong side...

i have now 19.5 where it should be 24
and 9.7 where it should be 12

the signal is coming through! and sounds ok now. in fact much much much better then the hiZ input of my interface =)

 

[scheppart]

update again!

i have changed the interface and now i have: (from tascam us144 ref1 to rme babyface)

23,2 V
and
10,7 V

this is much better! but not perfect. as i  sayed the DI is working ( i guess). any suggestion where the error could be?

Greetings =)

 

[useme2305]

is the Bo Hansen DI suitable for the LR Baggs magnetic active soundhole pickup? the pickup has an output load of 800ohms.
if not, is there a way to mod the DI to make it play nice with this pickup?

 

[Bo Hansen]

Useme2305,

This pickup is already active with built-in amplifier/impedance converter, so if you only need an unbalanced output on the guitar, it works fine without any extra DI box.

But if you need a balanced output on the guitar to be connected directly to a mixing consoles phantom powered microphone input, in this case you need a good DI box, for example my DI box, which will be perfect suitable for this work.

--Bo

 

[useme2305]

hey, i tried the pickup through one of my bo hansens and it sounds great.

i love your DI! i have three!

 

[Mondy]

Hi useme2305

I run a Takamine Triax pickup (which is a Baggs M1 but switchable to be either M1 or M1A) in passive M1 mode through a belt preamp 24dB gain stage (via a short 1.5 foot cable), then through Boss TU-3 for tuning and muting and then into my Bo-Hansen and the sound is just wonderful!! The Bo-Hansen and the M1/M1A work wonderfully together and as Bo said, the M1A or Triax in active mode will have a hot enough signal to go direct into the Bo-Hansen DI. 

 

[lars78]

i had built a couple of Bo´s Di´s with different transformers, and now we did a little comparison.

24bit/88khz WAV
interface: Universal Audio Apollo
preamp: UAD apollo onboard
vovox instrument cable 

Git: Les Paul, neck P90 pickup
Bass: passive Yamaha 5 string Jazz Bass style 

transformers:
Haufe ST8456
Neumann BV-107 (09107)
OEP A262A3E
Beyerdynamic BV310 005 034

passive DI - Monacore DIB-100
passive DI - cinemag CM-DBX
UAD onboard JFET DI input

http://starfishcoffee.de/DI_Test.zip
http://starfishcoffee.de/DI_Test_fotos.zip

 

[lars78]

Hello Bo !

I wanna build your Di-Box direct into a V672 preamp.
It is possible to connect the circuit without the TX to the preamp input

The input impedanz of the preamp is variable via choosing different "Re".
Wich is the correct input Z for the preamp ?

v672 Specs and wiring
http://starfishcoffee.de/v672specs.pdf

service manual and schematic
http://starfishcoffee.de/V672schematic.pdf

best Lars

 

[Bo Hansen]

Lars78,

Yes, you can do.

Remove transformer and the two 6,8K resistors, LED, XLR, and the componts around pin-1. (monitor jack and 10 K resistor)

Feed regulated +24 volt from the V672 pre-amp, and via a 100 ohm serial resistor connect positive 24 volt to + on the 100uF capacitor and negative/ground 24 volt to negative side of the 100uF capacitor.

Now you can feed the DI-box output signal from the negative side of the 10uF capacitor to the V672 input.

A input impedance around 10K will be fine.

--Bo

 

[pablobolche]

I just finished racking a dual ssl9k with Bo hansen Di.. pretty useful and great rack.. I was wondering how high can I go with the internal voltage for the DI as I have a psu I can omit the 10ma current limit.. From some experimentation I recall that the 3k9 resistor sets the internal voltage to 24v..
the thing is  I have some piezo pickup instruments that seem to go over the headroom for the DI and I think(could be wrong ) that if I lower the 3k9 resistor to XXX I would have a higher internal voltage and more headroom??
from the datasheet of the bc5xx it says i could go al the up to 50v no problem.. Is this reasonable or are there other issues to attend..
Gracias

 

[Bo Hansen]

Pablobolche,

This is a buffer amp / emitter follower with unity gain and operating on a supply voltage of 24 volts, this allows the input to receive a signal at about +19 dBu / 7.5 volts before the clipping level.

I guess a piezo pickup loaded with 1 Mohm has an output of about 1 volts when the guitar strings assaulted in the coarsest manner, and in this case you will have a headroom about 18 dB, and this is a lot of headroom for this purpose.

The 3.9 k resistor on the emitter of the last transistor is set to give a good drive for transformer types we use in this design, and this happens to be an internal voltage of 24 volts because the internal DI-box electronics consume 3.5 mA from the send and receive 6.8 k phantom resistors.

As an experiment, you can double the internal 24 volt supply to 48 volts with BC-550/560 transistors, and if you want the same current through the transistors that you have in the original design, just double the two emitter resistors 100 K and 3,9 k to 200 k and 7.8 k, or choose next regular value 220k and 8.2 k, in this case you get a huge headroom, but that is completely unnecessary for your application.
But of course this doubled voltage must be connected directly to the DI-box internal power supply rail.
Also note that 100 uF electrolytic capacitor must be greater than 50 volts.

--Bo

 

[pablobolche]

Great.. Thank you so much fro this di and for your reply.... Will do and post results...I have been havin fun and learning with this proyect...
Thanks  again...

 

[mac]

Has anyone tried Eds EA2622 in Bo's design?


Mac

 

[Bo Hansen]

Mac,

I'm sure EA2622 sounds good in my DI box if it is made as the original API.

The primaries (used as secondary in our case) can be connected in parallel or series, 150 or 600 ohm, so in parallel it have a ratio of 7:1 and give a loss of approx. 3 dB lower than Lundahl LL1538, and in series a ratio of 3.5:1 and have a loss of approx. 3 dB higher than Lundahl.

I would prefer conected in parallel for best output load match.

--Bo

 

[useme2305]

i would include a Hi/Lo switch to have both options. or would that be totally dumb?

 

[PdeP]

Hi guys,

I'm planning to build at least three copies of this promising DI.
One is for my bass rig (live and recording).
I'd like to hook it up this way:
Bass -> preamp -> effects (output impedance 10 kOhm) -> DI (balanced to mixer) -> unbalanced to power amp (imput impedance 600 Ohm)

Would this DI work well in this setup? If not: What parts would I need to replace on the PCB?
Also, I'd like to insert a volume control between the board an the unbalanced amp output because the power amp doesn't have a volume control. Would a 100k lin pot with a 15 k resistor between Out and Ground work (see attached file) or which other values would you recommend?

Yours sincerely
S

 

[audiophreak]

Hello All,
            Was just wondering if replacing the 10uf electrolytic caps with Tantalum would make any difference  , just curious... any thoughts ??

 

[Bo Hansen]

PdeP,

This design in its simplicity is best just as it is, and is primarily intended to match a passive Hi-Z guitar or bass guitar to a Low-Z balanced microphone inputs with phantom power.

In your case that needs some more features, I recommend you something else that already have alternative inputs for line levels and outputs with level controls that can drive a power amp.


audiophreak

Today the usual aluminum electrolytics good enough and usually more reliable than tantalum caps.

I recommend that you select a good standard electrolytic like Panasonic FC or Elna RJH or something similar.

--Bo

 

[audiophreak]

audiophreak

Today the usual aluminum electrolytics good enough and usually more reliable than tantalum caps.

I recommend that you select a good standard electrolytic like Panasonic FC or Elna RJH or something similar.

--Bo

  Thanks Bo