Bo Hansen DI layout

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Thanks Bo. PCBs should arrive tomorrow.

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Lately I've been making several of these and testing different transformers.  I'm planning on replacing all my Radial Pro DI with these and some point to point hardwired passive guys. I thought I would share my Mouser cart with those who plan on buying these PCBs and building them in the States:

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=12eddc2712

This is based on the new schematic on Bo Hansen's website and I use it in all my builds.

I'm using audio grade electrolytics and WIMA film caps. Most of the resistors are Vishay and connectors are Neutrik. Total price is under $11. The stock will change from time to time so make sure and scroll down and see if anything is listed as back ordered. I didn't include any headers as what's pictured in the new rendering as I just wire connectors directly to the board. Also, does not include an enclosure.

Hopefully this will be useful to the peoples. I'd check from time to time to see if availability for any of the items has changed.

Paul
 
Just wanting to join in on the chorus of praise for this DI box. I had been using either no DI or a horrible Rolls Matchbox before I built this Wednesday night. Used the OEP and all suggested components and mounted in 1590TBK.  Tested Friday with a PRS with Dragon II passive humbuckers into a Classic API VP26 with the gar2520 opamp---never heard a DI guitar sound so clear! And the output of this DI! I had to attenuate the VP26 even with its gain all the way down to keep my digital level around -18 (I guess this is normal?). Tonight I plugged a freshly setup Fender Jazz Bass with passives into the same signal chain. Again, cannot believe the clarity and full-range sound! Cranked the gain on the VP26 and attenuated back down to digital-safe levels, and was blown away by the grit/balls of the tone. Thanks Bo and everyone involved in this project---don't think I'll ever need another DI---except maybe another Bo for a stereo pair!
 
Wanted to share some photos of the latest one that I built. This is the second I put together with a Sowter 9045. These things are huge! I had no idea as I couldn't find dimensions on their website. This configuration was chosen with bass in mind, as according to the 9045 specs it goes all the way down and all the way up. The first one made like this is currently being used by the bass player for the tour I am currently on. He had been using a Neve clone of some sort. He also took this for a session he did recently and received many compliments from the engineer. The transformer was wrapped in electrical tape to prevent the case from touching the enclosure and was zip tied to some small L brackets that I made. The LED I used was a standard clear red one that requires slightly less current and voltage that what is currently on the BOM posted previously. I drilled a small hole then used a counter sunk bit from the inside and removed just enough material so the dome barely stuck out past the enclosure then hot glued it in place. The LED in this build is no longer being made, so I listed the panel mount in the BOM for ease availability and to look more professional for those of you who know how to do the fancy metal work. If there is better suited LED for this design please let me know and I'll gladly change the Mouser cart.

I later went back and hot glued everything that I thought could come loose as I'm building them with touring in mind. I can't have them failing and then be showered with scorn from my compatriots.

I still have an OEP, Carnhill, Haufe, and a Cinemag to build to test on various instruments, primarily acoustic guitar. I'll report back when I get to finishing them up.

Paul
 

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Fits in perfectly:

000029-Bo-kleiner.jpg


Outsideview:

000030-Bo-kleiner.jpg


Now I am on the way of building a Stereo one with PCBs a friend from the German forum did.

best Greetings,
Stephan

 
Hey Bo et al....

I am looking forward to receiving my boards from Volker soon.

I'm going to do a rack of them and am considering putting a 3PDT switch on the front to toggle between rear and front xlr's....

Still deciding whether this is a bit OTT with extra cost of xlr's etc but it could be handy..

Would this mess with the grounding scheme/ground loop suppressor at all?

Cheers,

matt
 
Hi Guys,

Could someone please confirm that either of these pair would work well?

Cheers,

Matt

http://ampslab.com/trans_2sa965.htm
http://ampslab.com/trans_2sc2705.htm
 
Matt,

These two transistor types are driver transistors for power amps, and is unnecessarily powerful for use in this DI box.

Instead, choose some of the types that I have recommended to my help page www.hansenaudio.se/techpage.htm

--Bo
 
Hi Bo,

Thanks for the info.

I was trying to find transistors that matched your suggestions earlier in this thread: "Vceo 30 volt as minimum, hFE from 200 and up, and fT from 100 mHz and up.", but was struggling to match any available ones up with these specs ... the Toshiba 2SC2240 match this but are not available reliably that I can find.

I am 100% sure I am making this more complicated than it needs to be...  :eek:

I'll  use some of the ones on your list.

Matt
 
Matt,

You can use almost any general purpose NPN / PNP "amplifier" small signal transistors on the market, it is not necessary to use extremely fine transistoret as 2SC2240 / 2SA970. You can certainly find some of the BC or 2N types at your local electronics store, I recommend on my help page.

--Bo
 
Could someone verify, that this is the correct pinout for a Sowter 9045  ?
I gif is original from Sowter, I added the numbers.
I don't know, what to do with the white lead ?

thanks,
Andreas
 

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kosi said:
Could someone verify, that this is the correct pinout for a Sowter 9045  ?
I gif is original from Sowter, I added the numbers.
I don't know, what to do with the white lead ?

thanks,
Andreas

Looks like  a center tap.  I think the best idea is to not use it at all, just get it out of the way and ignore it.

Center tap wiring is beyond my comprehension, someone with more knowledge would have to tell me why you would ever want to use one.  Most transformers don't have them.
 
You can ignore the white lead with the 9045 in the Bo Hansen circuit. Also, if you don't already have one, you should know that these transformers are very big and will need a decently size enclosure to fit everything in there. (See my earlier post with a pic to get an idea of it's dimensions).

I've built two DIs with the 9045's and use them exclusively on bass. They sound exceptional with in ear monitors and in a PA. Very big, very clear, even with the low notes. It seems to perform as the spec sheet states with minimal loss even down to 10 Hz.

Thanks!

Paul
 
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