Bo Hansen DI layout

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Bo Hansen

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Parkay909,

As a good alternative, use metal standoff/spacers that have an M3 thread at both ends. (for example Harwin R30-1011102 or longer) Drill holes in the bottom of the box, countersink on the outside of the bottom and fasten the standoff/spacers with nice countersunk screws.

--Bo
 
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Ricardus

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Parkay909,

As a good alternative, use metal standoff/spacers that have an M3 thread at both ends. (for example Harwin R30-1011102 or longer) Drill holes in the bottom of the box, countersink on the outside of the bottom and fasten the standoff/spacers with nice countersunk screws.

--Bo
Those Hammond enclosures aren't very thick on the bottom, so I don't think you could counter-sink them very well, which is why I used epoxy. I didn't want any thing like that showing. I just wanted it to be nice and clean.
 

parkay909

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Parkay909,

As a good alternative, use metal standoff/spacers that have an M3 thread at both ends. (for example Harwin R30-1011102 or longer) Drill holes in the bottom of the box, countersink on the outside of the bottom and fasten the standoff/spacers with nice countersunk screws.

--Bo
Thanks for chiming in! The Hammond I got is a little too thin to countersink a hole. Maybe I'll just use another Spinal Tap lunch box.
 

parkay909

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Those Hammond enclosures aren't very thick on the bottom, so I don't think you could counter-sink them very well, which is why I used epoxy. I didn't want any thing like that showing. I just wanted it to be nice and clean.
Thanks for the quick revert. I believe epoxy may be the way to go, and Ill probably use a different chassis for my last two builds.
 

Ricardus

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Thanks for the quick revert. I believe epoxy may be the way to go, and Ill probably use a different chassis for my last two builds.
They're a little big, which came in handy when I was using transformers that didn't fit on the boards, but I find the enclosure to be pretty ideal.
 

Whoops

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I don't see anyone using the the API 2622 type transformers for the Bo Hansen DI but it seems it could be a good option also:

Dual primary impedance of 150 or 600ohms
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Secondary impedance of 10K ohms
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Turns ratio of 1+1:7 (Primaries in parallel for 1:7, Primaries in series for 1:3.5)
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Encased in a mumetal can for magnetic shielding

There's a lot of option for this kind of transformer:
API 2622, Ed Anderson EA2622, CAPI CA2622, Cinemag CM-75101APC and CMMI-8PCA

Any reason why people are not choosing any of this options?

Thank you so much
 

Bo Hansen

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Whoops,

Of course it is possible to use API 2622/2516 mic-transformer style, but only in the configuration 7:1, and in this case the DI box gets 3-4 dB lower output level compared to Lundahl LL-1538.

I do not recommend using it in a 3.5: 1 configuration, because in our case the secondary is connected in series and is not particularly well adapted to drive a mic input.

--Bo
 
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Whoops

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Of course it is possible to use API 2622/2516 mic-transformer style, but only in the configuration 7:1,

Thank you so much Bo,
I was just finding strange that I didn't see anyone using a 2622 in this project, it's nice that it can be used

and in this case the DI box gets 3-4 dB lower output level compared to Lundahl LL-1538.

3-4 dbs lower, or even more is not a problem I have tons of clean gain in the mic preamps
 

studiostorm

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Hi, sometime ago I purchased 4 bo hansen di pcbs from 51x Audio. (Super duper high quality!)
3 of them work flawlessly.
One of them is much lower in volume and when i touch the strings (ground) on my bass/guitars I get more noise.
This doesnt happen on the other 3.
I have replaced the transistors, 4004 diodes and the capacitors.
Measured every component and they seems to read the same as the other 3.
Built all of them using Lundahl LL1538XL.
The ones that work sound AMAZING!

Anyone happen to know what to look for or how to go about troubleshooting?
Best/ David
 

Whoops

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Anyone happen to know what to look for or how to go about troubleshooting?
Best/ David

- Resolder/Reflow all solder joints
- check for solder bridges between tracks
- check all resistor values, it's easy to mistake 1K for 10K, or 560ohm to 560K
- do an Audio probe and probe the circuit following the schematic
 

Newmarket

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"One of them is much lower in volume and when i touch the strings (ground) on my bass/guitars I get more noise.
This doesnt happen on the other 3."

This sounds to me that's there's a good chance that it's a connection / wiring issue.
Sanity check - are the Instrument Input and Buffered Out connections swapped / mis-labelled ?
All wiring to sockets okay ?
 

mihi_fuchs

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I just built the DI Box with chinese mic transformers, which were left-overs of some microphone projects. I also recorded some bass samples and compared it a bit to two other DI Boxes (Soundskulptor MP573 DI input and a Samson MDA1 DI Box). For some pictures, the sound samples and see following thread: Bo Hansén's DI Box using left-over chinese Mic-transformers

Maybe some people here are interested in the comparison and recordings.

Cheers
Michael
 

micro1_de

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Hi there,

I´m looking for the data sheet of a Haufe ST8123. Does anybody can help me?

Thanks and best wishes

Reiner
 

micro1_de

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Hi Volker,

thank you for your Data sheet. The Haufe 8123 seems to be different. I can see and measure 8 pins and the resistance is is also very different, between 21 and 28 ohm.

Best wishes Reiner
 

johnsmith1234

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So I just read through 59 pages of this thread and my main takeaways:

1. ONLY use a RED LED or don't use one at all
2. Don't cheap out on no name brand transistors.
3. Pay special heed to Bo's earthing instructions. Use plastic phono jacks.
4. 99% of what you need is on Bo's technical page
5. Bo is extremely generous with his time and effort helping people on this site.


I also put together this shopping list of recommended items for the build. Further options are listed on the Hansen technical page (Hansén Audio Gothenburg) but this format might easier on the eyes for some people.


Transformer: Lundahl LL1538/LL1538XL/Haufe ST8456/OEP A262A3E (Listed in order from expensive to cheaper. Bo stands by the Lundahl stuff, Volker likes the Haufe, and the OEP is the value king). x1
Transistor: BRAND NAME ONLY (Philips, Fairchild, Omron etc.) BC560C x2.
Resistor: 3.9k 5% carbon film or 1% metal film resistor x1.
Resistor: 6.8k 1% 0,25w metal film resistor x2 (Essential that these are 1%).
Resistor: 10k 5% carbon film or 1% metal film resistor x2.
Resistor: 100k 5% carbon film or 1% metal film resistor x2.
Resistor: 1Meg carbon film or 1% metal film resistor x1.
Capacitor: 0.1 microfarrad of polyester or polypropylene type, minimum rated 50 volt, pitch between legs 5 mm x2.
Capacitor: 10 microfarrad 35v radial lead type 5-20% (capacitor pitch between legs 2-3,5 mm.) x2.
Capacitor: 100 microfarrad 35v radial lead type 5-20% (pitch between legs 2-3,5 mm.) x1.
Diode: Zener diode 12 volt 500mw/0,5 watt (Such asBZX55C12) x2.
Diode: 1 amp 400 volt. (1N4004 to 1N4007 is ok to use) x2.
Phono Jacks: PLASTIC JACK ONLY such as Neutrik NMJ4HFS, or NMJ4HFD2 x2.
XLR Jack: Metal XLR, MALE.
Chassis: METAL CHASSIS.
LED: USE ONLY RED LED, 3-5mm with as less power draw as possible. Not essential, but could be handy for troubleshooting.


My parts are currently en route. This will be my first DIY build. I used Mouser for everything except the transformer and transistors (BTW, is it me or is their postage really expensive? 20 euros minimum for what will be a half full padded envelope).

I picked the Lundahl LL1538XL transistor which I ordered from Don Audio. I got some FAIRCHILD BC560C Transistors from Langrex in the UK.

Pulled the trigger on the millenium di e to use as a case before I finished reading this thread. It appears like it will be too small but I will update the thread with my findings when everything arrives.
 
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Whoops

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Transformer: Lundahl LL1538/LL1538XL/Haufe ST8456/OEP A262A3E (Listed in order from expensive to cheaper.

There's much more options than that,
basically any Mic input transformer wired backwards with a ratio of 5:1 to 7:1 will work fine.

Amplimo TM2P
Cinemag CMMI-5C, CMO-5/200CT
Jensen JT-13K6
Lundahl LL1528, LL1578
Sowter 3678, 8230, 9045, 9145
Steven & Billington 829
Neve/MarinAir/St.Ives 10468/VT22670/T1454
Carnhill VTB-9045
Sowter 9145
API 2622
CAPI CA2622
Ed Anderson EA2622
AVDAudio TR2622
 

johnsmith1234

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There's much more options than that,
basically any Mic input transformer wired backwards with a ratio of 5:1 to 7:1 will work fine.

Amplimo TM2P
Cinemag CMMI-5C, CMO-5/200CT
Jensen JT-13K6
Lundahl LL1528, LL1578
Sowter 3678, 8230, 9045, 9145
Steven & Billington 829
Neve/MarinAir/St.Ives 10468/VT22670/T1454
Carnhill VTB-9045
Sowter 9145
API 2622
CAPI CA2622
Ed Anderson EA2622
AVDAudio TR2622

I know, I just put the three most popular options in. I mentioned that the technical website has more part options but this is a good starting point for people like me who would rather avoid too much option paralysis.
 

Whoops

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I know, I just put the three most popular options in. I mentioned that the technical website has more part options but this is a good starting point for people like me who would rather avoid too much option paralysis.

Also the PCB transformer Pinout is for the 3 models you posted, the other ones can still be used but there's more wiring involved.
 
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