Bo Hansen DI layout

[Whoops]

I have just sent an email to Pro Audio GC in France and asked for an explanation why they decided to use my DI-box design with copied PCB and my name, without asking me for permission.

--Bo

In the meanwhile they added another product with your name...

https://proaudiogc.com/en/27-active...for-2-x-oep-a262a3e-transformers-active-.html

 

[Bo Hansen]

In the meanwhile they added another product with your name...

https://proaudiogc.com/en/27-active...for-2-x-oep-a262a3e-transformers-active-.html

I received a response from the owner of the "Pro Audio GC" website, and he says he is willing to remove the sale of circuit boards and kits regarding my DI-box design, which he markets without permission.
I am very grateful for his goodwill to correct this mistake.

--Bo

 

[abbey road d enfer]

Have you protected your IP on this layout?

 

[Bo Hansen]

This whole DIY DI-box project with my circuit design that I presented here at the forum in 2004, and help with the first version of PCB layout made by Groupdiy members Luny Tune and Soeren-DK around 2010, and Volker Meyer since 2015 took over the distribution of PCB rev.2, is based on people's respect and appreciation for our commitment and work in this project.
So I trust that everyone respects my wish that this project is not copied and mass-produced by any person or company for their own financial gain.

I have many times received request from major audio equipment companies who want to buy my DI-box design to manufacture under their own name.
I have during all the years since I presented this DI-box project promised the DIY people that this DI-box design is free to use as a hobby project, without the risk that any company will accuse any person of using their circuit design, which they consider to own because I have sold or given license rights for this DI box to them.
This promise I will try to keep for all future.

It's incredible, but there have been over 330.000 visitors and more than 1.200 posts since the start Dec 2, 2009, which is here on this thread in "soeren_DK" beginning posts.
Could this be a record here on groupdiy, or are there more threads in this size?

--Bo

 

[Bo Hansen]

Have you protected your IP on this layout?

abbey road d enfer.

It is Volker Meyer who updated the current PCB rev.2 and since 2015 has helped us to manufacture and distribute this to anyone who wants to buy.
It is possible that he has protected "IP" for this PCB layout, I will ask him.

--Bo

 

[[silent:arts]]

Hi Bo, I didn't protect anything. At the end I only copied the PCB layout from Soeren since the original Gerber files were lost.
In my opinion this is not about IP, it is about respect.

 

[abbey road d enfer]

Hi Bo, I didn't protect anything. At the end I only copied the PCB layout from Soeren since the original Gerber files were lost.
In my opinion this is not about IP, it is about respect.

All the more a reason to chastize the french guy that took your work without a word. He probably doesn't make much money out of it, but it wouldn't have cost him anything to drop you a line.

 

[PhilipMarlowe]

Thanks for this wonderful design, Bo. A newbie question but can I just use any Jack and XLR connector or are these in the BOM list the ones needed for this build?

 

[Ricardus]

Thanks for this wonderful design, Bo. A newbie question but can I just use any Jack and XLR connector or are these in the BOM list the ones needed for this build?

The input Jack needs to be the switching kind, but an equivalent from any manufacturer will be fine. The output Jack doesn't need to be the switching kind, and any old one will do. BUT, they need to be the plastic kind that is isolated from the metal enclosure you're putting it in.

Any XLR should work. Neutrik, Amphenol, Switchcraft.

 

[johnchantler]

Finished assembling the first two of four boxes. These ones with Lundahl LL1538XL. Tight squeeze in this little Hammond box but it does fit. The other two will get the Haufe.

Sounds great

 

[Whoops]

Finished assembling the first two of four boxes. These ones with Lundahl LL1538XL. Tight squeeze in this little Hammond box but it does fit. The other two will get the Haufe.

Sounds great

Nice looking box, can you please share the box model?

Where did you do the front panel?

 

[johnchantler]

Panel fpd file can be downloaded here:
https://www.dropbox.com/s/n2m9twpg519ga4j/bo-hansen-DI-panel-lundahl.fpd?dl=0
I got these done at Schaeffer/Front Panel Express but I’m sure Frank could also do these and possibly cheaper.

boxes are Hammond 1455L801BK
https://www.mouser.se/ProductDetail...R6JtK3w%2BQ==&countrycode=DE&currencycode=EUR
I just used two nuts to raise the height of / make clearance for the PCBs.

 

[Ricardus]

Finished assembling the first two of four boxes. These ones with Lundahl LL1538XL. Tight squeeze in this little Hammond box but it does fit. The other two will get the Haufe.

Sounds great

View attachment 94430

I ended up going with a slightly bigger Hammond box because I did a few with off-board transformers, and needed the room.

 

[ToneShack]

Is CDIL a known brand, or no name? Their BC550 / BC560 work just fine in my V672X.

Yes, I use their BC108, & 109 in a fuzz pedal that I am working on. Seem to be pretty good so far.

 

[zenstyle]

I originally posted these in 2018 when I built them. I remain very happy with them. The cases are made out of Aluminum tubing cut by hand. The case design is inspired by the Countyman DI.

 

[Bo Deadly]

So I trust that everyone respects my wish that this project is not copied and mass-produced by any person or company for their own financial gain.

A circuit is just a network of electronic components. It is not a tangible form of expression and as such cannot by copyrighted. If it were, Berhringer would not exist. So someone can freely copy your circuit without your permission. If that was not your intention, you should not have posted it on a DIY website.

A schematic or layout in the form of a PDF or image is a tangible form of expression and therefore is inherently protected under common law copyright the moment it is published (such as on a DIY website). So if someone sold PCBs from your gerber files for example, that might be an issue.

Although I say "might" because there are addition limitations when you publish your content through a website that you do not control. Websites, such as this one, almost always have terms about ownership of the content that you post which you must agree to when you register. If the owner of this website wished to copy the content you posted here, it would be very difficult to stop them.

So I would say your ability to protect your creation is, at this point, greatly limited.

If you wish to monetize your creation, my recommendation would be that you create a website that you own with a domain that you own and with copyright statements that indicate that all content is copyrighted by you. Then I would sell something related to your creation through the site and seed archive.org so that the Wayback machine has an historical record of commerce related to your creation. Then you should register the name "Bo Hansen" as a trademark associated with said commerce.

You might think that there would be little money in such a venture. But the hardest part is brand recognition and you seem to broken through that barrier. If executed correctly, I think you could generate a significant profit.

Note that if you choose not to monetize your creation, eventually someone else will and they will use the name "Bo Hansen" to sell the product. And if they do and you don't do anything about it, you will not be able to challenge it later because they will say that you knew and didn't do anything about it until they had significant business.

 

[Newmarket]

A circuit is just a network of electronic components. It is not a tangible form of expression and as such cannot by copyrighted. If it were, Berhringer would not exist. So someone can freely copy your circuit without your permission. If that was not your intention, you should not have posted it on a DIY website.

A schematic or layout in the form of a PDF or image is a tangible form of expression and therefore is inherently protected under common law copyright the moment it is published (such as on a DIY website). So if someone sold PCBs from your gerber files for example, that might be an issue.

Although I say "might" because there are addition limitations when you publish your content through a website that you do not control. Websites, such as this one, almost always have terms about ownership of the content that you post which you must agree to when you register. If the owner of this website wished to copy the content you posted here, it would be very difficult to stop them.

So I would say your ability to protect your creation is, at this point, greatly limited.

If you wish to monetize your creation, my recommendation would be that you create a website that you own with a domain that you own and with copyright statements that indicate that all content is copyrighted by you. Then I would sell something related to your creation through the site and seed archive.org so that the Wayback machine has an historical record of commerce related to your creation. Then you should register the name "Bo Hansen" as a trademark associated with said commerce.

You might think that there would be little money in such a venture. But the hardest part is brand recognition and you seem to broken through that barrier. If executed correctly, I think you could generate a significant profit.

Note that if you choose not to monetize your creation, eventually someone else will and they will use the name "Bo Hansen" to sell the product. And if they do and you don't do anything about it, you will not be able to challenge it later because they will say that you knew and didn't do anything about it until they had significant business.

That is all correct to my knowledge.
However, it does seem quite a 'harsh' response to what was basically simply a request from someone who has been generous to the audio community.
It's not as if legal action or similar was being threatened.
But yes, it does raise interesting questions.
What sort of quantity over what timescale constitutes "mass production" ?
And branding / recognition is a commercial factor. It would indeed be an idea to "trademark" the "Bo Hansen" aspect.
That could then be used for production or licencing to third parties.
Technically the design is essentially an audio amplifier stage driving a transformer so little novel in the concept.
ie an active DI with transformer balanced output stage (not to say that the results don't sound good).

 

[Bo Deadly]

That is all correct to my knowledge.
However, it does seem quite a 'harsh' response to what was basically simply a request from someone who has been generous to the audio community.

I'm just informing the guy of the legal realities.

My prediction is that eventually someone will create a "Bo Hansen" labelled product but they will make it very inexpensive. They'll use a cheap transformer or, more likely, no transformer at all.

Filing a trademark is not expensive. But I believe there must be some kind of commerce or "trade" behind it. It's not hard to setup a simple ecommerce website. And there's no reason why you can't sell the PCBs for $100 so that you're not bothered much by orders.

 

[Bo Hansen]

Bo Deadly and other,

Thank you for the good explanation and interest regarding this.

Actually, it's not a big deal that we need to make so much sense of, but I'm in a writing mood today, so I can explain how my thinking is about this.
Sure, I fully understand that I have no useful legal right to prevent anyone from stealing my idea and fabricating it as their own product and name.
So there is no registered patent or copyright for my DI-box design.
What might prove that it is my original design, is that it has since early 2004 figured in connection with my name in a number of discussion forums and other places on the web, what this may be worth in the context, I do not know.

The only thing I can do is appeal to those who want to benefit from this popular DI-box design is a little respect, kindness and gratitude for all the time and work that I and some others who have run this project for more than 15 years.

Every year, someone or some company contacts me and asks for permission to manufacture this
DI-box as their own product, and has received proposals for compensation of various kinds.
But I insist that this design is for you DIY people and is free to use and build in small numbers for your own use and for friends and colleagues, and so it will remain.

Regarding the simple circuit solution.
Sure, it's "just an amplifier" that drives a step-down transformer, no major rocket research, but it stands out with some specific things which the market's active DI-boxes normally do not have.
I have seen some odd manufacturer who probably got some idea from my design.
Also discovered that Rupert Neve's RND DI-box which came on the market around 10 years later, has a fairly similar design, but it has a JFET as the input transistor.
If I had the same design ideas as Rupert, I can be proud.

Of course it was a thought with my DI-box design, not a coincidence that the circuit looks like it does.
For those of you who are curious about my way of thinking about this old design, I write a little explanation below:

It has a BJT input transistor instead of a JFET.
The reason is that in 1975 when I made the design I only had access to the JFET BFW10, and I thought it was more noisy than the selected BC109C that we had in our amplifier manufacturing, I also not need the JFET's high input impedance.
When I re-designed the circuit for this DIY project in 2004, I decided to keep the BJT input transistor, as it is easier for some of the DIY people to get hold of this than a good JFET.
(good branded BC550C we now use has even lower noise than the old selected BC109C)

This DI-box has 1M ohm input impedance, (not 10 Mohm) the same as most guitar and bass amplifiers have.
This gives a more recognizable load and character for guitars and basses.

It has two cascaded (in a row) emitter followers, an NPN at the input with low current for high impedance and low noise, a PNP at the output with high current to easily drive a transformer with ratio 5:1, which also gives a level loss of 14-15dB that is suitable for feeding a microphone input.
These transistors are in their simplicity only two unity gain followers "no gain no pain" without negative feedback, also using the combination NPN and PNP has some advantages, for example, good clipping behavior.

I have chosen a total current consumption of 3.5 mA from phantom powering, this leaves an internal supply voltage of 24 volts which is a good compromise between drive capacity and headroom.

It has input protection with two opposite 12v zener diodes and a 10k series resistor that withstands the worst case scenario regarding overload on instrument input.
Although zeners such as clamp diodes have higher capacitance than two ordinary diodes connected between input and positive and negative/ground voltage rails, I trust these zeners more as good input protection.

It has a special "ground loop suppressor" circuit to avoid having a ground lift switch, which often causes problems with Phantom powered DI-boxes, as the ground lead/screen is necessary for this.

I chose to remove the normal input parallel jack "Thru" because this loads the instrument both capacitively and resistively when a longer cable is connected to a guitar amplifier or similar.
Instead, there is a "Monitor Amp Out" which is impedance converted and does not affect instrument input, and it has the same level out as instrument input.
It also has no PAD or Low-cut switch in original design, I wanted to make it as simple as possible to minimize construction problems for the DIY people.

It is strange that it can be so much with two transistors some resistors and capacitors.
But it is as we say here in Sweden "there can be many features on an iron skewer"

Yes, these were my thoughts on copyright and how I thought when I designed it in the mid 1970's.

All the best from
Bo

 

[robinhuntmusic]

I use this DI daily, its a wonderful and great sounding design. I got the pcbs from 51xaudio. Thanks @Bo Hansen for this design, its ace