Bo Hansen DI layout

[Potato Cakes]

Nope and I wasn't expecting them but thats what comes with the standard Mouser BOM from the first page of the thread...

I noticed you used some upgraded parts in yours but I'd already ordered the BOM and thought that the transformer would make the most difference anyway so decided just to stick to standard BOM.

It was a nice surprise mind!

The little green terminal blocks make things so easy to dissassemble and re-assemble!! They are made by Phoneix if anyone is interested

Once again thanks to Bo, Volker and people who answered my questions in the thread. My brother loves them, they really make a difference to his acoustic live!

Thanks, Matt

When I had first submitted a BOM for this project while waiting for my PCBs I wanted to give the option building these using the nice Vishay/Dale resistors and audio grade capacitors. The Vishay resistors are definitely bigger than the more standard looking one and I've had problems with them not fitting well on certain circuits. But they make you feel better using them since they are bigger, and from what I have read in all the trade magazines and in manufacturers ads, sound is all about feelings...


Paul

 

[Bo Hansen]

Erazorblade,

Did you manage to solve the problem with the DI-box ?

Potato Caces,

It is not necessary with extreme audio file resistors and capacitors in this construction, it is enough to use standard carbon or metal film resistors and plastic film capacitors, for example the red Wima capacitor, and Jamicon standard electrolyte capacitor.

But what is important are good transistor, such as Philips, Motorola, Fairchild, National, SGS /Ates.
Do not substitute unknown types and brands from China and the like, they can be noisy and weird in other ways.

The cables inside the DI-box housing does not need to be shielded, the only thing that is important is that the box cover is made of metal and is connected according to my instructions.

--Bo

 

[Potato Cakes]

Bo,

Yes, cheaper resistors and caps would be great, but I tend to go a little extreme when selecting components for projects. It's a bad habit.

By the way, I just got back from a tour where I was using your DI on bass and keys. The bass player was using mostly a pick and using a radial Pro DI, which are solidly built and does a pretty good job. However, there wasn't much of a comparison to your DI with the Sowter 9045. All the low end that one tends to miss when a bass player uses a pick was back and the clarity of the notes was exponentially better. I was able to keep the EQ on the bass pretty much flat, occasionally bumping the high mids if the PA or the room was being difficult. And I liked that the level difference from a passive DI wasn't extreme, making A/B comparisons much easier.

The DIs I used on keys had Cinemag CM-9711s. Before they were using a passive rackmount Radial product, which is also fine. But with a loud rock band, either the sample patches used or the keyboard itself would get buried and I could not really hear what was being played no matter how loud I turned it up during big musical parts. This was especially the case when she was just playing pads. Your DI with the Cinemags made a remarkable improvement. Keyboard parts cut through much better, and again much clearer and defined than before. In her IEM mix, she asked to turn the keys down since apparently she could hear her parts much better than before.

I've built about 8 of these so far, and I've still haven't had a chance to try out the ones I've made with Carnhill or Haufe transformers, but I can say that I have experience with many types of DIs on various sources during my time on the road and your design is best I've used. More importantly, the Sowter versions are helpful in convincing bass players to leave their Avalon U5's at home.

Thanks!

Paul

 

[Erazorblade]

BO

yeah i could solve the problem. Everything is fine now and I also built a second one without any problem. thanks!

I've got one question left, I would like to build a 3rd one and use a Transformer which adds a bit more low frequencies or attenuates the higher mids (for bass DI).
The first two DI-Boxes i built with a Haufe ST8456.
Will there be any tonal difference using the Lundahl LL1538?

If they are sounding the same but the Lundahl has just a bit more headroom, then I don't care and will use a Haufe again, since they are half the price and do an excellent job.
The best would be if anybody could deliver sound samples of the same guitar through different transformers?

 

[Bo Hansen]

Erazoblade,

Haufe is very good, but Lundahl LL1538 have a ower all a bit better specs, and LL1538-XL have the best headroom in the low end.

--Bo

 

[Sinkia]

Hey guys !
I have read until page 25 and then I post my question.. maybe the answer is in between p40..

I have a bunch of old API 2623-4, I was thinking : What can I do with those..

I had never thought to use it in this project, but why not..

Do you think it could work with it?

Cheers

 

[Bo Hansen]

Sinkia,

API 2623-4 is a low-ohm line output transformer with three 75 ohm windings, can be configured 1: 1/75 to two outputs of 75 Ohm or 1: 2/75 to 300 ohms or vice versa.

This is ideal as a line output transformer for discrete op-amps modules as API 2520 and John Hardy JE-990.

But it is unfortunately not possible to use as output transformer in this active DI box project.

--Bo

 

[Sinkia]

Sinkia,

API 2623-4 is a low-ohm line output transformer with three 75 ohm windings, can be configured 1: 1/75 to two outputs of 75 Ohm or 1: 2/75 to 300 ohms or vice versa.

This is ideal as a line output transformer for discrete op-amps modules as API 2520 and John Hardy JE-990.

But it is unfortunately not possible to use as output transformer in this active DI box project.

--Bo

It was what I thought, but i had to ask first !  8)

So I guess I'll just make it with the lundahl or cinemag !

Many Thanks for your acknowledge !

Cheers

 

[Sinkia]

Hi there !

I come back again…


I really want to build some of this DIs..

Is this transformer is a good choice for this project ?

EA-10468 Mic Input Transformer
http://www.hairballaudio.com/catalog/parts-store/audio-transformers/ea-10468-mic-input-transformer

If not, could you maybe explain me on what point do I have to make my choice !

Thanks in advance !

 

[Potato Cakes]

That one should work. It looks like it has the same impedance values as the Carnhill 9045, which is listed as an acceptable transformer on Bo's website. I've build a couple with the Carnhill's and I know they work great, so I don't know why the Ed Anderson version wouldn't be great as well.


Thanks!

Paul

 

[Lagrange]

It is unfortunate that Thomann moved their 10€ Millenium DI-E to a smaller box that (most likely) doesn't have enough room for the Bo's active DI:

http://www.thomann.de/fi/millenium_die_dibox_passiv.htm

But for passive DI's the 10 euros for the box and connectors is a good deal, and the new box is really nice and compact. 

 

[[silent:arts]]

The PCB is 80mm x 50mm.
The Box is 100mm x 130mm x 40mm.

 

[Lagrange]

The measuments would indeed say that it should fit, but I actually started thinking that the dimensions might be for the older, bigger box. Earlier in this thread there were pictures from a build into an older version, and it seemed that it was quite an exact fit there:

http://groupdiy.com/index.php?topic=36569.msg518811;topicseen#msg518811

Based on the pictures it would seem that the width of the older box could be the 100mm, and the new box is definitely smaller. I own both, but unfortunately I'm travelling at the moment, so I can't measure them. :/

But looking at the pictures on Thomann's website one can already deduce something about the width. The nuts on the Rean jacks are 17,5mm, and if the width of the box was 100mm, one would need to fit almost 6 of those side by side. That doesn't seem possible. Measuring from the picture it would seem that the width would more likely be slightly less than 80mm.

 

[Lagrange]

The dimensions of the millenium DI-E are roughly 90x75x35.

 

[skovbakke]

Potato Cakes

I'm building this as a bass DI and have been looking at specs for the different transformers. You seem to really like the Sowter and as far as I could see you initially chose it from having the most linear specs in the low end. The Lundahl 1538XL seems to be even better spec'ed though, or am I misreading something?
So I wondered if there were other reasons for preferring the Sowter?

 

[Bo Hansen]

Potato Cakes,

When I built my prototype in the mid-1970s,  I used a Sowter 3678 microphone input transformer because I had a number of them on the shelf.
The only other option I had was very small Beyer, Sennheiser or Kemo, who could not stand much bass and had to high ratio.
At this time, there was not Lundahl transformers available to the public.

To day the Lundahl LL1538 or XL is the best for my DI-box design, it was no accident that I chose this when it came out on the market.

Before that, I used Lundahl LL1515 which was the predecessor of LL1538, and was the best mic transformer Lundahl made at the time.

Haufe ST8456 is also a very good, that fits my DI box very well.

--Bo

 

[Potato Cakes]

Hello, friends!

When I was building mine, I didn't have any Lundahl's with which to do any testing. If the 1538XL is spec'd better than the Sowter then definitely give them a go. I am using these boxes in a live setting, so the most testing I ever get is, "Does this sound better than the other thing I was using?" Either yes or no, then move on. There's not much time for tweaking or trying out multiple options. For me, the Sowter version is much clearer from top to bottom than anything any bass player to date has shown up with in their rig, and without all the distracting knobs and buttons that are necessary to be a hot seller at Guitar Center. I have built pairs of DIs with the Haufe, Cinemag, Sowter, Carnhill, and OEP, but I've only had a chance to really hear what the Sowter and Cinemag sound like on different sources through a PA, which again, has always been much more preferred than what was being used. Going with the 1538XL would be advantageous for the convenience of being able to directly mount it to the PCB, which will allow you to put it in a smaller enclosure. The Sowter required a bigger enclosure as you have to mount it off board, and the physical size of it is massive. Mr. Hansen definitely knows what he is doing and if he says Lundahl is best for his DI, then I would be inclined to believe it is the truth. Also, I bet you will find that the 1538XL is more readily available than a 9045. If I had to do it again, I would probably just use the Lundahl's, especially if it basically gives me the same if not better results, but I have this weird disorder where I do everything the hard way first.

At any rate, it's a great circuit, and again, many thanks to Mr. Hansen for sharing this with all of us!

Thanks!

Paul

 

[Bo Hansen]

Paul,

I'm sure there may be some special transformers from Jensen, Cinmag or Sowter that might have better performance than Lundahl LL1538, but these are physically much larger and also very expensive.

For example Sowter 9045 you mention, is a very good transformer, but it costs about 98 £/GBP, and it is almost double the price as LL1538.

Sowter produces very good transformers, and has a huge range of different types.
I use a lot of their transformers, but in situations where size does not matter.

Lundahl is one of the best in manufacturing transformers with a small convenient format, which many times exceed the performance of similar types from other manufacturers.
This is thanks to their own production of C-cores and winding technique.

--Bo

 

[Potato Cakes]

Bo,

Oh yes, those 9045s were not cheap. I definitely was not in a practical mindset when I was building your DIs. I saw the list of compatible transformers and wanted to build them all. However, when one tries to eat all the flavors of ice cream at once, it winds up giving you a tummy ache!

Thanks!

Paul

 

[Potato Cakes]

Hello, everyone!

I some of the guys I tour with have been asking me to build them some of these DIs as they are impressed at how much better they sound than what is typically seen on a guitar player's pedal board. LR Baggs, to be specific. The cases I have been using I think are slightly too big and I want to make some more in smaller cases. Could anyone here who has built a compact version share which enclosure(s) they used? The size I am referring to is the the Whirlwind IMP 2 or possibly smaller.

Thanks!

Paul