Making Bo Hansen DI better?

[jensenmann]

Build and then listen to it. If you have complaints then go into modding mode. This design is very good and not too fuzzy about parts. I´ve built it and it turned out to be my best DI. Unfortunately I lent it to a friend´s studio where it sits now. I fear I have to collect it with some friends from a southern Italian organization to get it back.

If you want to go esoteric then use polypropylene (Wima MKP for example) for all caps. That´s about it.

[toolz]

Also built this, and it's a fantastic DI box that never fails to impress me.

[lejon]

Originally Posted by jensenmann

If you want to go esoteric then use polypropylene (Wima MKP for example) for all caps. That´s about it.

Cool, thanks. This is what I'm after. I'm sure that the DI box will be great as it is but if there's something that can be easily improved just by selecting better components or something similar.

[toolz]

Originally Posted by lejon

Cool, thanks. This is what I'm after. I'm sure that the DI box will be great as it is but if there's something that can be easily improved just by selecting better components or something similar.

I'd guess the sound is in the design, more than the quality of the parts.

[lejon]

Originally Posted by toolz

I'd guess the sound is in the design, more than the quality of the parts.

Of course the design is the most important factor here. I just thought I could ask if someone has some suggestions. But it's also great to hear if people who have built it think that it can't be improved in any way. I'm just after the most high-end DI box you can possibly build..

[Jim Williams]

Originally Posted by lejon

Of course the design is the most important factor here. I just thought I could ask if someone has some suggestions. But it's also great to hear if people who have built it think that it can't be improved in any way. I'm just after the most high-end DI box you can possibly build..

Maybe try a different approach. I don't use DI's here. I use line amps with a 1 meg ohm input impedance. Then I only take the gain needed to reach line level and avoid the gain staging from attenuation/amplification of the DI technique. They are all AC powered and don't suffer from the limited current of the 48 volt/10 ma DI designs.

Any 500 series or similar preamp with a high impedance 1/4" input can do this.

[lejon]

Originally Posted by Jim Williams

Maybe try a different approach. I don't use DI's here. I use line amps with a 1 meg ohm input impedance. Then I only take the gain needed to reach line level and avoid the gain staging from attenuation/amplification of the DI technique. They are all AC powered and don't suffer from the limited current of the 48 volt/10 ma DI designs.

Any 500 series or similar preamp with a high impedance 1/4" input can do this.

This was a nice thought..! Do you know how input inpedance can be measured with multimeter, or can it be measured? We have a 80's Harrison console, so propably it could be possible to make high inpedance input box for the line input? EDIT: bear with me if I have stupid noobie questions, but I just don't know that much about electronics..

[Jim Williams]

Anything is possible, with proper funding! The Harrison line input cards are around 20k ohm impedance, balanced. That design will not work for passive electric guitars. That requires a 1 meg single ended input using jfet opamps or transistors for best noise matching.

[lejon]

Originally Posted by Jim Williams

Anything is possible, with proper funding! The Harrison line input cards are around 20k ohm impedance, balanced. That design will not work for passive electric guitars. That requires a 1 meg single ended input using jfet opamps or transistors for best noise matching.

Do you happen to have any suggestions for a simple schematic that would do the jfet based instrument to line level conversion? I would like to try to build one to hear what it sounds like.. Bo hansen audio has this: http://www.hansenaudio.se/FET%20impe...0converter.jpg and I found also this GuitarNutz 2 - JFET Buffer and buffer cable but they both seem to be made for different use than what I'm after.

[BuildaFriend]

Originally Posted by lejon

This was a nice thought..! Do you know how input inpedance can be measured with multimeter, or can it be measured? We have a 80's Harrison console, so propably it could be possible to make high inpedance input box for the line input? EDIT: bear with me if I have stupid noobie questions, but I just don't know that much about electronics..

I'm pretty sure that to measure impedence you just throw an ohm meter on the hot and ground. pins one and two or tip and sleeve.. but dont quote me on it.

[Studerfreak]

Originally Posted by BuildaFriend

I'm pretty sure that to measure impedence you just throw an ohm meter on the hot and ground. pins one and two or tip and sleeve.. but dont quote me on it.

We won't quote you on that because it is not the right method to measure impedance.

[dcollins]

Originally Posted by Studerfreak

We won't quote you on that because it is not the right method to measure impedance.

You can buy a meter that reads Z (impedance) directly, or do this:

http://www.cartchunk.org/audiotopics...MeasureFAQ.pdf


DC