Bo Hansen DI layout

[Bo Hansen]

Now my web-site fixed and opened again, but it will probably take a few days before Google's warning text will disappear.

ksor,
It is the only schematic available right now, I have the original on my desk as a reminder that I will change this so that it conform to the PC layout, but have not had time yet to do so.

The difference is not very large, the modified components are described in my help text, and the LED is labeled on the PC board where to sit.

--Bo

 

[ksor]

I want to change the XLR to a stereo 6,5mm Jack - what shall be connected where ?

 

[ksor]

Is the layout of the PCB critical ?

- I want it so small as posible and the trafo will be separate.

 

[Bo Hansen]

ksor,

Tele plug tip the same as XLR pin 2,
ring same as XLR pin 3,
sleve as XLR pin 1

No, PC layout is not particularly critical, but it is important that you carefully follow my instructions regarding grounding.

--Bo

 

[ksor]

ksor,

Tele plug tip the same as the XLR pin 2,
ring the same as the XLR pin 3,
sleve same as XLR pin 1

No, PC layout is not particularly critical, but it is important that you carefully follow my instructions regarding grounding.

--Bo

Thx Bo !

 

[Mondy]

No, PC layout is not particularly critical, but it is important that you carefully follow my instructions regarding grounding.

Hi Bo

If you are updating the schematic, would it also be possible to maybe clarify the grounding scheme on the schematic also, or maybe provide a simple diagram instead of text, as this aspect seems to be a source of confusion for many people, me included, who are building your wonderful little DI?

Cheers
Ray

 

[ksor]

Someone please confirm that THIS is where the LED should be placed and that the LED is the ONLY component that should be added:

 

[Mondy]

Hi Ksor

The LED should be moved to in between R6 and R8 with its cathode facing R6.

Also some values have changed…
R3 & R4 should be 100K
R10 should be 100R
C3 should be 100n
C5 should be 10uF

Hope this helps & someone correct me if I'm wrong!

Cheers
Ray

 

[ksor]

Hi Ksor

The LED should be moved to in between R6 and R8 with its cathode facing R6.

Also some values have changed…
R3 & R4 should be 100K
R10 should be 100R
C3 should be 100n
C5 should be 10uF

Hope this helps & someone correct me if I'm wrong!

Cheers
Ray

????? > Mondy

Placing of the LED in this link is not like that, I think: http://www.mentol.dk/diy/bohansen/silkscreen.pdf
And I think the PCB's on the FIRST page of this thread is the same: Anode facing the two 6.8K and cathode the 100uF - like in my schematic - right ?
Maybe there is some later change/update ?

The original schmatic - some postings earlier in this thread - has the same values as in my schematic - where did you get those changes ?

 

[Mondy]

Hi Ksor

The positive supply for the whole circuit needs to be obtained from the cathode (K) of the LED and the 100uF cap should be from this positive rail to circuit ground. The anode (a) of the LED needs to be fed only from the common point of the two 6.8K phantom power resistors.

Cheers
Ray

 

[ksor]

Hi Ksor

The positive supply for the whole circuit needs to be obtained from the cathode (K) of the LED and the 100uF cap should be from this positive rail to circuit ground. The anode (a) of the LED needs to be fed only from the common point of the two 6.8K phantom power resistors.

Cheers
Ray

??? > Mondy

I still don't undersand - is the PCB in the link I gave wrong OR is you'r first posting wrong about the placing of the LED ?

Please, where did you get the changes in component values ?

 

[ksor]

OK - I can see some shopping lists has OTHER component values than the schematic - what a mess - what are the correct values - the list OR the schematic ?

Has the trafo to do with these changes - Sowter, Lundahl or Heufe ?

 

[Mondy]

Hi ksor

Here is my schematic I used to create my own board in Eagle.

Please ignore the transistors as I used these just for the attached pad patterns for the custom PCB board I made. Here it shows the connection of the LED and the 100uF capacitor. I added a 100n capacitor in parallel with this capacitor for my version but this was not in Bo's design and can be ignored. The later component value changes are mentioned in Bo's website for the circuit and are just to keep the design updated etc. I used the specified Lundahl 1538 transformer and the DI sounds wonderful so keep up the effort on the build as the results are worth it!!

Cheers
Ray

 

[ksor]

Hi ksor

Here is my schematic I used to create my own board in Eagle.

Please ignore the transistors as I used these just for the attached pad patterns for the custom PCB board I made. Here it shows the connection of the LED and the 100uF capacitor. I added a 100n capacitor in parallel with this capacitor for my version but this was not in Bo's design and can be ignored. The later component value changes are mentioned in Bo's website for the circuit and are just to keep the design updated etc. I used the specified Lundahl 1538 transformer and the DI sounds wonderful so keep up the effort on the build as the results are worth it!!

Cheers
Ray

OK and ofcause ... now I understand your point of the "positive supply" !

Thx  for guiding me - witch transistors did yoy in fact use ?

I go for this version when you have it working very well !

 

[Mondy]

Hi Ksor

I used the BC550C and BC560C transistors that Bo recommended (Fairchild and Motorola). The schematic shows 2 PNP devices because, as I mentioned before, the pad pattern was what I wanted in my board design so I used the schematic parts shown more for their patterns than the actual components.

Sound is great with acoustic guitar and Bo Hansen is a top man for this elegant and hopefully timeless little circuit!!

Best of luck with your build. I will try and post up some pics of mine when I get a little time!

All the best
Ray

 

[ksor]

I need 2 peaces of Lundahl 1538 !

Where can I get them these days for what prices incl. shipment to Denmark ?

 

[Bo Hansen]

Ksor,
Yes, Monday's have insert the LED right, but as I have tell many times before, use only a red LED, to get a minimum of voltage drop.


Monday,
Yes, I will draw a separate block schematic that will explain the electronics grounding theory.

Thanks for a nicely drawn schematic.
The added 100 nF in parallel with 100 uF is OK, but perhaps misleading because it is not on the PC layout.
And ofcourse the first transistor is marked as PNP instead of NPN, but it's easy to change.
There are also missing value (100nF) for the input capasitor and pin id (8) for the case/core ground on the Lundahl transformer.
It is also missing from the XLR-1 connecting pad, a connecting to the DI-box metal case.

--Bo

 

[Mondy]

Hi Bo

I edited the schematic I posted for Ksor as you are right, it could cause confusion. The schematic was created solely to design the PCB board and therefore the components used were used for their PCB patterns only. I drew up an better version for the actual circuit below and I hope this may be of help. I'll take some pics of my build and post as soon as I can.

Cheers
Ray

 

[ksor]

Oh ... Mondy it's very nice !

Anyway you forgot  ;D the capacitor par to the 100uF  ;D ;D - but never mind - I know it's NOT on the original PCB,
but I have it in my Eagle and I have made a smaller PCB !

What's the difference between the XL and a normal trafo concerning sound ?

 

[Bo Hansen]

Mondy,

Yes, now it's right, very nice schematic, can I use it on my tech page?

Just a small thing, it would be good if "chassis" connection is drawn directly on XLR pin 1.



Ksor,

LL1538XL has a larger core, and can handle more level in the low end compare with LL1538.

--Bo