Kevin

Hi Friends
Since the last weeks i'm designing different DI Boxes in business card Format






Active DI Box works with easy to get standard electronics parts.
The passive Version works with different High End Transformators
Lundahl LL1935
Jensen JT-DB-EPC
Pikatron ÜP3096M
Cinemag CM-DBX
Palmer PMT02

Both DI Boxes have An Pad, GndLift and Merge Switch. Active Version can run on 2x9V Battery. Passive Version have a Polarity Switch.

I also did comparison with different DI Boxes to find out how different they sound, the difference in Level

P96DI Lundahl LL1935 -> 0.0dB
P96DI Jensen JT-DB-EPC -> -1.7dB
P96DI Pikatron ÜP3096M -> -3.9dB
P96DI Palmer PMT02 -> -0.2dB
A72DI -> +7.0dB
Bo Hansen -> +7.2dB
Behringer DI 400 -> +0.6dB

Sound samples can be found here
https://soundcloud.com/kevin-fricke-1/sets/di-box-comparison

Boards available in my White Market Thread or with every bigger order one is for free ;)

White Market Thread
https://groupdiy.com/index.php?topic=76303.0

Parts for the units
passive one

INPUT,THRUW   NRJ6HF   2xNRJ6HF
X1   NC3MAH   1 x NC3MAH
T1   JENSEN   1 x CM-DBX/JT-DB-EPC
T2   LUNDAHL   1 x LL1935
T3   PALMER   1 x PMT02
T4   PIKATRON   1 x UP3096M
RPAD1   0207_10C   1 x 4k7
RPAD2   0207_10C   1 x 510R
RFGNDLIFT1   0207_10C   1 x 51R
RPAD3,RPAD4   0207_10C   2 x 7k/6k8
C1   C050-075X030   1 x 10nF
GNDLIFT,PAD,180°,MERGE   ALPHAMINIDPDT   4 x ALPHA SWITCH


active one

R8   0207_10C   1   x   100k
RPAD6   0207_10C   1   x   4k7
R7   0207_10C   1   x   100R
R9,R12,RPAD2   0207_10C   3   x   100k
R10   0207_10C   1   x   1m
R11,R13,R2   0207_10C   3   x   47k
R14,R15   0207_10C   2   x   680R
R17,R18   0207_10C   2   x   6k8
RFGNDLIFT1   0207_10C   1   x   51R
RPAD1   0207_10C   1   x   510R
RPAD3   0207_10C   1   x   2k2
RPAD4,RPAD5   0207_10C   2   x   7k/6k8
PAD,GNDLIFT,MERGE   ALPHAMINIDPDT    3   x   ALPHA SWITCH
C7,C4   C025-050X025   2   x   47pF
C10   C050-075X030   1   x   10nF
C14,C15   C050-075X030   2   x   1nF
C1   C050-075X080   1   x   1µF
C8,C9   CE-020X050   2   x   22µF50V
C6,C2   CE-020X050   2   x   10µF50V
C5   CE-035X100   1   x   470µF25V
IC3   DIL08   1   x   TL072
D1,D5,D6,D7,D8,D11,D2   DO41-10   8   x   1N4005
D4,D9   DO41-10   2   x   ZF6.2
LED   KK-156-2   1   x   LED
2X9V_BATTERY   KK-156-4   1   x   KK-156-4
X1   NC3MAH   1   x   NC3MAH
INPUT,THRUW   NRJ6HF   2   x   NRJ6HF
« Last Edit: December 03, 2020, 11:15:22 AM by Kevin »


frans

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #1 on: November 16, 2020, 09:54:09 AM »
I wanted to ask what is the input impedance and the maximum level?
Insert witty one-liner here

Kevin

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #2 on: November 19, 2020, 07:11:19 AM »
Hi Frans
the active ones work with 1M Ohm input imepance, but you can use also line signals with them. there is a 20db pad working for that.
The input impedance with an transformers depends on the transformer used, also the maximum level.
Hope that helps

Whoops

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #3 on: November 20, 2020, 10:54:36 PM »
Hi Kevin,
do the active ones work with phantom power or just with batteries?

Thanks

Kevin

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #4 on: November 22, 2020, 02:37:20 PM »
The active one works with phantom or two 9V Block batteries. the jack in the input activates the battery/ phantom power also enables the di box ;)

Whoops

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #5 on: November 22, 2020, 03:12:44 PM »
The active one works with phantom or two 9V Block batteries. the jack in the input activates the battery/ phantom power also enables the di box ;)

Thank you so much Kevin,
is it possible to modify the input of the Active DI for 10Mega input impedance?
I would like to use that with some piezos.

Thank you so much

Potato Cakes

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #6 on: December 08, 2020, 01:33:33 PM »
Is there a particular enclosure that these PCBs will directly fit?

Thanks!

Paul

Kevin

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #7 on: December 09, 2020, 06:10:07 AM »
it fits in Hammond 125B Case but not perfectly. still need to do off board wiring
I'm working on a full metal case for this DI boxes. hopefully i get them this year ;) then i can offer also cases ;)

Whoops

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #8 on: December 09, 2020, 06:33:26 AM »
Thank you so much Kevin,
is it possible to modify the input of the Active DI for 10Mega input impedance?
I would like to use that with some piezos.

Thank you so much

Hi, Kevin did you have a chance to read my message?

Thank you

Kevin

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #9 on: December 09, 2020, 10:45:47 AM »
I don't see a problem why they don't should together with piezos. But lets look at the shematics and you will find the solution by looking for non-inverting op-amp input resistance and cahnge some values in the DI Box. that shouldn't be a problem. i would defintly go for R8 and R12, but check if you would change other values!


Whoops

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #10 on: December 09, 2020, 12:02:50 PM »
I don't see a problem why they don't should together with piezos.

They will work, but for most piezos 5 to 10 Mega input impedance provides a better load than 1mega

But lets look at the shematics and you will find the solution by looking for non-inverting op-amp input resistance and cahnge some values in the DI Box. that shouldn't be a problem. i would defintly go for R8 and R12, but check if you would change other values!

What would you advise to change and what values to have the input impedance at 10 mega?

Thank you so much Kevin

Cheers

Kevin

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #11 on: December 10, 2020, 01:50:37 PM »
They will work, but for most piezos 5 to 10 Mega input impedance provides a better load than 1mega

What would you advise to change and what values to have the input impedance at 10 mega?

Thank you so much Kevin

Cheers

As i said before please check the schematics on your own and go breadboarding and testing like we all do if want something special and want to modd something how we need ;)
I added the schematics to the last post of mine, you can use it to modify and test how you can change the input impedance. and then my board will also still work just with different values ;)
And as i said check for "Non-inverting operational amplifier" and learn about input impedance. with about more then 4700 posts you should be a guru in electronics and that will be a easy task for you! ;) ;)

Whoops

Re: P96DI & A72DI - Passive and Active Di Boxes in Business Card Format
« Reply #12 on: December 10, 2020, 02:49:25 PM »
with about more then 4700 posts you should be a guru in electronics and that will be a easy task for you! ;) ;)

No I'm not any electronics guru Kevin, I'm a professional mixing and mastering engineer that does audio electronics as an hobby and I also like to fix stuff and do the maintenance in my own equipment.
I have no electronics background or former education in that area, what I know I learned over here so I'm sorry but I don't have the knowledge to modify the input impedance on my own.
Your active DIs look nice congratulations for your work, I would like to use them Live with some bands but needed the 10mega input impedance.

Thanks anyway
Best regards


 

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