DIY 500 series STUDER 169 Recording Channel (Mic Pre + EQ) Documents Published!

[audiox]

Long time no see. But here we go again.

Studer 169 Mic Preamplifier & EQ section in a single 500 series module. See the drawing attached.

Fully discrete signal path available. The mic pre is discrete just like the original, but the EQ and the output stages allow IC or discrete op-amps. Swapping between the types is easy, no circuit modification required.

There are pads for wiring miniature toggle switches which provide the following options:

- high pass filter
- phantom power on/off
- input attenuator
- phase invert
- selectable LO and HI filter frequencies

There is also free space in the middle of the PCB for output transformer experimenting.

The board is single sided with large pads making it suitable also for the home etchers.

DOCUMENTS:

Schematic diagram
https://drive.google.com/file/d/0B_XBYPfmG8pVcXRLUk5qT2t5SU0/view?usp=sharing

Layout with component designations
https://drive.google.com/file/d/0B_XBYPfmG8pVMHJ0QmhKZkEzU1k/view?usp=sharing

Layout with components values
https://drive.google.com/file/d/0B_XBYPfmG8pVbXh5RDluTFdWUkU/view?usp=sharing

Copper mirror (for home etchers):
https://drive.google.com/file/d/0B_XBYPfmG8pVNnRhRHItZnozU0U/view?usp=sharing

Front panel:
https://drive.google.com/file/d/0B_XBYPfmG8pVLWE2b0s2bmpJR1k/view?usp=sharing

 

[weiss]

Great idea! Is it also possible to enable HPF?

 

[audiox]

Great idea! Is it also possible to enable HPF?

Yes, there are connection points for a high-pass filter switch. I just forgot it from the list.

 

[audiox]

Schematic published. Other documents will follow...

https://drive.google.com/file/d/0B_XBYPfmG8pVcXRLUk5qT2t5SU0/view?usp=sharing

Note. Options not shown for clarity. I will draw separate wiring diagrams for the numerous options.

 

[SoundOfRolf]

Absolutely fabulous!!!

This is just the thing I was looking for.

Great work!

-T

Ps. Just ordered panels and pcb's for the eq. Well no harm done. There's always need for just a good eq.

 

[KDE]

you should throw a line switch on it  H-Pad on the input of the pre

 

[audiox]

you should throw a line switch on it  H-Pad on the input of the pre

There are pads for wiring miniature toggle switches which provide the following options:
- high pass filter
- phantom power on/off
- input attenuator
- phase invert
- selectable LO and HI filter frequencies

 

[audiox]

Layout drawings & copper mirror for home etchers published. See the first post.

 

[Rocinante]

Awesome.  Very awesome.  Thank you.

 

[Jano1954]

Thanx Audiox for the nice schematics.
I am planning to build at least 2 of these modules during my summerleave.
I want to use the modules with the DOA's you use.
I am fairly new to this board and I am looking for a description of these DOA.s
I suppose you did publish them in the past, but I can't find it.
Either I am looking the wrong way or it is not there anymore.
Can you put me into the right direction or supply  with the schematics and pcb drawings for these DOA's?
Thank you so much
Jan

 

[audiox]

I am fairly new to this board and I am looking for a description of these DOA.s
I suppose you did publish them in the past, but I can't find it.

The Neumann OA10 could be one alternative:
http://groupdiy.com/index.php?topic=34105.0

 

[SoundOfRolf]

Any plans on ready made PCBs for those of us who can't etch?

 

[peterc]

Very nice project....

Peter

 

[Niketouille]

Hi,
Do you have any front panel template or drawings ?
Regards
G.

 

[audiox]

Do you have any front panel template or drawings ?

I will prepare the mechanical drawings when I have time. Possibly next week but can't promise.

 

[audiox]

Do you have any front panel template or drawings ?

https://drive.google.com/file/d/0B_XBYPfmG8pVLWE2b0s2bmpJR1k/view?usp=sharing

 

[SoundOfRolf]

Hello!

Questions, questions, questions 

You don't happen to have gerber files?
I'm planning to order some PCBs from dirtypcb or itead.
I asked Gustav, but he doesn't seem to do these?

You said in the EQ thread that:
- resistors 1% metal film
- 100n power decoupling caps, ceramic multilayer 50V or higher R=5mm
- pF range capacitors, ceramic, any voltage R=5mm
- nF range capacitors, polyester, any voltage R=5mm
- 10u electrolytics, 25V or higher R=2.5mm
- 100u electrolytics, any voltage R=2.5mm

Is it the same here? Any brand recommendations?

There are 5 different NE5534 at Mouser. Could anyone help me to pick the right one?

Is there room for option switches? Between the pots right?
I'd like to have the panel ordered with holes for the switches.

The pots come from AML right?
P1=2k2 rev. log OM-01-014 - 16mm - 1 gang
P2 = 2x 22K LIN center detent (order code OM-01-023)
P3, P5 = 2x 10K LIN center detent (order code OM-01-005)
P4 = 2x 100K REV LOG (order code OM-01-059)

And THANK YOU for this project!

-Tony

 

[audiox]

You said in the EQ thread that:
- resistors 1% metal film
- 100n power decoupling caps, ceramic multilayer 50V or higher R=5mm
- pF range capacitors, ceramic, any voltage R=5mm
- nF range capacitors, polyester, any voltage R=5mm
- 10u electrolytics, 25V or higher R=2.5mm
- 100u electrolytics, any voltage R=2.5mm
Is it the same here?

Yes.

There are 5 different NE5534 at Mouser. Could anyone help me to pick the right one?

Any of them will be fine. The -A version has guaranteed (lower) noise specs.

Is there room for option switches? Between the pots right?

Sub miniature toggle switches should fit. But may require some redesign of the front panel texts.

The pots come from AML right?
P1=2k2 rev. log OM-01-014 - 16mm - 1 gang
P2 = 2x 22K LIN center detent (order code OM-01-023)
P3, P5 = 2x 10K LIN center detent (order code OM-01-005)
P4 = 2x 100K REV LOG (order code OM-01-059)

Yes, originally designed for the 16mm Omeg potentiometers.

Other potentiometers: pin spacing 5mm, row spacing 7.5mm or 10mm.

 

[SoundOfRolf]

I found some very affordable pots, but the 2k2 and 22k pots are hard to find. Could I use 2k and 20k pots instead or 5k and 50k with a resistor in parallel?

 

[audiox]

I found some very affordable pots, but the 2k2 and 22k pots are hard to find. Could I use 2k and 20k pots instead or 5k and 50k with a resistor in parallel?

The value of the 2.2k revlog is non-critical. The 22k lin can be replaced with a 20k lin as well (affects the max boost/cut approximately 0.5dB).

If using other potentiometer types, please note that the dimension from the first row of pins to the front panel should be 4.8mm or less.