DIY equalizer based on Studer 169 (standard and mastering)

[MidnightArrakis]

Man... So after fighting with this thing for soo long, I can't find any 1U cases that it fits. Par-Metal are too small. Dan's new cases are just a little too small. Any one out there finish these up with a 1U casing that works? I'd like to avoid making these 2U if possible but I'll do it if no solution presents itself soon.

Try these:

https://www.metcaseusa.com/en/Metal-Enclosures/Combimet-19-.htm#galleryImg-9


https://www.metcaseusa.com/en/Metal...8270-69b5-11e5-ab58-bc764e20b40e#galleryImg-1


And.....if you -- REALLY NEED SOMETHING CUSTOMIZED!!! -- ..... I can design you any size of "rack-mount" chassis or enclosure along with any of the required PCBs, should you ever need that. This is what I do!!! See the attached PDF file.

/

 

[Cangore]

Hey everyone,
Today I tested the first Channel of my 169 Build and I‘m having some Issues.
This is my first self-etch Project so I‘m not too surprised.

Before hooking the Unit up i roughly tested for continuity between Traces, especially the Power Rails. Everything seemed in Order.
I should mention that I modded the board for 1 dB Steps as per the Graphs and trace-cutting guide provided by @benlindell. I think I settled for 900Ohm for pretty much everything on the Low Band + 6.7K Resistors on the Back. For the High I used 250,240 and 1K on the Back.
I tested every Single Component before Installation because I built two Units and expect decent matching.


At first, testing was promising:
(i used Motu Audio Tools and REW.

Unit passed some Audio powerded down. And roughly Unity when powered up.
Frequency response very Flat from 20-20K but some ringing below 10Hz.
Distortion seemed very even and minor across the Board.

The Gain Switches However changed very little about the response.
Full CW and CCW changed almost nothing. Maybe a half dB.

When I changed the Low frequency switch to a different position there was horrible distortion and erratic behavior before the PSU suddenly blew a Fuse.

I don‘t know what to check for. Any Ideas?

 

[Cangore]

So I got it figured out... dumb Mistake on my Part.
Also got the HF Boost and Cut figured out. I think there is Problem with the Trace Cutting Guide. after I did some modification I got it working basically perfect. but I'm getting some weird HF Roll-Off. Any Ideas Why that's the case?

 

[Cangore]

I'm also having some massive trouble getting Channel Two to Work at all.
Checked for continuity between Traces, corrected some Issues due to poor etching, swapped the Opamp's multiple times already.

would really appreciate if someone could chime in on the Matter.
This is the behavior I'm getting, seemingly regardless of frequency selection:

 

[tmmmmm]

Is there any chance, someone still has the files that were provided by @audiox? The links are down and Wayback-Machine missed them.
Thanks in advance!

 

[PatchDog]

Hi

I get news from Audiox and he's Ok that I sell the board I made...
So related to the post above, I have 3 board left If some are interested ? I could make others if come some interest.
I can provide BOM I used and frontpanel file that you can edit to your taste (.fpd file)
You need a L-Bracket.
build is easy, just the bypass switch wiring has to be made carefully for going on the good way. Switch need to have a long bat.

build is related to the original, so you can make standard or Mastering version, change frequencies... it's basically a 500 series revision.

10€ each + shipping. I will say only in EU.
I'm not a company, I can't provide an invoice or anything...

If any question, PM me...
best
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View attachment 95062

Hey man these look awesome. Do you still have any PCBs available?

 

[flyweight]

YEah I am also interested to make a stereo or dual mono unit.

 

[DarkSky]

Is there any chance, someone still has the files that were provided by @audiox? The links are down and Wayback-Machine missed them.
Thanks in advance!

I'm also be interested in this.

It looks like the entirety of the "audioxxx.googlepages.com" repository is long since defunct. but like you, I haven't been able to locate anywhere where it's archived. It makes older threads like this one less useful if most of the 'paydirt' info is offsite and no longer hosted!

 

[oran.outan]

Hi,

attach is the Audiox 19" original version files.

If people are interested by PCB for the 500 series version I have made, please message me...

best
0-0

 

[DarkSky]

Hi,

attach is the Audiox 19" original version files.

If people are interested by PCB for the 500 series version I have made, please message me...

best
0-0

That's super helpful. Thank you!

The schematic is very nice indeed. Elegant simplicity.

 

[Kvalitemil]

Standard version (+/- 3,6,9,12,15 dB)

http://audioxxx.googlepages.com/EQ_169_STD_schematic.pdf

Mastering version (+/- 1,2,3,6,15 dB)

http://audioxxx.googlepages.com/EQ_169_MAS_schematic.pdf

Shared documents (for both standard & mastering version)

http://audioxxx.googlepages.com/EQ_169_STD_layout_designations.pdfhttp://audioxxx.googlepages.com/EQ_169_STD_copper_mirror.pdf
http://audioxxx.googlepages.com/EQ_169_STD_frq_selection_lo_filter.pdfhttp://audioxxx.googlepages.com/EQ_169_STD_frq_selection_hi_filter.pdfhttp://audioxxx.googlepages.com/EQ_169_STD_frq_selection_table.pdf
http://audioxxx.googlepages.com/EQ_169_dimensions.pdf

Earlier this year I built a mastering eq for a friend of mine. It is based on Studer 169 mixer channel which has an equalizer that I like a lot (and there are many others sharing my opinion). The feedback that I got was very very positive. So I decided to draw a PCB for it to make it available to all of you (the prototype was a ratnest/veroboard version).

Several changes has been made to the original circuit. Potentiometers are replaced with rotary switches (for accurary). Original fixed frequency is replaced with 5 selectable frequencies.

The eq section contains only one op-amp. It can be used in unbalanced mode (input and output section not assembled) if extremely pure signal path is required. Debalancing and balancing amplifiers are however included in the pcb. If all components are assembled, it provides balanced input and output.

The eq op-amp is classic NE5534 but there are huge amount of pin compatible alternatives available. So you can replace it with better (or at least more expensive) if you want.

The PCB is single sided and suitable for home etching (large pads and thick traces). The board size is 194x38mm. So it fits easily in 1U rack case as well as in standard 40mm mixing console channel module.

Switches are Lorlin series CK. They are available everywhere and there are number of equivalent types from other manufacturers too. Types used are 1x12 shorting and 2x6 shorting. Non-shorting switches can be used but some additional switching noise is likely.
http://www.lorlinelectronics.com/pdf/CK.pdfI have made a lot of work to make this unit tidy looking and easy to assemble (all switches are on PCB). Please don't wire the switches. First, it looks horrible. Second, it increases noise pickup and long wires can cause oscillation (it is unlikely but possible).

As usual, I don't sell boards, components or anything related to this project.

Boards are available from Gustav:
http://www.groupdiy.com/index.php?topic=10776.0
**********

My other projects:

Neumann W492 EQ
http://www.groupdiy.com/index.php?topic=28332.0
Neumann OA10 discrete op-amp
http://www.groupdiy.com/index.php?topic=34105.0
Balanced 12 input summing amplifier
http://www.groupdiy.com/index.php?topic=29082.0
Balancing/unbalancing amplifier
http://www.groupdiy.com/index.php?topic=29333.0

Hi Audiox. Im new here on the forum. Im currently building the tranformer version of 169k from pcbgrinder. I would like to know what values on r24,r25. The link you posted needs access witch i dont have at the moment. Could you give me access or post a picture of it?

Awesome work and im really looking forward for this unit.

 

[ip_dalie]

Hi Audiox. Im new here on the forum. Im currently building the tranformer version of 169k from pcbgrinder. I would like to know what values on r24,r25. The link you posted needs access witch i dont have at the moment. Could you give me access or post a picture of it?

Awesome work and im really looking forward for this unit.

Hi Kvalitemil. This is all you need Studer 169 EQ in API 500 format

Cheers

Ipin