Studer 169 EQ in API 500 format

Help Support GroupDIY:

audiox

Well-known member
Joined
Feb 25, 2007
Messages
610
169_EQ_500_pic_1.jpg


Why? I had some spare time yesterday. And my friend is planning to build an API format console and he likes this eq. I know that he probably never actualises his plans but it was quite fun to do this...

Low shelving filter +/- 15dB. Default frequency is 20 Hz as in the original circuit,
but you can select a new value for C6 from this graph to change it:
http://audioxxx.googlepages.com/EQ_169_STD_frq_selection_lo_filter.pdf

High shelving filter +/- 15dB. Default frequency is 20 kHz as in the original circuit,
but you can select a new value for C4 and C5 from this graph to change it:
http://audioxxx.googlepages.com/EQ_169_STD_frq_selection_hi_filter.pdf

Presence/absence filter +/- 12dB. Frequency adjustable from 150 Hz to 7 kHz.

Schematic (see the layout drawings for the input section component values)
http://docs.google.com/fileview?id=0B_XBYPfmG8pVZGViZTg4YmQtMDM0Yi00M2IzLTkwYTYtOWE4Zjg2YTk0MDE3&hl=en

Layout with components designations
http://docs.google.com/fileview?id=0B_XBYPfmG8pVYTI0MWQ0NTEtYzVmOC00ODU4LTkzODQtZDBhYTFkYTc3N2U0&hl=en

Layout with components values (active balanced input)
http://docs.google.com/fileview?id=0B_XBYPfmG8pVNzM2OGQxMDEtZGM4MS00ZjYwLThlYjEtNWYzNzE1NGQyNTlk&hl=en

Layout with components values (transformer balanced input)
http://docs.google.com/fileview?id=0B_XBYPfmG8pVMmRhZmNkZWEtMjU2ZS00YmI1LWFjNTYtY2ExY2Y4NDFjY2Vh&hl=en

Copper layer for home etchers (the board is single sided)
http://docs.google.com/fileview?id=0B_XBYPfmG8pVM2U5MzM3ODEtN2E1Yy00NTBhLWE5ZTEtZGNlZWU3ZTUzYzJl&hl=en

PCB drill sizes:
Switch and potentiometers 1.3mm
Discrete op-amps 2.3mm
Transformer 1.0mm
Mounting holes 3.2mm
All others 0.8mm

Front panel
http://docs.google.com/fileview?id=0B_XBYPfmG8pVNWZlNzA1ZjktOTA3ZS00Nzg5LWI2NWMtMzEzMjAyNmEyMjkw&hl=en

Front panel supporting hardware
http://docs.google.com/fileview?id=0B_XBYPfmG8pVMjVkMDYzNTEtYzdhMS00ZDlkLWJjNWMtZGZjMGFiODAzYTNl&hl=en

---

Boards are available from Gustav:
http://www.groupdiy.com/index.php?topic=37783.0
http://www.groupdiy.com/index.php?topic=10776.0

Potentiometers are 16mm Omegs (to keep the costs down):
P1 = 2x 22K LIN center detent (order code OM-01-023)
P2, P3 = 2x 10K LIN center detent (order code OM-01-005)
P4 = 2x 100K REV LOG (order code OM-01-059)
http://www.audiomaintenance.com/acatalog/potentiometers_carbon_16mm_diameter_dual_gang.html

Switch is C&K (ITT Schadow), Alps etc.
http://classicapi.com/catalog/product_info.php?cPath=51_52&products_id=88

Transformer Studer 1.022.405.00 = Neutrik NTL1
http://www.neutrik.com/fl/en/audio/210_197961/NTL1_detail.aspx
http://www.canford.co.uk/Products/23-003_NEUTRIK-NTL1-TRANSFORMER-Analogue-audio-PCB-line-input
http://uk.farnell.com/neutrik/ntl1/transformer-1-1/dp/8314659
or ask your local dealer: http://www.neutrik.com/content/contact/worldwideagents.aspx

Discrete op-amp sockets
http://classicapi.com/catalog/product_info.php?cPath=71_77&products_id=122


As usual, I don't sell anything related to this project. All the information is provided "as is".

If you need stepped level and frequency settings but you don't need presence/absence filter, please check this:
http://www.groupdiy.com/index.php?topic=33996.0

**********

My other projects:

Neumann W492 EQ
http://www.groupdiy.com/index.php?topic=28332.0

Studer 169 EQ (stepped gain and frequency selection)
http://www.groupdiy.com/index.php?topic=33996.0

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
 

[silent:arts]

Well-known member
White Market Member
Joined
Jun 4, 2004
Messages
5,139
Location
Berlin, Germany
cool!
and so much PCB space left  ;)
ever thought of (optional) DOA footprints (your OA10 comes to mind), or some input and / or output transformers?
 

Joechris

Well-known member
Joined
Jun 3, 2004
Messages
320
Location
Norway
"if you can squeeze the preamp in there i'd be in for two"
rule of the tumb, maximum 4 knobs for a 500 series thing.

:)
 

Mbira

Well-known member
Joined
Jun 4, 2004
Messages
2,418
Location
Austin, TX
How are people doing the metalwork on these 500 series?  Is there a group buy I'm missing, or some inezpensive method?  This eq look really nice!  Thanks for sharing!
 

matta

Well-known member
Joined
Jan 11, 2005
Messages
1,640
Location
Cape Town, South Africa
+1 for the mic pre, makes for a great channel strip... and not much extra to add the pre, there is space on the PCB, panel spac is ata  premium though. Why not move the EQ IN switch to an off board toggle switch? Should clear up some space for a grayhill for the mic pre?

Cheers

Matt
 

audiox

Well-known member
Joined
Feb 25, 2007
Messages
610
okgb said:
if you can squeeze the preamp in there i'd be in for two

matta said:
and not much extra to add the pre, there is space on the PCB

Joechris said:
rule of the tumb, maximum 4 knobs for a 500 series thing.

I knew this... Joechris already answered, but seemingly not clearly enough.

Yes, there is enough space on PCB for the Studer mic pre. But you should also be able to fit the following controls to the front panel (in addition to the existing 4 pots and a switch)

- rotary switch for the coarce gain
- potentiometer for the fine gain
- phase invert switch
- phantom switch
- high-pass filter switch

Any volunteers to try that?
 

mpc3000limited

Well-known member
Joined
Aug 14, 2009
Messages
81
Location
Connecticut
I think it is fine as is, no need to complicate a good thing! there are plenty of pre's out there to choose from making a dual purpose eq/pre wasn't what you were after! Nice job as always you make useful PCB layouts for gear otherwise left to the wayside!
 

desol

Well-known member
Joined
Jun 20, 2005
Messages
2,064
mpc3000limited said:
I think it is fine as is, no need to complicate a good thing! there are plenty of pre's out there to choose from making a dual purpose eq/pre wasn't what you were after! Nice job as always you make useful PCB layouts for gear otherwise left to the wayside!

Yep, looks good to me to. I'm sure adding more in the way of discrete opamps, transformers, etc, would involve more re-design than easily suggested...and probably would make little to no difference...maybe worse. Keeps it affordable as well.

Bunch of board real estate left? Draw a naked girl holding a beer.

I've never had to pleasure to hear these...but i'm probably down for a pair. Cheers.
 

ChrioN

Well-known member
Joined
Aug 31, 2005
Messages
1,235
Location
Gothenburg, Earth
Optional DOAs and input/output transformers and its a sweet unit :)

If making all those choices up to the builder, it can be either very simple or pretty simple.
 

Baltimore

Well-known member
Joined
Nov 19, 2005
Messages
245
Location
Baltimore, MD - the Charm City
I think selectable frequencies for the high and low bands would be a better addition than the mic pre. And would make the eq much more versatile.  Either way, I'll probably build a pair.   Looks awesome!

Add transformer I/O and DOA option and I'll build more than a pair!
 

audiox

Well-known member
Joined
Feb 25, 2007
Messages
610
[silent:arts] said:
ever thought of (optional) DOA footprints (your OA10 comes to mind), or some input and / or output transformers?

ChrioN said:
Optional DOAs and input/output transformers and its a sweet unit :)

Baltimore said:
Add transformer I/O and DOA option and I'll build more than a pair!

The discrete op-amp idea came into my mind too but... In my mastering version prototype of this same circuit I included a socket for plug-in op-amp boards. My friend and his colleagues made comparison between NE5534 and NTP M-100 discrete op-amp but there was no difference. I understand the discrete op-amp concept in high gain applications like mic preamps but in eq circuit like this there is no real benefit.

Adding transformers... The nature of this eq is very neutral and adding quality transformers wouldn't change it much. I actually have a layout version which has a Studer 1.022.405.00 = Neutrik NTL1 (the original Studer 169 line input trafo) at the input and active balanced output. The line input trafo configuration of the 169 is not zero-field like in later Studers, so it adds a little coloration. But the effect is still quite minimal...

I publish the transformer version since there are so many who like the idea. The extra cost for those not assembling the trafo is only two wire links.
 

okgb

Well-known member
Joined
Oct 18, 2004
Messages
5,806
Location
Winnipeg Mb Canada
the idea to add the mic pre
was just like extending the other thread
about making the studer channel strip
if i was up to speed and smart enough
i'd help with the design
ever use a 550 a or b  , thats small
 

matta

Well-known member
Joined
Jan 11, 2005
Messages
1,640
Location
Cape Town, South Africa
I know front panel real estate is tough, though it can be done... this for me pushes the limits, 10 knobs, 4 push buttons:

DSCF1598retcrop.jpg


It is Dan's new 500 series Harrison Eq, talk about fitting alot into a SMALL space!

Matt
 

audiox

Well-known member
Joined
Feb 25, 2007
Messages
610
matta said:
I know front panel real estate is tough, though it can be done... this for me pushes the limits, 10 knobs, 4 push buttons

I never said that it is impossible. I have designed that kind of puzzles too, when I worked as an electronic designer. Doable but takes a lot of time.

But now we are talking about DIY project which must be easy to assemble, contain only minimum of mechanical parts and most importantly components must be cheap and easily available.

Do you remember the whining when I used (small but expensive) Sfernice potentiometers in the Neumann W492 project?
 

Latest posts

Top