Restauration of STUDER 169 console

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Well-known member
Nov 7, 2005
whell this small beast have great sound... and since i keeped one of few I had.... i spend some time using it in studio.

I notice that channels are actually very different in color and volume also noise level was different on each channel..
in studio I use it as preamps, expander for more channels to my MCI 500 and FX returns since my MCI have only 4 //

Studer is in use as 12 ch desk!!!

after some time I decided to do complete restauration of console

- For all channels recaping of electrolytic caps and tantalums is MUST!!!
after I open console and notice that 80% of FRAKO caps are lets almost dead i ordered panasonic and elna caps

almost all frako caps looked like this!!!


I/o Module Caps list is:

100uf/25v x8
220uf/25v x5
47uf/16v Tantalum x1
10uf/25v Tantalum x4

Cleaning faders is MUST !!! top end is in 90% dirty and make crackle while useing it I cleaned that too

also I notice that poor made trim pot is used in I/O module for Fader Buffer calibration RUWIDO 4k7 ... I relpaced it with multiturn Bourns one!!!  


still have to demagnetize transformers on modules and mod it for direct output!!!!!

STUDER 169 i/o module after restauration!!!!


List of recaping of each summing module !

100uf/25v x5
220uf/25v x3
1000uf/6,3v x1
1000uf/16v axial x2
0,47uf/35v Tantalum x1
3,3uf/25v Tantalum x2
6,8uf/25v Tantalum x1
10uf/25v Tantalum x3

also cleaned faders and thinking of replacing trim pots and recalibrating modules!!!!

thanks Damir will do recapp and other things in the future, one question: using reverbs units or other hardware as inserts on the 169 channels, is not clear to me how to do it, on the manual says connect the output of reverb unit to the hi level input (xlr)
is correct or there is a better way?

ciao filippo
on i/o modules REPLACE R47 trim !!!!!!!!!!!!
it make big difference on REV SEND, and output of each module in db!!!!!!!!!!!

that RUWIDO are BAD!!!!!!


pippo64 said:
thanks Damir will do recapp and other things in the future, one question: using reverbs units or other hardware as inserts on the 169 channels, is not clear to me how to do it, on the manual says connect the output of reverb unit to the hi level input (xlr)
is correct or there is a better way?

ciao filippo

Hi Filipo

whell you can connect 2 ways!!!

If you wanna use pre fader send ...use FB if you want post fader eq use SEND REV....

connect input of your reverb to talk back module .... on back of that modules is FB and SEND REV summing output (XLR out balanced) ... on talkback module also is MASTER send control for FB and SEND REV.
return output from your reverb into master section modules (XLR balanced inputs)... on top of that modules are line inputs balanced to use as FX return.. select pan and level and go!!!! :)

or you can return signal from reverb to 2 of channels and use them to color reverb with fx :)
Hello, great job and thanks for sharing with pics. I had one of these before and it sounded quite good but I bet yours sound even better now after the restauration.
This is bit crazy...

I have few modules from different revisions of 169 in my console... on 2 modules I dont have that BUFFER FADER TRIM.. and output on modules are different..removed factory trim and recalibrated all modules!!!!!

BINGO!!! INPUT MODULES ARE PERFECT!!! still to demagnetize tomorrow!!!!!! and route direct outputs from preamps!!!!!

bunch of I/o Modules ... you can see different revisions by different XLR colors on back of modules

ok here are Talkback module and Control room module

Recaping list for talkback module:

100uf/25v x4
220uf/25v x2
1000uf/6,3v x2
1000uf/16v axial x4
47uf/16v Tantalum x3
1uf/25v Tantalum x2
3,3uf/25v Tantalum x2
10uf/25v Tantalum x5

Recaping list for CTRL room module:

100uf/25v x2
220uf/25v x5
100uf/16v Tantalum x6

on CTRL room module remove RC 4136N from IC socket and clean pins ..they are heavy oxidated.

Recaping list for bridge meter:

220uf/25v axial x8

Modification for direct out :

I used idea that user 37518 explained in his racking design

Remove pins from patch bay that is on back of modules from connection points 95, 96, 97 on PCB .... and keep 98 yellow wire (on my modules) in place
that way you free patch points for use as unbalanced out!!!!

PBC is top mid connection point of patch bay on back of module (red wire)... extend wire and connect to connection point 14 or 15 on PCB under fader. (SIGNAL OUT)
PCM is lower left patchbay point (if looking from back)  (blue wire) ... extend it and connect it to ground point anywhere on module where you like module have ground point above connection point 98.. so i used that one!!!

leave PBL white wire patch point free...(maybe for future use)

thats it you have unbalanced exit from each i/o module !!!! thanx user 37518!!!!

Before modification:

After modification...follow red extended wire:


recaping of DC/DC converter in front of frame

how it looks original


Recaping list of DC/DC converter:

47uf/50v x1
220uf/25v x1
220uf/63v x2
1000uf/25v x6
2200uf/40v axial x2

OK now de-magnetizing!!!!!!!!

some time ago I found on this forum  THANK you 1954U1

quickly done the de-magnetizing procedure suggested:
sine wave at 30 Hz, 30 secs sweep 0V-3V [point of saturation], 30 secs sweep 3V-0V.

so now 28 input transformers to de-magnetize :eek:
That is great work on a great console.
What happened to all the wiper legs to those old pots?
And you might consider replacing those RC 4136's, at least in the mix/monitor section with something like a LT1359 or LM49740.  Jim Williams is big on this type of swap, and eliminates the coupling caps at the output.  I am going to try it on a certain British console that just don't sound good because it is loaded with TLO74's.
OK .....

cleaned frame.... looks like new.... ready to be loaded!!!!


whell ... after that tried to recalibrate all trims on master modules and realized that allmost all are scratchy and no good to be used....

whell more work replacing trim post!!!!!! not just RUWIDO on i/o channels ... I replaced em all on console!!!!

.. well ok I want studer in perfect shape!!!!

example BEFORE change of trim potentiometers  ... BAD, DIRTY, OLD....

and after .... NEW, FRESH.....

weekend is finish!! ..I will recalibrate and test console

hahahhahaa I just realized I forgot to replace 1 ..... 22k .... hehe thanx to camera!!! .... I go fix that too..

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