Studer 289, large custom configuration

[zamproject]

hello

I'm planing in the next few month to refurb/rebuild a large 5 frame Studer 289
I have questions and need advise regarding this

I actually run a smaller 4 frame 289 with 6 mono, 9 stereo input, 6 aux send/2st return and 4 bus/master, fully restored 3 years ago
I'm so happy with it regarding sound but quite limited with all stereo modules and total input (28)

The 5 frame desk have 18 mono with quadriphonic panpot, 6 aux send / 4ST return and 4 buss/master and need works to be on the top

My ides is to make a big configuration with both desk using the 5 frame desk (It's also possible to make a 6 frame but i don't want to definitely part one chassis)

target specification are:

-16 mono
-8 stereo
(32 input in total using 3 frame space)
-6 aux send with 4 stereo return
this will end in a 40 channel desk

-adding 8 stereo line out card for 16 patchable direct out trough insert

-For the bus/master i have to see what will be the best configuration
as i have 4 stereo compressor to load, 1 stereo filter and also the monitoring section (1 frame in total i think)
option is keeping the actual 4bus/master routing,
change to 6 bus/master (I can modify the ST sub group originally re-routed trough input as a bus/master)
or 6 bus + master (this could be done by chaining master modules, X input to 6 bus to 2 master)

So!!!

First, the PSU i think i have to add a bigger one or use 2 PSU to drive all this (5 frame full loaded..)
It's easy to calculate the total consumption as manual give all single modules needed current.
But i have no idea on how i have to calculate margin regarding PSU max output current.0%, 10%, 50% ???

Second, the summing
When looking at Studer history the 289 seem to be one of the first 32 input desk (for the biggest configuration), assuming 32 channels summing amp capability (with "less than 2 Ohm" input trafo on the bus/master unit)
What will append with 8 or 10 more input (saying 40total) loaded to the master bus?

Or are the limitation due to noise floor?

service manual say about noise
summing unit:
source 175Ohm (equivalent 18 input units)
bandwidth 20kHz
<6dB

input unit:
Noise voltage referred to the input
of the unit with a source impedance
RS=200 Ohm    NF < or = 4,5dB (equivalent to -124,5dB at input, measured RMS 30-20k)

do you think i can do a noise simulation (for 40 input) with my actual desk by recording 2 time 20 opened input routed to the master an sum it in my DAW?

All suggestions and comment are welcome!!!

Zam

 

[zamproject]

ok, i made some math regarding consumption

the actual set up loaded in the 5 frame desk is about 5.5 A under 22v.
Considering the 10 line out amp at full power, 220mA for a +24dBu output.
But my studio line level is +8dBu, in this case it's more around 4.5A total
The desk have 2x3A regulator

the configuration i want to build is around 8.5A for hi output setting and 6A for +8 setting
for sure I need bigger PSU 

 

[zamproject]

nobody ?  :-\

 

[zamproject]

Ok i have 2 question regarding recap

i use the Vishay/BHC (ex blue philips) asm series for all axial with success in previous restoration

This caps are not cheap and i need lot of them, i come across stock on an electronic web store, very cheap, but batch are from 2005 or 2000 (depending on uF value).

Can I consider 10 years old caps ?

second Q regarding PSU caps
I'm tempted to use this Epcos (need 2)
http://radiospares-fr.rs-online.com/web/p/condensateurs-aluminium/1909059/?searchTerm=B41570E8478Q&relevancy-data=636F3D3226696E3D4931384E4B6E6F776E41734D504E266C753D6672266D6D3D6D61746368616C6C7061727469616C26706D3D5E5B5C772D5C2E2F252C5D2B2426706F3D313326736E3D592673743D4D414E5F504152545F4E554D424552267573743D4234313537304538343738512677633D424F544826
But it is to big for the PSU module
How long can be the wire between the bridge rect <-->caps <--> regulator
i can find room in the frame to screw them.

Zam

 

[Orpheus]

I would post a link, but my phone is the only internet I have currently. Google "reforming electrolytic capacitors" It describes how to make a simple jig to reform old caps. If you're doing a lot, you can gang several jigs together off of one variac.

 

[zamproject]

Tks Orpheus

I think about this, but I have around 150 axial in the desk, not sure if i want to reform so much lythic, especially 10 or more years old (as I read 5min +1 min per month storage...),
It seems like after 1 or 2 years storage reform are needed...I'm thinking it was more
Maybe it's better to pay twice the price but have ready to use capacitor.

Zam

 

[Orpheus]

Depends on what the price is I guess. I've ganged up to five of them together with alligator clips mounted to a piece of plywood. At that rate it shouldn't take you more than an afternoon. Its not like you have to be sitting there staring at the things. I only do it while I'm soldering or something