GroupDIY

General Discussions => The Lab => Topic started by: roginator on November 29, 2008, 01:48:42 PM

Title: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on November 29, 2008, 01:48:42 PM
Whell I had luck to find a rare mixing desk from Austrian company WSW.
In the desk there were a lot modules looking like army comunication modules or something..so i could not take a deks ..but I got modules...couse desk will be museum exponat  ;)

with a little help of some ppl around the world
and info WSW web site http://www.wsw.cz/index1.htm

I realize that I have germanium microphone preamp so I decided to keep it and do cleaning, restauration ....

I have module 811-481... and I found this schematics of 811-483 mic preamp
(http://www.wsw.cz/10WSW_MIC_AMP/WSW_SCHEMA_MIC_AMP.JPG)


so after a a night checking all...I realise this is earliest version of discrete WSW preamp based on AC 151r germanium transistors and OA85 germanium Diodes
im no expert in this field

so after a lot restauration I did I decided to recap module with panasonic FM Caps and replace resistors with new one
 (I heard some older from early 60s are noisy) anyway no big job cca 20 resistors to replace..cant do any harm!!!

here is picture of module before I started cleaning and restauration


Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on November 29, 2008, 02:04:58 PM
OK recaping and changing restistors in progress here

ANY info on this module or sugestion is welcome!!!!!!!


Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: PRR on November 30, 2008, 03:06:43 AM
Built-in Limiter.

Ts7 gets rectified output, biases Gr1-Gr4 diodes on, shunts input signal.

Attack time near 30mS, release about 1 second.

May be a very flat limit curve, like 20dB:2dB.

May be no good for rock studio work, except to "squash" sound.
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: Whoops on December 26, 2008, 11:58:48 PM
Hi,
looks wonderfull.

How is the project going?
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: jensenmann on December 27, 2008, 08:02:10 AM
Damir, are you sure that this schematic belongs to your module? I can only see silicon transistors in the schematic but your module clearly uses germanium types. This difference might affect some parts values in the circuit
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: Rob Flinn on December 27, 2008, 09:00:40 AM
Damir, are you sure that this schematic belongs to your module? I can only see silicon transistors in the schematic but your module clearly uses germanium types. This difference might affect some parts values in the circuit

Agreed.  BC109c & BC140 were silicon th last time I used them.

If your amp is Germanium make sure it doesn't use a negative psu bore you power it up.    PNP transistors were more coomon for Germanium than Silicon, & certainly with the old Neve Germanium modules they use a -24v PSU.
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on December 27, 2008, 10:08:39 AM
Hi Guys


thanx

I continue with project

thanx to good ppl I got documentation on this module....Its Komandoverkstarker what is actually talk back modul...

also I have mic preamps wich are called StudioSteckverkstarker 811402 and im looking for schematics of this modules
I have tube and silicium WSW schematics of universal Amps like 811301 and 811403..BUT NEED 811402 schematics

here are documentations of module im working on ....
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on December 27, 2008, 10:09:35 AM
more documents
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on December 27, 2008, 10:12:37 AM
I hope this will be good preamp ..Im looking for mods ..ANY idea anybody!!!

also more modules waiting for work

I have one of this Komandoverksarkers for sale if anybody is interested ;)
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on December 29, 2008, 02:44:23 PM
ok

this module is done..recaped ..changed resistors and sound good..thought its talk back mic BUT still sound good.. 811481 is based on germanium Transistors AC 151r and germanium diodes AO 85..Im gonna keep it!!!!!

next is  original Universal amp  aka Studio steckverkstarker from 1964 also WSW....

based on germanium stuff

I got 4 in bad shape so decided to do restauration of 2 for my studio ..couse I believe this is first and last time I will SEE THAT ALIVE!!!!

Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on December 29, 2008, 02:48:05 PM
another shot of module 2 days ago!!
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on December 29, 2008, 02:57:10 PM
This modules are also interesting couse they as all wsw Mic preamps 811301 ( tube) and 811402 ( silicium transistor based) they have 3 different inputs on input transformer...Im still learning all this but as I see it has Mic and line input on same transfremer!!!

I have schematics of 811301 ad 811403

BUT LOOKING FOR SCHEMATICS FOR 811402 Germanium Studio steckverkstarker!1! and any info on them!!!!

so I decide to cleane 2 modules and start replacing old parts like caps and resistors!!!!
ordered missing panasonic caps ..so soon it will sing .....whille waiting here are few pictures of cleaned and  almost done module!!! one of 2


Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on December 29, 2008, 02:58:30 PM
started
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on December 29, 2008, 02:59:56 PM
still some work to do  here are pictures
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on December 29, 2008, 03:06:08 PM
This modules are using SIEMENS ADY 20, SIEMENS ACY 15, SIEMENS BZY 83, RCA 2N2613

just looking for Datasheets for that diodes and transistors

http://www.pemberton1.btinternet.co.uk/transistors/2n/2N2613.html
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on June 08, 2009, 05:16:05 PM
yeah done... all new resistors metal film 1%, trimpots replaced with new ones!!!
all new nichicon capacitors..cleaned fully 2 psc of germanium universal mic line preamp!!!!  8)

tested and working good...still need scematics for this 811402 preamps for calibration on interstage transformer, and 2 trims on main pcb!
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on June 08, 2009, 05:22:13 PM
other angle
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: roginator on June 08, 2009, 05:25:36 PM
Im done with my needs for germanium PREAMPS!!!!!
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: mono-poly on July 14, 2009, 05:11:02 AM
I can buy a whole lot off someone who wants to sell something in one deal.
Are people interested in some off the WSW modules?
It are the DI ones in the group pic on the left.

150 euro each
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: jpalden on October 02, 2011, 12:29:02 PM
@ roginator:
still searching for the 811402 schematics?
@mono-poly:
any modules left?
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: ljupcopavlovski on February 29, 2012, 06:32:08 PM
Please someone post scheme of WSW 811 402..thanks
Title: Re: Restauration of rare WSW gemanium Mic preamp from 1964
Post by: peeping tom on February 15, 2014, 11:59:23 AM
more documents

Hi roginator,
I realize that this toping is very old , but if you still have this schematic ( wsw 811481) please send it to me with better resulution if it's possible for you!(the one that is already here is difficult for me to read) I need it because I found old WSW pre that works on 9VDC batteries, but shares the same cirquit( except the resistor values) and I want to convert it to work on 24VDC.
Here is the diskussion I've started if you want to help me:

http://groupdiy.com/index.php?topic=55243.msg705173#msg705173

Best regards!
Mihail