Looking for Telefunken/TAB W395(a) & U374a schematics

[sismofyt]

It's one of those Kommando Verstärker thingies, combined preamp & limiter. It's also bandlimited, manual sayz 400Hz to 6kHz -1 dB but I don't know how fast it falls. Not too steep by the sound of it. It's really noisy and the limiter has the slowest release time on earth. But it makes whatever I put into it sound very up close, like if you had a center/phantom loudspeaker right in ya face. That can be usefull sometimes. Also ads a nice mild distortion... it's definitely not for eveyone though, so don't yell at me if you think it blows Bit like a U373 if you got that one.

I have two 'a's and the schematic of the U374 at kubi's site doesn't look like mine at all. There are more boards, transistors and a couple of devices I don't have a clue about. There's also an interstage trannie..

They're probably going for silly money on ebay :roll:

 

[[silent:arts]]

[quote author="sismofyt"]
I have two 'a's and the schematic of the U374 at kubi's site doesn't look like mine at all. There are more boards, transistors and a couple of devices I don't have a clue about. There's also an interstage trannie.. [/quote]

I just found the 'a' schematic and scanned it:

http://www.silentarts.de/lab/studiotechnik/tab/U374a_Schematic.pdf

 

[gyraf]

Damn, [silent:arts] :shock:

You just keep on posting stuff that should be nearly impossible to find..!

It's HIGHLY appreciated..!

Thanks,

Jakob E.

 

[[silent:arts]]

Thanks Jakob :grin:

I just found another variant of the U373, the U373P:
http://www.silentarts.de/lab/studiotechnik/tab/U373p_Schematic.pdf

 

[volki]

interesting, never heard nor seen the p-version. is it newer than the other versions?

as far as i can see from the circuit, there's only one setting for compressor mode (as opposed to three with u373a)

simplified gain control circuit and very different detector arrangement.
the circuit before the interstage trannie seems to perform some sort of amplification?
then there's something left out in the detecor circuit (that part which i never understood anyway :green: ), and there also seem to be some "smoothing" elements (transistor/diode/resistor) missing from gain ctrl to ground, and from detector to gain ctrl.

can anyone explain to me how exactly the detector circuit works in both comp and limiter mode? i can't really see why the limiter should turn into a compressor only because the center of those resistors after the interstage trannie is pulled to ground. also, in comp. mode you still get the limiter at +6db on top of that. how does that work?

for modding, it would be interesting to switch off the limiter feature in comp. mode, so there's a broader useably range of compression without the limiter squashing it. or even, a variable limiter threshold would be nice. so would be a variable comp. threshold. (uh my gawd :green: )
any suggestions?? :razz:

 

[sismofyt]

I don't know volki.. I'm not smart enough to figure out those diode compressors.. :? :roll:

THANK YOU for the U374a schematic 'not so silent art' :thumb: :grin:

So, the mysterious components are the HO650 diodes (#116 & 117) around BC108B (#6)! Any idea where the 400Hz-6kHz bandwith limiting is going on? Around the input of the limiter (lower left corner of the schematic) in conjunction with the BV 2559 interstage trannie..? I don't want to bypass that stuff, I'm only curious. I do however want to take the limiter out with a switch and for that this schematic is indeed very much needed!

You're a peach, silent arts :thumb: :grin: :sam:

 

[volki]

peach :?:
a piece of fruit?
another slang expression we poor auslanders don't understand :green:

 

[sismofyt]

Ich bin auch ein ausländer! :green: It was a compliment and, I think, an english term. Something you'd say to your girlfriend. I almost luv silent arts more than mine.. hahaha.. ****, hope she's not online

 

[volki]

right, i forgot - you're a polser, i'm a kraut :green: :green: :green:

 

[sismofyt]

Wud is a polser? It sound suspiciously like the danish, 'pølser', which is not exaclty a compliment though still in the food category :green:

 

[volki]

i didn't bother to look for the "ø" in my german font :green: :green: :green:
no offense though, i actually like pølser hot dogs a lot! and i don't really like the german "sauerkraut" (sour marinated cabbage) too much...

 

[sismofyt]

I'm hungry now! :? :roll: :wink:

Back on topic, does anyone know how those comps actually work?

 

[NewYorkDave]

I don't know, but I could sure go for some sauerkraut right now! :grin:

 

[sismofyt]

 

[Michael Tibes]

Hi Kubi,

I did just recently scan some Braunbuch stuff, if you wanna take care of it!
It's too big to go as a mail attachment. I scanned all the pages I have, not only the schematics...
If it's to much, I can just send you a CD, we're both in Germany. :wink:

Michael


[quote author="kubi"][quote author="[silent:arts]"]IYes, the Braunbuch itself, the holy bible of audio! If you find a spare copy of the Braunbuch, drop me a line. I need three hours to get to whereever it is located in Germany! :grin:

kubi[/quote]

 

[sismofyt]

What exactly is this *braunbuch*? No offense, but it sounds like the 3rd Reich's plan to take over the world or something... :shock:

I sorta picture this GIGANTIC leatherbound book with a big fatass TFK diamond on the front and thousands of module schematics.. :green:

 

[volki]

sismofyt, you're on the right path, more or less. it's actually a full documentation about the *whole* tfk/tab/siemens/maihak valve range from the 50's. VERY rare, to say the least :green:

btw, cool pic - food porn instead of gear porn for a change :grin: :shock: :green: :thumb:

 

[Michael Tibes]

[quote author="sismofyt"]What exactly is this *braunbuch*? No offense, but it sounds like the 3rd Reich's plan to take over the world or something... :shock:[/quote]

A VERY strange concept to call it 'Braunbuch' (brownbook) after the colour associated with Nazis is brown - and naming the amps V7x after the V1 & V2...
I would have chosen a different naming those days...

In fact I believe that it wasn't a complete book, but more like a folder concept in which the documentation and schematics of the german radio station gear was stored. I came across a collection of 2 full boxes with various of those books maybe 10 years ago, sorted everything and photocopied whatever looked like it might be of use one day. This collection is in 1 big folder now.

I have recently scanned the V7x Mic - and Lineamps and sent a cd with these scans to Kubi. I think I skipped the poweramps and the V 75 seems not to have a 'braunbuch' description, but the schematic is anyway available from another thread.
If I find the time, I will probably scan some more stuff in the future - the compressors would probably be most interesting.

Michael

 

[rafafredd]

Hey Kubi, would you upload it in another section at least for a few days?

because it´s easier to download for those of us that have already downloaded the entire content of your website. It´s a pain to check what I have already downloaded and what´s new, you know...

Thanks for doing this german module schem sharing!

 

[Michael Tibes]

[quote author="rafafredd"]it´s easier to download for those of us that have already downloaded the entire content of your website. It´s a pain to check what I have already downloaded and what´s new, you know...
[/quote]

Check this out: http://www.httrack.com, I like it :grin:

Michael