My new mixer...

Hi friends,

I just got my new mixer. Unfortunately, UPS delivered the mixer in really bad state, they broke the case (a custom case made of wood!) and almost all modules was loose, lots of knobs around the box, some pcbs damaged at the edges, some broken connectors... I cleaned all the disaster but still remains unpowered.

It`s a 8-4 configuration, it have 12 preamp modules, 5 full band eqs, 5 hi-lo eqs, 2 summing modules, 2 limiter modules, talkback module, tone generator, monitor section, aux section, vumeters and a speaker module
It have at least 24 transformers and looking at the channel pcbs seem to be all discrete design. Part numbers are:

micpres: KV800
eqs: FV81, FV80
limiters: RV80
summing: AM80
Talkback: AB800
Tone generator: TG800
Monitor: PV800
VU: AT800
Speaker: SL800


Here are some photos:



More photos including channels strip:

http://photobucket.com/albums/v321/synthi/

I`ll post detailed photos for the modules and pcbs when I can get the digi camera from friend for a few days.
Also may be I could get the schematics in september, the technician that used to service the gear at the studio where I get this mixer is out for holidays now...
I what to use it as a front end to my DAW,may be also for summing

I know some of you have have similar mic pres and eqs, any opinios, advices, comments, etc, are welcome!


Synthi.

Hey Synthi!

I didn't EVER think I'd see another one of them! :!:

I bought an IDENTICAL mixer a couple of years ago. The only difference in mine was that I did not have the sweepable eqs, it came with 8 x 3-band fixed eqs and 2 x 7-band fixed eqs.

According to Oliver Archut, these mixers were made between '77 and '81, they have very unusual circuitry for that era, i.e. the signal-path is mainly discrete, but there are ics in side-chain duties (apart from the comp and ducker which are mostly ic-based). They were made by R.F.T which means they would have been assembled at the Gefell East German plant, i.e Neumann East.

As I'm sure you know, they are single-rail +24v supply. The o/p transformers are lovely, I've used them on all sorts of kit.

One drawback with those mixers is the proximity of the psu to audio routing looms, my mixer had 60hz hum badly and do not think it was entirely due to dried-up filter caps. I ended up racking the eqs and comp and selling off the other parts (I still have 3 preamps left for myself to rack, Zebra50 and Mark Burnley also have some preamps).

The mixer I had was built to order for Deutsche Post! The standard of construction is very high, sorry to hear yours got a kicking in the post...

I would replace the psu electrolytic immediately, and see what the sound is like, I do suspect mine hummed due to ripple from the cap, but also the psu is very near much of the signal loom...

Still can't believe I've seen another :guinness:

The compressor / limiter is a funny device; it is a brick-wall design and can make things sound much smaller, however, I've found this can be quite useful on cymbals and sounds you want to compress down to sit in the mix. I would not recommend it for lead vocals!

I'm off the watch the cricket now, but I'd be happy to answer any questions if you have any. The console should be capable of sounding good, but if you want to keep it in one piece I suspect some work will be needed.

Cheers,
Justin

ps: Where did you get it?

:thumb:

So it's arrived! Excellent stuff.

I got a couple from Justin. I had my two preamps running on the bench and they do sound very good and clean with pleny of gain. I must get mine racked up and it use - I have been too skint to buy a case for them.

PLEASE get the schematics if you can.

Stewart

PS sorry to hear about the UPS fuck-up. I hope you were insured.

Hi thermionic,

Wow, its really good another diy member have the same mixer.
I got it from a radio station studio in Berlin, the mixer was used until now, so if UPS didn`t fuc**d the package, is still in working condition. I saw the PSU inside the unit, very big unit and yes, it`s near the cable and the transformers. Mine have a module for switching between normal operation and 24 volt batteries, so must be I could remove the internal PSU and run the mixer from a external linear 24V PSU, do you know how many amperes would be right for such unit?
I think you noticed in each channel the faders have a switch when at lower value, this switch send a signal using the big tuchel conector on the back for starting events, such "on air" lights, switch on tape recorders, etc...
The 4 red and amber buttons at right of the unit are blinking when a outside reporter send a signal to the mixer, for calling your atention.
I`ll never use these features but they are good to know.

It have direct outputs for each channel and groups, 2 switchable inputs for each channel, one of them carrying phantom power and also external inputs for the groups, so I think it could be used as 12 preamps instead od a 8-4 configuration, the channels and groups are all the same modules.

I`ll do my best for getting the schemos, I think will be very good information for the owners, and also for studying the design.

Best regards,

Synthi

Hey zebra!

finally is here, a bit trashed but I`m sure it will work as new
Now I`m in the process for the UPS reclaim.
I`ll keep you informed about the schemos.

Best Regards,

Synthi.

hi thermonic,

how could you pull apart such a cool little mixer?

I'm in the midst of reassembling a turntable, so I'll have to be brief and I'll be back in the week with some other thoughts.

According to a respected engineer who saw the console (I bought it at auction and had it despatched straight to an engineer who knew the auction organisers for an "escrow" service) the psu has a 160va transformer, I can't see any markings but I would reckon 160va to be about right.

How could I pull apart a cool mixer? After speaking with Mr Archut it became apparent that the circuitry is very nice (all Telefunken design, apart from the compressor which was RFT's own. Oliver does not rate the comp btw, but I think it has its uses), however, in typical East German fashion there are certain construction issues that let the side down... These issues are namely the psu proximity to the signal wiring, and the quality of the connectors. Being entirely modular, a design such as this will need very high quality connectors unless you want to be fiddling around with the modules all the time. My mixer simply did not sound good at all, there was hum all over the place and serious hiss and rfi problems (it picked up radio badly...). Mr Archut suggested that if I wanted to use the mixer in the studio it was probably best to rack the modules I liked as the topology is good.

I could have spent months debugging the mixer and figuring out why it sounded so bad, but when I got the modules on the bench they sounded great and I made the decision to rack.

It is definitely not my usual style to rack up a classic mixer, and I took much thought and time before committing to it.

If Synthi has time to restore the mixer, and modify out some of the design faults I am sure it will make a v.nice mixer indeed, however, I can state fairly accurately that it will require a considerable amount of time and determination to get it to the stage where it will be able to provide quiet service.

I will have a think about what documentation I have for the mixer and get back in the next day or two.

Cheers,
Justin

Thanks for the info thermionic,

I`ll try it "as is", I want a mixer not a rack of pres and eqs but if sound that bad, now I know that at least racking it will be a solution.
Please post any information you can find!
About the conectors, I think you mean the ones between PCBs, the inputs/outputs are Amphenol tuchel 3 or 5 pin , DIN style but with a screw for fixing the plugs, nice quality I think...
About the PSU, do you think a power-one or sola 24V 4A will power the mixer?
Thanks,

Synthi

Hey Synthi,

How come you live in Spain and find cool things like that, I never seem to get to know about things apart from e-bay!

Steve (Alicante)

Hola Microx,

Send me a messaje if you come to Madrid, we can meet here and talk about..hmmm, audio?

Best Regards,

Synthi

Hi there,

I have recently sold four mixers based on these modules. Before that I took out two modules each of the EQ's the limiters, the Output-section and the parametric EQ, since I thought I could rack them one day. Especially the EQ, wich is a passive EQ with gain make-up-stage looked interesting to me. But they are so long, it would take a 9-Unit-high 19"-rack to fit....
Btw. they don't have anything to do with the RFT Comany in Gefell. That was "VEB RFT Mikrofontechnik Gefell", the other was "VEB RFT Funkwerk Leipzig". RFT was just a general Name for the manufacturers that had anything to do with "Rundfunk" or "Fernseh"-"Technik". That were companies that have been nationalized. They hardley had any private companies since the 70's in East-Germany. "VEB" means "Volkseigener Betrieb" which means somthing like "People's Company".

Chris

Chriss, thanks for the info!

Synthi

Just an added note-

I also just received a console (well sidecar, Trident Trimix) delivered via UPS and the modules had been dislodged, bent, and broken, and a few knobs and faders actually look crushed, and this thing was packaged fairly well, well enough that this could have been avoided. So just fair warning shipping consoles via UPS.

Aaron

So I'm WAY WAY WAY behind the curve on this one, but I thought I'd throw in my two cents on this one for the record since a bit of the history above is off-base. These consoles/modules were not manufactured by RFT but rather Deutsche Post RFZ (Rundfunk und Fernsehtechnisches Zentralamt - directly translated "Broadcast and Television Technical Central Bureau) in former East Berlin. Now I'm sure many of your are asking, "What did the post office have to do with broadcast and television?" In East German society, for historical and political reasons, Deutsche Post, the federal postal service, was not only responsible for delivering the mail but also regulated most if not all communications networks including broadcast transmissions and telephone service. RFZ was the central technological development, research, and production center for broadcast radio and television in former East Germany, and made some pretty fine and unique sounding gear as well. Incidentally, they also made wire-tapping and eavesdropping devices used by the Stasi (Staat Sicherheit - State Security or the East German quasi-version of the CIA) to spy on just about everybody remotely suspicious in the former German Democratic Republic. Most of their designs were allegedly based on Telefunken ELA-Technik designs, or were allegedly under the supervision or consultation of ELA-Technik engineering designers. I have some of these, so look at the PCB's and you will see Deutsche Post RFZ on them and not RFT.

[quote author="Tillmann"]In East German society, for historical and political reasons, Deutsche Post, the federal postal service, was not only responsible for delivering the mail but also regulated most if not all communications networks including broadcast transmissions and telephone service.[/quote]

Just to add some more historical information: the former Eastern German radio and TV stations had no technical staff and equipment! All the technical things were managed by Deutsche Post. So everything from the microphone on was not in the responsebility of the radio / TV station. That's another reason that almost everything used in Eastern German brodcasting has written Deutsche Post on it: it was their property!

Olaf

He visto tu post y no he podido resistirme, interesante cacharro!!

Y además he visto que eres de Madrid también

Sigues teniendo la mesa en tu estudio?

Saludos a todos!

P.S. sorry for using a different language, but the guy is located in Spain like myself and wanted to reply in Spanish just for fun!

(original post: 11 years ago...)

11 years!!! 

I fell as it was yesterday!!!

synthi said:

11 years!!! 

I fell as it was yesterday!!!

Click to expand...

Me too!

Nice to see another" Madriders" around here