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Make a fixture that diverts the tape between the record and replay heads such that there is something like 1/2 a turn at 45RPM of delay. The replay chain then feeds the lathe modulation input while the tape machine input feeds the lathe automation.

A goniometer on the transfer console would probably be a good idea if doing stereo cutting, but I would suggest that having someone mixing and someone running the cutting is the way, it is too much for one operator.
Dear Dan,

I get the the idea with the tape diversion fixture, thank you. I will have guide track outputs on the STUDER B37, using the Rec heads as faux-replay. Would those signals carry the information the cutter automation needs? (thinking of bass response here)

And although I really like the sound of the word goniometer, I have to ask: what is it?

mart
 
Aaaah, ein Vektorskop!
That's on this list: "Those terribly interesting add-ons once I'm done building" :)
I've reserved a 1948 Philips GM 5655 for that.

Interesting thing, with which I could already do a little goniometering: the Mixer Desk has a so-called 'Correlometer' inbetween the VU meters. It looks at the phase between the outputs. Moving up = in phase, moving down = out of phase.

mart
 

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Hello again,

This week is big picture week. All the gear is shown in a sort-of 'Installation manual'. In drawing it in a few steps, I discover all kinds requirements I hadn't thought about yet, like 'the crate of the Center Section must have room for the Arm Rest', and 'after putting that Center Section into place, a break and a beer is probably a good idea'.
 

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Great! Now everyone is going to expect this level of detail and illustration! What's next? Marionettes doing an interpretive dance of a schematic?

Sorry. Just a little jealous...

That is amazing on so many levels.

Not only is the idea great, the gear is awesome. But to top it all off, they got some guy from Marvel to draw the diagrams.

I vote to make these the first images that appear when people Google 'diy recording'.

Now if you will excuse me I need to go practice my drawing skills.
Now, where did I leave my crayons.

Nice work! Looking forward to more updates.
 
hello all,

I've been lurking, chatting with Winston O'boogie and helping someone out with a STUDER Monitor speaker, but did not yet introduce myself. So here we go:

I'm from the Netherlands, living in Cologne (Germany) and have been professionally active as a tube gear designer from 2003 to 2012. Quite challenging, so now it is a hobby, in order to keep things nice.

I've built a small tube PA a few years ago (picture 1) for my own band, and you can see that I did not design the exterior much, just took the amp I liked most and varied a bit to my liking. The only thing not self-made was the mixer. I decided to follow the same path as with the PA, and look for great-looking examples. Within minutes on the web, one inevitable ends up with pictures of the REDD desks. That became my example, and I started collecting info in them, and design a very, very small interpretation/look-alike (picture 2)

I never finished it, because I stumbled upon the .37 drawings for sale. I bought them. It is 2.7 kg of paper (picture 3), and very, very complete. Sad thing is that I cannot share them here.

Someone wrote about old studio gear like the .37: 'Dude, these machines are so old, you cannot even connect them to something else. Only to your ears and to your heart.' Lovely.

Around the same time, a friend of mine gave me a beaten and battered STUDER B37 Tape machine (picture 4). And then I had an idea:

What if I build a desk like the .37, convert that STUDER to 4 tracks, build a few compressors and a record cutter, make it all as portable as possible, and call it a Mobile 7" Record Cutting Plant (picture 5, but I will make only ONE cutter, not FOUR, as shown).

It is a slow but deeply satisfying journey. The STUDER top plate has been sand-blasted, frame repainted, parts cleaned and the transport is 80% rebuilt (picture 6). The REDD drawings took long to understand, but eventually, I was able to design my own version: the .27 it is called. In complexity and possibilities, it lies between the REDD.37 and REDD.17. Nice: the REDD.17 was designed by the German EMI-engineer Peter Burkowitz (as was the .37, to be complete), RIGHT HERE in Cologne. So 'the REDD story comes full circle'.

Picture 7 and 8 show the top and back of the new .27 desk. It has the 3-unit architecture of the .17 (using the transport cases as bottom elements), but very much the 8-2-4 track lay-out and signal routing of the .37 mixer. I simplified quite a bit in the Monitor and Check circuits. And drastically reduced the number of amplifier slots to only 28.
The re-engineering and re-drawing of quite a large portion of the .37 drawings is coming to an end, and I very proud of the results.

Sourcing parts is extremely time-consuming, and I'm glad I'm almost done (picture 9), and also glad I tried very much to cut down on controls and amps.

The Cutter is behind on schedule, but I became a member of the Secret Society of the Lathe Trolls, and that helps a lot.

So, if you stumble upon a question I post here and think: 'what on earth does he need that for..??!' - the answer is: 'for this'.

This will probably take quite a few years to complete. I see it as my last project, because after I finished, I intend to use it. People can call me, ask if I can show up with a Beatle board and then cut a 7" record of a live venue. I like that. And make music with my band.

mart
Oh man! That 09 pic... where you find all these parts? I need these for MY mixer build :)
Following
 
I get the the idea with the tape diversion fixture, thank you. I will have guide track outputs on the STUDER B37, using the Rec heads as faux-replay. Would those signals carry the information the cutter automation needs? (thinking of bass response here)
The Sync output (playing back from the record head) generally has a slightly restricted HF response (10-12kHz) and a limited Signal/Noise ratio. Since the automatic pitch calculator uses mostly the high-level LF content of the signal it is perfectly adequate.
Interesting thing, with which I could already do a little goniometering: the Mixer Desk has a so-called 'Correlometer' inbetween the VU meters. It looks at the phase between the outputs. Moving up = in phase, moving down = out of phase.
This is arguably less efficient than a proper vectorscope. It was typically used when mixing so the SE would deliver a "vinyl-compatible" print, but the disc mastering engineer needed the extra information given by a vectorscope or similar apparatus.
The disc mastering engineer would use a tunable Elliptic Equalizer to fix any remaining issues.
 
Great! Now everyone is going to expect this level of detail and illustration!
No no no! A plea to you all: please don't stop being electronicians! I like you like that! Dont't raise the drawing bar!
And with drawings: I can help.
I vote to make these the first images that appear when people Google 'diy recording'.
Now THAT would be so cool!
 
Oh man! That 09 pic... where you find all these parts?
the REDD desks were made within EMI, but they were designed by a guy at EMI Deutschland, here in Cologne. And he based his designs on standard available german stuff. So almost everything in a REDD.17 or .37 is german. So I've been sourcing that pile here in Germany. And it took me 2 years.

Most difficult:
1) those REDD.17 handles (until I discovered that they're on almost every Telefunken M5!) :)
2) enough make-before-break switches
3) a REDD.17 mains entry (still looking for 2)
4) 68 Siemens TF sockets

The Sync output (playing back from the record head) generally has a slightly restricted HF response (10-12kHz) and a limited Signal/Noise ratio. Since the automatic pitch calculator uses mostly the high-level LF content of the signal it is perfectly adequate.
Wonderful. Thank you!

mart
 
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Great stuff, cardboard
I feel that the Painton faders are impossible to find.
I just went with the Eckmillers as I have a bunch.

What does the Redd.17 mains entry look like?

Best,
tom
I had the luck to find 10 Paintons in one go quite early in the process..! I only need one more... Otherwise I would probable have Eckmillers as well.

The REDD.17 mains entry is a reversed wall socket (second from left in the picture):
 

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I have no clue whatsoever. I have never been closer than 5 km to a blank disc

Then I KNOW you will be successful. To quote Mark Twain: “All you need in this life is ignorance and confidence; then success is sure.”

I think there are very few people on this forum that would actually attempt some of their projects if they really understood what it was going to take to finish. I consider that a good thing. Ask a child if it's possible; they will answer "yes" and proceed to do the work to make it happen. Ask an 'adult' if it's possible; they will answer "no" and proceed to prove themself right by doing nothing.

No no no! A plea to you all: please don't stop being electronicians! I like you like that! Don't raise the drawing bar!
I think I'm going to get a shirt with 'Electronicians' on it. That is a great term!

Part of my post was in jest. It's just really great to see the sort of technical drawings you produced. As for me, I don't think I could produce anything at that level without serious effort (that would take me away from soldering and wiring and that sort of thing) so I'll leave the art to the artists. Just very impressed with both the drawings and the subject matter.

And with drawings: I can help.
Be careful what you offer, you may get way more request than you expect. I, for one, would be thrilled to have some of my chicken scratch turned into something my wife could look at without her eyes crossing.

Again, great stuff. Can't wait to see how it progresses!
 
I had the luck to find 10 Paintons in one go quite early in the process..! I only need one... Otherwise I would probable have Eckmillers as well.

The REDD.17 mains entry is a reversed wall socket (second from left in the picture):
You are going all in✅
what are you going to to about all the metalwork/ frame?
 
what are you going to do about all the metalwork/ frame?
Aha, first U-turn back to the mixing console :)

In the .37 drawings I bought, a dissapointingly low number of dimensional drawings is included: one. It shows the earth connection label, picture below. Haha haha! Bummer.

redd.37-118 tag.jpg

There's a few photos in the internet of the REDD.37 and .51 opened up, and two Vintage King sales videos. These proved to be crucial in my reverse engineering. Sheet metal wise, the two types of desk are quite different, and I decided to stay as close as I can to the .37.

The three units (brilliantly called 'Left Wing', 'Centre Section' and 'Right Wing') I will make out of aluminum, welded together here & there, screwed together in other places. The most challenging parts are the 3 top plates, the 'Engraved Panels'. I need to CNC-engrave them, paint them Battleship Grey and then fill the engraved characters and lines with paint. Never done that, but I'm looking forward to it.

The next items that are quite a challenge are the racks where the V72 amps slide in, picture 2. I need them as 7-slotters. Sometimes they pop up on eBay as S67 racks, but have not been succesful at scratching one under my nails.

s67 v7x-rack 01.jpg

The back panels, with all the mounting holes, I hope to CNC as well.

And then, there is that enormous collection of black labels. This is white-behind-black name plate plastic, just as you will find next to your neighbour's door bell. Again, CNC, because there are some really wonderful symbols to engrave:

m-27 cs-u-links.jpg


When comparing that with the original, you can see I've greatly reduced the number of Siemens 3-pole 'U-links' (without losing too much REDD.37-functionality), but those sockets are so expensive that it is still quite an investment.

I will be posting more about the desk in June, carefully choosing what to show, not breaching EMI copyright.

regards,

mart
 
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