New stuff, only 60 years late

[thomasdf]

Man, what a projet, I am still amazed ! Thanks for the updates ! Eye candy for sure.
I have a SIFAM meter and want to redo its scale, so I'm curious to know how you printed on the plastic you cut ?

 

[abbey road d enfer]

Maybe that
https://www.amazon.fr/15-Feuilles-I...&sprefix=papier+vinl+imprimable,aps,69&sr=8-5

 

[cpsmusic]

What an amazing project! Truly inspiring! Here I am, agonising over some guitar amp repairs

 

[cardboard]

I have a SIFAM meter and want to redo its scale, so I'm curious to know how you printed on the plastic you cut ?

It goes like this:

1. I draw it in Adobe Illustrator

2. I save it as 300 or 600 dpi .png image

3. I put it on a USB-stick, take an A4 sheet of 1mm PE with me and walk 2 blocks to my copy shop (price-wise the most unreliable copy shop in the world, und unfriendly too) and ask him to print it on my sheet of PE. In German, the process is called 'Kashieren'. Special print, sheet taken off, sticky side onto sheet, and then hot-rolled.

I'll ask him what his sheets are called!

and if it helps, I could do the Illustrator part.

M

 

[cardboard]

Maybe that
https://www.amazon.fr/15-Feuilles-I...&sprefix=papier+vinl+imprimable,aps,69&sr=8-5

Maybe, yes. As said, I'll ask the copy shop gruntlerist.

 

[thomasdf]

Thanks for the info ! I am at ease with illustrator and it’s almost finished already. I’ll try that technique. I’m curious how I can keep the warm yellowish tone of the original LA2A meter, it’s not white like the Ernest Turner meters. I’ll do some testing

On the SIFAM, the scale can be removed and it’s on a thin plastic sheet

 

[cardboard]

Good morning Thomas,

About the yellowish stain: with ‚kashieren‘ (‚to apply‘), the layer they print for me can have any colour I give it, see below. However, I supply my own A4 sheet of plastic.

There seem to be, however, more ways to do this..

 

[cardboard]

Good morning!

At some point in time, I realised it would be a very good idea to collect and prepare all switches and controls for my mixer before any engraving takes place. So I've been collecting, inspecting, modifying, rearranging and rebuilding quite some stuff now. Almost all REDD.27 controls are in, except for nine pan pots.

One of the three switch boxes:


Building an 8-way (4-track) Line Key, to switch monitoring between desk Line Out and Line In (returns from Tape machine):


Two hours for one switch. While doing this, the words witchcraft and switchcraft crossed my mind. There she is:

In order to make this Line Key, I had to use parts of no less than three of those Telephone/Bundeswehr/Fernmeldetechnik/Kellog/Muir Head switches. It's a 2 inch stack now.

And, as feared and announced and expected, the finished switch indeed calls for a minor change of the engravings file. Hurray!

Here's the kitchen table:


Some more switches that got prepared and modified that session are the Echo Coupling switch, and the push buttons for Announce to tape, talkback to Studio, Buzzer and Red Light:


More to follow, for sure!

Regards,

mart

 

[cardboard]

Hello,

I'm awfully sorry that I've been away for quite some time - no particular reason, nothing serious or severe, just that something called life asked for some attention

There's quite some nice progress to report.

1. Engravings of the Mixer top panels. I asked for prices for the engraving of the top panels and for all the small black Trafolite name tags. The most affordable supplier still asks for an incredible 1400 euros! So, for 350 euros, I bought a used 500 x 400 cm flatbed CNC router, which I'm currently extending to 580 x 650, so that it is large enough for engraving a Center Section top panel. A buy like this is very dangerous for the progress of such a project - 'veering off' is it called (note to self: don't!).

2. Functionality of the Mixer. Because engraving is not yet possible, the electric design that I finished in November mentally started to sink in over the past few months and - inevitably - wishes for changes start to appear. I always take such 'bigger-better-faster'-fantasies with a large grain of salt, but in this case, they were good. Here's a few changes: a) On the REDD.51, EMI had installed 'stereo pan pots'. It is known and well-documented what they do, so I figured out what they are, electronically, and will incorporate one. Just one. And it needs a Diff Booster Amp*, so the vacant amp bay 'Test' was sacrificed for it. b) I traded in the Stereosonics on the M1 & M2 Channels for some more contemporary signal treatment. Using the same control positions for that, I could keep the panel lay-out the same. c. The Spreader on M7 & M8 stays, but a choice of frequencies is made available. So I can now, additionally, spread the top end, narrow the bass end, etc.

* best T-shirt word ever.

3. Workshop. I have acces to a workshop now. It is a shared workshop, run down all the way and it gets battered and beaten every weekend when the Bicycle-afficionados do their thing, but hey, I have access to a workshop now!



4. Tape Machine electronics. Gave the tape machine electronics quite some thought, resulting in the functional diagram below. I use as much of the originally available Relay control functionality as possible, but add qoute some more, since this is multitrack, and because it has Guide Tracks stuff.
All sections are tube, mostly ECC88 and ECC83. The regulated power supplies, oscillators and slaves are tube units as well.



5. Tape Machine Oscillator. The HF-section of the Studer B37 worried me a bit, but: good news. It turns out that my B37 has a later version oscillator, which is exactly a C37-oscillator. Yeeha! Not all is well yet, since I need to raise the oscillator Frequency quite a bit, but I have a working oscillator with which I can carefully and systematically start experimenting.



5. Correlator driver. Someone was so kind to lend me an EMI RS133 Correlator Driver. It is the portable model. It was dead on arrival, so after I repaired it (some wires broken at soldering point on the PCBs and a shattered fuse holder), I had it working on my bench (which is in the workshop I have access to now! )
I do like a bit of reverse engineering, but in this case, it was impossible. Two back-to-back sandwiched pcb's, squeezed in there, lacquered very shiny - traces so hard to identify. So instead I used its reaction speed to get the behaviour of my own design right. Nice nice nice!



Happy to be back, regards,

Mart

 

[thakava]

Hello,

I'm awfully sorry that I've been away for quite some time - no particular reason, nothing serious or severe, just that something called life asked for some attention

There's quite some nice progress to report.

1. Engravings of the Mixer top panels. I asked for prices for the engraving of the top panels and for all the small black Trafolite name tags. The most affordable supplier still asks for an incredible 1400 euros! So, for 350 euros, I bought a used 500 x 400 cm flatbed CNC router, which I'm currently extending to 580 x 650, so that it is large enough for engraving a Center Section top panel. A buy like this is very dangerous for the progress of such a project - 'veering off' is it called (note to self: don't!).

2. Functionality of the Mixer. Because engraving is not yet possible, the electric design that I finished in November mentally started to sink in over the past few months and - inevitably - wishes for changes start to appear. I always take such 'bigger-better-faster'-fantasies with a large grain of salt, but in this case, they were good. Here's a few changes: a) On the REDD.51, EMI had installed 'stereo pan pots'. It is known and well-documented what they do, so I figured out what they are, electronically, and will incorporate one. Just one. And it needs a Diff Booster Amp*, so the vacant amp bay 'Test' was sacrificed for it. b) I traded in the Stereosonics on the M1 & M2 Channels for some more contemporary signal treatment. Using the same control positions for that, I could keep the panel lay-out the same. c. The Spreader on M7 & M8 stays, but a choice of frequencies is made available. So I can now, additionally, spread the top end, narrow the bass end, etc.

* best T-shirt word ever.

3. Workshop. I have acces to a workshop now. It is a shared workshop, run down all the way and it gets battered and beaten every weekend when the Bicycle-afficionados do their thing, but hey, I have access to a workshop now!

View attachment 109363

4. Tape Machine electronics. Gave the tape machine electronics quite some thought, resulting in the functional diagram below. I use as much of the originally available Relay control functionality as possible, but add qoute some more, since this is multitrack, and because it has Guide Tracks stuff.
All sections are tube, mostly ECC88 and ECC83. The regulated power supplies, oscillators and slaves are tube units as well.

View attachment 109359

5. Tape Machine Oscillator. The HF-section of the Studer B37 worried me a bit, but: good news. It turns out that my B37 has a later version oscillator, which is exactly a C37-oscillator. Yeeha! Not all is well yet, since I need to raise the oscillator Frequency quite a bit, but I have a working oscillator with which I can carefully and systematically start experimenting.

View attachment 109360

5. Correlator driver. Someone was so kind to lend me an EMI RS133 Correlator Driver. It is the portable model. It was dead on arrival, so after I repaired it (some wires broken at soldering point on the PCBs and a shattered fuse holder), I had it working on my bench (which is in the workshop I have access to now! )
I do like a bit of reverse engineering, but in this case, it was impossible. Two back-to-back sandwiched pcb's, squeezed in there, lacquered very shiny - traces so hard to identify. So instead I used its reaction speed to get the behaviour of my own design right. Nice nice nice!

View attachment 109362

Happy to be back, regards,

Mart

Very cool!

 

[nsalis]

For comparison, you might be interested in the oscillator of the previous model (series 27).
Attach files
Nicolin Salis

 

[cardboard]

For comparison, you might be interested in the oscillator of the previous model (series 27).
Attach files
Nicolin Salis

Dear Nicolin,

Thank you very much for posting that '27 Oscillator. Apart from using a different tube, I see some differences, like the 2000pF caps on the plate going to the centre tap of the oscillator coil, etc, but since I'm not too familiar with how oscillators work (a bit like: 'a tank (a coil and a cap) and an amp go berserk'), I'm not able to learn too much from the circuit you posted.

Is there, for example in terms of sine wave symmetry, something to learn from it?

Thanks, and regards,

cardboard