World's Smallest All-Tube Spy Recorder - The Minifon P-55 

Would love to see more restoration videos of this. This thing is amazing

Thank you so much for sharing this Fran !!

2:36 Translation of the manual in German: "10 simple hints for the correct handeling of the Minifon P55 "S" and "L" 1) Install the batteries in the correct manner i.e. + on + y - on - 2) Check the motor battery meter - the indicator must be in the white field. If the playback volume is to low, replace the anode and fillament battery. 3) Insert all plugs completly into the sockets until the end. 4) Check the adjustment of the potentiometer (keep in mind the distance) 5) Use the right accessory for the intended purpose - e.g. (neck/throat microphone when dictating in the car) 6) When changing the reels make sure that the recording "speaking" head is in its uppermost position. 7) Put the recording wire reels on until they latch, make sure that the wire runs through the recording head's slot 8) Work only with the minifon when the lid is closed. Don't touch the rotating reels or the recording ("speaking") head 9) Press buttons quick and firmly until they latch. When rewinding, if the red light shines, press stop button immediately 10) *For the sake of optimal recording and play back quality use minifon original accessories and sealed minifone recording reels.* Beautiful 1950ies wording. Written by the engineers themselves - no marketing speak - except in the last line.

*That's what makes franlab unique on youtube* ❤❤❤

OMG this is the most impressive piece of electronic equipment I've ever seen for it's time period

5:56 - Literally "wearing a wire"!

Fran is pretty amazing too .

Holy cow that is one awesome artwork.. A piece of wire can’t wait to see you get it going fully restored

Fantastic! I wonder what else do you have in the vault...

Wow...what an interesting piece of history you have there Fran. Thanks very much for showing us this.

You never cease to amaze me with the relics of days gone by that you present. Thanks Fran for all the work you put into your videos.

Fran, in case you have to repeat such an actions with lots of screws, use my trick: (i) Place the plate with all these screw heads upside down onto a scanner and scan it. (ii) Print, cut and glue the image onto a foam plate of same size (thickness > expected screw length). (iii) Drill small holes into foam at screw positions. (iv) Start disassembling your item and stick screws at corresponding location in the image-on-foam, screw by screw. By these means you will never mix up screws while re-assembling your item !

Years ago I used to buy a lot of government surplus items. I thought of advertising as "Yesterday's Technology, Today!". I was a caretaker in the graveyard of technology. You have an amazing collection of old electronics.

What an amazingly neat workplace!

It's so great to have Fran back taking apart some antique audio equipment... Yeah!

WOW Fran, I'm impressed with that recorder for sure. Ahead of it's time for late 50's,lol. Thanks for the Vid

Oo! Techmoan is so going to want to get his hands on that! 8o)

"Fran, your mission, if you decide to accept it, is to rebuild this Minifon tape recorder, making it faster, stronger, better..... this spool of wire will self destruct in 5 seconds". A conflation of two TV show opening themes, obviously! Or perhaps re-using the same spool of wire to record both shows, except that the bias oscillator isn't fully erasing the original audio as the second TV show audio is overlaid on it. Is print- through more of a problem with a wire recorder, or less of a problem, compared to actual recording tape? I realize I am showing my age by actually knowing what print- through is...

I have one of these units. I acquired it as an 11 year old as a gift-repair, in its original advertising box. Fortunately, I fortuitously did not tear it apart. The unit was saved by the fact that I could not get the one rear main screw out. My unit is in like new condition on the exterior. Unfortunately, I have no accessories. Great vid!

That is such a cool piece of history you have there.

Yep Fran. I agree. Superb for its age. I’m a 69yo Retired electronics technician so I appreciate this high tech recorder. I was in Toronto, Canada at 11 yo (1961) when I first took interest in electronics. Tubes then & Transistor radios by about 1963 if memory serves me correctly. This must have been a very expensive device at that time. Hope you can restore to working order. Cheers - Trevor in West Australia

Wow Fran, what an incredible piece of miniaturisation. Must have been assembled by watchmakers. So great to see such engineering. Looking forward to next installment.

*[Techmoan wants to know your location]*

That was awesome, thanks Fran.

I enjoyed the peek-a-boo into the P-55... thanks Fran.

I'm loving your 60's analog equipment on your bench. My dad's bench looked like that when I was growing up. Course, he wouldn't teach his little girl about much of it. He did show me how to sort resistors for him. Bad Boys, etc. Love your channel!

The green battery padding is identical with the stuff you used to find on old Ping Pong paddles. That's a neat thing.

From one technician to another. Very well presented. Good camera work.

That was definitely one of the cooler items I've seen you showcase in awhile. Very, very cool!!

One of your best Fran, thanks

It is very elegant design. It is beautiful, thank you for sharing this

By now you've probably seen the other tube hiding underneath. Regarding those ratchets, they're likely used for pre-tensioning springs and then glued down when the desired pre-tension is achieved. If you have to undo them, try to gauge how much energy is stored in them for future reference. The construction has a lot in common with German made clocks of that era.

I would've messed up the wire with that tangle for sure. Nice demonstration of care and patience. I was given several working adding machines from the 40-50s when I was a kid. I kinda regret tearing them down for parts, now that I have some appreciation for this stuff. :/

woah, that circuitry is still futuristic....awesome video! mind=blown

Cool video I always think it’s amazing how ingenious people can sometimes be and how we take stuff for granted nowadays in our throw away society.. I had an old Geiger counter that took a 30v battery I used 10x 2032 batteries stacked in 2 piles of 5 in a 3D printed holder.

So cool, some of tech you feature I’ve never even heard of before 😍

Thanks for sharing this! Lovely piece of equipment!

Thanks for brought this out,nice. There's always something new to know out there.

Sooo coool very impressive for the time. I had no idea anything that small existed pre transistor.

Wow Fran thanks for showing us that 😊

Brings some memories! I demonstrated one as an educational student lecture to my classmates some time around 1957. I recorded a few seconds of the teacher’s voice before it was my time to give my presentation and then played it back at the beginning of my speech. Amazing!

I owned one of these. It belonged to a friend of the family who handed it on to me - this was in the late 80's. He said I could keep the recorder, but he wanted a copy of whatever was on the wire reels (there were 3 reels with it I think). I was into electronics so I was able to power the thing up with three separate power supplies. The rewind mechanism was broken, but it still recorded and played back OK. The reels spin very quickly even on playback - I think the wire runs at over 1 metre per sec. It's so fine though (like cobweb) that a reel still lasts 2 hours or so. The recordings I got off it I copied onto cassette. The gentleman I did this for has long since passed away, but I made myself a copy which I still have. One fine day I'll dig it out and digitise it. The piece he wanted most was a recording of a speech he'd given at a college here in the UK. I got some of it off but the quality was awful, mostly because of the hall acoustics (test recordings I made on it myself sounded much better, about par with a very cheap cassette recorder). Also, at the time the speech was recorded, the motor battery must have been failing because on playback the speed increased gradually until it was unintelligible. If I do ever digitise it I'll have a go at speed-shifting it down again. I sold mine eventually - you might think this a bad decision but we'd recently moved to a very humid part of the country, and the little recorder being in permanent storage was starting to succumb to mildew. I felt it better to sell to a collector.

Layers of amazing cutting edge technology in that Minifon. I was also amazed at the quality and condition of the plastic spools, possibly very early polyethylene terephthalate, and like modern PET, it still appears clear and solid. PS, I thought I could spot another tube below and at right angles to the top one. Also amazing that a square shape gave enough strength to hold up to vacuum in a very portable device. Thanks again for posting.

Amazing piece of history, and amazing video quality! Congratulations on the new lab!!

Very well made! At 21:04 you can see another tube left of the motor in parallel with the yellow wire. The big capacitor with the red mark is an old ERO brand (AFAIK, they don't exist any more). Obviously a foil capacitor. And the blue one is an electrolytic 6μF/8V. I assume it's a Philips brand.

When I was a kid in the early sixties I took apart one of my Grandad's old Medresco hearing aids. It had three tiny valves in it. It had a huge 1.5 V battery and a 22.5 V one in a big pouch which you kept in your pocket connected to the main unit which was clipped to your clothes with another lead going to an earpiece. I made a headphone amplifier with it. As far as I can remember the 22.5V battery lasted quite a while but the 1.5V one had to be replaced every few days. Compare this to my hearing aids that use a tiny zinc-air cell that lasts nearly a week!

Wow Fran, what a fantastic little machine. And how wonderful to see you firing on all cylinders again!

Very cool first tear down in the new lab!

Thanks for showing us this Fran. Staggering engineering.

Good thing you have steady hands Fran.

THAT was fun! Thank Fran

What a beautiful handcrafted masterpiece.

So beautiful. Ah ... The device is also beautiful. ❤️❤️❤️

Those caps might still work, test them. I'm using a century old one in my car. I love how the people of the early 1950s still had so much detail in their work. As for the drive belt maybe you could cut and sand some old tire tube & lap joint it around the large drum until the vulcanizing sets.

That's so cool. You're amazing at what you do. Thank you for posting this one. Hopefully you'll have an updated version of this working someday. Take care.

Thankyou Fran, for an amazing tech history lesson. The sensor & tube detail mind blowing. In awe as ever.

Now that is an amazing piece of tech. I’d like to see more of that!!!! I hope you get it working and show us all

Amazing piece of technology, thank you. The 1960s Volvo speedometer was the same spiral-barrel type of dial.

Really amazing Fran!!!

Great presentation Fran, and I commend you for taking the risk of dismantling it for your viewers sake... 10/10

What a beautiful machine. This was fascinating. Thanks, Fran!

Ok, I am a HUGE fan of old tech. Your detailed analysis and admiration of this old device won me over. I find, repair, and resell old tech like this simply as a way to play with it, admire it, and buy the next one. This thing is AMAZING. Subscribed. Where in the HECK did you find this!?

Astonishing! Both in its design and execution.

Thanks Fran. I love your enthusiasm and your sensitivity to this old equipment. I noticed the tube (valve) was from England where I am. Interesting we supplied this highly specialised part to a German manufacturer not long after the war. Show us if you get it working

so - the big question is - what's on the wire?

Wow! Amazing! All tubes! Never heard of wire recorders before.

Memphis TN had a Police museum a few years back, may still, that had one of these on display. Amazing!

That sure takes me back. As a boy, I was into tape recorders. This was back in the early 60s, so the small reel to reel was the thing. Early ones were, of course, voice only because there was no good speed regulation. My first was one that came with my sisters wedding ring set. Her new husband gave her the ring, and me the tape recorder. He had played with it in his barracks, as he was a soldier, so it had some cool things on the tape when I got it. I had may more as I grew, eventually getting one with a pinch roller that could reproduce music. I traded a gallon of blackberry wine for that one, the fellow how had it before me had recorded Winchester Cathedral on the tape. I saved that tape and used my old ones till I broke it trying to take it apart. Every one I ever had died that way, somehow I am no longer sure if I took them apart before they stopped working, or the other way around.

Holy crap! As an mech engineer, this is so cool. Hopefully you can restore it. Would love to see it operating

Thoroughly enjoyed seeing such an amazing piece of technology enhanced only by having you describe it too us with your voice. So glad to see the lab again and of course you and most happily glad to see things are going better for you now I'd be lost without your videos 😀

Very interesting. Thanks for sharing !

Brilliant Fran. I love examples of great design and engineering like this. Always love your videos 😊

Brilliant, when I was a child I was given an obsolete RC TX/RX kit and the receiver had 1 miniature square valve and 3 germanium transistors, the HT came from a 22.5V "hearing aid battery, so I would imagine these min valves where originally intended for hearing aids.

Hi Fran, really great Vid! If you sometime want to make that thing function, please take care of this "Mylar"-Cap. This is not a Mylar, it's a Paper-Cap, called ERO 100 and these are notorious for badly leaking after all these years. Here in Germany we call these often "Zahnpasta-Kondensatoren" ("Toothpaste-Caps") cause of the whitish-brittle sealing compound. But there should be some more electronics hidden somewhere. The P55 has 3 Tubes (DF67, DF67, DL67). The original price for the P55 in 1955 was 730DM -or roughly estimated around 3000...3500$ today...

Just came across your video/channel today. Very cool. Nice! Love these old gadgets and you are very nice presenting them. Keep it up! I have enjoyed.

Yessss! Classic Fran video with vintage tech. What a magnificent piece of tech!

Very nice speciment,it always amazes me that so much work went into developing all its parts and design.

I know next to nothing about electronics, but I enjoyed having a look into this little piece of history. Thanks Fran!

Whoever designed this machine was truly a genius.

Fran, Somehow I missed this video the first time around, but seeing it reinforces my faith in your ability to present fascinating and informative content. I love virtually “hanging out” with you during this 2020 quarantine to see what you come up with next. Like so many of your fans, I sincerely enjoy listening to your voice and I appreciate your gentle humor and wit. In a world seemingly gone crazy, you are an island of calm and serenity for so many of us. Please take care and get through COVID 19 safely.

what a cool device! Thanks for sharing.

Fascinating! What a remarkable piece of engineering!

Awesome, Fran!

Very cool! They also made a transistorized cartridge recorder that fits in the same housing. It runs on the motor battery only.

I would love to see this run! Fantastic machine, I love the old style, and the workmanship put into something like that compared to today's on a chip technology that takes zero craftsmanship to build. Thanks so much for putting this up!

That explains the baggy clothes back in the 50's, to conceal all that - high tech!!

My parents bought a mini-recorder for me Christmas of 1963 (11 years old). Shortly after Christmas, they had some friends over for a party. I was supposedly in bed, but I sneaked out and recorded several minutes of the adult conversation. I then replayed the recording from under my father's chair which caught the adults' attention and initially baffled them until Dad realized what I had done. Laughs ensued and I was allowed to join the adults.

...Wow ... what a flashback. Remember my father had one of those and I use to play with it.

Awesome Fran 👍👏☺️

I have this too. I bought in 1966 or something in Helsinki. These were already obsolete then. I have a green plastig bag for it. I’ve never tried to run it and never opened it so this was interesting.

Super video. Thank You.

Nice to know about this old recorder

Oh my, this is the good stuff! Thank you for showing it to the world!

Looks amazingly well designed and assembled! Thanks for sharing. Gotta be worth trying a new drive belt if nothing else. Also, can't help but wonder, what you might eventually find on that wire...

That they were able to create something this small decades before the walkman, that is actually insane knowing the state of electronics at that time..

It's like looking forward in time by taking a peek inside the past. Amazing 50's tech!!!

I hope you'll get it working again and demonstrate it! This is such a fascinating machine!

so is that where the saying "wearing a wire" come's from??? Fran always has the coolest stuff... : )

When you removed that spanner screw from the back - you voided your warranty... DUH-DA-DUH!!

That is astonishing! Love to see it going again.