Restoring the Iconic Braun SK25 Radio: A Vintage Design Masterpiece - part 1

In this video, I'll start the restoration of a Braun SK25 tube radio, the third iteration of Braun’s groundbreaking series of 'miniature' tube radios, a collection that paved the way for modern design even before the legendary Dieter Rams joined the company. These models, which broke away from traditional aesthetics with their sleek, minimalist designs, were a bold statement at the time and continue to influence design today. Though Rams would later become synonymous with Braun’s design ethos, these early radios set the stage for his work and are now celebrated in the Museum of Modern Art (MOMA). Join me as I restore this iconic piece of design history, bringing back to life a radio that helped shape the future of product design.

Interestingly, these pioneering designs, which later inspired the design philosophy behind Apple products, are experiencing a resurgence in popularity among young adults today. In their pursuit of a ‘vintage’ aesthetic, this new generation is drawn to the clean lines and timeless appeal of these classic radios. As the demand for authentic, retro pieces grows, these models are becoming highly sought-after collectibles, blending the past with the present in a way that resonates with modern sensibilities. Watch as I bring this vintage gem back to its former glory, making it a perfect addition to any stylish, contemporary space.

🎥 Back to basics Series
Many tasks in this video are covered briefly, without deep explanations of the theory—especially for those new to tube radio restoration. For a more detailed understanding, I’ve created a tutorial series called “Back to Basics,” which goes into the concepts in depth. I recommend watching those videos to better follow the steps I don’t fully explain here. The playlist is:

🎥 Other videos mentioned in this video:

🙏 Want to support the channel? ●●●●●●

#tuberadios #antiqueradio #radiorestoration

●●●● HUNDREDS OF OTHER VIDEOS TO CHOOSE FROM ●●●●
✿ DIY TEST GEAR: The title says it all:

✿ RESTORATION BUILDING BLOCKS: A series of videos showing detailed steps used the restoration process of tube equipment:

✿ HowTo's: Various videos on some simple techniques and projects:

✿ DIY CAPACITOR LEAKAGE TESTER PROJECT: One of the most viewed projects on my channel, with full design description and build instructions.

✿ DIY TUBE TESTER PROJECT: Complete design description and build instructions for this really handy device.

●●●● Plus full Playlists on some other completed restoration projects on this Channel ●●●●

📻 PHILIPS BX750A:

📻 TELEFUNKEN OPUS 2114:

📻 SABA UW-175-Z 3D:

📻 GRUNDIG 1070:

📻 SCHAUB-LORENZ GOLDY 58 type 3020:

📻 BUSH VHF64:

📻 GRUNDIG 3060A:

📻 TELEFUNKEN OPERETTE 8:

📻 GRAETZ SUPER 171W:

📻 LOEWE-OPTA MAGNET 3737W:

📻 BRAUN ATELIER 3:

📻 LOEWE-OPTA TRUXA STEREO 4741W:

📻 GRAETZ COMEDIA 616:

📻 SABA FREIBURG W2:

📻 GRAETZ MUSICA 4R417:

[petersvan]

Was a pleasure watching this video. This Braun is such a well engineered radio, definitely worth giving it your love and attention!

[daveys]

1:47 - Beautiful design on all these type of units, but that combi system is just perfect! Dieter Rams is a genius.

[BobAndersson]

What a little beauty! A huge smile on my face at about 27 minutes as I was really hoping you'd decide to "restuff" the selenium diode to maintain the original look. 👏👏👏

[DavidTipton]

I thought I had missed this one but I did see it, old age 👴 It looks like the radio was stored in a cupboard it's so clean. Great idea hiding the dropper resistors in the selenium case 👍🙂

[bofor]

Nice run through on that selenium changeover. You certainly didn't "stuff it up" 😃. Hopefully there are no other components that might cause a heavy current draw, which when replaced will allow the voltage to rise too high. Although like one of your other viewers I believe this radio will happily run nearer 200v on B1+. All those tubes are able to run at higher anode and screen voltages. The main issue in the radio will be the current ratings of the various coil windings and transformers.

[JonRig]

Stuffed up by EO&N! 😂 That made me chuckle!!! Great video, as always!!

[carlcoleman]

Great video, such a joy, just watching your videos ❤

[robharley]

Great video as usual Manuel! I re-fitted a very similar Siemens rectifier in a Blaupunkt radio a while back. The Selenium plates seemed to look fine, but curiosity as to what all the fuss was about with Selenium Rectifiers had me placing them under the microscope to look a little closer. Sure enough, minute deterioration was everywhere on the plates, even exposing small patches of the metal substrate. Yep, like old caps, they gotta' go. Very nice job replacing them! Thanks for all the great content. - JRH

[techobaz]

Great video as usual Manuel. Nice to see a really nice little radio for restoration, thank you.

[ralphj]

Making good progress. Just a suggestion (only my opinion, feel free to disregard or mock) is to check the temperature of the diode / resistor arrangement after the radio has been on for a while. Total dissipation around 3W, 1.6W ish in the 150 Ohm, generally not an issue but when enclosed inside a can!

[edwardhannigan]

Hey Manuel, Great video and info..Fab radio..Love your work..Ed UK..☺

[maartenschapendonk]

Have one on the shelves to do also. Curious to see the cabinet and the backplate done.

[mackfisher]

Manuel, I thought you demonstrate your homebrew resistor substitution box, but I'm guessing you wanted to use this as a teaching moment. Brilliant video as usual.

[andrewmcintyre]

The style of production, the el95 and the speaker is very reminiscent of the philips star maker portable reel to reel. It appears almost as if they sourced the parts from the same supplier.

[DJDavo]

Nice one! EL95 is btw nice sounding tube though:D
A while ago I worked a similar looking 50’s radio, i thought it was a Philips.. It was a “U” tube device… I still don’t like to work on such devices haha

[jonvincentmusic]

Saw the switch on the back and immediately figured it’s to turn the internal speaker off and on because there’s a two pin DIN speaker socket right next to it.

[TheEmbeddedHobbyist]

Nice little hide of the diode and dropper resistors.

[daveturner]

I was a little concerned about the restuffed rectifier. It appeared to me that where the leads were soldered to the external connectors that the solder barely came halfway up the leads. If so is this good for the long term?

[peterhollander]

I own the same model Braun radio, but it is a SK2. The difference is the dial layout.

[johnstone]

I have to wonder whether or not your conclusion on the B+ being similar to the earlier Braun model is correct. One clue to me is the fact that replacing the selenium with a silicon requires such a large value series resistor. i looked at the schematic of a similar set, the SABA 90 Triberg, which has the same tube complement (except for also having an EM84). It also uses a half wave rectifier..the same exact one as the Braun.If you look at the voltages on the SABA, you see 225 at the rectifier cathode for AM and 210 for FM...which I think is fairly close to what you got on the Braun without the resistor in line at full mains voltage. One thing you might check is the hv secondary winding ac voltage which in the SABA is shown at 210. With the resistor out of circuit, if the secondary voltage on the Braun is the same, then you can assume that the running voltages in this set should be higher than the other Braun. As you know, most German radios do run at higher DC voltages than that older Braun. Just my thoughts.