Repairing the 1961 transistor radio Braun T220

My blue 1961 transistor radio Braun T220 works pretty good but since I’m planning to put it on Ebay I decided it was time to do the electronics versions of an oil change: The re-cap. Changing all the capacitors.

Opening it up I could find eight metal capacitors and one biggie made out of paper. When old gear is failing, the first suspect is almost always the electrolytic capacitors. I have previously repaired a Samsung monitor and a Samsung TV where the only fault was a couple of bulging caps. Total cost to fix that was under a dollar.

 


All the old capacitors from the Braun T220

In this case where the radio is close to 60 years, there is no reason to keep any of the old caps. If they haven’t completely failed yet it’s just a matter of time and if you would measure their values they are probably all over the place. It wasn’t that much work. It took me around three hours to de-solder all of them and putting in brand new ones. I had to be extra careful not to break any of the many thin copper wires that were soldered left and right in a way you don’t see in newer tech.

 


The inside of the Braun T220, before the re-cap

Powering on the T220 again I was very happy to find that everything was working and the FM signal now was much stronger than before. Also the sound volume was louder and clearer in a way that I had not anticipated. I guess the radio now sounds like it did when it was new in 1961.

All in all the whole process was pretty fun and much easier than what I had imagined it would be. Everything turned out great, which is not always the case when you start poking around in ancient tech.

 

The inside of the Braun T220, post re-cap

March 2nd, 2019|Blog, Design, DIY, Hardware, Retro|

I’m building the BASTL Cinnamon State Variable Filter

This lazy Sunday I’m building the DIY kit version of the BASTL Voltage Controlled State Variable Filter for Eurorack.

It’s one of the missing pieces in my Eurorack system since I don’t have any good stand-alone filter. Actually I bought it about a month ago but I have been setting this aside until the new website was finished and launched. I expect this build to take around 2-3 hours.

Here is a video from BASTL where they demonstrate the Cinnamon.

 

January 6th, 2019|Blog, DIY, Eurorack, Hardware, modular|

How I got rid of high pitched USB noise – once and for all

Something I have been trying to fix for a long time is the annoying high pitched noise that I would hear in the background when recording sounds from my external gear. I guess it has been there more or less since I got my expensive Asus motherboard for the PC. That was years ago but it wasn’t really until I started building and using my modular synth that I started noticing the noise. Somehow it was enhanced by the modular to a degree where I couldn’t ignore it anymore.

I tried a lot of things to solve the issue including buying two kinds of audio ground isolators. They did work. Well sort of… First of all I had to use a lot of them, because I have a big selection of external gear I want to record. Secondly the isolators capped a good part of the lower end spectrum, so a bass sound or kick drum would sound very week. I could compensate with an EQ but it was just too much hassle and I would never get it to sound exactly like it did without the isolators.

Hi-speed USB IsolatorThere is this thing called an USB isolator which you can buy on the cheap from Amazon or from China, or whatever. And they really do work as promised, by removing just the USB noise and keeping everything else. The problem is, until now if you wanted an USB isolator that could be used for Hi-speed USB, meaning it should be able to shuffle enough data for more than two audio channels, they would cost in the range of $250-300. But luckily, technology tends to evolve and today a hi-speed USB Isolator is finally affordable.

HiFImeDIY is now selling a Hi-speed USB Isolator with a price tag of $79. I got mine a few weeks ago and I’m super happy with it. All USB noise is gone and I’ve had no problems like dropouts etc running 16 channels in 24 bit and 96 kHz sample rate.
So.. yeah I’m super happy. One less problem to worry about. :)

Fixing my original Nintendo Gameboy

Gameboy Color and Gameboy DMG-01

I was digging through my crates with old electronics and found my two old Gameboys, the original grey (now yellow) DMG-01 from 1989 and the newer Gameboy Color from 1998. I used them about 10 years ago when I had my latest chip tune phase. I also found the cartridge with Nanoloop 1.2. It still works but the battery on it must be going bad as all the old presets are gone.

The reason I used the old original Gameboy for Nanoloop was that the sound quality on it is better. It has less noise than on the Gameboy Color and a bit fuller sound as well. The screen however is pretty crappy so I used to do the tunes/noises on the Gameboy Color, which has a better screen and then record them from the original Gameboy.

When I turned on the original Gameboy today, first it didn’t go past the Nintendo logo. After doing the old magic “blow into the cartridge slot” technique I could get Nanoloop to start. Next two problems are 1: Only parts of the screen is working and 2: The joystick up and right doesn’t work. Lets see what can be done about that. The screen is easily fixed and I think the joystick is as well. Should be fun.

I’m also thinking about installing backlight mods on both Gamboys, but thats a project for another rainy day.

Finally it’s quiet

I recently re-wired my studio and also decided to fix a problem that have been plaguing me for awhile – USB noise.

Now exactly what is USB noise, you might ask. Well it’s a sort of digital, high pitch buzzing noise you can get whenever you have external audio devices connected to a computer via USB. For example my Waldorf Blofeld, XoxBox and LXR Drum machine has it.

It’s pretty easy to get rid of, either by disconnecting USB from the device or by using some sort of Audio Ground loop isolation thingy on the audio out signal from the device. I got a bunch of pretty cheap isolators from a local electronics store. They worked great for my synths. The noise was gone as soon as I connected them.

Recently I got another problem and this time it’s from my Eurorack modules. The two external soundcards I use to get 16 channels of sound into the computer, the Traktor Audio 6 and 10 are both connected to my computer via USB so that’s where the noise comes from. As soon as I connect audio out from any of my modules to any of the audio ins on the soundcards I get that dreaded USB noise on top of the wonderful analog sound. I tried to fix the problem with another cheap ground isolator but that didn’t work as it also cut away all the lower frequencies.

I figured the isolators probably had to high resistance so I looked online for something more sensitive. Today Mr postman brought me three of these from Thomann: The Sirius Pro Cable GL Isojack extension. They work pretty well, but not perfectly. The USB noise is gone, however there is a ca 20 dB drop in volume around 40 Hz, which means there is much less punch to the sound. I can compensate it OK with an EQ but it’s still doesn’t sound exactly what it did without the isolator, minus the noise of course. It will have to do for now, but I will probably get hold of a more professional solution in the near future. Like the Behringer DI800 Ultra-DI Pro, which has 8 channels of wonderful ground-lift.

If anybody knows a better solution please let me know.

August 3rd, 2016|Hardware, modular, Studio|