I’ve been waiting to get a good Power Bank so I can recharge my iPhone 6 Plus and my iPad when on the go. I didn’t want a too small Power Bank. I use my iPad quite a lot, so one of the main feature it needed was the ability to quick charge at 2.1 Ampere. After comparing the different choices I decided to get a TP-Link TL-PB10400mAh Power Bank. It didn’t take long before I had to test it out by measuring the capacity and the efficiency of the boost converter in it.
A friend of mine bought a new amplifier but he wasn’t pleased with the sound. He likes the aesthetic of older things, so he called me and asked if I could recommend a good old amplifier that could drive smaller speakers. The first one that I could think of was the venerable NAD 3020B. When I was young, this was the first affordable amplifier that actually sounded good. It’s not a power house by any means, putting out a (very conservative estimate) 2 x 20 watts. But the phono stage which is switchable for both MM and MC pickups is good, and the sound quality is excellent. So he scoured the used market and finally found a NAD 3020B. Unfortunately when he got it home, there was a loud hum from the output. So I told him to send it to me so I could fix it.
The results are in:
I’ve been very busy with different projects and one of them requires a custom enclosure. So I thought it would be a good excuse to learn Fusion 360. When the Raspberry Pi 3 came out, I did some overclocking experiments. But I settled with just passive cooling with some small aluminium heatsinks. But after seeing some experiments done with a larger copper heatsink combined with a cooling fan, I decided that I wanted to build a case with a silent fan with enough room for a large heatsink. I need it for my NTP server at ntp.jacken.se to get better performance.
I wanted to get a distribution amplifier for my 10 MHz lab reference signal from my GPSDO to feed my equipment, like my timer/frequency counter, signal generator and other stuff. I also needed a way of distribute a 1 PPS signal from my Trimble GPSDO to my NTP servers and other clocks and monitoring systems. The Trimble only got two 10 MHz outputs and one 1 PPS signal output, so I really needed to add more, especially for experimentation. I saw this video by Gerry Sweeney where he modifies an Extron 300MX video distributions amplifier, adding a rubidium reference standard and was intrigued. But I changed the modifications to fit my needs and here is the result.
Upgrading a Philips-Fluke PM6665 Frequency Counter with an Oven Controlled Crystal Oscillator – Up and Running!
I needed a frequency counter for my little lab at home. Naturally I wanted a HP Agilent 53132A or similar, but it’s way to expensive for my modest use. So I browsed around eBay and found an old Philips-Fluke PM6665 frequency counter with the optional 1.3GHz add-on board. With a 10 second gate time I can get down to 0.1 Hz at 10 MHz so that’s more than I need. It didn’t have the option of a better crystal unfortunately. When I tested the PM6665 against my Trimble 10 MHz GPSDO reference, the unit was off by 200.1 Hz. Without a calibration sticker on the unit, I’d say that’s pretty good for a device manufactured in the late 80s. I tried to trim it, but it uses an adjustable capacitor and you only needed to look at it for it to change settings.