Voltlog #290 – Riden RD6006 Output Noise Using Recommended Power Supply NVVV S-400-60

Welcome to a new Voltlog, this will be a rather short video cause I will only be addressing one short subject regarding the Riden RD6006 ripple noise. In my review of this power supply in Voltlog #284 I did measure the output ripple but that was measured while using a transformer to power the unit. 

That transformer has very little output noise so the results we obtain can be considered best case scenarios but this may vary in practice, especially if you are using the recommended switch mode power supply. The output of that power supply may not be as clean as the one from the transformer so in this video I’m going to measure the output noise with the switch mode power supply installed.

I’m using the recommended NVVV 400W 60V 6.6A rated power supply, this is what RuiDeng officially recommends to use with their power supply kit. In Voltlog 284 part 3 I took a look inside this power supply so I will link that video on screen if you want to check it out.

Voltlog #284 – Riden RD6006 Power Supply Review

Welcome to a new Voltlog, if you’ve been watching the channel for a while you might know I’m a fan of the gopher power supply units, I think they are great value for money, they’re simple and they have good specs, in fact I reviewed their latest revision in Voltlog #255 and it had very low noise at the output, even though it is a switch mode power supply. They’re pretty compact, they don’t take up much space on the bench so what’s there not to like about these?

But in recent years there’s been another company which has slowly built-up a name among hobbyists due to their really low priced power supply modules, the name of the company is RuiDeng and they’ve been selling these compact switch mode power supply modules for $20 to $30 for years. They were not great specs, the quality was not great, you needed an external power supply unit but they had a bunch of functionality built into that color TFT display and they were cheap so everyone gave them a try

Now RuiDeng has developed and released a new model RD6006 which resembles a real bench power supply. It has a bigger front panel and it comes with a separate enclosure and power supply unit which are optional.

Voltlog #280 – TPS62840 olmBoard Ultra Low Power Step Down Converter

Welcome to a new Voltlog, in this video we are taking a look at the TPS62840 ultra low power step down converter from Texas Instruments. It’s basically a buck converter with an input voltage of 1.8-6.5V, 750mA output current, with a quiescent current of just 60nA and active current of just 120nA. It also features very good efficiency at light loads of just 1uA it can offer 80 percent efficiency.

Other features include 16 selectable output voltages through an external resistor and a stop pin which when activated will completely stop any switching to eliminate any switching noise for a short moment, allowing you to take for example an ultra low noise measurement during that time. During that take power will be sourced from the output capacitors. So it looks like this is a pretty interesting dc-dc converter, with really nice features and it’s optimized for ultra low power devices.

Voltlog #260 – How do you test usb to serial converters? (CP2103 vs CH340E vs FT232RL)

Welcome to a new Voltlog, today we’re comparing a few different serial to usb adapters and the discussion started ever since I showed the CH340E breakout board I designed in voltlog #249. People wanted to know if this CH340E affordable chip would perform similar to the well known FTDI or Silicon labs chips, and I’m thinking at high throughput and reliability here, the kind of application where you are sending lots of data, fast and you need it to be transferred reliably.

So today I’m going to compare the CH340E with a CP2103, and the FT232RL. I wasn’t sure what measurements to take and how to test these but I devised 2 testing methods.

Voltlog #255 – Gophert NPS-1601 Review (possibly the best power supply in this price range)

Welcome to a new Voltlog, those who have been with me since the beginning of this channel, may know the first video I ever released, Voltlog #1 was a review of a switch mode bench power supply from Gopher Technology. It was the CPS-3205C and it was a great little unit, it has served me well over the years and I still have it.

At that time I complained about the fact that the unit has the output jacks on the back which is not really convenient for bench use. There were also other issues mentioned while measuring the performance of the power supply,  I will link that video on screen if you want to watch it but the video, audio and editing quality are lower than what you’re seeing today.

Gophert made some improvements to the original design and have now released a newer version of that power supply, it has a new model number it’s NPS-1601 but it’s the same range of 0-32V and 0-5A. There are other models with different ranges but this is what would correspond to the CPS3205 I reviewed years ago.

They have made a bunch of changes on the front panel, the most important one is they moved the output jacks to the front panel so now it’s easier to connect the output of this power supply but they are still not standard spacing so you can’t connect one of these adapters with banana jacks. They have also redesigned the front panel completely, they are still using 7 segment displays but now they also have a wattage display which can be switched on temporarily in place of the amps display, you press the watts button and it will show watts measurement for about 3 seconds before reverting to amps display.

The switch for A/V adjustment is now tactile instead of a sliding switch but the rest has stayed the same. I like this redesigned front panel I just wished they used a lighter color for the text, because for example there are some markings which are barely visible next to the LEDs.

Here is a set of pictures I captured during the teardown:

Voltlog #62 – Rigol DS1054Z Fan Replacement

Everybody knows this is a great scope for the money but as usual test equipment doesn’t use the best solutions in terms of cooling fans and associated hardware. They care mostly about keeping the unit cool and not about the noise the unit makes because usually these are used in environments where multiple equipment is run at the same time, the noise level is already high so it doesn’t matter much if a small 50mm fan is adding noise.

But it’s a totally different story for us hobbyists that are using these pieces of test equipment indoor, in our homes. We usually want units with passive cooling or with silent fans.