First Use of Maynuo M712 Electronic Load

[Electro Fan]

Ok, just barely getting started with the Maynuo M9712.  So far, so good.  More to come later but here is a photo showing that the gear is displaying the following values:

Korad KA300P Power Supply (in Constant Voltage mode)
Volts 1.16 (set for 1.16 and presumably delivering 1.16)
Amps 1.002 (set for 1.055 max and supposedly delivering 1.002)

Maynuo M9712 Electronic Load (operating in Constant Resistance mode)
Volts 1.004
Amps 1.0034 (governed by CV set on PS and CR on EL)
Watts 1.01
Ohms 1.00000 (set for 1.00000)

Radio Shack 22-812 DMM
Volts 1.155

Fluke 179 DMM
Amps 1.004

Lots of test leads too long; I'm working on getting those shortened up. Also trying to figure out what discrepancies are based on test lead resistance, and what is based on equipment not displaying accurate values.  I'm pretty sure the RS reads about 5 millivolts lower than the Fluke on values around 1.5 volts.  My hunch is that the Fluke and the Maynuo might be pretty accurate and the Korad and RS are a tad behind but before I go too much further I'm going to see if I can dial it all in a little better.

One initial comment on the Maynuo.  It's number one feature so far is the ability see Volts, Amps, Ohms, and Watts simutaneously on the display.   

Special thanks to LaurenceW for handholding me through Maynuo 101 and 102.

EF

[gbyleveldt]

I got the M9711 today as well and I'm seriously impressed with the accuracy of it. Measured it with my Fluke 87V and it's pretty much spot on.

[Electro Fan]

I got the M9711 today as well and I'm seriously impressed with the accuracy of it. Measured it with my Fluke 87V and it's pretty much spot on.

gbyleveldt, Congrats on the new M9711.  Looks like it is at least your second Maynuo product?  I'm sure it will love it's new position on your bench - that is one good looking bench full of gear!  Looks like you have a small ton of audio projects going on including some tube gear.  Welcome to EEV land; this is a great forum/site.  Keep us posted on your findings/thinking. EF

[gbyleveldt]

Thanks EF!

Yes, it's my second Maynuo product. The first one was their M8811 Programmable PSU. As I said before, I'm pretty impressed with the general quality of the brand, bearing in mind how relatively little the stuff costs. In fact, I'm thinking of getting another M8811 PSU - the only real issue here is that the PSU's can't be linked digitally in order to get tracking to work. The software that comes with it can only control 1 PSU at a time, so even from the PC it's not possible to link them. The command interface looks pretty simple though, it might just be worth it for me to write a little program to control multiple PSU's and thus get tracking that way. I did grab two isolated USB interface cables on my last order so that I can remotely control both the PSU and the DC Load - it's just a pity the software leaves a lot to be desired.

And yes, my main focus is on Audio - Digital Audio to be specific; No Audio nerd is complete with at least some tube gear to go with it

[Electro Fan]

Thanks EF!

Yes, it's my second Maynuo product. The first one was their M8811 Programmable PSU. As I said before, I'm pretty impressed with the general quality of the brand, bearing in mind how relatively little the stuff costs. In fact, I'm thinking of getting another M8811 PSU - the only real issue here is that the PSU's can't be linked digitally in order to get tracking to work. The software that comes with it can only control 1 PSU at a time, so even from the PC it's not possible to link them. The command interface looks pretty simple though, it might just be worth it for me to write a little program to control multiple PSU's and thus get tracking that way. I did grab two isolated USB interface cables on my last order so that I can remotely control both the PSU and the DC Load - it's just a pity the software leaves a lot to be desired.

And yes, my main focus is on Audio - Digital Audio to be specific; No Audio nerd is complete with at least some tube gear to go with it

I was just reading the Rigol DP832 manual - looks like in their 3 channel PS they implement tracking:
http://us.rigol.com/download/Oversea/DP/User_guide/DP800_UserGuide_EN.pdf
- Not sure how it compares overall to the Maynuo PS

[crt]

I had both of this Maynuo, M8811 and M9712 
So far it's good, only those M8811 that i can not control with my PC via software (not try with another PC/laptop yet)

same as gbyleveldt, i had plan to get another M8811 to make it dual supply
but those RIGOL DP832 had got my eye
still confuse which one should i got 

[H.O]

Same here, I've got a M8811 and a M9712 - then I found the DP832 so I've got one of those on order as well. Couldn't help it....

[gbyleveldt]

I really, really don't like the look of the Rigol... Really! I'll get a fright everytime I sit down at my bench.

[Electro Fan]

Same here, I've got a M8811 and a M9712 - then I found the DP832 so I've got one of those on order as well. Couldn't help it....

Gald to see some more Maynuo EL users here.  H.O., please let us know what you learn when you get your DP832 and compare it to the M8811.  What is the ETA on the 832?

[H.O]

Will do. The M9712 have been working very well for me but I haven't used the M8811 much yet.
I ordered the DP832 last week, was told it would ship within 1-2 weeks but we'll see about that...

[crt]

I really, really don't like the look of the Rigol... Really! I'll get a fright everytime I sit down at my bench.

+1 for that

Will do. The M9712 have been working very well for me but I haven't used the M8811 much yet.
I ordered the DP832 last week, was told it would ship within 1-2 weeks but we'll see about that...

Same, waiting for your review
DP832 vs M8811 
i hope those functionality at DP832 can turn overall points to positive side (because so far the only negative side is how its looks) 

[metalphreak]

Do you really need an isolated USB to TTL COM cable for the Maynuo power supplies? Is the output ground tied to the COM port ground?

I know it's an issue with the DC loads, because the COM ground is connected to the load terminal ground.

[H.O]

Hi,
I just measured mine and yes, the negative output terminal of the supply is connected to pin 5 (GND) on the 9 pin serial interface connector but not to mains earth/chassi ground. If you use a non isolated converter the negative output terminal will be tied to mains earth thru the PC since the PC GND is connected to mains earth.