Replacing Siglent SPD3303D with Tenma 2ch 30V/5A - Page 1
Forum section: electronics / testgear

author: leonerd
author_rank: Regular Contributor
timestamp: November 23, 2016, 12:42:51 pm
content: Someone tell me if I'm mad here...I have a Siglent SPD 3303D, which is starting to annoy me. It's a power supply that has a ~10 second bootup time which I find quite slow. It also has a 10mA current readout resolution which I find limiting for low-power microcontroller work.I'm actually thinking about replacing it with a Tenma 2channel 30V/5A unit, such ashttps://www.amazon.co.uk/POWER-SUPPLY-ADJUSTABLE-72-10495-TENMA/dp/B01I7R7MGM/ref=pd_lutyp_im_4_18?ie=UTF8&psc=1&refRID=B0WQ2T5M872ZDCXB51ZP.1mA readout and near-instant startup time.Two features I'd be missing are the third channel (which, given its limited control and no readout ability is basically useless anyway), and I'd lose the PC control which I have to be honest, in 18 months I've never actually used. I'd replace them with a 1mA current readout resolution.But am I missing something here? This "upgrade replacement" is about 1/3 the cost. I'd sell my Siglent (bought new for £300) and replace it with a £100 unit. This doesn't quite feel right somehow, but maybe justifyable given the requirements?

author: nctnico
author_rank: Super Contributor
timestamp: November 23, 2016, 12:50:58 pm
content: Can't you hack the Siglent PSU? IIRC 1mA readout is an option.

author: leonerd
author_rank: Regular Contributor
timestamp: November 23, 2016, 02:07:41 pm
content: Quote from: nctnico on November 23, 2016, 12:50:58 pmI'm not sure, I haven't seen much about that. I know the Rigol scopes have bandwidth limits in pure software and can be altered by a code, but I believe the difference between the 10mA and 1mA measurement capability in these PSUs may be a real hardware one.Besides, such an activity doesn't sit well with my ethics

author: Mark
author_rank: Frequent Contributor
timestamp: November 24, 2016, 01:33:10 pm
content: Slightly mad I would say... I have the Siglent 3303D and a couple of the 2-channel Tenmas.It really depends on how you use the supplies as to which one will annoy you the most.What annoyed me about the Tenmas recently is that I needed to step up in 1/100th of a volt every few seconds. This required pressing the V/I button to allow adjustment, then the right-arrow a couple of times to to select the correct digit, then turn the knob. A few seconds later, the Tenma would revert to displaying the output voltage again, so if I wanted to adjust the voltage by 1/100 of a volt it would need numerous button presses to do so.

author: leonerd
author_rank: Regular Contributor
timestamp: November 24, 2016, 04:57:24 pm
content: Quote from: Mark on November 24, 2016, 01:33:10 pmThat sounds like the sort of thing that, had you asked me this time last year, I'd say would definitely annoy me.But it turns out after a year of experience using the Siglent, I basically don't seem to ever do that sort of thing. I'll set it to a value and just leave it there. If I did want some sort of ramp like that I'd be looking at computer control, which after a year of use I've not ever done anyway. I suspect if I wanted to do that for real I'd put a more precise regulate-and-measure unit in front of the plain sourcing ability of the PSU anyway, so all the control would be done via that.But yes it certainly sounds an interesting data point to keep in mind...

author: Mitsch
author_rank: Contributor
timestamp: November 24, 2016, 06:52:44 pm
content: This TENMA power supply really looks like a KORAD/vellemann 3005.I bought a vellemann 3005 last week and I'm really glad about that. Accuracy is quite well, but don't trust the mA scale too much..

author: nctnico
author_rank: Super Contributor
timestamp: November 24, 2016, 07:21:13 pm
content: I'd go for a power supply which has knob for the individual voltage and current settings for each channel. OTOH keying in values like I do on some of my HP/Agilent power supplies isn't bad either.

author: ProBang2
author_rank: Frequent Contributor
timestamp: November 24, 2016, 07:26:08 pm
content: Quote from: Mitsch on November 24, 2016, 06:52:44 pmKorad is the OEM. It is rebadged as Vellemann, Tenma, Axiomed...I am sad to hear, that you have a problem. Perhaps You can improve the precision of the PSU yourself?Closed case calibration:https://www.eevblog.com/forum/beginners/korad-ka3005p/?action=dlattach;attach=61421

author: leonerd
author_rank: Regular Contributor
timestamp: November 28, 2016, 02:39:29 pm
content: Quote from: ProBang2 on November 24, 2016, 07:26:08 pmOoh that looks exciting. I shall keep reference to that.My Tenma has now arrived, so I'll give it a go tonight and see how I get on with it vs. the Siglent.

author: leonerd
author_rank: Regular Contributor
timestamp: December 01, 2017, 02:01:53 pm
content: Quote from: leonerd on November 28, 2016, 02:39:29 pmQuick update after a year: I think this was an excellent decision. I swapped the out the Siglent from my bench and put the Tenma in its place, and over the past year I don't think I've regretted it once.The Tenma boots up near-instantly (much faster than the ~20 second wait on the Siglent), and has that all-important to me 1mA resolution on the current readout. Very handy.The Tenma does lack the PC control option that the Siglent has, but in the past year I've not needed that once, and I don't really foresee much need for something similar. If I did want that I suspect I'd have/make/find some kind of dedicated control equipment to put in front of a fixed source such as this one, as part of a larger test setup.Occasionally I have slightly missed not having that third 5V output channel for powering small test equipment, but given it was shared-ground with the Ch2 output anyway I didn't make a lot of use of that beforehand. Instead I've made myself a separate, monitored 5V+12V utility PSU which powers various equipment including the LED illumination ring around my soldering fan.In summary: This was a good call.