instek vs Mastech DC POWER SUPPLY - Page 1
Forum section: electronics / general

author: SnakeBite
author_rank: Regular Contributor
timestamp: November 16, 2010, 01:16:42 pm
content: Hello,i want to buy a new PS and i can't decide which.i was thinking about INSTEK PSP-2010 which is good PS from a good company at good price range ($275 USD) and also has a great power range 20V @ 10A MAX.but then i saw the Mastech PS which also have larger power rang(30v @ 10A) and beter price ($149USD).my only doubt is which one is beter PS from durability and accuracy point of view.what do you think about Mastech company is it a good company or another low end Chinese company?thanksIdohttp://cgi.ebay.com/MASTECH-VARIABLE-REGULATED-DC-P-S-HY3010E-0-30V-0-10A-/120636320893?pt=LH_DefaultDomain_0&hash=item1c167c2c7dhttp://www.tequipment.net/InstekPSP2010.html

author: saturation
author_rank: Super Contributor
timestamp: November 16, 2010, 01:45:57 pm
content: There is a review of some Mastech PSU on this forum, just search for it, and our experience buying it from a distributor in CA [ who also sells through eBay] and I'd rate is 6-7 stars /10. Just know, you won't get much after purchase support or service even if it has a warranty. So, when you buy it, keep this in mind.http://www.mastechpowersupply.com/You should also check out the latest models, which offer some better features for the same money, such as fine adjustment control.I see you've selected a linear PSU, and these are easy to service. The devices are well made, in 1980s style technology and have good electronic characteristics.Instek is a top Taiwan based company, and they do give good support, you have may even a local support system in Israel. The PSU you've linked is a switching PSU, and those are more complicated to service, and worth getting from a reputable company. If you compare the cost of the Mastech switching PSU of a similar type, the difference is not very much and will not be worth the hassle if things go wrong. They are much more difficult to self service.Quote from: SnakeBite on November 16, 2010, 01:16:42 pm

author: SnakeBite
author_rank: Regular Contributor
timestamp: November 16, 2010, 02:25:28 pm
content: the two PS i chose is SMPS the Mastech i chose is SMPS not linar.anyways ... i didn't understand what you recommand more the instek or the Mastech in terms of safty, durability and accuracy .i really don't care about the service difficulty just to choose the beter one.my terms of good PS are (by order):accuracysaftydurabilitypriceIdo

author: cybergibbons
author_rank: Frequent Contributor
timestamp: November 16, 2010, 02:50:48 pm
content: They are very different power supplies.I own the GW-Instek PSP-2010 - I bought it as it was cheap, and also because it is programmable. I can use a PC to measure voltage, current and power, as well as control it.It's a nice bit of kit. Exceeds the specifications listed in the manual. Response to dynamic loads is fairly good, but I wouldn't run an audio amp off it. It's very efficient - I was running a 5V 80mA load day in, day out for almost 6 months on it. The one thing I don't like is the very narrow viewing angle on the LCD display - I much prefer LED displays, but then it does show a lot of information.There are a couple of photos of the insides on Flickr:http://www.flickr.com/photos/cybergibbons/sets/72157624189901913/. In line with the other pieces of GW-Instek gear I have, the construction is good. It looks better than the Mastech internals I have seen.

author: saturation
author_rank: Super Contributor
timestamp: November 16, 2010, 09:21:01 pm
content: Sorry, snakebite, you are right, the Mastech is SMPS. My mistake.http://mastechpowersupply.com/dc-power-supply/switching-power-supply/mastech-regulated-variable-dc-power-supply-30v-10a-hy3010e/prod_14.htmlMy rating was not so much the product alone, but the seller. I'm sorry.I do not own or know of the SMPS made by Mastech, but their linear supply, which I do own, is well made.There are a threads of Mastech supplies at the rcgroups forum and their experience covers over 2 years of use:http://www.rcgroups.com/forums/showthread.php?t=833118As for your requirement in bold my 1803 supply meets all your requirements after 7 months of ownership, but it is linear:accuracy: stable down to the uV, typically mVsafety: short circuit, fuse, protecteddurability: no stats, but given RCgroup experience, its been around for at least 2006 or longer and popular, no long term issuesprice: very high value for priceQuote from: SnakeBite on November 16, 2010, 02:25:28 pm

author: SnakeBite
author_rank: Regular Contributor
timestamp: November 17, 2010, 09:38:36 am
content: thanks for the reply.judging by the post in rcgroups it's good supply for charging batteries but i don't think it's good for electronics use because in page 2 the supply show 45v and the meter attached to it show 44.3v so it's not accurate at all.cybergibbonscan you add a picture of your PS attached to multimeter that i can see how accurate is it.thanksIdo

author: cybergibbons
author_rank: Frequent Contributor
timestamp: November 17, 2010, 12:33:49 pm
content: I've tested at no load, full load, dynamic load (motor, stalling it), and switch on. I don't tend to take pictures as they prove nothing and show a single condition.It is within specs for full and no load, to the best of my ability of testing with a Fluke 17B and Uni-T UT71D. Noise is noticeable but acceptable.It's slower to deal with dynamic loads than a linear supply. But it doesn't overshoot when recovering.

author: saturation
author_rank: Super Contributor
timestamp: November 17, 2010, 02:11:35 pm
content: You are welcome.Vout is stable and accurate to the uV I find impressive in a cheapo PSU, but the internal volt meter reading is off, this is true, at least in my Mastech. Its part of the price paid for being cheap and I do need to use a separate DMM to monitor output, its typically off by predictable amount.But if your work requires you punch in and get the voltage you want regardless of load and can't tolerate the Mastech volt meter reading to 2% accuracy, the cheapos are not suitable.Quote from: SnakeBite on November 17, 2010, 09:38:36 am

author: cybergibbons
author_rank: Frequent Contributor
timestamp: November 17, 2010, 10:23:43 pm
content: I forgot to mention - I think that the control and voltage readout are one and the same thing on the PSP-2010, as in, it uses closed loop control.

author: Murphy
author_rank: Regular Contributor
timestamp: November 19, 2010, 02:22:15 am
content: Panel meters on equipment shouldn't be trusted to great accuracy anyway. It's good practice to always double check the output with a separate instrument that was designed for accuracy.I mean I'm sure there is great gear out there with spot-on panel meters but in my experience they're usually just a ballpark estimate.

author: saturation
author_rank: Super Contributor
timestamp: November 19, 2010, 11:47:32 am
content: Yes, I agree too, but many high end supplies, particularly programmable digital ones where control loop and readout are in the same circuit, what you dial is near what you get, but at a price.For busy production or testing labs, it will save time from using a meter to double check output. For me, what matters is high stability in the supply output in my little research lab, I can measure as you say, with a meter designed for accuracy.Quote from: cybergibbons on November 17, 2010, 10:23:43 pmQuote from: Murphy on November 19, 2010, 02:22:15 am