0-32V, 0-5A, with USB control, Protek P6035 & Quakko HY3005DP

[bfritz]

Wanted to buy a couple fairly compact PC controlled supplies.  I wanted at least 28V out at 5A.  I'm interested in the PC control, as automating efficiency testing on DC/DC's would make some of the work I do much easier.

Found the Protek P6035 first.  It is avaliable online for $350-$400 USD.
http://www.protektest.com/Prodinfo.asp?prodid=P6035

After a little more digging, I found what is probably the original manufacturer version as a Quakko HY3005DP.  The Quakko,  gotta love the name (shaking head), is available at only $200. 
http://www.mastechpowersupply.com/dc-power-supply/linear-power-supply/programmable-dc-power-supply-32v-5a-lab-grade-hy3005dp/prod_49.html

They look identical, and have identical specs.  I assume Protek is buying relabeled Quakko units, and selling in the US.

Anyone have experience with either unit?

Or, have you seen other identical supplies, with yet another name?

At $200, if the caps die after a couple years, It would pay to just replace them.  The price is pretty good at $1.25/watt. 

[saturation]

A very recent review:

[firewalker]

This doesn't simply overshoots... It;s a damn cannon!

Alexander.

A very recent review:

[Bored@Work]

Ouch, 25V for 1s at the output when turned on. That is a magic smoke generator, not a power supply.

I would guess that the digital part takes a second to boot and that during that time the analog part doesn't get a control signal and happens to drive the output to 25V.

[BravoV]

Scary stuff, its more like a detonating device than a power supply.

Really curious what kind of power supply with usb interface can be built diy style with $200 ? Excluding time, effort in building it of course.
 

[phil_jp1]

Ouch, 25V for 1s at the output when turned on. That is a magic smoke generator, not a power supply.

It's more like magic smoke extractor 

Really curious what kind of power supply with usb interface can be built diy style with $200 ? Excluding time, effort in building it of course.

Take Dave's regulated power supply schematic (a few recent videos), add some USB enabled microcontroller with PWM, and ADC, or with external high resolution ADC and DAC, and you've got yourself a programmable power supply with usb control.

[firewalker]

Actually a usb enabled mcu isn't necessary at all. Only a serial port mcu is needed and a FT232 chip or similar.

[phil_jp1]

Actually a usb enabled mcu isn't necessary at all. Only a serial port mcu is needed and a FT232 chip or similar.

Or that. It's just, MCU with USB support is much cheaper than MCU + FT232 (or similar).

[NiHaoMike]

You can also use a FTDI in bitbang mode to directly drive the DACs and ADCs, but then you can't use the power supply without a PC.

[bfritz]

saturation,

Thanks for finding the YouTube video.  That is good to know!!!

I might buy one anyway.  The comments at YouTube from the person who posted, were otherwise good on the supply.

I learned while working at a larger company, to never assume how a power supply will power up.  Some of the HP/Agilent units can be set to power up with user defined voltage and current limits.  On a couple occasions I powered a supply up while attached to the circuit, and toasted some components.  It's been a long time since I've powered a supply up with anything attached.

I'm guessing the problem with the Protek / Quakko is that until the micro powers up, the output gets enabled.  I might be able to hack a little circuit together to get over this issue.  So, I'm going to look a bit more, but may buy the unit anyway, and see if I can come up with a simple "kludge".

Does anyone have any recommendations on a PC controllable power supply capable of 24V or greater, and 5A or more output current, for a decent price?  I have a difficult time justifying Agilent prices for this.

[metalphreak]

The guy who made that video posted it up for me to look at, after seeing my videos on the Vantek unit I have. He's not happy with the Quakko killing all his projects and wanted to know if the Vantek does the same. It doesn't

Review: https://www.eevblog.com/forum/index.php?topic=5844.0

Really, you shouldn't be getting *any* voltage spike on power on, as the default mode once started is to have the output disabled! I've not see the internal design of the Quakko unit, but you would think it was designed not to output anything until the microcontroller has fully powered up. It's quite common for these chinese power supplies to have identical looking cases, front panels, displays etc, but have completely different levels of internal components.

$195 Buy It Now (inc shipping) http://www.ebay.com/itm/Programable-Variable-Adjustable-DC-Power-Supply-0-32V-0-5A-USB-/270873486836?pt=LH_DefaultDomain_0&hash=item3f115165f4#ht_500wt_1413


Isn't there a Mastech rep on the forums here? It would be nice to know whether this is a one off problem, a design/firmware issue, and whether it's been fixed. Otherwise I'd steer clear of the Quakko unit especially when there are alternatives without the problem for the same price.

[saturation]

Hello bfritz:

You're welcome.  Given the costs of programmable PSU, $200 might be justified if you can mod it to correct the problems.   I think metalphreak did a great job evaluating another clone that works better for the same money.   It will pay to test it thoroughly as metalphreak did even if its the same brand, as quality control is unknown and you could have different problems for the same model.  Its seems more amendable for DIY repairs and upgrades. 

saturation,

Thanks for finding the YouTube video.  That is good to know!!!
...

[bfritz]

The guy who made that video posted it up for me to look at, after seeing my videos on the Vantek unit I have. He's not happy with the Quakko killing all his projects and wanted to know if the Vantek does the same. It doesn't

The problem with the Vantek version, is that I'm in the US, and the Vantek is 220V.  So, unless I want to move all my electronics hobbying into the laundry room where there is a 220V outlet for a dryer, It's not going to work so well for me.

The units look so close to the same, that I'm a bit surprised they would work so differently.  I'm now guessing that perhaps the unit showing the output pulse at power on, may have a bad connection on the circuit board, for the circuit that surpresses that output.  I'm guessing the circuit is nothing more than a transistor or FET with an RC time constant to keep the output disabled till the micro powers up.

I've emailed the Vantek seller on eBay to ask if they have 110V units for sale.  If not, I'm going to take my chances with one of the others.

[saturation]

The ebay links says its switchable, 220v-110v.  metaphreak has a photo also shows such a label and a switch, albeit its blurry.

The guy who made that video posted it up for me to look at, after seeing my videos on the Vantek unit I have. He's not happy with the Quakko killing all his projects and wanted to know if the Vantek does the same. It doesn't

The problem with the Vantek version, is that I'm in the US, and the Vantek is 220V.  So, unless I want to move all my electronics hobbying into the laundry room where there is a 220V outlet for a dryer, It's not going to work so well for me.

The units look so close to the same, that I'm a bit surprised they would work so differently.  I'm now guessing that perhaps the unit showing the output pulse at power on, may have a bad connection on the circuit board, for the circuit that surpresses that output.  I'm guessing the circuit is nothing more than a transistor or FET with an RC time constant to keep the output disabled till the micro powers up.

I've emailed the Vantek seller on eBay to ask if they have 110V units for sale.  If not, I'm going to take my chances with one of the others.

[Circuitous]

 I'm embarassed to admit that I bought a Quakko HY3005DP about 5 months ago.  I was looking for a programmable supply to improve my tests of a SMPS that I had designed.  The Quakko had the right specs, and the few reviews available provided no contra-indications.
 
What a waste of money, this is now on the top shelf acting as a bookend.  I'll pobably use it once in a while, but with extra care.
I found that the output voltage varies significantly with even slow changes in the load.  I didn't write down the details, I just stuck the thing on the shelf and left it.  If requested, I could drag it out and do some measurements.
I waited a few months and did some additional research, and during that time I stumbled upon the just released Rigol bench power supplies.  After viewing some detailed reviews, I picked up a DP1308A (3 output) power supply, and it's amazing!  The DP1116A would match the requirements Bfritz stated.
It is more expensive than a Quakko, but reasonable compared to Agilent and other high-end manufacturers.

At the very least, I'd recommend watching the video reviews (just search youtube for Rigol DP1116A), they're quite interesting.

[bfritz]

I'm embarassed to admit that I bought a Quakko HY3005DP about 5 months ago.  I was looking for a programmable supply to improve my tests of a SMPS that I had designed.  The Quakko had the right specs, and the few reviews available provided no contra-indications.
 
What a waste of money, this is now on the top shelf acting as a bookend.  I'll pobably use it once in a while, but with extra care.
I found that the output voltage varies significantly with even slow changes in the load.  I didn't write down the details, I just stuck the thing on the shelf and left it.  If requested, I could drag it out and do some measurements.
I waited a few months and did some additional research, and during that time I stumbled upon the just released Rigol bench power supplies.  After viewing some detailed reviews, I picked up a DP1308A (3 output) power supply, and it's amazing!  The DP1116A would match the requirements Bfritz stated.
It is more expensive than a Quakko, but reasonable compared to Agilent and other high-end manufacturers.

At the very least, I'd recommend watching the video reviews (just search youtube for Rigol DP1116A), they're quite interesting.

I myself really like to put information on bad devices I run across, onto the internet.  I figure that doing so is a good deed, and will result in others doing the same.  In the end, this will result in the bad manufacturers having more difficulty doing business, and the good ones a better chance.

I'm not yet sold on the Rigol supplies.  They look pretty!  A power supply's lifetime has a lot to do with how good the heat sinking is on the power IC's.  Things like the response of the feedback loop have a lot to do with how well the supply meets my needs.

Regarding buying the Quakko, or some of the others...  At a couple hundred bucks, if the supply gets a bit flaky, I can convince myself that adding some output capacitance is ok.

For the price of the Rigol units, I can pick up a really good used HP/Agilent supply on eBay, and have a piece of test equipment that I can sell for almost the same price 5 years from now.  So, until I see some good tests like the one I detail below, I'm going to hold off on purchasing a Rigol.

I have yet to see a good test of the Rigol units.  Most of the tests are simple DC, and the capability to set the output voltage and current limits.  That is the simple stuff to get right.  I want to see an oscilloscope looking at the output, use the remote sense capability of the supply, and see a load step from about 100mA to maximum, and then a step from maximum to 100mA.  If the output looks good and only sags a small amount, and doesn't ring or oscillate, that would speak volumes for the quality of the unit.  If that is designed well, I can believe they got the rest right as well.

saturation,

A couple of days ago the only links I could find of a Vantek unit for sale were a 220V only version, but the picture on the front of the unit in the ad on eBay did not have the name Vantek on the unit.  Of course those listings are now gone.  I'm wondering if there are a bunch of different versions of this supply for sale.  Another possibility is that the unit shown in the YouTube clip you reference in the second message of this thread, has damage to a circuit that surpresses the output until the supply powers up.  A lot of micros will pull their output pins to ground until the micro exits reset, and if the unit has a high side P-Ch MOSFET for a switch, it would explain why the output is enabled until powered up.

So, there are lots of unanswered questions about the Protek, Quakko, Vantek supply.  It looks like a good buyer beware situation right now.

The Rigol units look promising, but I have yet to see what I consider real testing of these units.  At the prices they are selling for, they need to be right.

[phil_jp1]

I'm embarassed to admit that I bought a Quakko HY3005DP about 5 months ago.  I was looking for a programmable supply to improve my tests of a SMPS that I had designed.  The Quakko had the right specs, and the few reviews available provided no contra-indications.
 
What a waste of money, this is now on the top shelf acting as a bookend.  I'll pobably use it once in a while, but with extra care.
I found that the output voltage varies significantly with even slow changes in the load.  I didn't write down the details, I just stuck the thing on the shelf and left it.  If requested, I could drag it out and do some measurements.
I waited a few months and did some additional research, and during that time I stumbled upon the just released Rigol bench power supplies.  After viewing some detailed reviews, I picked up a DP1308A (3 output) power supply, and it's amazing!  The DP1116A would match the requirements Bfritz stated.
It is more expensive than a Quakko, but reasonable compared to Agilent and other high-end manufacturers.

At the very least, I'd recommend watching the video reviews (just search youtube for Rigol DP1116A), they're quite interesting.

If that's possible, could you do the teardown of your Rigol power supply? Just put out some photos on this forum. It would be really interesting to see the build quality of those PSUs.

[metalphreak]

The rigol's look nice but they are 3x the price Shahriar did a good review over at http://thesignalpath.com/blogs/

The thing about all the chinese clones, is they can all have the same outward appearance, but with completely different internal design. When I have some more free time in the holidays I'll build an adjustable current load device and properly test this power supply.

bfritz: mine does indeed have a 220/110v switch on the back, so you can use it in the USA.

[saturation]

I consider all the "no-name" brands as buyer beware; its a reason tear downs help find value in those unknowns and warn us what needs to be fixed if we go with no-names, as metalphreak did.   Some products might be too complex or highly integrated to be repairable, such as a defective DSO or a DMM, and thus, not worth risking so a thorough testing is the only route.

Rigol is in a different league from the no-names, they have a better reputation, and charge accordingly.

So, there are lots of unanswered questions about the Protek, Quakko, Vantek supply.  It looks like a good buyer beware situation right now.

The Rigol units look promising, but I have yet to see what I consider real testing of these units.  At the prices they are selling for, they need to be right.