KORAD KA3305 Adjustable 30V, 5A DC Triple Linear PSU & Bonus Content

[@LMerryman]

I know this is late in the game for posting response, but for those who are still interested in this ( it is still being sold as of today ), to only turn on or off power for one channel, press the channel you wish to control first to make it active, then press the power button.

[@FriendlyWire]

This is a great video review! I especially like the comparison of the sound level, I have been wondering exactly about that, and you answered it :-)

[@rvd2339]

Is it possible to output a negative voltage? If you output 5v on both channels, connect Channel 2 + to Channel 1 - and from this you connect your circuit ground. Now as it works then channel 2 - should be at -5v and channel 1 + should be at 5+. I understand how it works and how to configure it but someone on the Eevblog tried this and it does not work. Maybe it works when you connect channel 1 + to channel 2 -.

[@kluzz]

I always upvote blue smoke. :)

[@GadgetReviewVideos]

👍 23:15 There’s a reason I never edited or published that video. Well that and I found it surprising that the Korads displays are more accurate, update faster, and was calibrated better then the more expensive Rigol PSU. I don’t review things I don’t thing are worth recommending. One of these days I will calibrate that Rigol when I have time.

[@RobekRupa]

You can turn on or off one Chanel. Select Chanel and pres on. Also it is capable of auto start after power main power

[@markrichards5630]

Why oh why can't you use the Amps knob without hitting the channel 1 button again? That knob has no use while the voltage knob is active. Seems like an extra step that isn't needed. Am I missing something?

[@GadgetReviewVideos]

You can push in the Amps knob also and change the current amps, or. you can hit the channel button as. you mentioned. I guess I was used to the older power supply and would hit the channel to move to the next setting.

[@stephanedesrosiers2436]

Hi, great video. I see at the end of your video that you also have a Rigol DP832 power supply. How would you compare the 2 models? I would be very interested to have your opinion about these 2 models. I thank you.

[@GadgetReviewVideos]

I guess it depends on what you use the power supply for. The Rigol is good for programing voltage stepping and other features like logging to a USB key. If you just need something for power then the Korad or more then capable and better at putting into series/parallel for higher voltages/current. The Rigol also has a max of 3 amps per channel compared to the Korads 5 amps per channel. Plus the Korad runs quieter for most tasks. For most of the general power applications I need I usually turn on the Korad first.

[@stephanedesrosiers2436]

@@GadgetReviewVideos I thank you. At equal price, which one would you choose? I live in Canada; The KA3305 with shipping ended almost at the same price that the DP832... :-(

[@GadgetReviewVideos]

@@stephanedesrosiers2436 It sucks that the Korad goes up in price for you. In that case I would go for the Rigol, it’s 3 Amos per channel but most people won’t need or use 5 amps like on the Korad. And the Rigol gives you room to grow if you want logging, or stepping profiles being it’s a programmable unit.

[@djseba3]

Hey. The power supply has 2 outputs 30v 5A. How to get 30V 10A? Is it possible to set on the power supply so that the output has a regulation range of 30V 10A?

[@GadgetReviewVideos]

When it in serial mode will connect channel 1 and 2 together to double the voltage so 60VDC at 5 Amps max current. When in parallel mode it can do 10 Amps at 30VDC. Higher voltage scan be dangerous, even lethal. When serial or parallel modes are enabled the leads need to plug into the corresponding marked jacks that’s written under the jacks.

[@MarshallSmith27]

is the input voltage selectable? I really like this KA3305 and I need one now (110v) but I will be moving to England next year and I'll need the 220v

[@GadgetReviewVideos]

Yes, it's selectable with 110V and 220V on the back. I just pulled mine off the shelf and checked for you.

[@GadgetReviewVideos]

FYI, you will have to change the fuse from a 110V/10A to a 220V/5A fuse if you select 220. It says this in the back also. But might want to buy the fuse in the states before you move. I don't know how hard it might be to get the fuse in the U.K.

[@MarshallSmith27]

Thanks for checking and replying so fast! From what I've been able to ascertain, this power supply for the money is hard to beat. I haven't really found anything else. I was going to buy two KA3005D(or P) but then I saw your video for this one. Plus this one comes with the extra 5v output. What do you think?

[@GadgetReviewVideos]

It's kind of funny I'm replying on my phone since my internet is down, and the internet is down because I shut my power off to the house, adding a breaker for more power to an outlet for the electric spot welder. And now I'm leaving you input about power supplies when I'm taking a break, lol. I own the triple version of the KA3005D also, I bought it refurbished and was the first one I bought. They have both held up well, I have three korad triples together all running parallel to generate 30 amps DC to test a shut and they all survived. Creating a 30A load was a different story, but I figured it out also. I have a fondness for the older one, just because of a preference and probably because it was my first and I got used to the controls. But they are both good for the money. I would toss the banana cables they come with in the trash (they are cheap) and get some nice ones from Frankie. Also I would buy it from SRA solder, link in the description. They are the inky authorized reseller to handle warranty work on korad in the US. You might even find other options refurbished from them if cost is an issue, that's the refurbished place I bought my firs one.

[@MarshallSmith27]

Gadget Review Videos An electric spot welder is definitely on my soon list! The rear of the supply didn't happen to say what type fuse it requires for 240v did it? I've decided i'm going to buy this supply and i might as well get the fuse at the same time.

[@TheGordy1950]

The fan in mine runs all the time at a low speed even when only set down to 50mA. I have not tried to load the power supply with more than a 100mA load. Is the fan supposed to run all the time?

[@GadgetReviewVideos]

This is OK, Mine will start to run slow after about 10 minutes even if I dont use it. Dont forget the 5V-3A rail is always on so this will generate heat. What causes electrics and components to fail it heat. So the fact that the fan runs is a good thing but its still a lot quieter then most other power supplies I have owned or used. The older ones would have a fan that just ran at one speed most of the time until you load it then it kicks on high and is really loud. They dont monitor the temperature and adjust the fan like this one and some of the other new one. I like the balance between low and quiet when not under load, and when it is under load its still quieter then most others even pushing 10 Amps if you run channel 2 and three together. Scott

[@TheGordy1950]

Yes but, mine runs at start up. Is that okay or is there a fault somewhere? Should I be concerned?

[@GadgetReviewVideos]

TheGordy1950 No, I wouldn't be concerned. Some has to do with the room temperature (my house might be cooler) and the accuracy of the thermistor or what ever they are using to measure the temperature. As with most chips, resistors and even multimeter and PSU their is a rated 5% or 10% accuracy. It cost a lot more money for the chips that are percision down to less then 1%. So the chip measuring the temperature is probably either a 5% or 10% rated accuracy. This small different may turn your fan on low if the chip is reporting a little different then the chip in mine. Or again the room temperature also is a fracture with ambient temperature. It it's nothing to worry about.

[@MitLomasdelmirador]

Have you got the schematic circuit ?, thanks

[@GadgetReviewVideos]

Nope, sorry I don’t have the schematic.

[@gordselectronicshobby3853]

I received mine today and noticed something was rattling around inside and decided to take the cover off. I found a nut inside and I could not locate where it should have been. The only place it would fit was the handle screw so I put it on one of the screws for the handle. Once that was taken care of I decided to power it up and see if everything was working properly. It made the transformer thump sound that was heard in the video however the power supply worked just fine. I then decided to tighten all the screws and nuts especially on the transformer. I found that the transformer nuts were not very tight. That alone ,would cause the transformer to make the thump noise and I was right. After tightening the nuts did indeed stop the thump. I advise everyone that buys this power supply to check if anything is loose or rattling inside before power is applied. Hope this helps...........

[@GadgetReviewVideos]

Good catch on the floating nut. Maybe missed durring assembly or came off durring shipping? Enjoy the new power supply You might still get the thump once in a while. If you sit and turn it in and off and the caps don't drain all the way during the off cycle then you have less of a chance hearing the noise. If it's unplugged and drains like in my review then you power it back on their more of a chance it might happen. I would suggest lock tight on the handle nut good catch. And because you broke the locktight on the transformer nuts I would put some back on again in the threads. Transformers have a constant vibration and the will work loose again if they don't have some good red/blue lock tight. Red is probably better for a transformer. Here are the reasons why you hear the turn on action, and also the reason it triggers my battery UPS units because they detect a drop on the line. First, the power line is 60 hertz. The point in the cycle that you happen to turn the power off will magnetize the transformer core such that the transformer will present a very low impedance to the ac power next time it is turned on. The transformer core acts like a big magnet during the inrush and pulls on the metal making the noise you hear. This only happens for a few milliseconds and then the transformer waveform will settle. This few milliseconds it happens may cause a drain on the mains lines, like it does with the supply line my lab and why my UPS kicks on. I've had some transformers like my 20 Amp auto transformer cause such a drain with the inrush that it tripped the breaker. My UPS backups are so sensitive they will turn on and try to supplement the drain on the line back to a normal level. Sometimes you hear this effect on the core of the transformer and sometimes you don't depending on the amount of inrush current. The amount of inrush depends on where in the AC input cycle was when you turn off the power as to what happens the next time it is powered up and if you hear the noise result. For example if you happen to turn off the supply during the ac input crossover point (zero voltage) , you likely will not hear an inrush result the next time you powered up the supply. Scott

[@gordselectronicshobby3853]

The thump from the transformer still happens every once in a while but, is much quieter since the nuts have been tightened. I know I mentioned this before and I also know from experience that putting wood shims between the core and the coils helped solved that problem which was done often in the design of larger transformers. The thump as mentioned is not an issue to be worried about and is normal... Some have mentioned the clumsy setting sequence which is a pain however, once you get use to it it becomes logical why they designed it that way.

[@lextr3110]

you should change the low rpm 120mm or 140mm noctua fan with a speed adapter and a tunnel is needed to blow the air out of the case or something..

[@GadgetReviewVideos]

On what power supply, the old one or the new one? The new unit already controls the speed of the fan based on the temperature. If I add a separate speed controller this will conflict and could cause the PSU to over heat. I wouldn’t recommend adding any other speed controller. The fan is a decent fan, it is the quietest bench power supply I own even at full power.

[@JAKOB1977]

A quick question, I got 2 Korads, 1x KD3005P and 1X KA3003P (both P comp versions and one is KD 5A and the other is KA 3A) Can I put those 2 Korads linear PSUs in series to get 8AMP out (5A + 3A) It's these. imgur.com/gallery/B7ZOQ3J

[@GadgetReviewVideos]

I have not tried it on the single channel units. If you want increased amperage it would need to be parallel, not series. I personally would keep the voltage and amperage the same, so you might get 6 Amps. As for the hardware in parallel together together it should be fine if you keep the voltage and amperage the same. I did once out three of the 3 channel identical units together. They were all set to parallel for 10 Amps each, then I wired the three units together for 30 Amps to test a high current precision shunt while using multiple heat beds from 3D printers as the load. This worked without an issue, and the single channel one are mostly the same power supply parts so it should work. just be sure to have them set them at the same voltage and current.

[@MrDrifterNL]

What is the model number of the older version? Any picture I find that looks similar to the older version doesn't have the 5V rail.

[@GadgetReviewVideos]

The older one in this video is the KA3005D-3S, also known as the KA3005P-3S for the programmable one. They stoped making this model over a year ago, so it’s hard to find. The -3S is the main part of the model that indicates it’s the triple version. The other singles are still for sale but don’t have the -3S in the model number.

[@MrDrifterNL]

Thanks for the quick reply! That explains a lot. The pictures I found are of the -2S.. How has the KA3305 been holding out? Any strange anomalies?

[@GadgetReviewVideos]

Nope, it’s been running good. In fact both of them are still running good.

[@MrDrifterNL]

Thanks for the info (and video)! Looks like I will be ordering one.

[@GadgetReviewVideos]

If your in the US, (maybe canada also) then I would recommend SRA solder. They are one of the main authorized resellers that will honor and back up the warranty if you have any issues. www.sra-solder.com/korad-ka3305d-precision-variable-adjustable-30v-5a-dc-triple-linear-power-supply-digital-regulated-lab-grade

[@SantaClaw]

I started out by removing the handle from my KA3305, makes it alot more useful as a storage area... :P

[@GadgetReviewVideos]

If you need the space and some place to put stuff on top then it would make sense. I move mine sometimes from one bench to another, so I kept the handle on. Thanks for watching, Scott

[@Popart-xh2fd]

7:21 where did you get that power resistor? I can't find it in Aliexpress...

[@GadgetReviewVideos]

Ahh, some things are not new and you can't get on aliexpress. Unfortunately I just went to the eBay sellers for CTS surplus that I bought mine from in Ohio and found out they closed down and scrapped everything, noooooo! Well the one you saw me use was a Dale RH-100 100W 1% 1 ohm wire wound power resistor. I was able to find some on eBay. The smaller ones have solder terminals on them like the 50w and 25w ones. I've put 4 25W together on a big heat sync and it's not the same, they get to hot. So the single bigger one is much better if you need to resist this kind of power. I did find some on eBay, try this search,. Some may say Mexico on them, some might not. Mine doesn't say Mexico on the 100W one but some of my 25W ones do. They are manufactured by Vishay, so they were not cheap when they were originally new. But they are had to damage and hold the tolerances great. Most wire wound resistors will be more accurate over the years unlike the newer cheaper ceramic and surface mount style resistors. And being made from Vishay they are quality. I bought a bunch of used ones, even found some new when looking over the warehouse stock and they all checked out great. I think I've only had one bad capacitor from that place and will miss that place. Now I don't know how I will get cheap local quality used electronics parts :-( www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xdale+rh-100+100W+1+ohm+1%25.TRS0&_nkw=dale+rh-100+100W+1+ohm+1%25&_sacat=0

[@WojciechMajstrzyk]

Ok, I don't like the fan noise comparison - in older unit you have dead short, but the voltage set to 30V. So power supply selects the highest voltage tap from transformer. (if it switches tap, when actual voltage drops, not the set one, I will revise calvulations) So the difference Vin-out is roughly 32-35-is volts and current 5 apps. Power that is dissipated is 150W! - in ka3305D you connect a 1 ohm resistor and have 5V and 5A, so you dump 25W power into the resistor, but inside the supply you have the lowest tap (~8V after rectifier) so you dissipate just 15W (8V-5V)x5A. That's 10% of the power In older model!

[@GadgetReviewVideos]

@ 4:12 without any power out you can hear the fan. Sort of like the oscilloscope fan running at a constant. With the new one, yes the fan will increase as it heats up but is quieter. The point was the old one uses a set RMP on the fan based on the stage of the power supply you set even when it’s not hot. I used the resistor because the new one with a shunt dead short on a meter wasn’t putting out enough noise to hear on camera an I must of edited it out not thinking about it the way you saw it. But that also means instead of dissipating the extra power internally it may have switched to a lower tap on the transformer since it couldn’t put out the voltage I had set.

[@lextr3110]

the display on the unit is flashing.. is it the camera

[@GadgetReviewVideos]

Yes, it is the refresh rate of the camera and the display conflicting. I don’t see this flicker in person.

[@TheDefpom]

You can see me using my one of those in some of my videos.

[@GadgetReviewVideos]

Nice, how has it worked for you?

[@TheDefpom]

Good, I have been happy with it, the need to press the channel button each time you want to change a setting is a slight pain but that is pretty much it, current limiting etc all works well. I haven't used the memory features myself yet though.

[@GadgetReviewVideos]

TheDefpom Well if you tend to have what I call "Fat fingers" then I recommend setting all the memories to 0V and 0A. I kind of stole the fat finger term from tech with typing on a keyboard, but it could apply with this also. If you use the keypad lock then I wouldn't worry about setting memories to 0. But I know in more then one manufacturer I've hit the memory button and didn't realize I changed the settings causing a magic smoke incident. I'm also used to having to select the channel before changing settings on other power supplies, so this didn't surprise me on this unit. It seems to be almost standard when you dealing with more then one adjustable channel outputs. But if your used to a single channel power supply I can see were it's a little different at first and something you have to get used to doing.

[@Mazeisaspace]

There are several versions 3305D and 3305P ? -

[@Mazeisaspace]

oh programmable vs fixed

[@GadgetReviewVideos]

Yup, it’s just an add on module for the programmable one.

[@friedmule5403]

Could you please tell me where you get those leads from, that you use on the 100W load?

[@GadgetReviewVideos]

Fried Mule Those are 50 cm / 20 inch 13AWG banana cables I bought from 99centHobbies on eBay, user f-t-2000 otherwise known as Frankie’s Store now ran by his brother. But he still sells the same quality accessories. www.ebay.com/itm/50cm-20-034-Silicone-Test-Leads-with-Banana-Plugs-1-Pair-Red-Black-/200873022764?&_trksid=p2056016.l4276