TSP

[@Thesignalpath]

*Please note that this circuit is for demonstration only. There are many other issues to consider here. Stability, capacitor driving capability, OpAmp safe regions of operations, etc. The purpose here is to explore the noise behavior and exchange ideas. As I mentioned in the video, there are many ways to improve such a circuit.*

[@raymonddompfrank1789]

Yes Shariar, you clearly state that the circuit is just for educational purposes and I'm absolutely convinced that you'd come up with all its shortcomings easily. However, some of your followers might want to start by just copying your circuit as-is, since you're showing it in the video, playing with input voltages that seem reasonable and seeing that it doesn't work and instead maybe even blowing up their $ 20 power opamp, even with enough heat sinking and limiting current. The real educational value starts there... I *am* one of your followers, enjoying your videos of high quality in several respects.

[@guyvanburen]

The Signal Path would love an ep on frequency synths. I believe eval boards up to 6 or 7 GHz are within budget

[@alexdavis9794]

Stability can be tricky. You can certainly learn a lot by figuring out ways to fix it, but knowing where the dragons lie (and how to avoid them) before you get there is probably a better way. There are plenty of cases where you can design and prototype something and it works fine, but is marginally stable. Sometimes this results in a circuit that only goes haywire under very specific conditions. Trying to track that down can be very educational, but I think knowing the tricks beforehand makes it a better experience (and certainly a less frustrating one). A good resource I've found for this is a set of presentations from Texas Instruments: e2e.ti.com/support/amplifiers/precision_amplifiers/w/design_notes/2645.solving-op-amp-stability-issues. Which goes into a number of simulation tricks to diagnose stability issues before blowing up $20 amplifiers. FWIW, I'm also a follower. The amount of technical depth Shariar brings to all his videos is fantastic, and I've definitely learned a lot by watching. [edit: this didn't seem to get tagged as a reply to Raymond above, but it was meant to be]

[@lifegetahun8330]

@@guyvanburen ujjfjjtj

[@lifegetahun8330]

@@guyvanburen jjjfijijgs

[@alterratz665]

I suppose this is the first TSP video featuring something I can actually afford. And by that I do not mean the Keysight scope :-(

[@ZlayaCo6aka]

At exactly 14:07 the 900 KILOHERTZ "hump" transforms into a nice modulated carrier waveform; carrier at approximately 900kHz, first u/l sidebands at approximately 880kHz and 920kHz, second u/l sidebands at approximately 860kHz and 940kHz, third u/l sidebands at approximately 840kHz and 960kHz.

[@leocurious9919]

This.

[@rocketman221projects]

That op amp costs almost as much as the power supply. You should try filtering it with a suitable ferrite bead and a couple of ceramic capacitors to see how it compares with the op amp solution.

[@TheCrazyInventor]

Are you wearing a wireless microphone? I noticed the shape of the noisy signal around 1MHz changes as you speak. When you don't speak, I can clearly see some sort of carrier wave that is being modulated, so I'm guessing the circuit or scope is picking up the wireless mic signal.

[@GolIden]

That actually seems like the reason that's there.

[@alklapaxida850]

thank you for the videos you make it's always nice to have many opinions on a topic and as always very interesting.

[@7head7metal7]

It's always a pleasure to see some Burr-Brown components :) A similar drop down voltage for higher output current is happening in the BUF634, which I'm currently using for a project.

[@blahblahblahblah2933]

RIP BB.

[@ereisch]

I'm going to go with the RF signal from his wireless microphone coupling into the sensor leads. At one point where he's quiet for a second, the carrier with very little data can be seen.

[@alexanderzheligovsky1439]

Interesting... the op-amp is speced for a minimum +-10 V power supply voltage, that's 20 V in unipolar mode, so I think it'd be a good idea to pick a different op-amp. It would intersting to see the step response of this one at high load and even lower supply voltages.

[@CyberBoy8799]

Dave - CAD Trial Edition lol

[@beenn15]

I wonder how long the trial is good for lol

[@shazam6274]

@@beenn15 It is probably only a few minutes, but since Dave has to tell you, it will take at least 45 minutes.

[@JetNmyFuture]

That power rail probe is a cool accessory - on my wish list for sure.

[@orgitellohugues]

You should try a capacitor multiplier circuit instead. Much lower noise, less power burned and more compact. The noise is comming from the DC voltage monitor. Thank you for your great work ;)

[@thegoodhen]

Came to say that. I have just tested a capacitance multiplier today and it works wonders! Sure, the line regulation is lost, but I have just built a circuit which uses the 7809 regulator as a reference and as long as the transistor base current is high enough, the output is fairly stable... and I suppose one could always toss in an opamp and stabilize it more... :D

[@xDevscom_EE]

Where can we get this new version of Dave-CAD with color highlight support :D. Thanks! Is the hump from 800k-1M due to the display panel thingy LED drive?

[@danmenes3143]

Why not use an LM317 or LM1086 variable linear regulator instead of the op-amp? Much cheaper devices, comparable supply rejection, and in the case of the 1086, less than half the drop-out voltage. It would be much the same circuit as you have presented, except the output would track 1.25v higher.

[@mikeydk]

I am having some problems with my Dave CAD, especially when I want it to draw circles and straight lines, but in general it looks terrible. Do I need to install a driver or something to make it look better?

[@Chupacabras222]

I'm afraid it's a hardware issue.

[@electrobob]

Please do a comparison with an LC filter.

[@PlasmaHH]

Many years ago I had some switchin PSU that I took and modified in a smilar but possibly better way, you might want to have a look if its possible here too: The voltage setting was done via some crude DAC mechanism setting a reference voltage which then was fed into the switching converter. I removed it from there, made it drive the linear output (opamp+transistor) and modified that voltage to add a few volts to feed the switcher (actually I think I modified the feedback from the switcher), so it generated a higher output voltage. Worked quite ok.

[@pirateman1966]

Would LC filtering the output have made any noticeable difference? I wish you'd shown that with your nice setup. Also, you are driving the PS from another SMPS, and a cheap one at that. Would that not have affected the output as well?

[@joshmyer9]

You might want to ping scanlime; she has a copy of DaveCAD cracked by Tuco Crew, maybe she can hook you up with an ISO.

[@yaghiyahbrenner8902]

wtf is scanlime.

[@yaghiyahbrenner8902]

oh the cat women... I prefer signal path's cat.

[@blackbrayn]

kzbin.infovideos

[@TheDefpom]

That op amp is a pretty neat device, 2 amps capable, that could be very useful as a low current power supply replacement in older equipment which uses linear supplies.

[@OneBiOzZ]

you can actually get op amps up to 100A like the PA50 by apex, problem is they are very pricey, $20 or so for the one used, $500 for the 100A PA50, if your after a power supply replacement in old equipment that need 2 amps best use a switcher module and manually set a couple of LM317s would be cheaper

[@AlexandreKandalintsev]

I'm not sure, it costs a fortune. Also not granted it can drive capacitive load. I'd go with a discrete pass element, it should be much cheaper, although it would require a separate over-current and over-temperature protection.

[@borkowsm]

Becasue level of this noise do not change in both circuits (even slow OPA it has some noise reject) I count on external 7-digit voltmeter - noise change with change voltameter display 11.0 to 11.1 :)

[@OneBiOzZ]

That noise bubble looks a lot like FM radio harmonics to me

[@Shadowdncer]

At around 900MHz I'm thinking about home automation gadgets on an ISM band.

[@christiantesch2722]

900kHz not Mhz, so i would also assume it comes from AM Radio stations

[@blahblahblahblah2933]

Depending on the switching power supply controller, 900kHz is in the range of switching frequencies. That noise wasn't very heavily attenuated by the addition of the opamp, but the PSRR of the opamp has likely fallen off a cliff by that frequency. Could also be anything else in the room...maybe the cat; does the cat have a pirate radio station? Definitely looks like a modulated signal.

[@OneBiOzZ]

it does not look like AM to me, looks more like FM

[@uwezimmermann5427]

It's unlikely that any local rf source would couple this strongly into a 25 ohm load. However, it most probably comes from a spread-spectrum oscillator driving a dc/dc converter.

[@MarkTillotson]

There's scope for trying a LC pi-filter on the output too, as a purely passive way to reduce noise...

[@bradjohnson3600]

thank you , im going to use this in the ham radio room and really do care about RFI

[@amicklich6729]

Good grief my friend, that is the mother of all scopes! 8/ ....The Keysight I should mention.

[@seabreezecoffeeroasters7994]

Lucky for you DaveCAD is open source. Where have you put the fork repository for it :) Love your channel and the higher end information provided, this one is great too!

[@jpvoodoo5522]

What is the thing that the battery is connected directly to? I thought the LCD part was a buck boost converter itself?

[@antibrevity]

Well, if this particular circuit is impractical, then it would be nice to see someone develop a practical solution ;) . Thanks for the video!

[@akosbuzogany2752]

Is the 900 kHz the sps frequency? They do sometimes intentionally make them spread to conform the noise limit measured on a single chanel.

[@tribulationprepper787]

Do the small DC to DC DROK type adjustable Buck step down converters produce much audio noise? I will be using 12 volt battery input and powering a 6 volt portable short wave radio. I hope you will answer my questions. If this could add audio noise, could you suggest a simple remedy? Thanks

[@AlexandreKandalintsev]

That noise changes roughly every second. So, it can be one of displays. I'd say it's a power supply display updating (or display cable radiating).

[@shazam6274]

Try a Low Freq, High Current, Common Mode Filter. I've recently been measuring the performance for these from Laird (available from DigiKey & Newark): assets.lairdtech.com/home/brandworld/files/SIP-DS-CMX1211%201113.pdf , assets.lairdtech.com/home/brandworld/files/CM5740Z241B-10.pdf . Most EMI filters have 2 issues for my application: 1) low current, 2) do little below ~ 40 MHz (the rating in Ohms or dB is typically @ 100 MHz). Also add a 4.7 uF MLCC on the output. Even the large Filter ("CMX1211...") is smaller & cheaper than the silicon solution here, and probably works better at removing noise. Perhaps some experiments, measurements & Tutorial about EMI Filters could be in the future? P.S. the probe is worth more than 1/2 my car & the 'scope about 1/3 my house.

[@kaimac1]

The 900 kHz noise could be from the TFT display?

[@alexanderwikstrom1829]

I didn't know that the trail version of Dave Cad had the ability to use multiple colors. Now I am curious to if the pro version has some extra nice features that Dave isn't using.

[@Jerry_from_analytics]

Pro version has layers, I've seen Dave using it.

[@tarungeorge3060]

Can I connect a battery directly onto the output without a diode in order to charge it or will it destroy the module?

[@markusreichel3896]

I am just a hobbyist, but just adding a bypass capacitor to the output of the power supply would also decrease the noise?

[@antibrevity]

You don't want more capacitance at the output of any bench power supply because it allows overshoot in current-limiting mode and can thus fry the very load that you are trying to protect. Current-limiting modes are supposed to protect against dead shorts, yet capacitors inherently dump current into such a short. Capacitive filtering at the output is a crutch used to fix a poorly designed power supply. I like the DPS/DPH models as they were initially a great value, but they are quite noisy. That noise is not harmful for most hobbyist applications and there are circuits like this one that can reduce this noise. It's still hard to beat the DPS prices and features and I'm unaware of competitors to the DPH buck/boost models, but the manufacturer has understandably leveraged customer demand into higher prices across the line.

[@Sloxx701]

900 kHz... Flourescent lighting maybe, wireless microphones, the dc/dc converter you're using or another smps in the room somewhere, an AM radio station... I dunno it's a lot of ideas. I see modulation so I'm thinking the mic or radio... I could be way wrong though

[@alexdavis9794]

Hey Shariar, One other comment on the OPA544 - I'd be really careful using a power op amp as a straight buffer in this application. They frequently have very poor capacitive load drive capabilities, and may happily oscillate when presented with capacitive loads you'd otherwise not look twice at connecting to a power supply.

[@Thesignalpath]

Yes, of course. As I mentioned this is just for exploring the noise.

[@alexdavis9794]

Sorry, on a re-read of my original comment I realized I should have worded it differently. I'm sure you're aware of the array of issues in a design like this - I should have worded it more as a general comment or addition to the conversation in the comments. It is very cool seeing the noise benefits of even a simple op-amp LDO in this sort of demonstration.

[@yngvenystrand167]

I think I would try a simple LC low pass filter on the output, possibly two stages, instead of this solution. It should get rid of most of the noise. Sure, it will cause some minimal voltage drop, but with proper design that shouldn't be much of an issue. Especially as the output voltage regulation of cheap power supplies like this probably isn't very good.

[@johnsnowlow1883]

Hi came across your video. Hence can you help build the noise suppressor module. I am using something similar like this. Source power comes from lead acid battery 12v directly into this portable unit. I hope to power a raspberry. Let me know whether you can help. Thanks

[@BlackXeno]

Hi, I just wonder if instead of using a powerful op-amp, one could use a normal one with an output power transistor (maybe in class A power stage or the like, maybe even with one transistor) and still having a noise rejection. Is an output external transistor let easily the noise pass thru?

[@billwest257]

Just out of curiosity what does this setup look like with the rail probes input grounded together? Could the noise be common mode that is unaffected by the op amp?

[@EmbSysDev]

Where can you get scope probes like that for the bread board ? Looks very handy.

[@SproutyPottedPlant]

I'm allergic to spurs so they can shuffle along somewhere else. Would all the noise also become RFI and interfere with HF radio?

[@naohwatson854]

The hump most likely comes from an external source since it was not affected by the filter. Furthermore, it must be outside your control since you do not turn it off for this video unless you want to teach us a lesson or it is an integral part of the setup such the opamp or lights in the room. It also seem to have some form of "communication" but it is be too broadband for AM radio or psu noise. Could it be noise from a CDMA mobile base station on top of your apartment?

[@cxyzh1234]

Noise source is the Voltmeter with led display?

[@bradjohnson3600]

AC line noise filter will often work for DC if current rating is ok. (The terminal size is a little small from most DC loads is only problem )

[@jonka1]

Very interesting as a 'mind opener' to solutions. Please run a comparison with LC filtering as an alternative that looses less of the output power.

[@JLSoftware]

OK, 7:13 I was lost after that. Sigh. Which one of those 4 boards IS the power supply?

[@gregcooler]

Great video! Thanks for sharing it. Is the hump from a spread spectrum switching frequency for the DCDC? Can you please do a review of the R&S RTO series scope?

[@epatto]

I'd guess the 900 or so kHz is the buck-boost, operating in spread spectrum.

[@TheDefpom]

Couldn't you of also used a current pass transistor instead, with its base being driven from a smoothed supply? This would of reduced the 4V gap you have, which means you currently cannot use the power supplies full voltage range in this case. Using a pass transistor would of reduced the different to less than 1 volt, probably closer to .7V.

[@Thesignalpath]

Not exactly, because then the voltage would be a function of the load as the junction voltage changes with both current and temperature.

[@dougvb9048]

I agree that a simple emitter follower with filtering on the base would filter out much of the noise. Could you break out the feed back loop within the power module to the transistor's emitter to remove the voltage drop error? I have one of these units and was going to give that a go. BTW, that's a broadcast station, right? If it is, then some those spikes you are seeing may be direct induction from the inductors in the power supply...ie if you getting radio stations, you will get other stuff. Cheers doug

[@mikek5206]

I can't find the answer to the 900KHz hump in the comments...did you ever post it? My guess was wireless mic or AM radio

[@joes5669]

My guess for the puzzle noise: PWM current mode switching regulator operating at ~900KHz inside the DC/DC converter module.

[@AlexTaradov]

What is that scope probe attachement that goes to the breadboard? Visible at 12:28.

[@clee2423]

can you use capacitance multiplier to reduce the noise ?

[@jankowalski4651]

Mine 2 wire voltmeter (which looks just like yours) makes some noise . Is that the source of remaining noise.

[@t1d100]

Might another approach be an adjustable voltage regulator, such as the LM317? Its functional diagram shows that it includes an op amp and it is less expensive. I guess its main downfall would be that it cannot handle as much current. The old LT1083 would have been a good candidate, at up to 7 amps, but it is out of production. An AVR would not boost, I suppose.

[@rodstartube]

1:03 can you please tell me how to search that battery pack ??? i mean, the product name or a link, thank you!

[@electrobob]

The OPA544 datasheet says minimum +/- 10V supply, so your opamp might not work properly at 15V input.

[@otherbasis8505]

What about low-Q ferrite beads? Something similar to what we've seen in FSH3 repair video.

[@joelholdsworth]

If you install the Opendps firmware, you can customize it to give you the correct voltage readout

[@antibrevity]

This model is a DPH buck/boost unit, so I'm not sure if OpenDPS will work here, though it has been tested on other DPS buck units. See, for example, this thread: github.com/kanflo/opendps/issues/197

[@coloradowilderness3139]

I powered my dc buck module with a transformer . Transformer spec : input volt= 220v, Output volt= 24v , 190VA. I used bridge rectifier to make AC to DC and 1000 microfarad-50V capacitor to smooth . Now float voltage 35V. Buck spec : input = 5v - 32v. 5A After connecting the buck module burnt within 10 seconds. Before i used the buck with 12V 60A battery to power up the module and charged 18360 battery pack of my Bosch hand drill . I could not understand why transformer damaged the module. I guess : 1) buck module can't tolerate ripple to the input side . 2) Float volt may cause damage. Am I correct ? Any suggestion ? Waiting ......

[@TheArachnoBot]

Old post but just saying this in case some stumbles upon this comment. The "float voltage" youre talking about is the peak to peak voltage. Unless you load the transformer, this is the voltage it will output. So you connected a 35V supply to a module with 32V max input and it went up in smoke. No surprises there.

[@yaseribrahim68]

Can someone provide a link to the battery??

[@A13tech]

using capacitor mulitplier should be easier. I would like to see diferences between capacitor multiplier and opamp solution.

[@sykskysyk]

Can you provide a link to where you purchased the battery pack from?

[@proyectosledar]

thanks

[@milenedejong1400]

is the voltage meter a bit noisy ?

[@ElecDashTronDotOrg]

Can you please provide a link to that Battery Module?

[@Paxmax]

Hmm.. dat heatsink though! Looks too me like som Thermalright Sk- ... something. There is quite the dramatic back pressure when trying to increase airflow over those...

[@vaualbus]

I think that noise come out from the microphone. It is an dsb signal and is modulated. The only thing i can think is the microphone transmitter.

[@kaimac1]

It's pretty wide though - each sideband is 100 kHz.

[@vaualbus]

Kyle McInnes ya but really what could be else?

[@victornpb]

I would guess the noise is coming from driving the screen. I think it would be wide like that

[@geiolaz]

Isn't that noise generated by the power supply screen?

[@williamanderson7215]

Would have been nice to see a noise comparison with a linear reg.

[@chrisw1462]

Pure linear regulators don't make noise. They may pick some up from elsewhere, but so would any regulator.

[@leozendo3500]

The 900kHz noise looks like a ham radio transmission waterfall graph and it even jumps around indicating the change in bandwidth.

[@DavidLightman]

HAAHAAHAHAHA Davecad trial edition HAAHAAHAAHAHA PRICELESS!!!, excellent video as always from you thank you

[@combin8or]

I fully expected that DIY output filter design would be some sort of black magic active filter operating in the 10s of GHz.

[@nezbrun872]

It'd be especially useful to see practically how engineers made these measurements before 2014 when the $3,000 power rail probe first came to market, so we can make a judgement as to whether SMPS designers can justify the purchase.

[@ChrisSmith-tc4df]

While I generally agree with shazam that additional L-C output noise filtering should be the primary approach, I believe that this article from Wenzel provides insight on how one can more effectively use a “power op amp” to significantly reduce noise - particularly in the troublesome LF range. Think of it as the Bose noise cancelling headphones for low-noise voltage sources. www.wenzel.com/documents/finesse.html

[@shazam6274]

The article is interesting for low current applications. I have noise reduction needs in the 20 to 50 Amp range.

[@ChrisSmith-tc4df]

I agree that scaling up to 20 to 50 amps would be more challenging, but with respect to Shahriar’s use case in his video, the power op amp that he’s chosen would be able to inject sufficient inverse noise current into a correspondingly low resistance shunt on the order of 100 milli-ohms - perhaps much less. In a pure AC configuration, one benefit for the power op amp is that it is only burdened with carrying the noise power, so it should run quite cool - even at full load. Unfortunately, that configuration would require higher rail voltage on the op amp to effect a bipolar output about the target output voltage. By purposely introducing an offset into the op amp circuit to cause it to draw DC current statically through the shunt, a new virtual mid-point could be established within the anticipated noise amplitude and reduce or eliminate the higher op amp power supply requirement. Even better, use the power op amp as a driver for a large bipolar or FET transistor to scale up even higher. I propose this only as an interesting way to use a power op amp in this use case. Otherwise, L-C filtering or a downstream high-current adjustable LDO would serve the same purpose as the op amp series regulator, but at a much lower cost, better rejection, and available survivable current limiting.

[@Stefan_Payne]

Is that an LGA2011 non square HEatsink? ;)

[@stevec5000]

You really can start a car with one of those battery packs but not if the car battery is very much discharged. With the ones that I have tried the car battery has to still be at least 8 volts and won't work if it's very dead because most of those jumper units check that they are connected to the battery first and polarity is correct before turning on the output and if the battery is really too dead it won't turn on.

[@UndernetSystems]

Thank you for making this very interesting video.

[@CATA20034]

I would say that your measurement isn't correct. You should measure close to the output capacitor of the PSU. All those wires from the output until they reach your probe will couple noise from switching. Related to that hump from 900khz...is it spread spectrum? I'm confused because I saw it arround 900k....quite high.

[@AlexandreKandalintsev]

Totally agree, long wires compromise performance. In my measurements every centimeter from output cap makes transient response worse. Also, wires work as antennas.

[@simontay4851]

Wouldn't a large inductor and multiple capacitors of different values on the output be just as effective or better than this.

[@Thesignalpath]

It is more difficult than you think. An LC network will have its own impact on rise/fall behavior of the power supply not to mention on the CC/CV switch over. But is is worth trying it to see what is the best you can achieve.

[@kl1nk0r]

Here is my guess: The noise hump is due to the dcdc converter operating in burst mode due to light load condition :-)

[@JackZimmermann]

While watching Dave's video, I was hoping he would do noise measurements. Thanks! But trying to convince my wife of getting the oscilloscope you have is going to be kind of a battle. I'll probably ending up selling my body to science-(fiction).

[@uwezimmermann5427]

How much of the noise you measure at the output actually comes from your battery pack? Inside you most probably also have a dc/dc converter converting the Li-battery voltage to 12 V. I would assume that the 1 MHz spread-spectrum signal comes one of the converters and the 60-odd kHz come from the other converter.

[@elvishfiend]

Uwe Zimmermann nope, no switching is done in the battery pack, it's just 3x LiPo in series. They'd never be able to get enough current to start a car otherwise

[@vidasvv]

Thank you for another great video! You should make a video how you tracked down that blob of noise on the high end and how to minimise it if possible and can it be done by the average Joe without the use of high end equipment. I just noticed the "blob" appears around 900MHz, maybe cell phone tower near by ? 73 N8AUM

[@shazam6274]

Check the AM Radio Stations in the area, also possibly a fluorescent lamp.

[@MarkTillotson]

900kHz, not 900MHz, vidas v

[@vidasvv]

eye sight plus old timers lol yes, after looking at it again i can plainly see it much better once i bumped up the video resolution to 720 !

[@AdrianHiggins83]

Broadcast band ?

[@Ender_Wiggin]

god damn that oscilloscope

[@isoslow]

If you want a power opamp try TDA2050, it is dirt cheap comparing to a 20$ BB part. Also you can whack a simple discrete output stage inside the feedback loop with two transistor and two diodes to a regular small signal op amp and save even more on a fully functional power opamp. But after that you don't need a complete output stage, you can do it with a small signal OPA and a single pass transistor. Your circuit doesn't make too much sense, you could've used much more sophisticated filter other than a simplest RC one, if you decided to use a power opamp after all. Also do not try to filter stuff that comes to MHz region with an active circuitry, it needs to be a few orders of magnitude more complicated. For that better use low-Q inductors and very low-ESR high quality ceramic caps. Also you will need a nice board layout. 900Mhz noise is from a radio mic transmitter.

[@pratwurschtgulasch6662]

your oscilloscope costs more than my tractor :D

[@bbugl]

you're in the us, right? isn't 900MHz some cellphone thing in the us? i'm from austria and it's 800MHz here but i think it's different overseas. might be wrong, though.

[@fbnx4219]

It is at 900 kHz

[@bbugl]

oooh. my mistake. now that i think about it he said it measures up to 1 MHz... soooooo my bad

[@rsutherland76]

900Khz at 200Khz wide I think is noise from the microcontroller.

[@RIGeek.]

900kHz seems like a local AM station. 73!

[@avejst]

Thanks for sharing 😀👍

[@alexanderzheligovsky1439]

It would be interesting to see what noise an LM317 would show in a similar circuit, something like this: farm5.staticflickr.com/4487/36856666644_5cb6089f2f.jpg . A better way to do the RC ciruit of the zener diode: farm5.staticflickr.com/4458/36901499104_2c3a121339.jpg And to throw a TPS7A4700 into the mix too (it's a VERY low noise linear regulator).

[@786jinga]

Just when i thought how i am use this cheap power supply for RF after seeing eevblog video. Here it is...!!!!!

[@ZlayaCo6aka]

The gross inattention to detail demonstrated in the comments makes both my kilo and Mega hurts!!!

[@JerryWalker001]

Dave-Cad is rubbish, It keeps crashing and all the text is in Australian.

[@MarkTillotson]

Are you saying its really How-Are-You-Doing-CAD re-skinned?