+/-/0v DC circuit, from DC +/0v ---- something simple to build?

[abbey road d enfer]

Ok, find me such a working schematic (single active coil, single voltage input, +/- output / same current) on www or anywhere else (any literature, credible source) and I will donate USD25 to maintain this site.

Money is irrelevant. Someone much cleverer than me has found a way of making a bipolar converter with a single active coil (and two additional). I don't know how, nor particularly care, because I have nothing to prove, nothing to lose. I never claimed to be an smps specialist. I just buy them.
OTOH, I don't declare out of the blue that it doesn't work.

 

[adamasnan]

@adamasnan
can you please draw the smps schematic you bought, if it is essentially different from the schematic I posted in my replay 10 I will donate an additional USD25 to maintain this site

Hey, I am not really to be trusted with such a task

Sooo.. if I get the meanwell units, I should still put an LCR (or some other??) filter at the output yes? I really hope they work better than the ebay ones, because I will need to buy 2 of them @ 25 euros each+vat

 

[moamps]

Sooo.. if I get the meanwell units, I should still put an LCR (or some other??) filter at the output yes? I really hope they work better than the ebay ones, because I will need to buy 2 of them @ 25 euros each+vat

I's new product, I didn't try it so I don't know is the additional filtering needed or not. So please don't listen to my advice.

 

[moamps]

.... Someone much cleverer than me has found a way of making a bipolar converter with a single active coil (and two additional). I don't know how,...

It's pretty much the same as if someone told you "here are a few resistors and just one transistor and make me a push-pull amplifier". Using only that one IC and one active coil, bipolar output voltage cannot be produced. Purely out of scientific curiosity, I bought these two SMPSs, so we will soon know exactly what they are about.

 

[abbey road d enfer]

It's pretty much the same as if someone told you "here are a few resistors and just one transistor and make me a push-pull amplifier".

No. It's someone that says "I have made something out of this and this" and you say it's impossible.
I give him the benefit of the doubt, until proved wrong (or right).

 

[moamps]

No. It's someone that says "I have made something out of this and this" and you say it's impossible.
I give him the benefit of the doubt, until proved wrong (or right).

It is clear to me that the problem is actually what I said. Nevermind. We'll find out soon who's right.

 

[abbey road d enfer]

It is clear to me that the problem is actually what I said. Nevermind. We'll find out soon who's right.

When I wrote "I give him the benefit of the doubt, until proved wrong (or right)", I was not referring to you. I was just meaning that I could be right or wrong to believe this product works.
I'm not in competition with you. Read my sign.

 

[moamps]

I'm not in competition with you.

Then why do you moderators feel such a need to quote almost all my posts? Am I talking nonsense?
You’re not really competing with me,  you just want to constantly show who’s the boss here.

Read my sign.

You should start acting according to the signature you wrote yourself.

 

[JohnRoberts]

Then why do you moderators feel such a need to quote almost all my posts? Am I talking nonsense?
You’re not really competing with me,  you just want to constantly show who’s the boss here.You should start acting according to the signature you wrote yourself.

Ooops... I just quoted you too...  :

Do I need to apologize?

JR

 

[abbey road d enfer]

Then why do you moderators feel such a need to quote almost all my posts?

Please calm down. I tend to quote either stupid or interestinf posts. Pick your choice.

Am I talking nonsense?

No, but sometimes you profer opinions that would benefit from being substantiated. AS I DO, ALSO, SOMETIMES. If that happens, I try to analyse why I did something wrong and make amends. Haven't you noticed that?

You’re not really competing with me, 

I"m glad you recognize that.

you just want to constantly show who’s the boss here.

I think you're projecting your way of thinking on me. I don't want to compete with anybody. I have enough flying hours, I don't need medals.
If it is your perception of me, let me assure you you're wrong.
I know there's a couple of members here who don't like me, think I'm arrogant and bossy. When they're asked to give concrete examples of such a behaviour from my part, it turns out very often that they misunderstood me. OTOH, when I've been subjected to such opprobrium, several voices rose to testify of my usually helpful attitude. Well, you can't please everyone...
You have to understand that, as a moderator, I must , as much as I can, try to maintain a tolerant attitude. I'm not advocating candour either.
I try to navigate between openmindedness and scepticism.

You should start acting according to the signature you wrote yourself.

Give me proof that I have acted contrarily. You'd be surprized at the number of cases when I had to admit wilfully that I was wrong or misleaded. Please read carefully and analyse my posts in this thread. Your position is very hostile, while I was suggesting something that we don't know makes this product work. I only made suggestions and guesses and warned that I was not the most competent person on the subject.

 

[adamasnan]

one of my posts never before got so many replies! thanks !

 

[abbey road d enfer]

one of my posts never before got so many replies! thanks !

Unfortunately most of these rants are not very useful to you.

 

[moamps]

.......Your position is very hostile, while I was suggesting something that we don't know makes this product work.....

I'm sorry if I was rude and hostile to anyone, and I apologize for that. You said "while I was suggesting something that we don't know makes this product work". We? I don't know about you, but I know how such SMPS can work and what it can't do, and I'm trying to explain it to you, but you refuse to understand it. We may be lost in translation, which I am probably most to blame for. BTW, I made my first SMPS with bipolar output voltage approximately 30 years ago, using  LM711 comparators and one 12V SLA battery for powering field audio recording equipment.

Because of all this and the funny replays of your colleague, I will completely reduce my participation in the forum, except maybe when I want to buy or sell something. I will also post my observations about this SMPS in this thread when I get it and test it, to know who was right, and that other forum members don’t buy that SMPS if it doesn’t do what it should.

 

[abbey road d enfer]

You said "while I was suggesting something that we don't know makes this product work". We?

I maintain that we, you and me, and probably others, don't know what makes it work, because it actually works. If we had a schemo, we may know why. You certainly know how an smps works, but saying this particular one does not work when there's evidence that it does work shows you don't know everything.

  Because of all this and the funny replays of your colleague, I will completely reduce my participation in the forum,

  It'll be our loss...

I will also post my observations about this SMPS in this thread when I get it and test it, to know who was right,

  As you know, I'm not interested in who is right.

  and that other forum members don’t buy that SMPS if it doesn’t do what it should.

I suggest you re-read the original post.
"I bought this buck converter on Ebay -- but it exhbits too much parasitic noise to be useful, but it does work."

 

[Bo Deadly]

I will also post my observations about this SMPS in this thread when I get it and test it, to know who was right, and that other forum members don’t buy that SMPS if it doesn’t do what it should.

Why would you bother? That SMPS is just cheap knock-off parts (never heard of XLSEMI) with a bunch of chokes in series as a poor excuse for a transformer. It might be fine for fixing the old Realistic receiver in the wood shop but it's almost certainly a disaster for pro-audio. Not all SMPS are created equal. I have always had good results with MeanWell SMPS.

 

[adamasnan]

I will completely reduce my participation in the forum, except maybe when I want to buy or sell something.

MOAMPS DON'T GO! you have helped me so much in the last year or more, you helped me modify my Sonosax SX-PR for direct outputs, and you helped me figure out why I couldn't get signal from an RFZ V742! Forget about the online quarrels, it goes with the territory, and it's not real! Please stay!

 

[moamps]

I did some additional research and the conclusion is that I was actually wrong, and I have to correct myself. There is a relatively new variant of the SEPIC-ĆUK SMPS power supply where all three coils are active and they do not have to be magnetically coupled for the SMPS to work. I was convinced they had to. The fact is that if magnetically coupled coils are used, the output ripple is lower. How much is ripple in absolute value, I don’t know, but obviously is not small. You can see the following video on youtube where basically everything is explained
https://www.youtube.com/watch?v=XMnjllRMoy4&ab_channel=JulianIlett
The kit presented in the video may be interesting for some members here, it is cheap and easy to make, the reviews are mostly positive, but some problems in the work have been noticed (outputs are followed by regulators to get stable and clean voltages). The circuit can probably be easily modified to get + / 12V and + / 15V (100 to 200mA) which can be very useful for some applications (GSSL, etc.).
Anyway I’ll test that SMPS when they deliver it to me, but there’s no need to report my observations, so this will be my last post in this part of forum.

 

[abbey road d enfer]

Why would you bother? That SMPS is just cheap knock-off parts (never heard of XLSEMI) with a bunch of chokes in series as a poor excuse for a transformer.

How can you be so affirmative of a product you don't know? The video provided by moapms shows that it's a quite interesting product.

 

[Bo Deadly]

How can you be so affirmative of a product you don't know? The video provided by moapms shows that it's a quite interesting product.

I don't think it's too much of a leap to say that it's not going to work that well. Clearly with 3 cheap chokes for coils the leakage inductance probably stinks, it's not isolated and they're not even shielded. Even the usual cheap China ones from Ebay use shielded inductors. And I don't know what you find that interesting about it. It's just generating the negative voltage from the positive using a voltage multiplier technique so that they don't have to use a specialty transformer. But now the feedback is not coupled to the negative rail and the diodes are probably making noise at half the switching frequency. The more I look at it, the more I hate it.

 

[abbey road d enfer]

I don't think it's too much of a leap to say that it's not going to work that well.

The links provided by moamps clearly show that it does work well.

Clearly with 3 cheap chokes for coils the leakage inductance probably stinks, it's not isolated and they're not even shielded. Even the usual cheap China ones from Ebay use shielded inductors. A

So you are assessing the performance of a product by looking at its components. Don't you know components are just a fraction of what makes a circuit tick? Design is the most important factor. You can't judge a book by looking at its cover.

And I don't know what you find that interesting about it.

I said it's interesting because it goes against preconceived ideas, formulated by moamps who said it couldn't work, which he admitted was wrong.

It's just generating the negative voltage from the positive using a voltage multiplier technique so that they don't have to use a specialty transformer.

That's what I suggested when I wrote "I imagine where there's a square-wave, there's a way to produce rectified voltages of both polarities."

The more I look at it, the more I hate it.

I repeat you can't judge a product by just looking at it.
I suspect you haven't checked the link provided by moamps, which gives all teh expalbnations and provides links to other articles by Analog Devices and EEtimes. If they have deemed the subject worth publishing, there must be something in there that's more than BS.
Now your concerns about noise and shielding must be considered in the context of the application. There are many pieces of gear where noise is an insignificant factor (within limits). If you look at the kit
https://www.banggood.com/Original-Hiland-DIY-USB-Boost-Single-Turn-Dual-Power-Linear-Regulator-Multiple-Output-Power-Module-Kit-p-1022517.html?akmClientCountry=FR&utm_source=Youtube&utm_medium=cussku&utm_campaign=672526_1022517&utm_content=1081&cur_warehouse=CN
you'll see that all the outputs are through linear regulators. that indicates the designer is very much aware of the noise from the unreg outputs.