I'm going to call it out, hope I'm not breaking any forum rules here.
I don't think the OP intends to buy a bench supply at all. I think they are simply looking for attention.
They never specified a budget, then it was $2000, now $6000... Either seems a totally ridiculous amount to spend on a bench supply for amplifier repair, nevermind as a hobbyist, and right off the bat too.
And they admit they don't even have other crucial equipment where the money would be far better spent.
The "requirements" are based in fantasy land and the OP routinely ignores good advice of knowledgeable people.
And then, 3 x 16A supply in the workshop, apparently. Which may be true but it doesn't seem in any way typical so I am sceptical. Most whole house supplies in 250v countries, as I assume Denmark is, are 63A or 80A at most of which 3 x 16A would be a sizeable chunk.
But of course they're probably not even from Denmark.
To others I suggest don't waste your time trying to provide any advice, as taking advice does not seem to be the OP's intention.
I don't think the OP intends to buy a bench supply at all. I think they are simply looking for attention.
They never specified a budget, then it was $2000, now $6000... Either seems a totally ridiculous amount to spend on a bench supply for amplifier repair, nevermind as a hobbyist, and right off the bat too.
And they admit they don't even have other crucial equipment where the money would be far better spent.
The "requirements" are based in fantasy land and the OP routinely ignores good advice of knowledgeable people.
And then, 3 x 16A supply in the workshop, apparently. Which may be true but it doesn't seem in any way typical so I am sceptical. Most whole house supplies in 250v countries, as I assume Denmark is, are 63A or 80A at most of which 3 x 16A would be a sizeable chunk.
But of course they're probably not even from Denmark.
To others I suggest don't waste your time trying to provide any advice, as taking advice does not seem to be the OP's intention.
I do not think that you break any rules, you are polite and give your opinion.
If I did look for attension, I think there would be many other ways, but let me explane futher🙂
First
about the prises, yes 2,000$ is an insane amount of money and not something I'd ever hope to spend. But after my search in all sort of places, I did find out that most I could find, did cost above 2,000$. If I had written 500$ as the upper limit, I'd risk sorting the perfect solution out because it costs 700$. So 2,000$ was because I had not found anything below that and hoped someone knew that Wing Hong Ding makes one for xxx$.
The 6,000 was a comment about that if I did not care about the price, I could just buy one and then get the buest.
As farly new in the electronic world, I do run into limits that I do not expect. Example: You can wary easy get a PSU with micro Amp adjustments but try to find a unit that can the same in Voltage. Or you can without a problem get a 500V 1A PSU or a 15V 60A but it looks like nearly impossible to get a 25V 10A-20A.
And I had no idea before I do ask all of you, to me is it a new world with not always logic limits.
If I in any way seems like I ignores great advises, is it only because I do not understand the English language in a high enough grade and that I on top of that also do not understand the electronic world.
In Denmark do we have 400V that is made of 3 x phases, each with 16 amp.
That do by no mean make it posible to add the current but it do mean that I can let a unit be alone in that 240V outlet and still use the other two "¤=V phases for the rest.
No if the rest was BS then would Denmark also be that, but unfortunately do Denmark also contain stupid people like me🙂 I do not know if or how I should prove I am from Denmark, google could easily be used to translate to Danish.
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Sorry to seem I do not want advices, but it's only due to me both not understanding electronic and English. I try my best and hope one day to get better, but right now, do I only have to believe in every info enyone say on any article or video. And when I then need to know that it is in fact true, I do ask here. 🙂
Harsh words...
I think friedmule is genuine, but as he stated not skilled and uncertain, I will not take away his curiosity for electronics by labelling him a fraud.
So friedmule stay curious, read and ask, there's no such thing as stupid questions, took Edison thousand errors to get the light bulb working.
I know English can be a barrier in pickling up knowledge, I find it difficult to, all those technical terms. years ago a borrowed from library books by a Danish guy Jan solberg, applied electronics, theese books helped.
Keep it simple dude.... see what happens when you don't.
Start out small like a Heathkit 2718 Tri-power supply.. many on Ebay, about 40USD.
Learn...step forward ...again simply
Go jump on a High Voltage supply right out of the gate and die ugly like this thd
Start out small like a Heathkit 2718 Tri-power supply.. many on Ebay, about 40USD.
Learn...step forward ...again simply
Go jump on a High Voltage supply right out of the gate and die ugly like this thd
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I second this advice except for the rectifier/caps which are already in the amp in the first case.
I have fixed thousands of amplifiers and my method was a variac with a lamp socket in series with the AC power output socket.
A range of lamp globes power ratings eg 40W, 60W, 100W etc (incandescant filament type, not CFL or LED) allows run up of amplifiers without risk of blowups and amp can be run at lower AC supply voltage whilst measuring and diagnosing.
Complicated variable DC supplies is inviting operator error and is overly costly when the above simpler arrangement is superior.
Dan.
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You are both right! 🙂 Hmm I was thinking, what if I bought 4 cheap PSU's like 10V 5A and then put them in series? It will do that I can use them as I like and still have some extra voltage / amps if I need.
Some of my start to learn projects is to buy different components, build some circuits from image search and see what happens if I change that value with this and so on.
FriedMule and I have exchanged words privately on this matter but I will also publically apologise here.
I too hope it does not stifle any curiosity.
As you say - there are no stupid questions - unfortunately in this online setting it is easy to view everyone with suspicion. I have become too cynical.
Well we are high end diy, so why settle for less than a power supply with tuby output..🙂
And yes, skip rectifier/cap for rep. I mainly use mine with the mentioned for new builds..
Do yourself a favour and do as max headroom suggests, he is an experienced guy, money better spend on good DMM and a scope plus signal generator, i found most of my stuff over several years, bought good used quality.
You will run into problems doing this, trust. The options suggested are with good reason.
Have a look at what the suggested Heathkit offers and find something similar, or follow the transformer + variac route and use a dim bulb tester (search for it) to provide current limiting.
Really, you don't need more than 30v and 3A for most things. The single most important thing in my opinion for prototyping is the ability to limit, and see, current draw, so you don't fry things when you make a mistake in your circuit.
Typically if you need more - like 50V and 6A - the power supply already exists in the unit! So, there is no need for a bench supply. And power testing an amp on a bench supply doesn't tell you much about how it will really perform anyway, since that performance depends so much on the power supply itself.
If that power supply has a fault, simply repair that first before proceeding.
Or you can test the circuit at a lower voltage on your bench supply if you must. Most circuits will work at lower voltages, at least enough to tell if they function at low power levels.
On my bench I have a single supply which goes to 28vdc 3a, it has two dials for setting voltage and current, a voltage and current meter on the front.
For prototyping and most repairs I have found it adequate. It uses a module which cost a few dollars from China and a 24v transformer from a broken UPS, and it's in the UPS case, so it cost next to nothing.
I have parts aside to make it dual rail and beef it up a little so it does 30v, but I haven't found a need so far.
Most of the time it is set to minimum current to begin with and wound up a little once I can see everything is ok in the circuit.
If you need a ground ref you can always split the rail with 2 resistors and capacitors.
Seriously, don't go crazy on the bench power supply, at least to start with.
Going overkill on this won't help you to learn anything, it will simply leave you with less funds for other things to progress your hobby.
Spend the money you saved on some good books on electronic and amplifier theory and read up. Experimenting alone won't get you far - ideally you need something that can help you to understand how things work hand in hand with experimentation to really "get" it.
I would also get familiar with a simulator such as ltspice. Invaluable for pre-prototyping and you don't need anything except a laptop and plenty of patience.
Genuinely, I wish you the best but you are trying to over think this without having any context to base your decision from. Once you get something, anything, as basic as possible and start actually doing things with it - you will start to understand better what you need from your equipment. Until then it is an unsolvable problem.
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I am wary happy guys, and I sure will do as you suggest! My last question about 4 PSU was more to ask if that was even possible🙂
My idea was to get a cheap PSU, exactly as you suggests, one I maybe later can buy more of, when I need it, and if they can go in series or parallel, then why not? 🙂
Some "genius" told me that I simply "had to have" and I would regret it if I didn't got that!! He suggested min +/-25V and 50V and at least 20A.
So I did just said ok, believed him and started on this strange journey. To my luck did you all say, hay, hold your horses, are you planning on power a whole city or just build / repair things, do you want to spend all your money and have nothing left to the rest?!
That have learned me a thing, this "genius" may not give advice's geared toward my needs but maybe only toward production facilities.
Thanks so much for using all that time and energy to undo what he told me and to try to push some sanity into my brain! 🙂
EDIT: I'll look at every advice again and do my best to follow them. Unfortunately is there no place to learn electronic, other then the internet, wary old books and try out.
My idea was to get a cheap PSU, exactly as you suggests, one I maybe later can buy more of, when I need it, and if they can go in series or parallel, then why not? 🙂
Some "genius" told me that I simply "had to have" and I would regret it if I didn't got that!! He suggested min +/-25V and 50V and at least 20A.
So I did just said ok, believed him and started on this strange journey. To my luck did you all say, hay, hold your horses, are you planning on power a whole city or just build / repair things, do you want to spend all your money and have nothing left to the rest?!
That have learned me a thing, this "genius" may not give advice's geared toward my needs but maybe only toward production facilities.
Thanks so much for using all that time and energy to undo what he told me and to try to push some sanity into my brain! 🙂
EDIT: I'll look at every advice again and do my best to follow them. Unfortunately is there no place to learn electronic, other then the internet, wary old books and try out.
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I am glad that you did react, imagine that everybody did think so and just ignored me, that would permanently end my journey. But you did say what other may have thought, and thereby let me explain myself. 🙂 So I am grateful!! 🙂
This is a nice simple high voltage/current circuit, I will build and use this at some point, maybe add extra output transistors.
So that circuit ammeters and voltmeters built in a old chassis, two 4 way rotary switches that couple in different watt incadent loads, say starting with 40w bulb and switch up to 200w
So that circuit ammeters and voltmeters built in a old chassis, two 4 way rotary switches that couple in different watt incadent loads, say starting with 40w bulb and switch up to 200w
Attachments
Looks really great, thanks! I will properly lower the voltage to below 50V for safety🙂 Do you know about ripple to expect?
Ripple depends on how heavy you load the supply, adding more capacitor later is easy enough when a lower ripple is really needed.
Ripple will be in low Mv, depending on the chosen decoupling, same or better than commercial amps psu, most amp circuits can easy handle ripple without any hickups.
Thanks a lot, maybe it could be fun for me to experiment on changing the ripples, to higher and lower values, just to learn what do matter most🙂
I know that it would be a simple question here, but as you all say, start simple🙂
About simulating some suggested LtSpice and it looks like it display the result of a circuit. But is there some simulators that shows where something is wrong, i.e. a short, electrolytic caps in the wrong direction and so on?
DC as supply is preferable, but to get genuine clean dc and current is not an easy task.
I'm not familiar with simulators but they duplicate real world circuitry to an degree, some designs might work in simulator, then you build it and find oscillations and current parasitic due to layout and wiring, but yes, say you simulate the above shown voltage regulator to see how it behaves with lower trafo volt, you see some resistor values might need lowering to.
I'm not familiar with simulators but they duplicate real world circuitry to an degree, some designs might work in simulator, then you build it and find oscillations and current parasitic due to layout and wiring, but yes, say you simulate the above shown voltage regulator to see how it behaves with lower trafo volt, you see some resistor values might need lowering to.
Yes that's exactly what I was thinking, by simulating a circuit, I can tinker around, change components, "fihgt the ripples" and so on, then later buy some eBay components and burn as many of them off as possible, all while learning, reading, seeing videos and having fun🙂
"all" it takes is a simulator where I can see if I make a short, if something is not doing as I thought. A simulator with "only" graphs may not do that in a clear enough manner for me to understand.