Need a design for a rectifier bridge producing 300V DC using a 450V 1000 micF 1mf cap

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phi112358 said:
Does it have less ripple to use a center tapped trafo than using a diode bridge and a polar trafo?
I don't know what a 'polar trafo' is, but fullwave rectification is fullwave rectification however you do it.

Can I use a 1uf-10uf capacitor in parallel with each diode in the bridge?
No. Maybe you meant to say 1nF-10nF?
 

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Imagine a nice amp made from solar panels ....

Silicon solar cells are 0.6V no-load and usually accounted as 0.5V loaded.

300V then needs 600 cells. That is a LOT of joints to go bad.

We "need" a battery to play at night or on very cloudy days.

An "organic festival" near me has solar-powered music PA. I can't comment on stellar sound quality because it is hardly audible from the mainway (none of their acts tempt me to go closer). I strongly suspect the cells charge the batteries and we hear "lead-acid battery", not "solar electric".

If an amp is any dang good, it is good on any semi-tolerable electric supply. Audio currents should return through local B+ bypass capacitors, not go out pass batts to sun-cells in the yard (or back to the dam generator at the utility power source).
 
I don't know what a 'polar trafo' is, but fullwave rectification is fullwave rectification however you do it.

No. Maybe you meant to say 1nF-10nF?

Okay, what type of caps across the diodes? Mft? Or electrolytic? If I cannot use the milifarad cap would 2 200uf caps with a resistor in between plus 4 10nf caps, one across each diode?

I saw a link I posted before with a 3 tap trafo using 2 diodes going in to a diode bridge. Is that the best way to go or should I get the trafo made with 2 taps 0 and 213+4, 1v per diode, so 0 and 217v is what I mean by polar, no center tap.

The rectifier in fig 6 i posted before used 6 diodes, using a bridge after the two diodes. It claimed to use 100 percent of the trafo all the time

This trafo maker seems to be accustomed to center tapped trafos and gave me one that measured out to 560v with no load. that had a center tap. I used 2 diodes and got around 270vac from it. is 213v and zero correct for a diode bridge? I will be adding the 10nf caps across all 4 diodes. What will the trafo measure while unloaded? 240v?

These are 6n14nas (EL84 SOVIETversion) and the 12ax7 is a 6h2n-eb. that means these only take 6.3v, they dont require 12v only the autobias takes 40ma 13v ac

found this circuit. Think I might go with it EL34 Single-Ended (SE) Tube Amplifier Schematic EL-34for the 300v and 6.3v both DCLook good?I notice only 2 caps between diodes. Should I use 1 in parallel with each diode?
What would I need to change to do that?

Thanks

EL34 Single-Ended (SE) Tube Amplifier Schematic EL-34

If there is no point in that circuit above, and I should go more simple, I can do. I like the idea of the lt1085 for the 6.3v THe ukranian person I got the modules from told me these sound best DC.

I do not know if so many chokes are necessary as in the pic in the post above. I will use the lt1085. Does anyone have a better design for the 300vdc? I am thinking of requesting a non center tapped, 2 tap 0*250, 0&6.3, 0&6.3, and 0&13v for the autobios Would that be better? to get 300V DC? It seems inductors resistors, caps, and the diodes, all reduce the final voltage and it may be best to start with 250v

Slow down.. collect your thoughts before hitting that post button..!
<snip>

If you use fullwave rectification 4 diodes, then you will use both halfs of the trafo at all times. but the voltage will only be V*1.2 if you use two diodes and don't use both halfs of the trafo at all times via the two diode method. this is what I read, and I tried a 2 diode rectifier on a center tapped trafo and got a similar voltage increase to 1.2, I think it was voltage * 1.0 but I was not using caps. Supposedly you need to be using 4 diodes to get the higher voltage you need.

Look at figure six of this link... Linear Power Supply Design

It says you get V*1.2 from a 2 diode rectifier only using half the trafo at any given moment where with the 4 diode arrangement, it says you use the whole trafo all the time, therefore the coefficient going from AC>DC rises.
 
What voltage transformer would provide 300VDC? I am getting one made to produce300VDC

What voltage transformer would provide 300VDC? I am getting one made to produce 300VDC. Will use a 4 diode bridge. Should I get a center tapped or only a 2 tap transformer? My mains is 220VAC.
 
EL34 Single-Ended (SE) Tube Amplifier Schematic EL-34 This one uses 240VAC to get 300VDC.

Is that a good schematic to get 300VDC? (the rectifier/filter part)? Or should I go for a CRC filter with no inductor and a lower V on the trafo? That looks like a CRCLC filter Is that the best way to go?

Or is that even a good schematic for my 300V needs?

you need to budget power... what load current at 300 volts dc? so that unloaded terminal voltage will be much higher than 300 volts..
100ma

Sorry, 150ma max. Just to be safe. It will be a monoblock with 2 soviet el84s and 1 soviet 12ax7. They all take 6.3, no 12v requirement. But I do need 40 ma at 13VAC for the autobias. I need 1200ma and another 600ma @ 6.3vDC

What will that transformer read when its unloaded? I can get center tapped or only 2 taps on the hv part. What should I request and what should it read when unloaded?

This maker seems to want to use center tapped on the hv. I told him I want 2 taps Should I use a CRC or a CRCLC filter and will that make a voltage difference?

Ahh, Sorry, Dont worry about CRCLC. I don't need to do the CRCLC filter, Just want to use a CRC or even just one 200uf capacitor and 4 diodes, because there are already filter caps in the circuit that needs 300VDC I am not going to use center tap, only 2 taps
 
That layout creates a split voltage supply but they have connected the load across the + rail and - rail so their negative is no longer referenced to ground.

I'd like to avoid the complications of isolating negative from ground and for my intended design so full wave (not bridge) should work out fine.
 
you need to budget power... what load current at 300 volts dc? so that unloaded terminal voltage will be much higher than 300 volts..
Im just going to get a 2 tap trafo. Should I ask for 217VAC @150ma? I am using 4 old soft telefunken diodes with 10nf caps in parallel to each one and 200uf for the reservoir capacitor. I calculated 217V by dividing 300 by root 2 and adding 1v for each diode.

Do I need 217V? @150ma? I am guessing that would read 240VAC when unloaded and 217V @ 150ma, becoming 300V after the diode bridge and the 200uf reservoir cap. Is that correct? Should I be asking the maker for 217VAC @150ma? OR do I add more voltage because of the resistor I must put before the reservoir cap? What is a good resistor value? First, is 217V@ 150ma a correct value? I will figure the resistor later
 
Sorry it turns out that these modules already have filter caps built in, so I will only use 1 200uf filter cap and a resistor for this rectifier. Going to use a 4 diode bridge with 10nf in parallel with each diode, then a 200uf filter cap. I am guessing I will need a resistor before the filter cap. No resistors for the 10nf caps in parallel to each diode.

Regulated is also unneeded for the6.3v and I can use AC, I will just use a choke.

Too much heat generated by an unnecessary regulator, If AC can be used, which I found out it can, I will try that first

> voltage will only be V*1.2

You are confusing voltage and current.

Slow down. Read. Collect your thoughts.

Thanks, I knew something was not right there. Current. Ok, not Voltage. I am just panicing because the maker can adjust the voltage requirements only for the next day or so. and I think 217V is what to ask for because of the 4 diodes taking a V off each and 300/root2=213V. +4V for the diodes=217V He had made it center tapped and he also made 2 12V supplies These are soviet copies which require 6.3V, only 40ma @13V for the autobias,

so I am getting him to make it polar for 217VAC @ 150ma and I am not sure that is correct. I just want to get it right this time. That IS not voltage, I see.

That layout creates a split voltage supply but they have connected the load across the + rail and - rail so their negative is no longer referenced to ground.

I'd like to avoid the complications of isolating negative from ground and for my intended design so full wave (not bridge) should work out fine.
sorry, I confused V with I. At least I didn't actually try the 1000uf capacitor yet, So still not feeling as dumb as I might have, frying the whole thing with that 1000uf beast. Which is probably only good for frying things. And will hopefully find a good home, I will just keep it far from live terminals for the time being.

In a discharged state!
 
Silicon solar cells are 0.6V no-load and usually accounted as 0.5V loaded.

300V then needs 600 cells. That is a LOT of joints to go bad.

We "need" a battery to play at night or on very cloudy days.

An "organic festival" near me has solar-powered music PA. I can't comment on stellar sound quality because it is hardly audible from the mainway (none of their acts tempt me to go closer). I strongly suspect the cells charge the batteries and we hear "lead-acid battery", not "solar electric".

If an amp is any dang good, it is good on any semi-tolerable electric supply. Audio currents should return through local B+ bypass capacitors, not go out pass batts to sun-cells in the yard (or back to the dam generator at the utility power source).
progress is going slow on solar. Here is a link to a record chart.

Cell-Efficiency-Chart.jpg


It seems more blurry than it used to be.

Many of the high numbers are using concentrators for the sunlight so only some of the high efficiency ones really work without massive mirror systems, etc... We need to get more out of the UV spectrum which can penetrate clouds imho, for those things to work anywhere with clouds. Plus UV should have more energy. Patience is still possibly the wisest strategy but I would love one of those systems that reroutes the cells according to V and current needs, I have seen 3.6v cells before, I believe. I know are actually fragile if you hold them when they arent sealed into a panel, in lacquer, on a fibreglass background.

:cop: @phi112358 - please do not start multiple threads for the same topic, your threads have been merged.
I have a different question now.

I am going to use a non center tapped trafo with 4 700v telefunken diodes, and a 200uf cap for rectification. Getting a trafo made right now. I need to know the voltage to request for 300VDC @150ma after the rectifier bridge. That is my question now, it is different than it was before.. I am hoping to get an answer before maker starts winding trafo.

I was assuming 217V but don't know if I need to go a little higher because of the 200uf filter cap I am now using. ALready took the overwhelming majority advice and not going to use the milifarad one. Just need to know the voltage to request for the 300VDC I am down to a pretty simple question. how many V to get 300VDC? using a 200uf cap as advised and a 10nf cap in parallel to each diode. 150ma 2 tap trafo
 
:cop: All of your questions relate to basic power supply design, so belong in the same thread.
Can I delete this one and then post a simpler one, asking for the correct voltage for the trafo. I have read that it is not 217v but it is 240, because the rc filter will affect the DC voltage.

Are people saying to get a trafo that is 240v when loaded, then after a bridge and an RC filter, it will give 300V when loaded? Or are they saying to use a trafo that reads 240v unloaded?https://www.diyaudio.com/forums/report.php?p=1371273

this person says 240vac will rectify to 300vDC after bridge annd reservoir. Is that trafo 240vac under load? or 240dc unloaded?
 
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Voltage drop under load depends on things like the impedance of the transformer, the reactance, the power factor of the load etc. It can be estimated by using a manufacturer's data sheet but a custom transformer is an unknown quantity.

Have you oversized your transformer? For example, I am expecting to pull a very maximum of 30w from my secondary HV so I am using a 50w supply.

Over supply helps the transformer voltage to stay stable under load and (with adequate regulation) avoids sag.

Why do you need exactly 300v? Sometimes near enough is good enough. You may be overthinking it.

240 will probably get you 330ish after regulation. (240 X 1.414 - 2 diode drops - other losses).
 
Voltage drop under load depends on things like the impedance of the transformer, the reactance, the power factor of the load etc. It can be estimated by using a manufacturer's data sheet but a custom transformer is an unknown quantity.
I can make a request for a specific voltage at a specific current. He understands that much of my attempted Thai communication

Have you oversized your transformer? For example, I am expecting to pull a very maximum of 30w from my secondary HV so I am using a 50w supply
I am getting the trafo oversized. That is one thing this maker offers a great deal for. Each one will weigh a couple kilos and probably about a 6" cube.

Over supply helps the transformer voltage to stay stable under load and (with adequate regulation) avoids sag.

Why do you need exactly 300v? Sometimes near enough is good enough. You may be overthinking it.
The Ukranian seller who sold me the amp, recommended exactly 300VDC for the high V

240 will probably get you 330ish after regulation. (240 X 1.414 - 2 diode drops - other losses).

So I recalculated after learning about ripple and the diode drops and got 222V. If I ask for 222V@ 300ma capacity, will that ensure a closer result to 300VDC than 240?

Maybe the people saying 240V rectifies to 300V were talking about 240 unloaded trafo, and that drops under load.

I am thinking the ripple will end up as 3v but I used 300V+10V(ripple)+4V(four diodes)/1.414 I got 222V result. thinking that overshooting by about 9V will account for things like wires and the resistor and the capacitor, maybe even the 4 10nf caps might change it more.

I think it only requires 100-150ma

Would asking for 222V @ 200ma be good or should I go on and ask for 222V @ 300ma?

He will do it, and make a pretty one. He just takes about 2 months to do any custom job unless I want to pay him more for speed. 222V assumes extra losses, just a few volts over 217V because I was expecting losses from the wires, the resistor, and the 220uf cap.

All I need to work out after that is the value of the resistor to put before the reservoir cap and whether the 10nf caps in parallel to the diodes need any resistor added with them. But the maker is so slow, I will have another month minimum to work all that out. Just need the specs before he starts. Luckily I pretty much know he has not started yet. I like this guy because he also takes copper wire and any type of trafo or core for some type of discount, plus he has a discount "slow mode".
 
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Lucky the person who I bought the amp from wrote back with good advice and works with valves often. Thanks for all the info and I know the resistior value to put in parallel with the 220uf caps. I guess I will go with Japan Chemicon because they always come out stable against the other brands I have tested and they even look well made, plus they can be found for very cheap here. Then I will either get wima or something else for the 10nf per diode. Glad I went for 700V on those after reading up.

The Mass produced el84 kit (from guess where?) I bought came with no answers and a seemingly broken, field pipe transistor. These modules I bought from Ukraine are using a chip on the autobias, some old military caps, and I had a good feeling about it when I saw it. The seller does not even make them fulltime but she is there when I ask questions. It is amazing she speaks English. She even threw in an extra valve of both types and that wasn't in the description of the item on eBay. I had some OTs made out of some C-Cores I found at a scrapyard that I am praying are going to work. If they don't, the selller did provide proper winding instrucrions so I will either redo or get them redone. They look beautiful. I used 2 sets of C-Cores per OT. I know I really should not be reusing things like that because they arent guaranteed to conduct audible frequencies but something told me those are going to work. I will know in a month or so, and post details of the finished monoblocks here when they are all done.

She told me that in Ukraine, the shape of the sinusoidial wave changes so that often 1.3 is a better approximation than 1.41, when converting to DC. It is 1.41 here, I am pretty sure, but I will check on a smaller trafo soon. Next thing will be to find some chassis that shield the tubes and each monoblock.
 
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