I would actually make room for through hole resistors, to make it
easier to replace resistors with simple tools.
That is actually the comment I least expected. Removing SMD resistors is simpler than removing TH resistors but the wise thing is to design so that they don't need to be removed. Anyway, one will have a hard time finding SMD resistors that can withstand the voltages used in this circuit.
And this to make it adjustable 🙂
300K ohm 10 turn wire big potentiometer LITTON SERVOTECHNIK W. Germany P47461B | eBay
300K ohm 10 turn wire big potentiometer LITTON SERVOTECHNIK W. Germany P47461B | eBay
This is information about the LR8 has been around for more than 15 years in this forum. Not a new news, sorry to burst your bubble.
The LR8 was mentioned as early as 2005 below and several more threads over the years.
https://www.diyaudio.com/forums/tubes-valves/68965-benchtop-ps-3.html#post783579
I don’t completely blame you though, the forum’s search parameter limits the minimum characters leading you to make a wrong conclusion.
Cheers!
A lot of technologies are "forgotten" and needs re-examining . No harm in this, the comments shows that several people discovered something new and useful.
1206 resistors can handle the voltage. At least from TME thats what I have seen. Yes I could make a full power supply with the rectifier, filters and so on...some radios I own have tube rectiffiers and when replacing it with a diode one for some reason the noise became much more problematic.
I might just do it for practicallity. You can use a heatsink for the transistor on that one because you can bend the transistor out. I cant make a mounting for the heatsink on the board because quite frankly not everyone feels like buying a heatsink for 3 dollars so the holes would be there with no use
I might just do it for practicallity. You can use a heatsink for the transistor on that one because you can bend the transistor out. I cant make a mounting for the heatsink on the board because quite frankly not everyone feels like buying a heatsink for 3 dollars so the holes would be there with no use
The reason of the diode creating noise is obvious.
You could move the regulator to the side and have both possibilities so either a PCB mount heatsink for very low power applications or by mounting the IC to a larger heatsink or chassis. The more versatile you can design the board in a small size the more situations you can use it in. The 3 $ will only count if you buy the heatsink for that specific purpose in that specific device that has a wooden casing for instance. The added PCB footprint/pads cost nothing extra.
You could move the regulator to the side and have both possibilities so either a PCB mount heatsink for very low power applications or by mounting the IC to a larger heatsink or chassis. The more versatile you can design the board in a small size the more situations you can use it in. The 3 $ will only count if you buy the heatsink for that specific purpose in that specific device that has a wooden casing for instance. The added PCB footprint/pads cost nothing extra.
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The last post is more than 10 years old so I guess the chances of anyone coming arround the topic is unlikely.
I guess it depends on what you mean by deterioration and what is connected to the output, particularly what types and values of decoupling capacitors. With decoupled ADJ pin, you have much more high-frequency loop gain which makes the regulator more prone to ringing, but when you manage to keep that under control, you will also have much faster settling after a load step than without ADJ decoupling.
Is it really a good idea to use a bypass capacitor when the datasheet does not specify one? I mean with these voltages...
Again I dont see a problem with it. In this case you cam mount it to anyy heatsink you wish because its on the edge of the board, Missing only mounting holes. The reason I missed them out because not everyone is happy about buying a 3 dollar heatsink when they have a huge garbage pile of them. I cant satisfy everyone to make a version of the board for every heatsink out there on the planet.
The IC tho will never require a heatsink. With the gain of the output pass element the most current that will ever be needed to be sourced by the LR8 regulator is not more than 3-4mA not even coming close to the 10mA rating and I dont think that there will be anyone dropping from 400V to 200V at 200mA...thats just not smart and it would be the only case we would hit the thermal dissapation limit of the TO92 LR8 part
Of course I mean the pass transistor when I wrote regulator. Sorry.
Correction:
You could move the pass transistor to the side and have both possibilities so either a PCB mount heatsink for very low power applications or by mounting the pass transistor to a larger heatsink or chassis. The more versatile you can design the board in a small size the more situations you can use it in. The 3 $ will only count if you buy the heatsink for that specific purpose in that specific device that has a wooden casing for instance. The added PCB footprint/pads cost nothing extra.
The footprint of many popular heatsinks is the same but it is up to you.
Correction:
You could move the pass transistor to the side and have both possibilities so either a PCB mount heatsink for very low power applications or by mounting the pass transistor to a larger heatsink or chassis. The more versatile you can design the board in a small size the more situations you can use it in. The 3 $ will only count if you buy the heatsink for that specific purpose in that specific device that has a wooden casing for instance. The added PCB footprint/pads cost nothing extra.
The footprint of many popular heatsinks is the same but it is up to you.
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also talking about the heatsink thing.... How do you want to isolate the metal tab of the transistor from the heatsink.....were gonna see full rectified voltage on it and I wouldnt trust the mica insulator let alone a silicone thermal pad or a capton one. I heard about ceramic ones tho.
Good point. If there is any risk of Vin decreasing faster than Vadj, you should at least put a diode between Vadj and Vin when Vadj is decoupled to keep the decoupling capacitor from discharging through the regulator.
PS: Look not to brag or anything, but this would be for personal use only. In my radios and stuff. It has probably 0 selling potential, so I dont have any reason to go as far as creating a real proper product, so I call it good enough. But I would go as far as making a fully done regulator. But yeah dont see a reason to actually really make this into a very proper thing. Sorry.
When I was taught a profession they taught me to do stuff right at once by stating design goals and desired results. That saves time. If the intention is not to make a proper design one is f**king around and that is OK too but often not the goal in audio. The difference between mediocre and good (or single purpose and versatile) might be 10 minutes and a few Eurocents.
In post #18 you said you would run these everywhere from now on which made me comment to make it more versatile for various scenarios 🙂
In post #18 you said you would run these everywhere from now on which made me comment to make it more versatile for various scenarios 🙂
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I understand and agree. Thats why my actual amplififiers are done proper.
However this is done for just a quick and dirty working fix. Its proper enough for the application. Overbuilding is also not a solution
However this is done for just a quick and dirty working fix. Its proper enough for the application. Overbuilding is also not a solution
LOL, you post a simple circuit and everybody takes shots at improving it whether you ask for it or not 😀
Since we're talking versatility, shouldn't we pick a transistor with higher Vce? TIP50 is only 400V. And some of the high(er) voltage ones come with a built-in diode.
Since we're talking versatility, shouldn't we pick a transistor with higher Vce? TIP50 is only 400V. And some of the high(er) voltage ones come with a built-in diode.
That is what fellow DIYers do when they see a design that will fail or may not perform as intended. Certainly when the person says to run the device everywhere from now on. The word "everywhere" means quite some things in my languages so it could be used in anything from a fifties mono radio to a modern tube buffer. We could also look the other way and enjoy some Schadenfreude but since we are men that do DIY audio we decided not to. It is also a cultural thing I noticed. BTW you are doing it yourself as well 🙂
Circuits can be simple but circuits can also be too simple. PCBs can be too simple too limiting the use of them for other purposes in the light of the "everywhere" statement.
Circuits can be simple but circuits can also be too simple. PCBs can be too simple too limiting the use of them for other purposes in the light of the "everywhere" statement.
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