Hi guys, can anyone advice on a source (kitset OK) for an adjustable with a working out voltage of around 40 to 40 V, Prefer dual supply but can of course use 2 single's.
Bought this one from F/Bay, which was no good
https://www.ebay.com/itm/2534773923...+gy4VJXZfyk0LVeh5iBAfqyK7qs=|tkp:BFBMqsDW845g
As it will only adjust to 38V, supplier claims that manufacturer changed design & did not advice suppliers!!
Cheers
Bought this one from F/Bay, which was no good
https://www.ebay.com/itm/2534773923...+gy4VJXZfyk0LVeh5iBAfqyK7qs=|tkp:BFBMqsDW845g
As it will only adjust to 38V, supplier claims that manufacturer changed design & did not advice suppliers!!
Cheers
Also likely fake LT1083 ICs as with almost all cheap garbage. So you want an "adjustable with a working voltage of around 40 to 40V"? This could be interpreted as a 40V single voltage PSU. The thread title is "Adjustable P / S up to around 50V". You prefer dual supply but also can use single PSU's?!? There is some inconsistency here 🙂 Another parameter is a phenomenon called "current".
Please make up your mind what it is you want. IF you want a 50V PSU of cheap quality maybe a 48V SMPS as used in telecom is the PSU for you. If it should be a quality 50V 1A PSU (for instance) for a critical audio application then a 50V 1A linear PSU might be a good choice. Only you know what will be connected to this PSU....
If you just want 50V then a LM317 PSU/PCB can be used with TL783 instead of the LM317. Same pinout, different part values, 50V output 700 mA max. current. Noisy but cheap.
Please make up your mind what it is you want. IF you want a 50V PSU of cheap quality maybe a 48V SMPS as used in telecom is the PSU for you. If it should be a quality 50V 1A PSU (for instance) for a critical audio application then a 50V 1A linear PSU might be a good choice. Only you know what will be connected to this PSU....
If you just want 50V then a LM317 PSU/PCB can be used with TL783 instead of the LM317. Same pinout, different part values, 50V output 700 mA max. current. Noisy but cheap.
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Hi, Thanks for your reply, sorry about the newbie description, to clarify
The unit is required for a phono amp so must be low noise, SMPS not suitable. But as advised a 50V 1A linear adjustable PSU, would be ideal.
Cheers
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The unit is required for a phono amp so must be low noise, SMPS not suitable. But as advised a 50V 1A linear adjustable PSU, would be ideal.
Cheers
-
The supply I might get around to building some day would use a floating regulator, using an obsolete Motorola regulator chip designed for lab-grade supplies. There's an example of a similar floating regulator in an app note for the LM10CH. Better lab supplies will also have a switching pre-regulator to reduce the amount of power wasted in the linear regulator.
Yes using obsolete ICs is fashion in audio 😉
When it is a 50V 1A (maximum!) linear PSU and an LDO is used together with a 2 x 22V transformer loss and heat will be reasonable. I guess that preamp will consume not even 0.25A in reality. The point is that we need hard numbers to be able to say something useful.
The parameter “current” is quite determinating.
When it is a 50V 1A (maximum!) linear PSU and an LDO is used together with a 2 x 22V transformer loss and heat will be reasonable. I guess that preamp will consume not even 0.25A in reality. The point is that we need hard numbers to be able to say something useful.
The parameter “current” is quite determinating.
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Ive looked at AN211 and i would like to add that i am currently working allong similar lines
Hi there, here is a design I did a while back along these lines you might like to take a look at.
It worked Great Except "I did not employ a current limiter", but................
The supply worked great for the last 7-8 years until a recent shorted FET took it out again as I was working on my Class A amp design !! He,he,he
🙁
I never got around to building the higher current version yet as it is currently on the top of my to do list now...........
With Current limiting of course in the next configuration for sure !! 😉
My next iteration is gonna supply 8-16 amps up 45V or so using the LT 317HV's and some big BJT's that I have here just for that big Class A design I am doing at this time.
My peak input voltage will come from 4 x 200 watt toroid's 35v windings in parallel to make just shy of 50Vdc.
Anyhow here is the thread of pretty much this same topic of discussion.
Lots of good info here,
https://www.diyaudio.com/community/threads/lm3886-problem.261125/post-4037783
I had re-posted this circuit again recently and got great reviews on it not to long ago
I hope that this can be of use to you, as I am exploring this design again to repair the one build and finally do a Very High Current version.
This Regulator produced less than 100uv P_P up or so to 3.5 amps in my First iteration.
Found here is the data sheet for the LM317hv,
https://www.diyaudio.com/community/threads/lm3886-problem.261125/post-4039972
My First iteration is found here,
https://www.diyaudio.com/community/threads/lm3886-problem.261125/post-4064510
And, Here will find the higher current designs and LTspice files for them,
https://www.diyaudio.com/community/threads/lm3886-problem.261125/post-4073963
I finally did get some HV opamp's to try in the design as well !! 😉
Cheers !!
jer 🙂
It worked Great Except "I did not employ a current limiter", but................
The supply worked great for the last 7-8 years until a recent shorted FET took it out again as I was working on my Class A amp design !! He,he,he
🙁I never got around to building the higher current version yet as it is currently on the top of my to do list now...........
With Current limiting of course in the next configuration for sure !! 😉
My next iteration is gonna supply 8-16 amps up 45V or so using the LT 317HV's and some big BJT's that I have here just for that big Class A design I am doing at this time.
My peak input voltage will come from 4 x 200 watt toroid's 35v windings in parallel to make just shy of 50Vdc.
Anyhow here is the thread of pretty much this same topic of discussion.
Lots of good info here,
https://www.diyaudio.com/community/threads/lm3886-problem.261125/post-4037783
I had re-posted this circuit again recently and got great reviews on it not to long ago
I hope that this can be of use to you, as I am exploring this design again to repair the one build and finally do a Very High Current version.
This Regulator produced less than 100uv P_P up or so to 3.5 amps in my First iteration.
Found here is the data sheet for the LM317hv,
https://www.diyaudio.com/community/threads/lm3886-problem.261125/post-4039972
My First iteration is found here,
https://www.diyaudio.com/community/threads/lm3886-problem.261125/post-4064510
And, Here will find the higher current designs and LTspice files for them,
https://www.diyaudio.com/community/threads/lm3886-problem.261125/post-4073963
I finally did get some HV opamp's to try in the design as well !! 😉
Cheers !!
jer 🙂
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Even better, someone liked that chip so much that he designed a replacement circuit using discrete components. Imagine the pleasure of "rolling transistors" in a voltage regulator to see how it affects the sheen of the cymbals.
https://web.archive.org/web/20130502001005/http://www3.telus.net/chemelec/Projects/MC1466/MC1466.htm
I came across a pre-regulator circuit in a magazine sometime in the '80s (probably Elektor, maybe one of their circuit special issues); I tried using it once, but smoke came out so I gave up and cheated by using a Variac. There's a more recent Elektor power supply that has a similar pre-regulator.
https://www.iascaled.com/blog/rebuilding-the-elektor-400w-power-supply-introduction/
Still it would be optimal if OP tells us what the phono preamp really consumes. A simple low noise linear PSU will already be sufficient unless OP wants the best of best.
Hi, The specs say my phono amp pulls less than 700mA, so I have gone with the TL783, a pair are on the way from the UK.
So swapping them into two single 317 board will be simple enough (it needs to be simple for me). then I will see what the noise level is with my MI cart which has a healthy out put of 0.8mv.
Will report back, thanks everyone for your help
Cheers
So swapping them into two single 317 board will be simple enough (it needs to be simple for me). then I will see what the noise level is with my MI cart which has a healthy out put of 0.8mv.
Will report back, thanks everyone for your help
Cheers
Hi, So now I have finally found a board that would be suitable.
https://www.google.com/url?sa=i&url...hUKEwi5iqiL5Mb3AhVTjtgFHdNBAo8Qr4kDegUIARCtAw
but as i have already ordered the separate TL783, I will continue along that part. interestingly this board accepts AC or DC input & is adjustable.
Thanks for all your help
https://www.google.com/url?sa=i&url...hUKEwi5iqiL5Mb3AhVTjtgFHdNBAo8Qr4kDegUIARCtAw
but as i have already ordered the separate TL783, I will continue along that part. interestingly this board accepts AC or DC input & is adjustable.
Thanks for all your help
Yes that is because TL783 is an adjustable regulator like its low(er) voltage cousin LM317. You will have way less noise compared with SMPS but be aware that lower noise linear PSUs will give better results. If the device really consumes 700 mA then maybe it is a good idea to use one TL783 per channel. It will divide the heat. With 700 mA current you'll need a larger filter cap than in the PSU in the link! 2 x 1000 or 2200 µF 80V in CLC/CRC would be nice.
It is always wise to measure the real current. I recently had a DAC that "needed" a 5V 2A PSU but it turned out to consume less than 100 mA. It seems that the manufacturer just choose an off the shelf SMPS.
It is always wise to measure the real current. I recently had a DAC that "needed" a 5V 2A PSU but it turned out to consume less than 100 mA. It seems that the manufacturer just choose an off the shelf SMPS.
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