SV: Re: [sdiy] Linear PSU options .. 7815/7915 vs LM317/LM337 vs 723 etc

[Seb Francis]

Hi Karl,

Thanks for the replies.

I don't mind the brain bit .. I made the power supply for my modular 
with 2 723s so I can just recycle that brain power.  But the component 
count is quite high, so I was looking for a simpler solution (i.e. lower 
component count, less PCB real estate).

I've definitely rejected the 7815/7915 option now and at the moment am 
leaning towards the 317/337.

Seb


karl dalen wrote:

>I forgot, if you want superior perfromance
>for almost zero money but have to use your brain
>use the 723, it can be used for negative voltages too.
>
>If you want the least hasse and stress 
>and no brain use, take the 317/337!
>
>KD
>(brain use means that the 723 is not
> entierly straight forward to use.)
>
>--- karl dalen <dalenkarl at yahoo.se> skrev:
>
>  
>
>>Forget about using 78xx/79xx, use the 317/337 they
>>are way better for SDIY use and general audio.
>>
>>Ua723 are an old faggot (made in 1968) but way superior
>>to 317/337 and a "large number" of the never LDO,s on the 
>>market. The 723 is just the clasic regulator cirquit
>>assembled onto a chip.
>>
>>They are all dirt cheap!
>>
>>KD
>>
>>
>>--- Seb Francis <seb at burnit.co.uk> skrev:
>>
>>    
>>
>>>Someone just suggested the LM317/LM337 are supposed to be better than 
>>>the 7XXX series.  Has anyone ever done a comparison between these?
>>>
>>>Seb
>>>
>>>
>>>Seb Francis wrote:
>>>
>>>      
>>>
>>>>Hi,
>>>>
>>>>I'm almost getting to the stage where it's time to move my 
>>>>multi-compressor/gate/distortion project from the breadboard to PCB.  
>>>>The final piece to design is the PSU.
>>>>
>>>>The requirements are not too unusual .. +/-15V at probably 200mA max, 
>>>>and I want it to run from a standard AC wallwart (or maybe I'll stick 
>>>>a transformer in the box - I haven't decided yet).  My first thought 
>>>>is to use a 7815 & 7915, but I'm wondering is there some 'better' PSU 
>>>>design?  What are some other options, and what actually are the 
>>>>advantages in going for a more complex PSU?
>>>>
>>>>I've seen plenty of power supplies based on the 723, but I don't need 
>>>>variable voltage or current limiting and it doesn't have to be exactly 
>>>>+/-15V - near enough will do as long as it is a clean DC voltage!  
>>>>Would I expect to get less noise from a 723 based PSU compared to 
>>>>7815/7915, or is this more a question of the smoothing, decoupling and 
>>>>board layout?  Are there any options which will make a better PSU than 
>>>>7815/7915 but without the complexity of a 723 based PSU?
>>>>
>>>>Many questions, I hope some kind person can help me :)
>>>>
>>>>Seb
>>>>
>>>>
>>>>
>>>>
>>>>        
>>>>
>>>      
>>>
>>    
>>
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