Bonsai:
What I want to do is use a generic non center tapped wall wart and have a very low profile board space solution for bipolar dc.
So for high psrr op amps would you recommend something like wall wart >> rectifier >> filter caps >> 7815/7915?
The lt3080 doesn't have a negative voltage version and there are some threads about it blowing up.
What I want to do is use a generic non center tapped wall wart and have a very low profile board space solution for bipolar dc.
So for high psrr op amps would you recommend something like wall wart >> rectifier >> filter caps >> 7815/7915?
The lt3080 doesn't have a negative voltage version and there are some threads about it blowing up.
The Sparkos products look very good. I don't think their opamps will best a 4562 or 797 and some of the newer opamps out there. If they are using TPC, then there is no reason why their PSRR should not be very good either. Remember, although most opamp output stages are class B into heavy loads, they are assuredly class A into typical =>10k loads.
For your regulator, if the total current draw is reasonable - 10's to a 100 or 200mA max, then using a single output winding AC wall wart can work. However, if you are looking for the best performance, I would build a decent power supply in its own housing with pre-regulation and supply DC into your main audio board which would then have local regulation.
You can use 7824 for the pre-regulators and 7818 for the on board regulators.
For your regulator, if the total current draw is reasonable - 10's to a 100 or 200mA max, then using a single output winding AC wall wart can work. However, if you are looking for the best performance, I would build a decent power supply in its own housing with pre-regulation and supply DC into your main audio board which would then have local regulation.
You can use 7824 for the pre-regulators and 7818 for the on board regulators.
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What is the advantage of using the same regulator (78xx twice), once for pre-regulation?
All of my two channel preamps will be well under 200ma, and even a 6 channel mixer could fall under 200ma.
So I'll think on whether or not to do a dedicated supply box. The idea was to have a generic solution for most of my future builds.
All of my two channel preamps will be well under 200ma, and even a 6 channel mixer could fall under 200ma.
So I'll think on whether or not to do a dedicated supply box. The idea was to have a generic solution for most of my future builds.
Many 3pin IC regulators have pretty terrible performance above 100kHz.
Interference that gets past the isolating transformer, then passes through the regulator with little attenuation.
The HF garbage can reduce the performance of the analogue circuits that depend on a clean supply.
Adding a good pre-regulator topology can very significantly reduce the interference that passes through to the analogue circuits.
Interference that gets past the isolating transformer, then passes through the regulator with little attenuation.
The HF garbage can reduce the performance of the analogue circuits that depend on a clean supply.
Adding a good pre-regulator topology can very significantly reduce the interference that passes through to the analogue circuits.
Back on this topic again - with some specification changes.
*************board space available is roughly 50x40mm.*************
One day I'll do it all correctly with a proper sized board and case, but that's not this project.
Keeping the battery designs separate, this will be strictly for use with dc transformer wall wart - or ac if advised.
+-15v for 6 x ( ti ina217, ssm201x, that 151x variant mic pre ic's ) x 2 mixer.
and +48v phantom
(maybe that 1580 if the summing section requires balanced inputs.)
As of now leaning toward ltc3265 for +-15v and lt8570 for the 48v.
I figured since I'm already into switch mode with the 8570 why not make things simple and use one ic for the bipolar instead of 7815/7915's??? I suppose it's not really necessary but it would be better to have a flexible range of dc input voltage.
Is it better to pick the higher frequency switch converters, ie ~1.5Mhz as opposed to the ltc3265 at 500Khz?
ltc3265 Charge Pump Generates 2 • VIN_P, so guess I'm shooting ideally for 8vdc input to regulate 16v>15v. About how high can I go with the dc input voltage before I'm generating heat, or are these too low current to worry about heat?
*************board space available is roughly 50x40mm.*************
One day I'll do it all correctly with a proper sized board and case, but that's not this project.
Keeping the battery designs separate, this will be strictly for use with dc transformer wall wart - or ac if advised.
+-15v for 6 x ( ti ina217, ssm201x, that 151x variant mic pre ic's ) x 2 mixer.
and +48v phantom
(maybe that 1580 if the summing section requires balanced inputs.)
As of now leaning toward ltc3265 for +-15v and lt8570 for the 48v.
I figured since I'm already into switch mode with the 8570 why not make things simple and use one ic for the bipolar instead of 7815/7915's??? I suppose it's not really necessary but it would be better to have a flexible range of dc input voltage.
Is it better to pick the higher frequency switch converters, ie ~1.5Mhz as opposed to the ltc3265 at 500Khz?
ltc3265 Charge Pump Generates 2 • VIN_P, so guess I'm shooting ideally for 8vdc input to regulate 16v>15v. About how high can I go with the dc input voltage before I'm generating heat, or are these too low current to worry about heat?
If you're designing a mic preamp, then there's little point in building a bipolar supply. Just use a single rail with a proper bias when needed and coupling caps in between stages. It will save you a lot of unnecessary trouble.
Samuel Groner gave me a lot of help on a mic preamp here: http://www.diyaudio.com/forums/soli...ic-mics-any-glaring-errors-2.html#post3443254
If you're using switch mode, a regulated ic with a LC filter might be all you need. The higher the frequency, the easier to filter it.
Samuel Groner gave me a lot of help on a mic preamp here: http://www.diyaudio.com/forums/soli...ic-mics-any-glaring-errors-2.html#post3443254
If you're using switch mode, a regulated ic with a LC filter might be all you need. The higher the frequency, the easier to filter it.
That depends, actually. With a bypass cap on the ADJ pin, probably so, otherwise a good modern 78xx/79xx would most probably fare better.
I had a design change and will need about 200mA now for the +-15v rails. Unfortunately the ltc3265 is 50ma on each regulator so does it make sense to parallel two of these to get up to 200mA?
The next best idea was this:
ITX1215S XP Power | Power Supplies - Board Mount | DigiKey
The idea of staying with the charge pump was to avoid inductor noise, but I already have one in the phantom supply and it's shielded.
Is there a problem with paralleling the 12v dc input to 3 different converters/regulators?
The next best idea was this:
ITX1215S XP Power | Power Supplies - Board Mount | DigiKey
The idea of staying with the charge pump was to avoid inductor noise, but I already have one in the phantom supply and it's shielded.
Is there a problem with paralleling the 12v dc input to 3 different converters/regulators?
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