L-Adapter

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Now that’s quick work, sir! Thanks, appreciate the effort. Will it be sold complete with parts - or a mini kit? Any idea of pricing?

That's Tea's area of expertise. Ask him later on.

If you want to private message me feedback on what you are looking for for parts that will help with making a minikit. Generally transistors are given a priority. If a few resistors prove hard to find without a GB that can be done too.

Caps and heatsinks I would shy away from, and avoid a full kit. Full kits shipped internationally has become a expensive problem as they all have to ship as packages now via USPS. That starts at 24.00 USD.

Sorry for off topic. But if want to help form a kit feedback is welcome.
I have gotten tons of request for something that would power a Raspberry Pi, so I think this will be a handy board for that and other low voltage high current digital products.
 
What's the noise figures for 3A consumption with something like 2.5 - 3 V dropout ?
There are quite few competitors for Raspberry but not so many for an audio-PC (40-80W)
What's the difference in consumption vs a normal PC-psu ?

I have an linear power supply (LT1083 / picoPSU) for my audio-PC and I was thinking of LT1763 for my Tinker board, probably hardwired (I should have finished it by now). I think L-adapter feels the bill as well but most probably it will go through the normal period of the GB so it will take the place of a contender.I like it's simplicity
 
diyAudio Chief Moderator
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V(onoise) in LTspice says 187.4nV Rms (1.5 μV pk-pk) integrated over 1Hz to 1MHz for C1=220uF. Practically you get what you see in post#1's scope pic (blue line). Includes the attenuated ripple and scope noise plus probing imperfections. Was shot at high current draw near 3A. Its for 20MHz scope integration though and the load isn't ideal. Its a micro controlled soldering iron that possibly back emits noises of its own. A computer would also do so or worst through its DC/DC converters of course.

Linear PSUs typically have an efficiency of 60%. Getting better when fitted with very good regulation transformer and SiC Schottky Diodes. But even when with minimal Vin-Vout LDOs they will not exceed 75%. Good PC switchers are 80-85% efficient on average these days.

The L-Adapter style PSU in my subjective experience can be substantially more dynamic, more spatial, cleaner and smoother, than LM317 and LT1083 when used for powering analog circuits but I don't know if that will have any relevance to powering audio server computers and the like. My Class-D SMSL desktop amp sounded surely cleaner with it nonetheless.
 
I just built one. 11V input from a SMPS, LC at the output and into the Ghetto-L-Adapater.
5V out at 500mA takes about 6 minutes to stabilize (could be the fresh elcos) and stays really stable then. Ripple is hard to measure.
 

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diyAudio Chief Moderator
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Being a several amps capable series power supply, I wonder if a negative rail can be done.
The BJTs have complementary devices and the LM334 can be turned upsidedown, I guess.
A bit more juice (up, let's say, to 24V) will be perfect for small power amps...

A negative rail is technically possible I believe. More output just takes higher value VR1.
 
diyAudio Chief Moderator
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I just built one. 11V input from a SMPS, LC at the output and into the Ghetto-L-Adapater.
5V out at 500mA takes about 6 minutes to stabilize (could be the fresh elcos) and stays really stable then. Ripple is hard to measure.

Congrats. How many mV difference your build makes in six minutes? Have you got a bleeder resistor across the output (R1)? Helps with output cap charge and setting up. Mine is boring, I set it for 10.35V on 250mA e-load to watch it over time, its doing 20-30mV change for cold set and forget thermal equilibrium. Warmed up for long, on/off, or cold on. Uses Chemi-Con KY C1 C2. Here is the loaded start up capture also. No over-voltage spike, linear climb & stable early plateau. Each horizontal division is one second in time.
 

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Thanks. I do use a 1k bleeder. Currently I use a pretty big heatsink (I wasn't sure about what was needed and just picked one that seemed ok and was on hand). Difference is about 30mV. I let it run for 4h today and checked what happened with a change in load. Drawing 800mA voltage was 5.067V, switching to a draw of 400mA it went to 5.088V. It went to 5.081 first and climbed to 5.088 over 8 seconds and then stayed there.
Unfortunately I didn't store the data of the logger of the benchtop meter. If it is of interest I could repeat that and post the log.

Caps are Nichicon Muse, 220uF 50V, again I used what was in the drawer.
 
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diyAudio Chief Moderator
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So same difference we got. Your Vo change between loads also confirms the Zo spec. Which is not bad for a non reactive non error amp design. Will end up to about 0.02Ω at higher currents. Output cables loss will dominate at such consumption levels.