L-Adapter

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R

rhythmsandy

Member
Joined 2012
Salas said:
Haven't researched that aspect because its a general supply and who knows the interaction in each different application system but as it doesn't have many parts the transformer and the reservoir capacitors are the main quality target items.
Click to expand...
Salas how stiff is the power supply on dynamic current demand? like voltage sag? How much variation have you observed? like for 0.1A the output Voltage being 12V and for 3A output would go to 11.8V? Or irrespective of the dynamic demand is the supply is proper target voltage being set?
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
I had some Zo figures in the guide derived from voltage drops with a DC electronic load. Measured at the Vout connector before output wires. "35,25,20mΩ Zo at 1,2,3A load". For 1A up-swing from each previous loading if I remember well. You may back calculate the mΩ and Amps to dynamic voltage drops.
 
K

KeLLoGsX

Member
Joined 2011
Yeah, I know of toroidy. But I really am a beginner at this and meant a more specific technical recommendation.

edit: I have this already, can I use it
Triad VPM24-1040
Maximum Power: 25VA
2. Input Voltages: 100, 120, 220, 240VAC, 50/60Hz
3. Output Voltages: 12VAC @ 2.08A or 24VAC CT @ 1.04A
 
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Bensen

Bensen

Member
Joined 2003
KeLLoGsX said:
I’m planning my build of the L-adapter, going to use it to power up the new Rpi 5 with Picoreplayer. Do you have any recommendations for toroidal transformer?
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I use 30VA 6Vac, better take a transformer with secondaries of 7VAC or 8VAC. I would not take more to avoid to high dissipation. I came away with only 6V's because I use HFA25PB60 diodes, which I compared with multiple other diodes and gave a very low voltage drop.
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
KeLLoGsX said:
Yeah, I know of toroidy. But I really am a beginner at this and meant a more specific technical recommendation.

edit: I have this already, can I use it
Triad VPM24-1040
Maximum Power: 25VA
2. Input Voltages: 100, 120, 220, 240VAC, 50/60Hz
3. Output Voltages: 12VAC @ 2.08A or 24VAC CT @ 1.04A
Click to expand...
Yes you can use 12VAC if your load is not power hungry at cruising mode not creating too much continuous extra dissipation. Since for 5V DCout a typical off the shelf 9VAC Transformer is already the max spec needed. An Rpi 5 running just a music player app won't be power hungry I suppose, only for a while when booting.
 
K

katopis

Member
Joined 2007
Building some new psu’s for my next project!A new special tube preamp!Salas 6V6 triode preamp heaters!L adapter is needed everywhere!
 

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J

JMMF2019

Member
Joined 2020
Is there a possibility of using it to power a ham transceiver?
Of course the transformer size would be huge and heavy.
Will be using RX most of the time, TX rarely and for few seconds only.
Power supply:13.8 VDC ±15%
Current drain / power consumption:RX: 3 A
TX: Max 23 A
 
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