L-Adapter

Jump to Latest
S

savvas

Member
Joined 2004
Leds are bright all the time and transformer is a little warm. I must point out that as far as consumption goes since I have 8 VAC secondary (25 VA winding) resulting 9-9.5 VDC (fluctuation I get) there are some watt wasted. A better pair would be a 7 VAC (in the future someone could test if going above 2.5 VDC Nick suggested would be of any benefit)

I would suggest a 30-50 VA tx since newer SBCs are getting more powerful everyday

----------------------------------------------------------
Still send via my L-adapted Tinker
 
Salas

Salas

diyAudio Chief Moderator
Joined 2002
Paid Member
Measuring DC across the diode located in front of the big transistor, while the computer revs up at its most, tells how much DC remains at peak consumption when watching for that 2.5V minimum threshold.

Transformer secondary choice must also allow for minimum mains voltage experience in someone's living area.
 
S

savvas

Member
Joined 2004
Yep, you mentioned it before, there it's the right place to measure the difference in voltage in and out. Mine is 4 - 4.5 VDC and the aluminium plate is just warm. If I was gonna use the in-board heatsink I would certainly have aimed for 2.5 - 3 VDC (summer is hot here)

With just few mVolts above 5 VDC, it worked for hours without problem, so I will leave it there for Volumio testing. As I've mentioned the only problem was with the cable. Raspberry could be less demanding but I'd suggest to take extra care for this, so you don't run in wrong conclusion if you run into problems
 

Attachments

  • l-adapter_tinker.JPG
    l-adapter_tinker.JPG
    340.3 KB · Views: 823
V

vanofmonks

Member
Joined 2006
Sorry if this has been specifically covered in the thread, but I'm trying to finalize my order before the group buy ends and I saw a post where the output could be modified. Ultimately I would like to supply either 26v 1.6A or 26v 3.2A. Is either of these possible with the L adapter? Is it just a matter of changing the value of the adjustment pot?

Thanks,
Chris
 
alexkosha

alexkosha

Member
Joined 2013
Salas said:
Very nice looking DIY system. Can't tell much about the sound capture, seems full. The dog napping on the rug isn't annoyed for sure. :)
Click to expand...
Yes. My sound via general presentation is very enjoyable and it seems I have correct amplitude/frequency respond from that setup (subjective, not measured yet). As I mentioned, it is impossible to get right recordings from iPhone mic made in such big volume room, a-specifically when I’m moving. Our dog is also audio-holic and he approved that DAC performance too... :).

However, I stepped on same mine again -> GND loop. I elevated all UltraBiB by 10R (L-adapter was floating), but got shorted PSU zeroes to earth via RCA cables returns from amp side. So, local GND 10R elevation is canceled. It means that all my PSUs are floating now with no reference. I hope it is ok.
 
S

savvas

Member
Joined 2004
It's been great experience so far with Volumio, mine L-adapter is too floating. It's amazing what can be done with so much little effort, I'm referring to both L-adapter and Tinker/Volumio.
This combination gives a very clean sound with great space between the instruments/voices. Having done the test also with a DAC against two other smps power supplies I wouldn't pick them as an option because in both DAC and PC the sound although sweet is also muddy.
It remains to put it in direct comparison with the linear regulator powering the same device (most probably my audio-PC)
 
S

savvas

Member
Joined 2004
It's a double LT1083 one. Nowadays I don't seek to get the last bit of quality upgrade in my projects and so the differences I spot in my listening tests are not subtle. My experience so far with L-adapter and LT-1083, is that linear psus have a more quiet background resulting more well-defined instrument / voice presentation. SMPS have some strong points but the compromises must fit well with your taste.

All smps are not made the same though so I must state the ones we tested in A/B comparison: original from RME, ifi's and general PC psu
 
A

altsouza

Member
Joined 2005
Toroidal (Newbie)

Hi,

I will use 2 Salas Ultrabib's (5v) for Katana's Dac and Controler, 2 ultrabib for 15v+- for Katana's Opamp, and 1 L adapter (5v) for Isolator (Pi).
Can you recomend Toroidals for these 4 Psu???
Any help is welcome.
If possible give Buy link, specs etc...
Thanks

Antonio
 
You must log in or register to reply here.
Top Bottom