Reflektor-D builds

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#201
freebee said:
Help! Checked all part values but LEDs won't fire up. As far as I know the LEDs are in the right position, according to the manual. Have taken some pics, perhaps someone has an idea? Thanks! :lifesavr
Click to expand...
Are M1, M2 the right types in the right places and not accidentally swapped? Is your Rx/J/D position resistor making sufficient contact? Recheck. Leds cathodes should be at the square pads. You can check without removing them by using a 9V battery. (+) wire to round pad, (-) wire to square pad. Touch the wires just briefly to each Led's pads. They should light up one by one. If not, they are either reversed or overworked with the iron and gone.
 
#205
freebee said:
Thanks for your help. It's working now. There was nothing wrong with it to begin with apart from me not leaving the power on long enough for the capacitors to charge. I know, not very smart and overcautious. 😉
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Its C2's large value. Important for filtering the LED Vref well below 1/f down to seismic subsonic area. Because clocks can be peculiar to subsonic noise. But has to charge up sufficiently first with the ~2mA current mirror bias available there.
 
#206
Hi Salas,
Today I can built the R-D. It was very easy to build and it working at the first power up.
I need anyway your confirmation that I am in the safe and correct side.

I need the Vout 3,3V at 600mA.
The R1 is the parallel of 1,5 and 1 ohm = 0.85
I first used the 1 green led and the 62 ohm as R6.
Whit those value, with a load of 5 ohm I can get 3.24V.
To reach the 3,3V stable after 30 minutes I need to increase the R6 up to 136 ohm ( 2 x 68 in serie).

With the values above the R-D is nicely stable at 3.3V and the heatsinks are hot but not so hot.

I am quite sure that the R-D is properly setup but I would like to have your confirmation 🙂

Thanks and Regards,
Enrico
 
#208
emyeuoi said:
Hi Salas,
Today I can built the R-D. It was very easy to build and it working at the first power up.
I need anyway your confirmation that I am in the safe and correct side.

I need the Vout 3,3V at 600mA.
The R1 is the parallel of 1,5 and 1 ohm = 0.85
I first used the 1 green led and the 62 ohm as R6.
Whit those value, with a load of 5 ohm I can get 3.24V.
To reach the 3,3V stable after 30 minutes I need to increase the R6 up to 136 ohm ( 2 x 68 in serie).

With the values above the R-D is nicely stable at 3.3V and the heatsinks are hot but not so hot.

I am quite sure that the R-D is properly setup but I would like to have your confirmation 🙂

Thanks and Regards,
Enrico
Click to expand...

Hi Enrico, by what you describe it seems well set up.
 
#210
Stixx said:
Collecting parts for a Reflektor-D build (3.3V out).

I do have some parts in my drawers, for C2 I would have 470uF SilimicII or 1500uF Pana FM or 1000uF Pana FC.
Any preference from your side, Salas... or just try any of them?
Click to expand...

I would prefer a 1000uF Nichicon Muse.🙂 470uF Silmic II is good also but not as deep down below 1/F noise filtering value which can be detectable a bit or not at all, depending on the client circuit. But a smoothie in the audio band. Pana FC is good and dependable but bland in the mids & highs. Better in energy storage than in filtering positions.
 
#217
Hi Salas,

I ordered some reflektor and BIB regs from tea bag for the sdtrans384 sd card player and the associated syncDAC, which contain separate digital and analog sections.

I understand there are about 15 or more embedded local LDOs with Oscon caps in those sections...and after reading the following posts of yours,...would I need any adjustment to the regs, as you mentioned about tweaking the open loop gain etc and on the stability issue with bypass caps..? Please advise and thanks 🙂

Post #509
http://www.diyaudio.com/forums/vendors-bazaar/246003-modifying-subbu-v3-dac-51.html

Post #6083
http://www.diyaudio.com/forums/powe...ic-salas-low-voltage-shunt-regulator-609.html
 
#218
Posts #151 - #155 here show how to tweak OLG and decide which suits best. You will need an extra K117GR per Ref-D.

Stability issues don't premeditate, tackle them only if they will happen in a certain regulator-load system. Too complex to predict in not fully analyzed combinations. Oscon caps are not in the low value nF category so they usually curtail the reg's bandwidth enough not to trigger odd interactions. Simply check the rails are tame when done if you got an oscilloscope. In case of a problem we will examine the system and we will see what we may tweak.
 
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