Reflektor-D builds

[merlin el mago]

Thanks Salas, have you opened a new thread?

 

[Salas]

Not yet, when I will have test PCB.

 

[merlin el mago]

If not very expensive I will try, thanks for all support to us and to develop always such a great products, I hate SMPS powering audio devices.

 

[merlin el mago]

Almost ready.

 

[dahlberg]

Does anyone have a recipe for 4v output voltage. I managed to get 4,6v with 2 orange kingbright leds and a jumper. I was aiming for as close to 4v as possible still staying above. I have green, red, yellow and orange on hand and one 1N4148.

 

[Salas]

Hmm.. maybe an orange and an infrared? Or a green and an infrared when bit short from target. If you haven't got any IR LED in hand, an old useless remote control could donate one.

 

[dahlberg]

Thanks

One of these should do it I guess.

https://www.mouser.se/Kingbright/Optoelectronics/Infrared-Data-Communications/Infrared-Emitters/_/N-6qrgl?P=1z0z63xZ1z139kbZ1z0ysu0Z1z0yt2p

 

[Salas]

Yes, look at their datasheets there. There are forward current vs forward voltage curves. If its the 1k R6 resistor style REF-D you use, there are 2mA running in the Vref. If its a JFET mod then its almost IDSS of the individual 2SK. Maybe 20% less because the voltage threshold isn't the 10V IDSS test level across the FET but only near 2V. You want at that current in the LED curves, the colored LED VF + the IR LED VF + 1.22V residual from the mirror transistors Vbe to give 4V total.

 

[dahlberg]

It's jfet mod. The order is already sent, 1,2v, 1,3v, and 1,6v forward voltage according to the datasheet so it's trial and error in a week or so... Mouser are usually pretty fast.

 

[Salas]

If you got female pins installed for quick trials then no pain. Let me know what happened.

 

[Salas]

P.S. Their forward voltage nominal is stated at 20mA so you will have a good variety of lesser than nominal VF to mix and match with colored LEDS at the circuit's much lower mA Vref running current.

 

[dahlberg]

Female pins and trial and error, I'll be back

 

[merlin el mago]

Salas for 5.25V & 440mA: R1 1 ohm + two green LEDs = 5V, how to add 0.25V?

 

[Salas]

Add little Rx value analogous to your Vref current for 0.25V extra drop via Ohm's law V=I*R

 

[merlin el mago]

Starting at 10R for example?

 

[Salas]

You will have to calculate. If its a build with R6 1k then the Vref current is about 2mA. In that example 120 Ohm would bring 2mA*120 Ohm = 0.24V. If its JFET mod and you aren't sure about the exact Vref current, the 10 Ohm will develop a drop that will show the way. If it is 0.4V then 4mA is running. So 62 Ohm would bring 0.248V extra.

 

[merlin el mago]

Yes Salas R6 is 1K, thank you.

 

[merlin el mago]

Salas work like a charm 5.24V powering BIII of mine friend Antonio, it's substituting a TP Placid HD waiting he likes more your work.

 

[Salas]

Nice it worked at target in one shot. How do you like it yourself?

 

[merlin el mago]

I don't have any digital SPDIF source to try, tomorrow comes at home Antonio with a CD transport or streaming with SPDIF output to try, I will keep informed.