Reflektor-D builds

[Salas]

The PF5102 looks to have a different pinout as well.

In places where gate and source are joined together (running at IDSS) it fortunately does not matter bcs those pins are again side by side although not in the same pin order

 

[MagicBus]

I'll make the boards compatible with both through hole and SMD and see where I can get. Thanks Salas and Tea-Bag!

 

[MagicBus]

Finaly, I'm taking the SMD route... Do you think I could get away without selecting them for IDSS?

 

[Salas]

2SK880GR should stay in check for max Id hence not too strong bias for other elements in the reg if random

 

[MagicBus]

Ok. I can't go back now. Thanks again Salas!

 

[pistollero]

Hello, i used 9 v transformer for 3.3v.
Can i use 12v for 5v or is too much?

 

[euro21]

Hello, i used 9 v transformer for 3.3v.
Can i use 12v for 5v or is too much?

IMHO 9V AC is even too much (over 10V DC raw supply output) ... for 5V DC out.

Unnecessary heating.
I use 7.5V AC 40VA transformers for 5V Reflektor and 6V AC for 3.3V.

 

[Salas]

More Vac is beneficial for the input Mosfet's parasitic capacitance but the enemy is heat. In relatively low CCS setting situations it can be afforded.

 

[pistollero]

More Vac is beneficial for the input Mosfet's parasitic capacitance but the enemy is heat. In relatively low CCS setting situations it can be afforded.

Ok.. how much low???

 

[Salas]

No lower than Euro21 mentioned for Vac and no higher CCS mA than 65C on sinks with your trafos higher Vac

 

[pistollero]

No lower than Euro21 mentioned for Vac and no higher CCS mA than 65C on sinks with your trafos higher Vac

?? Do i measure temperature of sinks not higher than 65 celssius?

 

[Salas]

Yes measure the temperature on the sinks and don't go higher with CCS setting for more than 65C heat there given your transformer and mA combinations.

 

[bern]

Hi,
I have got couple of 2SK117GR with relatively low IDSS 2.8-3.1mA. Can I use them in the J1 position? If so what value resistor 'RR' should I applay ?
You suggest RR "When IDSS J1<4mA use 47R" But due to low IDSS maybe I should use resistor with lower value than 47R?
Thanks,

 

[Salas]

Yes you can use them. 33R should do since your J1s are << 4mA

 

[AnthonyA]

Hi Sir Salas

Just a question out of topic

Is there any good way to filter something for car audio head unit or processor . That is always on. Requirement about 7.5a. Max 15v? Low dropout.? Shunt type.

Best regards

Anthony

 

[Salas]

Shunt type for that application, no, I don't think so

 

[daansan]

I am considering to build a buffalo 3 se pro (ess9038 dac).

This particular dac requires upto 750ma but apparently also uses much less chrrent at lower sampling rates.

Even if we could pump the reflektor d to 750ma at 5v, would using a reflektor d be a smart thing to do?

 

[bern]

Hi,
I would like to ask about JFET in the R6 position.
I guess the same output voltage can be set by using lower voltage LED (eg RED) with high IDSS JFET in R6 (eg 2SK117BL=12mA) OR
higher voltage LED (eg GREEN) with lower IDSS (eg 2sk117GR=5mA)
Assuming that both combinations gives the same Vout what combination would be preferable?
Is the use of high IDSS JFET in the R6 position can compromise the sound or can I expect other unforeseen situations eg vulnerability of Vout due to the temperature drift etc.?
I have few pieces of spare 2SK117BL with IDSS 10-12mA and I wonder if I could use it in the R6 position...

 

[Salas]

I am considering to build a buffalo 3 se pro (ess9038 dac).

This particular dac requires upto 750ma but apparently also uses much less chrrent at lower sampling rates.

Even if we could pump the reflektor d to 750ma at 5v, would using a reflektor d be a smart thing to do?

If you put its Mosfets on a good external sink with pin extensions or use the Mini variant that only uses external sinking the heat would be successfully exchanged.

But in general to use CCS biased shunt regulators where there is frequently much waste between idle and peak load demand, its an inefficient choice for energy management. They are like Class A amps with a CCS i.e. most wasteful when not utilized close to full. They may sound good but that's another thing. Its up to you.

 

[Salas]

Hi,
I would like to ask about JFET in the R6 position.
I guess the same output voltage can be set by using lower voltage LED (eg RED) with high IDSS JFET in R6 (eg 2SK117BL=12mA) OR
higher voltage LED (eg GREEN) with lower IDSS (eg 2sk117GR=5mA)
Assuming that both combinations gives the same Vout what combination would be preferable?
Is the use of high IDSS JFET in the R6 position can compromise the sound or can I expect other unforeseen situations eg vulnerability of Vout due to the temperature drift etc.?
I have few pieces of spare 2SK117BL with IDSS 10-12mA and I wonder if I could use it in the R6 position...

You assume correctly. The lower mA choice would be more welcome for keeping the BJT Mirror at lower current noise and self heat. You could drop the BL JFET's Id with a source resistor though. Bit difficult to squeeze in there but there are some tiny through hole ones or obviously SMD.