Reflektor-D builds

[Mull3t]

Sorry for being thick headed... by two wire mode you mean two pairs?


So are you saying to wire Kelvin to terminal strip? Then normal wiring to end nodes? Distances are relatively short overall.

 

[Salas]

With "two wire mode" I mean classic send and return pair not four wire Kelvin.

Yes close Kelvin at the terminal, from there normal. Use as thick wires as practical for that short run.

 

[stew1234]

Are there any recommendations for JFETs that easy to source to use at R6 for the JFET mod? 2SK117 only seems to be available on ebay and I'd prefer to buy from one of the well-known sites.

 

[bsk]

I used the 2SK209 on cheap ebay SMT adapter board.

 

[Salas]

Indeed. As recommended before, along with the 2SK880GR, its the same JFET in a surface mount package.

 

[freebee]

Help! I made a stupid mistake and swapped MTP3055VL and IRF9610 around and got smoke. I had everything set up for 5v and thought I had copied a previously built one to perfection.

Which parts most likely need replacing? I thought I saw a resistor smoke, but it might also have been the 2SK117GR.

 

[Salas]

MTP3055VL is NMOS when IRF9610 is PMOS. Malfunction rightfully happened. I would expect stress on M2 but current mirror shut down. Thus no stress on all the small transistors.
Also a big strain on M1 (the higher the Tx the more). So replace M2 with new proper MTP3055VL and M1 with another IRF9610. Let me know if OK or what abnormal behavior happened next.

 

[Salas]

By the way also check if R1 on the reg and the diodes on your rectification system are still good.

 

[freebee]

Thanks Salas. I was working late on it and probably too tired. Serves me right . Can I order these parts from you or should I try Mouser?

 

[freebee]

Can I test diodes in circuit? Resistors measure fine.

 

[Salas]

I don't have enough semiconductor parts for assembling more than a couple of boards myself. Let alone sinks reservoir caps etc. Only few samples of various bits for experiments I usually keep. Try Tea if he can help with M1 M2 spares. Or Mouser if you have a list of things to add for reaching free shipping threshold.

 

[Salas]

Can I test diodes in circuit? Resistors measure fine.

The DMM's diode check function should work there.

 

[freebee]

Again thanks. Will order parts from Mouser.

 

[Salas]

Alright. Let us know what happened with the fix. Till then, stay safe.

 

[freebee]

I am in confinement and trying to stay safe . Let's hope I won't electrocute myself before I'm allowed out.

 

[freebee]

Stay safe too and hope everybody is well.

 

[Salas]

 

[freebee]

Hi Salas, I use a Reflektor-D with my Buffalo II DAC which sounds great. I have just increased CM to a Mundorf 22000uf 25V (C1 is an Audyn True Copper 0.1uf) which to my ears sounds even better.

I noticed that whenever I hold the heat sink with my hands the DAC looses lock. Could this be a grounding issue? The DAC itself is not grounded. The transformers and IEC are. Any idea how to solve this issue? The Buffalo is also very sensitive to light switches even though I have already put some filtering in place.

 

[Salas]

Could be interference. You can ground a sink's leg pad each with a wire to chassis, but this asks to insulate the MOSFETs also.

 

[freebee]

Ok. Thanks. Other than that it sounds great!