Superlux S502 MK2 test, teardown and improvements

[Emmathom]

I have a question regarding the wire colours in the S502 1st version. What relationship exists between the XLR pins 1..5 and the colours?
In the S502 MKII the relationship is as follows:

XLR pin 1: black, GND
XLR pin 2: red, +phase L
XLR pin 3: yellow, -phase L
XLR pin 4: blue, +phase R
XLR pin 5: white, -phase R

Thanks in advance for clarification
MicUlli

Hi @MicUlli sure I will have a look in the weekend...
PCB stuff is going foward ?
Regards

 

[micro1_de]

Hi @MicUlli sure I will have a look in the weekend...
PCB stuff is going foward ?
Regards

In my opinion it is the same.

Reiner

 

[MicUlli]

Hi @MicUlli sure I will have a look in the weekend...
PCB stuff is going foward ?
Regards

Yes, thanks
Boards arrive next week. I ordered 5 pieces in order to get confident with the design. Test next weekend

 

[MicUlli]

In my opinion it is the same.

Reiner

Thanks a lot Reiner,
as i can see it looks different for the S502 1st version:

XLR pin 1: black, GND
XLR pin 2: white, +phase L
XLR pin 3: red, -phase L
XLR pin 4: yellow, +phase R
XLR pin 5: blue, -phase R

It is important for correctly soldering the wires for the different versions

 

[micro1_de]

Thanks a lot Reiner,
as i can see it looks different for the S502 1st version:

XLR pin 1: black, GND
XLR pin 2: white, +phase L
XLR pin 3: red, -phase L
XLR pin 4: yellow, +phase R
XLR pin 5: blue, -phase R

It is important for correctly soldering the wires for the different versions

Ah, thanks!!

 

[Clem777]

That's exactly what I read on Thomann customers' reviews... interferences with MkII and none with MkI... But I guess it comes from the circuitry, not the capsules, so @MicUlli 's board should solve that

Thanks, finger crossed

 

[Emmathom]

Thanks, finger crossed

Look also to my post #179

 

[Clem777]

Hi @Clem777 I've read in Thomann users reviews that a guy exchanged the original Y cable for a "pro snake stereo Y" https://www.thomann.de/fr/pro_snake_splitkabel_stereomono_xlr.htm and then this high sensibility to interferences disappeared... (or you make your own Y adaptator with good quality cable and Neutrik connectors > that's what I will do)

Do other MKII owners encounter the same problem?

Thanks, I had saw this review. I tested all the xlr-5/3 Y cables I have including the pro snake, a Neumann from the RSM191, and cables assembled by trusty local professionals. I guess my MkII is from a bad batch.

 

[olafmatt]

I have been using a S502MkII for a while now for recording ambience for film (TV actually). RFI pickup seems to be higher than on other mics indeed.

As part of the tripod mount I use a short "pigtail" cable made from thin star-quad mic cable (see pic). On the mic end of the cable the XLR plug has a wire link between pin 1 and the connector shell. This seems to help a little with RFI.
The real problem seems to be the location of the RF filter caps (those 22n caps to ground). They connect to ground on the PCB which then has about 5cm of wire to the XLR connector which connects pin 1 to the mic housing. Maybe soldering 22n caps directly onto the XLR connector and then shortest wire to mic housing would help. The way they are located now they only prevent oscillator hash leaving the mic, but not so much RFI getting into the mic.

And speaking about wires, I always wondered whether it wouldn't make sense to modify the two wires coming from the mic capsules. There is enough space behind the capsule mount (in the angled part of the main mic body) to put the JFET, ferrite bead and 1G resistor right there and then run four wires into the main mic body.

 

[Emmathom]

The real problem seems to be the location of the RF filter caps (those 22n caps to ground). They connect to ground on the PCB which then has about 5cm of wire to the XLR connector which connects pin 1 to the mic housing. Maybe soldering 22n caps directly onto the XLR connector and then shortest wire to mic housing would help. The way they are located now they only prevent oscillator hash leaving the mic, but not so much RFI getting into the mic.

Yeah, you should try this mod. if you feel easy with it ! If you do, please let us know (and add picts)

And speaking about wires, I always wondered whether it wouldn't make sense to modify the two wires coming from the mic capsules. There is enough space behind the capsule mount (in the angled part of the main mic body) to put the JFET, ferrite bead and 1G resistor right there and then run four wires into the main mic body.

That would surely be productive too ! There's space behind the "interface" on which the capsule screws on.

I (we !) hope that the @MicUlli circuit will not suffer from the same defect...