Siemens W295B - Newb needs advice

[joydude]

Hi all,

Thanks for such great info on this forum - it gave me the courage to purchase a Siemens W295B knowing I had to solder up a Tuchel and possibly do a recap at some stage. Previous to this I’d done plenty of residential wiring but had never actually soldered anything. . . didn’t even know what a capacitor was!

Anyway – made a bit of a hack of the solder job as I used a bigger (thicker gauge) wire than needed but I managed to get everything put together according to spec. Put a multimeter on it and it’s got current going the right places. Also using 24 V 1 Amp filtered power.

Problem is it sounds someone’s talking through an electric tin can. Opening it up I was surprised to find TWO original orange GSF capacitors (photo attached) whereas the Kubarth schematic (and other pics on the internet) show only one. I've attached a picture of my W295  with 2 orange caps. As I'm limited to one  attachment per post I'll post a comparison W295 immediately following this one showing the single orange cap.

So, before I get adventurous and pull out the capacitors to test them somehow (my cheap multimeter doesn’t test capacitance) my questions are these:

1) Should I resolder the tuchel with smaller/correct gauge wire, i.e could that be the cause of such a problem as I described?

2) Why would my unit have two capacitors instead of one as per the schematic?

3) Assuming tuchel is not the problem and I need (or want) to replace the existing caps, can someone recommend a suitable replacement? These GSF ones are labeled 100/35 which I understand to mean 100 Microfarad and 35volt respectively – though I’m not sure where to go about getting a replacement that will do the best job for this application.

Thanks for your help. This board is awesome.

 

[joydude]

Hi - posting this for posterity.    Have solved issue. Basically a grounding problem. So to all those thinking about buying one of these units. . .mine works beautifully well.

The main thing is that you can't wire it according to the diagram! I am posting the correct (worked for me anyway) wiring instructions below, which I found on this forum:

______________________

hi synthiaks

yeah thanks for the suggestion , I got a regulated switching psu with similar specs to a siemens / telefunken desk psu I think(2amp 48watt). this was actually very cheap (£7!!) and compact.

when I wired it up there seemed to be a noticeable drop in hum + hiss from the wallwart but looking at daw analyser it was still very high.

what I then did was tie up the audio output ground to pin 1 (with input ground) + also bridged pin 1 + pin 2 (connected to 0v). im not sure if connecting output ground helped but I think it was bridging pin 1 + 2 ( I thought it was doing this internally anyway), guess its set up for chassis grounding rather than plug + play, im not sure,  but . ...

now its passing super clear audio, these siemens modules are crazy quiet, line level audio coming through perfectly with no gain or attenuation + noise floor now indistinguishable from my dac (120db dynamic range)!


anyway thanks again for the help.

alex