Soundfield ST250

..I have a dead Soundfield mic here (AMS era) -no output whatsoever. The power LED is on, but no signal out of the box.

I'd love to DIY new set of electronics (can anyone say 4xGyraf G7 electronics followed by a nice matrix encoder/decoder!!! :twisted: ) but this has to be repaired for a frined of mine... :sad:

Anyone here got any schematics or info of what voltages should be on which pins? Since it's a total failure to pass any signal, I assume that it's something 'spinal' like a PSU...
BTW, everything inside the cigarette-packet-sized PSU/preamp/matrix box is surface mount and is packed in there tighter than a camel's arse in a sandstorm, so it's not easy to start looking for power on IC pins, though in the absence of any information, I might have to start there.

Keith

Hi Keith,

No damn help at all I'm afraid, but the thought of you >DIY'ing< a Soundfield just made me think...



:shock:

Woohoo!

Back OT...can you take a stab at what rails are going about from the pcb traces and groups of decoupling caps etc?

Mark

Oh yes,

And the manual is no help here, but has an interesting "theory of operation" appendix:

Manuals!

Mark

did you ever find schematics for the AMS ST-250? I have one here that is noisy --- an intermittant whine

On a side-note - Calrec's patent on the SoundField technology, presented 1978, must be expired by now, 37 years later?

Any takers?

Jakob E.

this schematic is for it's cousin in case it could be useful

any luck in fixing the mic? I have one in the same condition, probably...
Thanks!