For decoders, try calling Tim at Digistar. If anyone knows, he will. I've had nothing but good results when dealing with him. Look on the advertizer's index in the back of Model Railroader for his phone number.
One thing you'll want to consider when running sound equiped locomotives on DC. If you're consisting locomotives, the sound equipped locomotives require more throttle than non-sound locomotives, hence, the non-sound locomotive will be spinning it's wheels while the sound locomotive is crawling. I operate on a friends DC layout every month and his sound equipped locomotives operate alone for this reason.
Good luck on your quest
I am looking for a dc dcc sound system comparable to the BLI Quantum Engineer level. I would like to find a company that has some inventory to sell! QSI talks big about all the neat things they have, the things they can do, etc. etc. etc., but in fact- most of their stuff is in the continous "coming soon" mode.
Is having access to (some) DCC features during dc operation available thru other manufacturers? I am looking at 2 upgrades- (1) DCC ready loco (for dc operation) upgrade for sound powered by dc and (2) a "kit" to add to the "classic" original dc loco, no boards included as original. (how crazy is that?)
Are there some "good" sounding dc dcc sound cards for dc usage?
I know this may be a tall request......
Thanks to all!