I know the Sparkos modules lowered the noise floor a good 10dB. The more direct conversions now available use the KSC1845 (maybe KSA992?) so I'm sure you're quite right. I've used these once but forgot to do a "before" measurement to note the improvement. I think your advice of replace on sight is a good plan.
Strange, the 2275 manual and schematic call RE11 and 12 1Meg Ohm resistors, but my unit also has 680k pieces.
Just curious, did you also get an increase in gain?Just wanted you to know I did what you suggested and changed the resistors from 680K to 470K and after I did, it fixed the distortion! Thanks again for posting this fix.
I just found a strange volume linearity problem with these and posted it. They change the curve and create a big jump in the back end. Probably most people will never hear it but its there. Here's the link. BA312 replacements vrs original IC - volume linearity
In your linked thread you stated you were going to see how a set of Sparko Labs replacements would compare.
Just got them this week. I need to pull a receiver and try them - hopefully right after xmas.. I also ordered some BA312's from China I'm going to try. I'll let y'all know..
Sweeet! Keep us updated
I tried the OPs resistor mod, but it didn't help with the distortion I was getting from BA312s in my Marantz 2275. I did the Sparkos mod/upgrade kit and wow - much less floor noise and no more distortion. A great alternative for those who may have tried the mod but didn't have any luck. I may have to get set for my Sansui next! No affiliation.
