I just got an SWR 350 amp (red face model) that was sitting on a shelf unused since 1998. I ran it into my Ampeg 4x10 (8 ohms) and SWR Workingmans 1x15 (which I just got used from musicgoround.com). It turns out that the 1x15 has a resistance of 4 ohms so obviously somebody changed the speaker in it because it should be 8 ohms. The speaker has no markings. The combined resistance should not be a problem since the SWR 350 is rated for 2 ohms. My problem is that the 1x15 output is very fuzzy/distorted pretty much throughout the range of bass notes and the 4x10 is fuzzy when I pluck the low E string. The fuzziness is usually there but sometimes goes away. I took the amp back and A/B'd it with my 1x15 and a new one and it worked fine with the new one, however the 1x15 still had the distortion even when I replaced the speaker with a reconed 1x15 from a SWR Son of Bertha (upgraded 1x15). I hate to think that both cabinets are blown because the Ampeg sounded fine before. I replaced the instrument cable with a Planet Waves and both equipment cables with Monster's and tried others to eliminate those as the problem. This amp also has a tube pre-amp. I replaced the tube 3x's with no success. Anybody else ever had a similar problem. Sorry for the long, first post.