You may have an impedance mismatch.The 2-15 from the ConcertBass is a 4ohm cabinet. Some 200S heads were wired for 16/8 ohms. The jacks were labeled. Some of the later ones were wired for 8/4 ohms,also labeled as such. (although you can go inside and tap the transformer for whatever way you want it,if you know what your looking for.)If labeled 8/4,make sure you attach cabinet to 4ohm jack. If you have the 16/8 you really shouldnt use it until you go in and re-tap the transformer. There are schematics on this sight that will assist you. Or...you could rewire your cabinet. I believe those had 2 8ohm speakers wired in parallel.If you rewired in series,it would be a 16 ohm cabinet. Probly not a good idea. You didnt say if your Hartke was tube or solid state. If tube,same rules apply as with Sunn 200S.If solid state,most of them would match up to just about anything,but the poweroutput would vary,depending on what load you attached. Higher the impedance,the lower the output. For instance the Concert Bass solid state head put out rated power at 4ohms,,I think it was about 120watts.Easily used with 8ohms,but only put out about 80watts. Also usable at 2ohms,somewhere about 160watts (as I recall). Hope this helps. I also have a 200S,but mine does not distort like you discribe.Mine is very smooth,and has some very nice full deep sonic qualities up on 7-8 and pretty loud. Afraid to go higher for fear of speaker damage. You may also consider re-tubing if you dont know how old they are.
