if any one has some recommends for powerfull senny replacements...
that would be great. cos i'm worried my last pair of senny iem's are gonna go bad. ive tried loads of alternatives.
KB Ear KS1. Some of the best sounding IEM's I've used at any budget, and these are CHEAP (25 bucks at the moment. Replaceable cable and ear tips too.
I now wish I'd done similar. Unfortunately I ordered the new ones and disposed of the old. Mistake

That's a shame. These old K240's are easily my second most used headphones. They're lightweight and comfortable, not to mention they sound fantastic. Compared to the K7XX they sound similar (though the 240's are a little less bassy), but the K7's are heavier, less breathable, and rattle and squeak whenever I move my head!
A friend back when I bought the originals asked to borrow them to compare with his Stax electrostatic headphones. Crazy money headphones. His verdict was that the Stax were slightly better, but fearsomely heavy and fearsomely costly and if he'd know of the Sextets he wouldn't have bought the Stax.
I've heard of those - iirc they need a bespoke amplifier to power them. The K240's, despite being 600 ohm headphones, work and sound great straight out of an old iPod - although they're rather quiet without using a dedicated headphone amp.