The Rothwells are easy to get hold of in the UK and do the job. You can use them at either end of the SB-303 connection. Popular wisdom is that they should go at the amp end but the difference will be marginal at best (assuming shielded ie normal) interconnects.
On the subject of power handling...in hi-fi contexts speakers are rarely damaged (imho) by continuous driving at high levels (unlike, say, PA speakers where you can get the coils to glow red - and eventually the cones catch fire!). What most often kills speakers is power rail DC across the terminals (faulty power amp o/p stage), or instantaneous high-level very distorted transients (near square waves!) that kill tweeters through very rapid heating of the voice coil. This latter effect is nothing to do with the power of the amp per se. A 20w amp can destroy any (hi-fi) tweeter just as well as a 200w one if you dump all of its "power" very quickly into a fairly fragile, thin, piece of wire. Under normal circmstances that won't happen because the energy spectrum of real music is such that the tweeters rarely recieve much "power" to dissipate as sound or heat. However, under distortion conditions all bets are off!. You are better off having an amp that is very hard to drive into distortion in the first place. This means not only one with a high overload threshold on its input stage, but also one where the output stage and power rails will be stable when presented with challenging signals. I'd rather run a 200w amp with massive operating headroom into 50w speakers than the other way round. I'm talking about solid state class A or A/B here not valves - which are a different animal in this respect, since by their very nature their power stages "degrade" somewhat more elegantly (usually). However, they can still suffer from the input overload problem although depending on the design this can actually sound quite nice..sometimes :o) Using the Rothwell (or other makes) on ANY amp has benefits in terms of lowering the chance of input overload and also reducing the overall gain of the system, making it unlikely the amp will ever get near its limits on output. As a side benefit, the volume control operating range on the amp (if you are using a pre-amp stage) becomes much more useful as the normal setting for listening is generally shifted to around 12 o'clock giving finer control. Older amps (hard to be definitive on when exactly but let's say anything before 1990 to be on the safe side) were designed to operate with some inputs (tuner or tape for example) giving full output at 150mV...now CD players and the SB can swing 2v+ at full op... you can see this is going to be a problem. Even today, some amps only offer 500-750mV inputs - although there will be a CD input which should be OK. The effects of driving the input stage of a pre-amp into intermittant overload can vary from harsh obvious distortion to a generally "muffled" sound. One reason (imho) that passive pre's are a popular upgrade is that this whole effect simply cannot happen - it's VERY hard to overload a pot!....although transformers are another matter... I would get the 303 serviced to be on the safe side, regardless. Probably £150-200? depending on what needs doing. The mains connectors and socketry should be replaced with modern (much better) versions and electrolytics will definitely be out of spec by now if the amp has been used since new. -- Phil Leigh ------------------------------------------------------------------------ Phil Leigh's Profile: http://forums.slimdevices.com/member.php?userid=85 View this thread: http://forums.slimdevices.com/showthread.php?t=29722 _______________________________________________ audiophiles mailing list audiophiles@lists.slimdevices.com http://lists.slimdevices.com/lists/listinfo/audiophiles
