This question is aimed to TRUE Elec Engineers, not fuse or wire directionality believers.
Even NASA uses fuses, just like most everyone in high end audio does. Fuses have come a long way, baby. NASA started studying advanced fuse concepts twenty years ago which, ironically perhaps, is about the same time advanced audiophile fuses were introduced. Coincidence? Now, NASA might not give a hoot about sound quality but audiophiles certainly do. - Ex NASA Range Rat |
Let me try & respond to some of the comments made recently. - First, a fuse will NOT protect a speaker from a DC fault. If and when a fault occurs, the speaker wire, especially the tweeter wire will melt and catch fire WELL BEFORE a fuse has time to act. Therefore your speaker will be destroyed, saving the fuse. The ONLY sure way to ensure that the fuse will blow before the speaker is to use a crowbar circuit. I dont like the idea of that. - Secondly, normal relays, regardless of whether they can carry HUNDREDS of AC amps will NOT be able to break a DC circuit, In a fault condition, The DC will arc and continue destroying the speaker and the relay. At most, if one is lucky, the relay may save the speaker but it itself will most definitely be destroyed. Look at relay specs CAREFULLY and note that MOST are rated at no more than 30 Volts DC. I have +/- 90 Volt rails. - The amp I am building is high power BIPOLAR transistor based so in case of a fault, it is more likely to fail as a short than an open circuit and hence more likely to destroy speakers as compared to a MOSFET output stage one. Hence the need for a reliable speaker protector. - Most commercial amps use a relay in the output MOSTLY to avoid thumps when first powered on. Altho they MAY protect the speakers in DC fault cases, their intention is the former not the latter. - Thirdly, SSRs made with back to back MOSFETS driven down to a few milliohms will make a PERFECT wire, nobody (except the superhumans on some of these threads on this site) will hear the existence. - As for the NASA fuses/relays, I know about them, they are encapsulated in nitrogen under pressure so that they MAY be able to break DC but they cost in excess of $200 or so for a 15 amp relay. - The control circuit I intend to use is one by Rod Elliott and here it is: http://sound.whsites.net/project33.htm Thanks |
cakyol - As for the NASA fuses/relays, I know about them, they are encapsulated in nitrogen under pressure so that they MAY be able to break DC but they cost in excess of $200 or so for a 15 amp relay. >>>>Nice that you know all about them but apparently what you don’t know is that advanced audiophile fuses can oft exceed $149 and sometimes even exceed $200. Maybe NASA needs to step up their game. Audiophiles have two or maybe three conflicting requirements, cost, sound quality and protection. |
This is more like it: https://www.mouser.com/ProductDetail/Infineon-Technologies/IPB017N10N5LFATMA1?qs=sGAEpiMZZMshyDBzk1%... 100V, 180 amps, 1.5mohms (almost lower than the speaker wire itself), about 80 nanosecond turn off time (increase that becoz of inductive speaker load) and only about 8 bucks a piece. In theory, it looks perfect, the only issue is with switching MOSFETS, they dont unfortunately specify the frequency response.... |
