A Beginners Guide and Other Thoughts on Audio - Epilogue: Fuses
Roger Modjeski and Anthony Chipelo | Published on 7/27/2024
Last month’s Roger’s Corner represented the last chapter of Roger’s audio book, “A Beginners Guide and Other Thoughts on Audio.” While there are no more book chapters, there are a lot more thoughts and content from Roger on all topics audio. So, in the coming months, Roger’s Corner will continue to periodically appear in The Muse. In the very first edition of Roger’s Corner where it was announced the book chapters would be published, we kicked off with a letter to the editor Roger wrote to John Atkinson of Stereophile. So, for this edition of Roger’s Corner, I thought we should conclude the book with another letter to the editor Roger wrote to John Atkinson, this one on the topic of fuses.
Roger was opinionated about a lot of things when it came to audio, but his strongest and perhaps harshest opinions were reserved for what he called “boutique fuses”. In a nutshell he hated them. Unfortunately, his opinions on “boutique fuses” resulted in his forum on Audio Circle being shut down. As a little taste, check out this link to the topic on Roger’s old Music Reference forum:
https://www.audiocircle.com/index.php?topic=105425.0
By the way, I would be neglectful if I didn’t point those of you interested back to Audio Circle where Roger’s closed Music Reference forum exists, albeit buried with the other archived manufacturers circles. There are more discussions about fuses in the Music Reference forum, as well as many other discussions on audio. So, while you are there you might want to peruse some of the other threads as well, there is a lot of good information, and not just from Roger: https://www.audiocircle.com/index.php?board=124.0
Roger spent 40 years of his life designing audio circuits none of which used “boutique fuses”, although I know of some audiophiles who have swapped out the OEM fuses in Roger’s components for them. How do I know? Simple, those components came to us for repair. In each case the fuse failed to provide the necessary protection that it should have. The damage varied, but in each case, it was an unnecessary repair.
As he would with anything that piqued his curiosity, Roger tested a few of these “boutique fuses” and while I will not post his findings publicly, suffice it to say he was appalled. I will say this though, none of the “boutique fuses” Roger tested were Underwriters Laboratories (UL) approved. Since this testing was done years ago, I cannot say whether any of these fuses, or others Roger did not test, are UL approved today. However, if you are someone that is concerned about safety and your equipment (as you should be), Roger would certainly urge you to find out what laboratory testing and what approvals any fuse you may be interested in has received before buying them.
So, you might ask: What brand of fuses did Roger use in Music Reference components? The answer is: Littlefuse. Specifically, ceramic high breaking. Yes, they are laboratory tested and UL approved.
A Beginners Guide and Other Thoughts on Audio
Roger A. Modjeski
Epilogue: Fuses
Dear John,
I feel it is important for the public to know that many of the premium fuses will afford no protection in certain applications. In particular, tube fuses must be of the high breaking construction to do their job. A high breaking fuse is filled with sand in a ceramic body. The sand is most important as it fills the space when the fuse element vaporizes in a high breaking application.
When a tube fuse blows in a DC circuit of high voltage it does not melt, it violently vaporizes forming a conductive plasma that continues until the entire energy of the power supply is dumped into the circuit destroying the tube it was meant to protect and possibly damaging the output transformer, and other components associated with the tube. I have seen these fuses cause extensive damage in several amplifiers. I have seen melted fuse holders (plasma is hot stuff).
Read Full Article