Synergistic Orange and purple fuses popping


Synergistic Orange and purple fuses popping

I recently upgraded all my gear with the new Synergistic orange and purple fuses (15 in all) What a difference! My Cary SLP-05 preamp with 8 Vintage Tungsten  6SN7 tubes is having problems with the Orange and Purple Synergistic fuses in the power supply. For some reason when I turn on the preamp amp after warming up the powersupply unit, the 2 power supply fuses pop. So far Synergistic has been gracious and replaced them twice now. I increased  the 2 large slow blow fuses from 1amp to 2amps after asking Cary audio what I should try. I also spoke with Synergistic and they agreed their fuses are sensitive but all the stock fuses I ever used have worked flawlessly. Any body out there with any similar problems and maybe a solution? Any upgraded hi-fi fuses that may be less prone to popping? I think it may be due to a current rush (tube related) when I go from off to on. Help!



Are most of them UL rated and if so is it obvious? Any suggestions on a brand that is better than the standard. I did hear the improvements so I'm buying in to the snake oil argument.

Well then enjoy the fire and hope snake oil is a good extinguishing agent.

Well then enjoy the fire and hope snake oil is a good extinguishing agent.

Remember snake oil often had alcohol or cocaine as the main ingredient. Pretty sure that crap worked.

Very early on one of the first generations of SR fuses popped for me. At that time, it I was recommended to go a value higher than the originals. This was due I think to there Million-volt treatment. I think it weakens them a bit.

Anyway, going forward I always have gone slightly higher in value even today with the new purple versions.

Also, I would go for the slow blow at least for your power supply.


Thanks Ozzy for some helpful tips. I did increase the amps to 2 from 1 on the SR slow blows and they still popped. I 'm waiting to hear back from Cary to see if they condone a higher fuse rating. Not sure what it will take and if I'm pushing things to far. They sure do sound good in all my other componenets. I wonder why the naysayers can't hear any more. Best money snake oil can buy imho.


I blew a blue in my preamp after a few months.  I got an orange and blew it in a new preamp from the same manufacture in a few months.  The orange was two increases over the stock.  

I put back in a common ceramic at the rated value and it has been fine ever since.  My opinion is that the fuses are not stable but lots of people like them, I don't.

I've had 5 different Cary tube products they all used the 560uf filter caps in the power supply. Mine all did the same thing they were all older units too. They would start running hotter and I had to be very careful flipping from standby to on. They would pop a fuses. I'd change the 2 or 4 560uf caps and the problem would go away. They will leak oil too. LOL I thought I had an old Harley the first time one took a dump. Left a puddle of oil. :-)

I was using ACME at the time in my Macs, Carys, VTL, Threshold. I was given SR to try. I wound up paying for blue and orange fuses. 10 or so..


Can you leave the preamp switched on and only use the power supply switch to power it up thus avoiding the surge?

@gregtheis if you’ve already received replacement fuses from the factory and the problem persists, than there’s one of a few issues at play here. As others have stated, Synergistic fuses are built to a very tight tolerance. They don’t blow unless there’s an issue. In this case, are you using a fast blow fuse but should be using a slow blow fuse? If so, that’s the problem (I see that you specified slow blow so this is not the issue). Otherwise, as Old Heavy Mech stated, you likely have one or more dried out capacitors and so a massive surge at start up. If this is the case, you are also burning through tubes faster than you should. It’s not a big deal to change out caps in a tube circuit, and one big bonus, you’ll get better sound as well as longer lasting tubes when you do. Lastly if none of these suggestions sound palatable to you, we will make certain you get a full refund through your dealer.


Yours and music,

Ted Denney III

Lead Designer/CEO Synergistic Research Inc.

This is result of inrush current, I had the same issue with my Coincident 845 SET amp and former Cary push pull. I went up a couple values both times, no more failures. My take is as long as fuses are blowing they are doing job intended to do.


Perhaps they are undervalued to whats stated on fuse. If they are blowing on startup, they'll also blow if equipment suffers some other failure.

Thanks everyone for all your input and great advice? Since Cary just did a complete factory overhaul on my SLP-05 I and I retubed it as well I think I will try a higher value slow blow after double checking with Cary first. I'm going to confirm if they changed the caps and fix if they didn't. Also I will try turning the preamp on first before the power supply and see if that solves it. Thanks Ted and Synergistic. You have been great incidentally at trying to help resolve this and even replaced the popped fuses , no questions asked. Very refreshing when you consider the feeling you get with a $400 pop with these new purples.


Not coupling/decoupling caps, FILTER CAPS. 

Here is the rub. There was a thread about V12i blowing fuses on the forum, HE had sent it to Cary, They did a (so called) complete rebuild and they started blowing coupling caps.

I told him my story and sure enough Cary had NOT replaced the filter caps but everything under the sun including one transformer.

Cary gets it back and replace ONE bad filter cap and one blown coupling cap.

The tech, was assuming the guy before him (AT CARY) did replace the filter caps (He didn't). The customer gets it back again and this is when I read his thread complaining about Cary. I would too.

He post a pic off site you can see they didn't even do a Hexfred upgrade but changed all these big old honkin' coupling caps. You know what it takes to charge big caps? Ask the filter caps that blew.. LOL

The whole story is He had 3 V12i. 2 mono one stereo. ALL started doing the same thing.

After Mr. Ralph, chimed in and confirmed my suspicion, the guy quit posting about his amps.

I have no idea what he spent, but V12i mono blocks or stereo amps are a sight to behold and listen to if they are done right. Blown up they are just a sight.  A Cary V12 - V12r should outlast my grandchildren. I paid 165.00 plus postage and tax for all 4 560uf filter caps. I paid almost that per coupling/decoupling cap combo. Copper foils and teflons. Magic!

It takes me about the same amount of time to swap and bias valves, (10 minutes) vs. swap out all 4 FILTER caps.

BTW I offered to fix his Cary for FREE, if he would pay for the parts and shipping. Silence!!! :-) I am still looking for a second V12r. My wife won't give me mine back. I'm using a MC225 and a MX110. Women. :-)


I would certainly get another brand that is UL approved as these fuses sound like to much trouble.


Wow am I learning some stuff about my gear! Your insight is extremely helpful. Now I have a place to start. Any thoughts on a decent Hi FI fuse that works as well as the cheapies until I get the caps replaced? By the way my wife has tolerated my obsession for 38 years and now that I have the Evolution Acoustics mm3's (all 1500 pounds) in our family room, I realize she is a keeper. HA!

OP Fuses are in the ears of the listener, I seldom recommend a brand. I use SR blue and orange. I also use ACMEs very good fuse.

Those speakers are heavy. Man alive. I've tipped up a few over 600 lbs. Heavy enough. :-)

Cary likes fancy fuses, and a good power cable. My Mac, Threshold, First Watt or VTL didn't give a hoot. Huge power supply usually means fuses don't do squat. :-) A large enough and well constructed power cable is a different matter. Everything likes the right PC. 

I'm a small planar/ribbon guy. My monitors are hybrid line source design. 425lb each but there is no bass of any kind in them. GRs servo and my SAT Bass Columns. I'm a happy camper.

I have a couple of friends that get mad about the whole fuse thing. Me I'm an old beat up heavy mechanic. I haven't seen everything, but I sure have seen a lot. Either they sound better or they don't. 50/50 for me. I think it's because of the age and type of gear, fancy fuses affect my gear less.


oldhvymec and other audio nuts out there:

noromance solved my fuses popping on start up. I just reversed the order and turned the power supply on last as the rectifier tube in the preamp warms up slowly. Wala the fuse held. Now to break in the new purple fuses and hopefully hear what many are claiming. Better overall sound!

As a continuing audioholic, I''ve spent considerable energy and resources upgrading everything over many years. The result I have lets me pretend I am at a rock cocert  or a symphony orhestra with somme pretty good realism. No more concerts since the whole pandemic so this is the next best thing. Lots of fun and never ending quest for the holy grail. It's either that or bars and women. Wife wouldn't like that so she lets me do my stereo obsession. Next thing I'm gonna tackle the room acoustics. Called Synergy and started researching their stuff. It will probably be my next post.


Good! :-) If I don't do anything but have people prove me wrong, you still got a fix.. That's better than eatin' bugs. :-)

Time to feed the chickens! Come on Dog.. 


Not proving you wrong and really appreciate you sharing your vast experience on this. I know you were right as this is likely just a temporary fix till the caps get worse. As you suggested and so did Ted from Synergy, the preamp shouldn't pop a slow blow fuse when you turn it on unless something is not right!

Well being able to use it is a good start.. :-) I have to roll a C2500 in and a C45 out of my system. I'm so lazy! :-) BUT I just got it fixed. Wife is driving me nuts as usual. She will listen for 2 days and come out with a list.. LOL Good ears. The FIX will be a pair of matched Blackburn or Telefunken. 

I would like to try a Cary pre like a 98 or 05. I'm so use to tone control and Mac, tough to change. I've heard a few Carys though...

Happy Happy..

Fuses do NOT make ANY difference to the sound. Anyone not agreeing suffers from the audiophool syndrome. There will be scandalous resistance to this comment but just take my word for it.

Use UL approved, slow blow properly rated fuses which came with your system originally.

If you are still popping them, there may be a fault in your system.

Remember, fuses pop for a reason (typically to avoid a fire). Do not do anything weird (like installing higher rated snake oil fuses) to give the insurance companies any excuse not to pay for your burned down house.

I have the same Cary pre-amp with the orange fuses and I didn’t have to go to a higher value. I also have some exotic 6F8G and Marconi BL-63 tubes installed in it. My Cary amps are another story however as they will blow at the stated fuse value needed. 


Tell me more about those tubes you swapped. What have you tried and how do they compare to something like my vintage Tungsten? I'm interested in how you ended up with the tubes you have. Also now that I have the purple SR fuses I'm breaking them in. What direction did you find sounded best on your Cary preamp? I I have the hot end going in from right to left. Jury is still out on benefits over orange SR.


My Purple Fuse blew after only a few weeks. It uses the same Large, Slow 2A as the previous Orange and Blue fuses, which had no issues. I have advised the retailer and expect they will replace them, but what comfort do I have the next one will repeat? And I really thought the Purple was a major advance.  Neal

It’s interesting that I have only had problems with SR fuses and not any other standard fuse. They were all slow blow and even rated at two levels above the standard. My preamp manufacture cautioned about using a higher rated fuse and I didn’t want to get into a warranty dispute in case I had a problem.



Synergistic has been quick to respond and replaced any of the fuses I popped at no charge and were willling to work with me to analyze posssible causes. My solution was easy. I turn my Carey SLP-05 preamp on first and then the power supply. The problem we all seem to be having is the current rush when we turn the power supply on. It is apparently a bigger issue with tube equipment. Also our gear could have weakened caps? Since I have replaced all my gear with Orange and now some purple fuses the music has become more real and musical. Improved imaging and detail, etc. The purple are even better. You do have to have good equipment to here major improvements and decent hearing as well. I replaced the fuses on my othe system in FL with the orange fuses but the improvements were not as dramatic. Good equipment there too, but not like my main system here in Chicago. I still wonder whey the cheap fuses never popped?


Glad you got yours figured out, Greg

I had a post last year where I tried the SR Blue in an integrated amp and it blew upon first power up.  The dealer recommended going to a higher-rated but Audio Research did not condone nor recommend this.  There was no problem whatsoever with that amp and this only occurred with the SR fuse.

The current ORANGE30 sale had me considering another go as I have changed electronics to different ARC models now with separates.

I talked to another dealer today, nice lady out in CA, and she said many customers up the values but nonetheless if I want to give it another go at the mfg ratings they are happy to sell and give a full refund if they pop.  This frustrates me that the problem even exists.  Spending $110 each at this point in the game is meaningless....I really wish I could comfortably try them out to let my ears decide if anything happens....oh well.

It's a dilemna for sure,

They really do sound better with good gear. Synergistic told me the cheaper fuses are not very accurate on their rated values so they could be significantly higher than their rating. If that's the case the manufacturers would have to be careful not to rate their recommended values as high.  Moving to a higher amp rating is  Synergistics normal suggestion and they say their amp ratings are very accurate. It worked for me and the technician at Cary was OK with a small jump in amp rating. I called first just to clarify things.

God luck



"Synergistic told me the cheaper fuses are not very accurate on their rated values so they could be significantly higher than their rating."


Have you ever looked at the catalogs from the major fuse companies? Maybe by cheaper fuses they mean imported fuses from dubious sources such as China.

If you buy fuses from a major US company than you can be sure of it's rating. If you pull up that fuse type and current rating data from that company there is likely an entire page detailing every characteristic that can be measured! They need to know exactly  how the fuse they are selling, that will wind up in consumer products, medical products ad other diversified electrical gear will behave under adverse conditions. Things like how quick it will blow during a direct short, how long that a 10 amp fuse will last passing 10.2 amps of current before it expires, if a current surge, say during startup that exceeds 10 by a large margin will hold for a specific time before it blows and so on. These important facts are presented in the manufactures catalogs. They MUST meet certain standards to get UL approval and to get that approval is not easy. 

Do these fancy fuses have all of that behind them? Even if they start out with a UL listed fuse, by modifying them, they will not meet the specs anymore.

Wait until someones house burns to the ground and the investigators pinpoint the cause to an amplifier and to there horror find it has snake oil fuses in it. That will be the end of that particular company until they open shop in another name.




I blew a purple Saturday and am bummed. The system was off and it had to be static electricity. SO I ordered another at 2 amps versus 1 amp SB from ALfred. I assumed it was my fault. I really dont like he stock fuse.

So where is @ted_denney on this thread?  

It’s his product that is popping and failing. Static electricity blowing a fuse?

Sounds like junk stuff to me.

Sorry but I'm not ready to play Russian Roulette with my gear or life if one of these "specialty" fuses causes a fire. 

I run Mac, Cary, VTL, DIY all are in metal cases, where is this fire suppose to happen at? I don’t own a single piece of gear that can catch on fire and cause a fire in any of my rooms. I could see if maybe a carpet caught on fire or the drapes. All of my gear is on something that can’t catch fire. Even the carpet can’t catch fire.

Am I missing something? Fuses in my gear are for GEAR protection, it has nothing to do with my protection, or my house. My home is protected by breakers. I don’t have any fuses on my stove or dryer or hot water heater or blower motor for the house, the well pumps, the TV or the computer or the plug in wall heater or the heating blanket or the heat lamp for Jr, or my back massager or my FRIGGIN ELECTRIC JACKHAMMER.

You people are NUTS. Fuses in stereo gear are to protect THEIR junk not YOURS.. Good lord what a bunch of numb nuts..

A Cary V12R has 5 fuses FIVE! That is for fire protection.. It was for Mr. Hads Amps not my house..

cakyol, you know better than that BS. Burn down your house with an amp. Funniest thing I EVER heard. The house has circuit breakers. The amp has stupid protection that all.

Here is a good one a guy buys a solar battery and put it in his house to run his stereo. BUT it gets hot and the fans come on. So he takes the heavy steal case OFF the battery and tells me he didn’t cause a potential fire issue. That is the only thing he did with a lithium battery in the center of his house. He was so stupid he could not understand the danger by removing the vapor and fan cooling control. He was preparing a bomb on his living room floor for him and all his apartment neighbor to enjoy. IF he would have left the metal case intact it was a bad idea. Lithium batteries blow up. NEVER locate large lithium batteries or even a cash of smaller ones inside a domicile. BOOM..

Stereo gear not so much.. maybe a tube fire it's all show and GLOW in a tube..

I did see a Trailer full of class D amps catch on fire in Brazil (I think) it was a BASS hootenanny and the thing overheated. Large generator trailer to power it.. Burnt right to the ground once the aluminum and magnesium caught fire.

“ Synergistic Research Quantum Fuses employ a custom alloy treated with 2,000,000 volts of electricity! “


Just think about this statement for a while 😏

I blew a purple Saturday and am bummed. The system was off and it had to be static electricity.

And how would we know that?
Unless it is an X-Files episode,  we do not have ball-lightening or static at 1A ratings.


SO I ordered another at 2 amps versus 1 amp SB from ALfred. I assumed it was my fault. I really dont like he stock fuse.

I have heard about being committed to a cause, and going “All in”… But why would you put a 2A fuse in a device that wants a 1A d fuse?
(It is like deciding to double a prescription dose.)

maybe very large cat jump through window, take like to amplifier and rub with fur..

The best responses are: Those fuses are not UL rated! Danger, danger Wil Robinson.

Bottom line for me is I agree with oldhvymec and see no danger except a possible fuse pops and they cost a lot. If it pops it's doing it's job. Meanwhile my stereo sounds like heaven on earth. Yeah It's worth the effort and it's a PINTA but isn't that what real high end is all about. Were all sick and stupid!! Just ask my wife.


@gregtheis -- I just read the initial posts. Since you went up 1A, go up another amp or two. I did that successfully throughout my system with the SR Orange, with only one failure in a preamp when I plugged in ICs for subs (tho they weren't powered up). As you discovered, SR is very aware of the turn-on "rush" problem with some components, but has in effect refused to build their fuses to UL industry standards. Most, but not all, developers over spec their products a few multiples to avoid having lots of warranty returns, given the variety of user situations. Asking is a good idea, because some don't (seems like poor design, but I don't really know). Alternatively, consider Audio Magic's Ultimate Premier fuses, which are built to industry spec and really good -- I've just burned in a couple -- or the even the pricier Quantum Science fuses out of Hong Kong or thereabouts, which have been highly reviewed on What's Best Forum. And keep ignoring the naysayers.


Thanks for all the great advice and ideas. It makes sense that the manufacturers over spec to reduce warranty problems.  I will do some more research and try some other quality fuses in the future. That said I really like these purple fuses. Yes I have mostly Orange in both systems but as I replace things I will be trying more of the crazy purple fuses.  Those Audio Magic are the ones with the beeswax I think and they have some QC problems I believe. Never heard of the Quantum Science fuses. Worth a look though. I still can't believe these can make the diffreneces I've been hearing. Like I said before, I love that snake oil!


Greg, I found this forum & this topic by doing a google on 'do Synergistic fuses really sound better'.  On another forum I no longer frequent I read more than 2 members swearing by them, and since then I have always been interested/tempted.

I recently upgraded from a SLP 90 to a preowned (from Cary) SLP 05 that I had them put "The Ultimate Upgrade" on before they shipped it, and this was the unit I was most interested in re-fusing with Synergistic (especially now, as they are on sale).  What you have discovered about turning on the power supply last is advice I will heed whether I refuse or not, but I do have a question about this:

What direction did you find sounded best on your Cary preamp? I I have the hot end going in from right to left.

Am I missing something?  I believe on mine, the fuses plug into the back of the power supply from back to forward?

And I agree with just about everything you have typed about this "hobby."


I did the SLP 05 Ultimate Upgrade as well, along with the older Tungsten tubes.  Maybe that combo with the fuses is the improvements we are hearing. I was afraid to try different directions on the fuses after the original problems so I never tried reversing them. They are as you say hot end going in right to left. fuse info/writing reads from left to right going in to back of power supply. I'd be interested to heare if anyone has tried them reversed and has any opinion. They sound right to my ears the way they are. 


They are as you say hot end going in right to left

Greg, thanks for getting back to me on that.

But this is where I am confused (and maybe it is me, because although I can solder & de-solder, the theory of electronics is beyond me); in mine, the fuse inserts in the fuse holder and then the fuse holder plugs straight back into the back apron of the power supply, which actually seems more 'forward and aft' than 'right and left', but as I typed, maybe I am missing something?


Also, keeping in mind my limited grasp on electrical theory, tonight I did turn on my pre-amp as was suggested above . . . turned the pre-amp/6sn7s to 'on' and then turned the power supply on so everything powered up at once.  Why is that a softer start than turning the power supply on and getting the rectifier tube  going and then firing up the 6sn7s?  I believe you that it is, but I am not understanding why.


Hey, thanks again for getting back to me!


Hi again Matt,

I'm no expert either but unless I'm mistaken we have it right. The hot end is the forward end of the fuse which as you say goes straight in to the power supply. The SR is on the other end which is the fuse holder itself with the fuse values showing left to right as we read. Also, I think the power supply rush when turning on the unit first before the power supply eliminates the current rush because the rectifier tubes warm up slower. Again, someone else is the forum like HeavyMech knows way more on this stuff.

Happy listening