Hi-Fi Tunig Fuses & Parasound A21


Hi,
Have any Parasound A21 owners replaced the stock fuses with the Hi-Fi Tuning fuses in their amp? I understand that there are four 8A slow blow internal fuses and one 12A slow blow fuse on the rear panel. This is a awesome amp as-is. Just my curiosity.

Please share your experiences.

-Thanks,
milpai
Not Parasound but I have replaced every fuse in my ARC PH7, Ref 3 and ARC Classic (tube) monoblocks with HI-FI tuning fuses. None are ever comming out!
I did not put them in all at once. I did them one at a time and moved on to the next. They even worked great on the Maggie speakers. I know what I hear and none are comming out!

Len W
Replace the AC Main fuse first, and if you appreciate the differences that makes(a VERY likely probability); replace the rail fuses as well. Happy listening! BTW- NONE of my HI-FI Tuning fuses are coming out either.
Thanks Len and Rodman99999.
Roadman99999, I like your idea of first replacing the AC Main fuse first.
BTW, what differences did the fuses make in your systems?
The best way I can describe the difference is, "more organic". ie: Vocals sounded more as though they were coming from an actual body(chest resonance), upright bass had a woodier body resonance, I could hear more skin and stick on drums, could sense more of the rosin in the sound of bowed instruments. One probably wouldn't miss these things, if they never listened to live music(or, at least, not often or closely enough).
I agree with Rodman 99999, also Maggies are known for the ribbon tweeter with outstanding high`s, the fuses gave an obvious improvement with even more resolution way way up in frequency, that was a pleasent supprise.
Len W
Milpai,

Glad to see you are thinking about this upgrade. Agree with the above description of benefits in general. I realize these are a fairly spendy add-on, especially if you are replacing multiple fuses. But for the benefit I think they provide in terms of improved sound, I am surprised at least some high end manufacturers do not specify them as OEM.
Thanks again guys. I would start with the AC Main fuse first then.
Given this option for the A21 is it the same on the A51's?
Hello,
I am thinking of replacing the stock fuses of Parasound Halo A21 and have a couple of questions for this audience who have hands on experience with fuse replacement.
1. It seems to me that the main fuse which is in the signal path would be the most important fuse to replace and would yield the max improvement in sound. Replacement of the 4 internal fuses in the rails not being in the signal path might be optional. Would you agree?
2. My fuse options are Hifi tuning Supreme and Synergistic Quantum Black. I read rave reviews of Hifi tuning fuses used in Halo A21 but not so much on the new Synergistic Black fuse. Did anyone have an opportunity to compare these two fuses?
3. I tried cleaning the main stock fuse with DeOxit Gold contact cleaner and the result was a very harsh sound as if the fuse was not broken in. I have also found that the sound changes with the direction of the fuse. In one way it is relaxed with a very clear mid-range specially the voice with a little loose bass. The reverse direction produces a very fast, punchy sound with a controlled bass but it had a tad hazy mid-range specially the voice.. I wanted to get both but it is not possible at least with the current stock fuse. Did anybody experience this behavior with the direction of the fuse be it a stock or an expensive audiophile fuse?
Thanks
FYI  The Parts Connexion has a sale on HifiTuning Fuses going on now.  I am awaiting the arrival of four silver star fuses.  They were 60% off!!
Thank you. I have just bought one Hifi Silverstar for the main fuse. Will try it and let you all know the result.
6.3A fuse ?
I have also found that the sound changes with the direction of the fuse. In one way it is relaxed with a very clear mid-range specially the voice with a little loose bass. The reverse direction produces a very fast, punchy sound with a controlled bass but it had a tad hazy mid-range specially the voice.. I wanted to get both but it is not possible at least with the current stock fuse.
This is not caused by reversal of the fuse but how it makes a connection. Quite often by reversing the fuse you get a better connection because the fuse sits better in its holder and thus there is a lower voltage drop across it.

IOW its the connection, not that its reversed. If the only way to get the fuse in the holder is by removing the fuse cap, you might not have much option but to reverse the fuse to see if the contact is better.

atmasphere
5,020 posts
11-16-2016 10:59am
I have also found that the sound changes with the direction of the fuse. In one way it is relaxed with a very clear mid-range specially the voice with a little loose bass. The reverse direction produces a very fast, punchy sound with a controlled bass but it had a tad hazy mid-range specially the voice.. I wanted to get both but it is not possible at least with the current stock fuse. This is not caused by reversal of the fuse but how it makes a connection. Quite often by reversing the fuse you get a better connection because the fuse sits better in its holder and thus there is a lower voltage drop across it.

IOW its the connection, not that its reversed. If the only way to get the fuse in the holder is by removing the fuse cap, you might not have much option but to reverse the fuse to see if the contact is better."

Sorry, Charlie, nice try. But that’s simply not true. When the fuse itself, without the fuse holder even involved, there is a bigger voltage drop for one direction over the other. Hel-loo! Besides, careful and thorough testing reveals that the direction of the FUSE is actually more obvious in listening tests than any directionality the contacts of the fuse holder may or may not produce. More importantly, the direction of all wire, not only the wire on fuses, is directional. You can say that it’s the contact until you’re blue in the face, it’s no skin off my nose. This is an excellent example of the Backfire Effect, the more someone’s belief is challenged the more he believes he must actually be right. Common in this hobby, I might add.

From the silent majority, we have a 180 (or is it 360?) degree view on the subject of fuse directionality.

atmosphere = +100

geoffkait = -100

From the silent majority, we have a 180 (or is it 360?) degree view on the subject of fuse directionality.

atmosphere = +100

geoffkait = -100

Atmasphere is certainly not alone in his contention, which btw he has indicated in past threads he has confirmed via measurements. See my post dated 10-28-2016 on page 58 of the long-running thread https://forum.audiogon.com/discussions/synergistic-red-fuse?page=58, in which I cite relevant comments not only by Atmasphere but by three other highly experienced designers of well-regarded audio electronics.

I also state in that post, as a highly experienced electronics designer myself (in the defense electronics field), that "claims of directionality in fuses [are] fundamentally irreconcilable with any reasonable understanding of how electronic circuits work." While also completely recognizing, of course, "that an understanding of how electronic circuits work can’t explain or predict everything about what we hear or don’t hear from our systems."

Finally, even if contentions that fuses inherently have audibly significant directional characteristics are correct (which they are not), it would stand to reason that the effects of any such directional differences would be completely swamped by the much greater directional differences that would presumably be caused by the vastly greater lengths of the associated wiring. In the case of AC mains fuses that would include the wiring in the primary of the power transformer, the internal AC wiring of the component, the wiring in the power cord, and presumably even the AC wiring inside and outside of the house.

Geoff (and others, most of whom are also not electronics designers) will of course disagree with all of this, but that’s how I (and the four well-regarded designers quoted in the post I referenced) all see it.

Regards,
-- Al


Fuses are not in any signal path except in the broadest sense that many of the electrons used by an amp can somehow become signal…sort of…One of the most telling aspects of the premium fuse charade promoted by, as an example, the athletic SR fuse salesmen in the main SR thread, is an utter lack of understanding of or desire for any sort of reasonable technical explanation of how or why these "special" (and relatively expensive) fuses work their magic. I asked once, and was told to call SR as why should these SR Super Fans do the "heavy lifting" for me?…they simply have no idea beyond referring to the Quantum Tunneling or high voltage exposure or other nonsense used in SR promotion baloney. I smell fraud all over this stuff, and any other inexplicable techno tweak like tiny aluminum "transducers" (some know what "transducer’ actually means), and have tested the efficacy of Special fuses and found them to be a silly waste of money. The astonishing imagined benefits of pricey fuses is simply one of those head scratchers to people who are in the amp design business, and any of them I’ve asked about this stuff simply say something like hey, fooling people into thinking what they paid through the nose for is worth it if enough others claim it to be so is all some people need.
Wolf Man wrote,

"Fuses are not in any signal path except in the broadest sense that many of the electrons used by an amp can somehow become signal..."

not true. Fuses can be in the signal path and often are. Electrons are not signal anywhere at any time.

Woofman:

"One of the most telling aspects of the premium fuse charade promoted by, as an example, the athletic SR fuse salesmen in the main SR thread, is an utter lack of understanding of or desire for any sort of reasonable technical explanation of how or why these "special" (and relatively expensive) fuses work their magic."

not true. There are many reasons why aftermarket fuses work their magic.

Wolfman:

"I asked once, and was told to call SR as why should these SR Super Fans do the "heavy lifting" for me?…they simply have no idea beyond referring to the Quantum Tunneling or high voltage exposure or other nonsense used in SR promotion baloney. I smell fraud all over this stuff, and any other inexplicable techno tweak like tiny aluminum "transducers" (some know what "transducer’ actually means), and have tested the efficacy of Special fuses and found them to be a silly waste of money."

Off the top of my head I'd say your system is not what you claim it to be or your hearing isn't what you're claiming it takes me. You know, given that thousands of audiophiles have good luck with aftermarket fuses.

Woofman:

"The astonishing imagined benefits of pricey fuses is simply one of those head scratchers to people who are in the amp design business, and any of them I’ve asked about this stuff simply say something like hey, fooling people into thinking what they paid through the nose for is worth it if enough others claim it to be so is all some people need.

Not true. Not all aftermarket fuses are expensive. The word expensive itself is open to interpretation.

geoffkait you are just a voodoo’ist, as is most of the stuff on your website.

http://www.machinadynamica.com/

Real techs above are trying to tell you something, in a nice way, just incase you have something wrong upstairs.

Cheers George
Post removed 
@indranilsen - Let us know the results.  It's good that you're trying one fuse.  Every audiophile fuse has their own sonic character.  The Hi-Fi Tuning fuses use silver and gold in their fuse elements and end-caps (in different variations/combinations).  This introduces the character of both silver (forces waveforms to be faster) and gold (gives somewhat of a warmth - can be interpreted as warm glare).  If you end up liking this character, then feel free to buy more Hi-Fi Tuning and add them into your amp.  If you don't like this character, then you've only bought one fuse.

georgelofi
1,822 posts
11-16-2016 5:21pm

geoffkait you are just a voodoo’ist, as is most of the stuff on your website.

http://www.machinadynamica.com/

Real techs above are trying to tell you something, in a nice way, just incase you have something wrong upstairs.

Cheers George

Ouch! Very ouch!

The idea that fuses and power supply components are not part of the signal chain is not entirely correct. Anything coming in from the A/C, power cables, fuses, rectifiers, regulators, or power supplies can all become part of the output signal.

An operational amplifier circuit (whether discrete or monolithic op amp) will only pass through the actual signal if the signal is coming in on the inverting input of the op amp AND the negative feedback gain is unity gain (0 gain) or less than unity gain (i.e. it’s forcing op amp to de-amplify the signal). In this case, the waveform signal will actually route itself around the op amp using the negative feedback line as a pathway.  That being said, even with unity gain, the type of op amp or power supply elements will still influence the character or sonic signature of the audio.

If the negative feedback circuit is set to create a "gain" (or amplify), it increases the voltage of the waveform by using voltage from the positive/negative rails from the power supply (i.e. +/-15V). This additional voltage is sent through the output pin of the op amp. It this case, the fuse, power cord, A/C elements will contribute to the character of the waveform (in the sense of affecting how the op amp slews in relating to the input waveform, how far/fast it slews, character of the DC noise, etc.).

In a power amp circuit, the output transistors have to create massive gain (turning a 1V input into something like 15-100 watts or more). It has to use the A/C power coming in to create this voltage, so your signal is actually something like 98% A/C voltage.

https://www.youtube.com/watch?v=7FYHt5XviKc

I’ve posted that link before, but it’s an excellent lecture on how op amps actually work.

Actually, I perjured myself. On a unity or less gain, the input waveforms are, indeed, going around the op amp. However, they are getting sucked back into the output pin. The op amp is having to generate twice as much output voltage, since half of that is coming from the negative feedback. So, in all cases, the output of an op amp is always going to be based on positive/negative power supply current (i.e. fuses, regulators, A/C, etc.).  Think of an op amp like faucet where you have to push down on a button to produce water output.  The harder you push on the button, the faster water comes out.  All op amps or transistors are variations of this idea, hence the old tubes being used to be called "valves".
An example of a fuse in the signal path I think everyone can understand is a fuse in a speaker. Case closed.
Auxinput, thanks for the explanation. After reading all the posts on how a fuse can or cannot interact and affect the signal path, your's has what seems to be the least amount of spin. 

It could very well be that due to my bias it sunk in but I've been temporarily swayed by arguments that go against what I actually hear only to come back to believing what I actually hear. :-)

All the best,
Nonoise

@auxinput- I ended up ordering Hifi Tuning Silverstar (the main fuse) and Classic Gold (rail fuses) which are on their way. I would first try the main fuse to see if this improves the sound at all. If yes then I would replace the rail fuses. I would post all result hopefully by the end of next week.
I wanted to find if folks here have an idea of how much changing the rail fuse would contribute to the overall improvement in sound under the assumption that changing fuse improves sound quality. Any feedback would be greatly appreciated.
Also did anybody compare performance across Hifi Tuning (Classic Gold, Silverstar, Supreme) and Synergistic Research Quantum Black fuses?

Thanks.
Indranil
Still, no proponents of the Magic Fuses and their ability to make cellos sound better have EVER offered up any reasonable explanation for this…good, simple Littlefuses that cost maybe 6 bucks do the job just fine (failing if need be…that’s the job), and the entire premium fuse market is simply the "lets get a tiny item cheaply made in China for big bucks…small and easy to ship, make up a technology and provide the myths, and sell ’em to the unwary." Excellent business plan…and it works! If you think you and your system are sensitive enough to allow you to hear what premium magic fuses supposedly do, you may actually need these things to validate yourself. Otherwise, do what actual music and sound professionals and amp designers do…ignore the nonsense of silly and fraudulently marketed psuedo tweaks.
wolf_garcia
2,673 posts
11-19-2016 1:46pm
Still, no proponents of the Magic Fuses and their ability to make cellos sound better have EVER offered up any reasonable explanation for this..

That’s simply not true. Repeating that line a hundred times actually doesn’t make it any less false. There are none SO blind as those that will not SEE.

Geoff, note that he said "reasonable explanations."

First, as I have explained in detail in various fuse-related threads here, measured differences that have been reported among various fuses are too small to account for the sonic benefits that have been reported.

Second, as I see it the other kinds of explanations that have been proffered by you and others, such as reduced susceptibility to the effects of vibration, reduced susceptibility to RFI/EMI, exposure to what has been misleadingly referred to as "quantum tunneling," etc., are descriptions, not explanations. They describe some of the physical characteristics of the fuse, or how it has been manufactured.

But in the case of a mains fuse, for example, they do not explain how differences in those characteristics relative to say a Littelfuse or a Cooper Bussman fuse would affect the AC in a manner that would improve the sonics of a component, much less the sonics of a wide variety of components that are completely different in design and perform completely different functions. They also do not explain why those differences would not be totally swamped by the corresponding effects of everything else that is in the path, including circuit wiring and wiring in the power transformer, which involve far greater lengths. They also do not explain why in cases where the fuse upgrade does in fact make a difference why that difference is always for the better, regardless of the design of the component, the function of the component, the system it is used in, the AC voltage that is being provided, and regardless of whether the application involves AC or DC currents.

And they certainly don’t begin to address the effects of the fuse in a manner that would provide any kind of quantitative perspective. To clarify what I mean by “quantitative perspective,” in an automobile-related forum no one would assert that the weight of a paper map placed in the glove compartment would dramatically affect the acceleration or the gas mileage of a car, due to the obvious insignificance of its weight, relative to the weight of the car. We all have a quantitative understanding of that. But in audio quantitative matters and matters of degree are less obvious. So as I said in a post in the SR fuse thread:

… audio is somewhat unique in that there are countless technical variables that can be cited for which it is not readily possible to define a quantitative threshold separating what may potentially be audible in some systems from what is unquestionably insignificant. In the absence of that kind of quantitative perspective there is essentially no limit to what a perceived or claimed sonic effect can be attributed to. Or misattributed to.

Consistent with your comment just above, repeating a hundred times that explanations have been offered does not make it so. At least when it comes to "reasonable explanations."

Regards,

-- Al


There are none SO blind as those that will not SEE.

There none so blinded with their own voodoo, that "they can’t see the forest through the trees".

http://www.machinadynamica.com/

Cheers George

relating to this quote:

"Otherwise, do what actual music and sound professionals and amp designers do…ignore the nonsense of silly and fraudulently marketed psuedo tweaks."

I would like to say that amp designers have a completely different set of requirements to work against. They are working against limitations on cost and manufacturing processes. They need to weigh the availability of individual components when the equipment is actually manufactured or assembled. The idea that a Hi-Fi Tuning fuse can actually improve the sound is valid, but when it comes time to have these amps/equipment built on time and on demand so that they can ship to their distributors/retailers, the available of individual components becomes critical. What happens when a set of fuses are not available for weeks? A company like Bryston/Classe is not going to be able to wait to ship 20-50 units.  Also, cost of every single component adds up and the company's goal is always to use the cheapest components that allow them to meet a certain threshold (difference between a $4 Littlefuse and a $60 Hi-Fi Tuning becomes significant).

However, we also have companies like Audio Note or Audio Research who do focus on actual individual components (even down to what kind of carbon resistors are used or the type of solder). However, their manufacturing output is a lot less and item cost is a lot higher.

Music and sound professionals have an entirely different set of responsibilities and don’t have time to be critical about every single piece of equipment. I’m sure recording studios have something like 2-5 million dollars of equipment (tons of devices - racks and racks of equipment) and need all their time to focus on recording/mixing/effects/etc. They need equipment that is good enough to meet the bottom line, but they are not going to spend another 1-2 million and hours of time when "off the shelf" equipment is going to be decent enough to produce their product. In their industry, time is money. Unless your Cookie Morenco, who has tremendous focus on how individual components and wiring affect the sound. However, that is a very small niche market.



Al, are you speaking with the lawyer side of your brain or your EE side? Setting aside the Quantum Tunneling issue for the moment, since that’s kind of a red herring for this discussion because Synergistic Research use Quantum Twerking on many of its products - it’s not unique to its fuses. No need to get all worked up over the name of their process in any case. 

So, lets summarize what we know about aftermarket fuses and what it is about them that is responsible for better SQ compared to a fuse from Joe Blow. Get it, Joe Blow?

1. The purity of the wire inside the fuse is superior, e.g., high purity copper or high purity silver.

2. The end caps are better conductors than Joe Blow’s, either pure copper, pure silver or gold plated copper.

3. Fuses incorporate vibration control, which can be substituting a ceramic body for glass, use of fluid inside the fuse body as damper, and or beeswax a la Audio Magic.

4. Some Aftermarket fuses address RFI/EMI using absorption materials either inside the fuse as with Audio Magic or outside the fuse body as with Synergistic Research (graphene).

5. Wire directionality plays a role in the SQ, too. As it would even with Joe Blow’s fuse, but it would be easier to hear the difference in direction with aftermarket fuses since they are are superior to begin with, you know in terms of conductivity, noise and distortion.









georgelobrow
1,827 posts
11-19-2016 2:33pm
Geoffkait:There are none SO blind as those that will not SEE.

george pondered this, thought for a moment, then pulled the trigger,

"There none so blinded with their own voodoo, that "they can’t see the forest through the trees"."

http://www.machinadynamica.com/

Cheers George

Whoa! Hey! George, if you keep this up I'm going to have to consider promoting you to associate shill.


almarg
Geoff, note that he said "reasonable explanations."

Yes, I know. Please note that the explanations I listed are quite reasonable, at least to a reasonable person. In fact, I don’t think it would be going TOO FAR to say they are SO reasonable that it’s a confounding mystery why someone didn’t come up with aftermarket fuses prior to 20 YEARS AGO.

Geoff Kait
No not shilling, just trying to keep things honest. 
You have yet to come up with any real explanations of why you firmly believe that mains fuses the magic cure and are immediately detected as being directional, and so can transform the sound of a system as you say. 

Cheers George 
These discussions of the perceived sound qualities of fuses and cables, etc. never cease to amaze and amuse me - passions are stirred and frustrations are aired, never with definitive resolution.  

And... skeptices rely on science and engineering principles, while believers "hear what they hear."   

I tried the Audio Horizons Platinum Reference fuse in my ARC Ref 3 Preamp and was able to discern, perhaps, a subtle difference... not really certain... it was so subtle.  

In the words of one now very much infamous "at this point what difference does it make" - "Never the twain shall meet." 
 
Those who hear an improvement will never be persuaded they really don't, and those who do not hear a significant improvement will never be persuaded they really do.  C'est la vie... 

Post removed 

georgelofi wrote,

"No not shilling, just trying to keep things honest."

Good. Then you won’t mind answering a few questions.

1. do you think directionality of fuses is audible when used in speakers?

2. do you think there are audible differences among various mains cables themselves? How about among mains cable connectors?

3. do you think there are audible differences among various capacitors in the mains circuit?

4. are you aware that HiFi Tuning’s data sheets show differences in directionality in both measurements and audibility of fuses in AC circuits (as well as in DC circuits)? In other words, directionality of fuses in DC circuits is not really as controversial as uber skeptics like to believe or pretend to believe, whatever. Wake up and smell the coffee.

Then George wrote,

"You have yet to come up with any real explanations of why you firmly believe that mains fuses the magic cure and are immediately detected as being directional, and so can transform the sound of a system as you say."

to be honest I did not say any such thing. Please don’t put words in my mouth. Furthermore, there are many reasons why aftermarket fuses are superior to stock fuses (in sound quality), not only directionality. as I just got through explaining. But directionality is one of them.







 
bassdude wrote,

"These discussions of the perceived sound qualities of fuses and cables, etc. never cease to amaze and amuse me - passions are stirred and frustrations are aired, never with definitive resolution.

And... skeptices rely on science and engineering principles, while believers "hear what they hear.""

Actually it's that aftermarket fuse manufacturers rely on science and engineering principles while skeptics rely on gut reactions or they ignore science and engineering principles.

then bassdude wrote,

"I tried the Audio Horizons Platinum Reference fuse in my ARC Ref 3 Preamp and was able to discern, perhaps, a subtle difference... not really certain... it was so subtle."

Did you try the fuse both ways? Besides there are many perfectly good reasons why someone might not hear certain tweaks. One certainly cannot say based on your experience that aftermarket fuses are very subtle. Most people have entirely different results.




Since some say you need 170 hours break-in on your Special fuse (SR fuses anyway), and if you buy into the nonsense of "fuse directionality," you're tasked with trying to remember how your system sounded before the fuse was replaced. You spent the bucks…you have GREAT ears…you really want the fuse to mysteriously impart some magic…it won't of course, but you might think it does and that may be all you need. I had the opportunity to get ahold of some SR fuses (loaned), tried them in everything I use, and hey…they did ZERO to make anything interesting happen, except one blew as apparently the ratings are as vague as the technology, such as it is. Note geoffkait is an athletic supporter of SR stuff, claims to not actually USE fuses in his gear, and has marketed utterly laughable and useless tweaks (he literally sold a bag of "special" rocks to place near the wires…or someplace…) through his little company so he knows how to sling the silliness.
Post removed 
Post removed 
Indranil

"auxinput- I ended up ordering Hifi Tuning Silverstar (the main fuse) and Classic Gold (rail fuses) which are on their way. I would first try the main fuse to see if this improves the sound at all. If yes then I would replace the rail fuses. I would post all result hopefully by the end of next week.
I wanted to find if folks here have an idea of how much changing the rail fuse would contribute to the overall improvement in sound under the assumption that changing fuse improves sound quality. Any feedback would be greatly appreciated.
Also did anybody compare performance across Hifi Tuning (Classic Gold, Silverstar, Supreme) and Synergistic Research Quantum Black fuses?

Thanks.
Indranil"

I am a big believer in the HiFi Tuning silver fuses. I have about a dozen components in my system and have a similar situation as you do with my Adcom amps. I too have purchased silver fuses for my main amp fuses and, I also first bought and tried 4 gold fuses for my Rails.
My first degree was in music. While my principal instrament was the string bass and electric bass, the main focus of my study was leaning toward music arranging. I love hearing all the detsils in music. The breathiness and occational sharpness of reeds, the initial draw of a bow, not to mention all the vaious percussion instraments.
Now your mileage may vary, but clearly hearing these details is why I like the silvers so much. The silvers bring out the details that I love without sacrificing too much warmth. Seems like regardless of whether it's tubes or fuses, it's always a balancing act between sharpness/detail and/or warmth/analog. I've tried a number of different fuses, AMR, HiFi Tuning, SR, etc. I keep coming back to the silvers.
There is a BIG difference between the silvers and the golds. While the silvers are very detailed with some warmth, the golds are very warm, but you sacrifice some of the detail.
My own experience with fuses is once you have about 30 hours on them, you're going to have a pretty darn good idea of what they will sound like when they are fully burned in. They won't be doing an about-face on you.
So put the silver main fuse in your amp (on my Adcoms this made a very noticeable improvement), put some hours on the fuse and get used to what it sounds like. After that, have fun inserting the golds, doing one at a time to gauge directionality of each rail fuse.
Just a side note: Most of my components were impressively improved by upgrading fuses but a couple, like my two tube preamps, gained no benefit whatsoever - likewise in many of my components the fuse was directional, but in some areas music sounded the same in either direction. In the case of my rail fuses I didn't hear a difference based on fuse directionality.
Now, here's a little advice from tube rolling experience. Hopefully, you will like the way your amp sounds after the five new fuses but if you don't, there are some ways to ultimately get to where your ears Will be liking what they hear.  If you think the silver fuse is too bright after 30-40 hours, note how it sounds and then put the gold fuses in. The gold fuses will temper the detail/brightness of the silver and you might have good balance of detail and warmth. For me, the silver was fantastic sounding but when I added the four gold fuses into my rails, my amps sounded overly warm and I lost some of my precious detail.
Jim McShane, of audio tube fame, once told me you need to match tube types when they are a left channel/right channel pairing. So, the tubes in V1-V2 need to match, and the tubes in V3-V4 need to match, and V5-V6 need to match; but the tubes in V1-V2 do not need to match the tubes in V3-V4, etc.
So, when I put the 4 gold fuses in my Adcoms & the sound turned way too warm & analogy for my taste, I pulled one gold out of the left side and the right side rails and re-inserted one original fuse in each side giving me an original and a gold for each side. As if by magic, I now had a sound that was just a little bit warmer than before the golds were first tried and I still had my detail and slam.
I just recently bought silvers to try in the rails. I'm now using one silver and one gold in the left and right rail channels in two of my Adcoms.  unfortunately, I only have about 10 hours on them so I can't make a final decision. If you want I'll keep you posted.
I blew my hifi-tuning gold rail fuses in my Revision A+ of my McCormack DNA-1. MY bad.  After calling Steve McCormack he discussed his preference for the silver star over the classic gold and supreme fuses.  He was disappointed that Hifi-ftuning stopped producing the silver star in favor of the supreme fuses.  He tried the supremes on two separate occasions and just did not get the openness and clarity of the silver stars.

After speaking with Steve, I googled silver star fuses and fortunately, Parts Connexion had them in stock at 60% off!!  Instant order.  In the interim, I procured Bussman ceramic body "microwave" fuses so I could listen till the silver stars arrived.  The Bussman weren't bad in the sense that I had music but the subtleties were MIA.  The sound was "matter of fact".

The fully run-in Silver stars have really opened up the soundspace.  There is "space" between and around instruments allowing each contributor to shine on each cut.  Great stuff.  Steve knows his stuff.

How does the fuse add "space" around instruments? Does it make the electrons go faster? Slower? Adds molecular grease of some sort? Electron happiness? Electron purposefulness? Do the caps and diodes and transformers simple feel better working with the juice once it's been through a half inch of "special" wire? Maybe I should call Steve…he must know.
@toolbox149
I have replaced both the main and the 4 rail stock fuses of my Parasound A21 amplifier with Hifi tuning fuses. I replaced these fuses in sequence. First replaced only the main fuse by Hifi Tuning Silverstar fuse and it immediately improved the sound in all areas. What I liked the most is the blacker background and the improved clarity. Not sure how it dropped the noise floor but it did.
Then I replaced all 4 rail fuses with Hifi Tuning Gold fuses (couldn't get the Silverstar in 8A rating) with the arrow pointing to the flow of the current i.e pointing from the transformer to the capacitor. The result wasn't so impressive. While it further increased the clarity but the instruments started sounding very hazy and smeared. The overall sound was also veiled. It has been 20 odd hours since I replaced the internal fuses and they might still be going through the break-in interval. I tried flipping the fuses such that they point to the transformer to see if that resolves the haziness issue but it didn't.
Did you have similar experience when you replaced the rail fuses inside your amplifier? Did you find any break-in period with these fuses? Any feedback/help in this regard would be greatly appreciated.Thanks.
Like most anything that impacts the electrical circuit of a piece of kit, break-in is necessary. Obviously this requires patience, a virtue few of us in this hobby possess in abundance. I don’t have an electrical engineering degree that might help inform me as to why things in this quizzical hobby happen as they do but they do occur. There is plenty of anecdotal evidence of such all over this site. Perhaps the mystery is part of the appeal.

As far as Steve McCormack goes, I know what my stock amp sounded like and what it sounds like post SmC Audio mods. Nuff for me!



It took about 4 days for my HiFi Silverstar fuses to break in. I kept the amp on 24/7 and would turn up the volume now and then to get a handle on the sound. I still don't know or understand how anyone can hear an immediate improvement, but that's been my experience. By the way, I replaced all the fuses at the same time, if that helps to clarify anything.

All the best,
Nonoise

Indranil

Your experience is an exact replication of my results. The silver in the main was excellent but when I added the four golds in the rails, the overall sound was way too warm with a loss of upper mid-range detail for my tastes.  It was warm to the point of getting a little muddy.

I would recommend burning them in for at least 30 hours before you start making any decisions. Like I said above, whether your burning in tubes or fuses, after about 30 hours of burn in, you'll have a pretty darn good idea what they will ultimately sound like. 

If after 30 hours of burn in, you still don't like the sound, try replacing two of the gold fuses with your original fuses. So, each rail side L & R will have a gold fuse and an original fuse.  That sounded better to me.   Now I have a silver and a gold on each side of my rails, which is a very nice balance.  I see where you can't get silvers anymore, so hopefully the gold & original combo will work well for you.

If you somehow can get a couple of silvers, if possible I would only buy two and do a silver and a gold combo in each side of your rails.  Four silvers in the rails plus a silver in the main fuse might become too bright rendering details like female vocals and brass instruments a little harsh.  Too much of a good thing.

Do you have any tube equipment in your set-up?

Just remember it's not whether you have all of your fuses upgraded or half of your fuses upgraded.  If you like the resulting sound, you're the big winner!  So then just sit back and enjoy the music.

Toolbox