Pass Labs and Fuses


I continue to enjoy my Pass Labs Int-60 amplifier with my horn based system. My listening area has been intensively treated for acoustic - speaker interaction and it is always a joy for me to listen to a Dialed In system.

For my latest listening experiment I decided to evaluate the sonic differences using three fuses in the Pass amplifier. A brand new Bussman fuse, a Synergistic Research Blue fuse and a Synergistic Research Orange fuse. I keep this amp on 24/7 as suggested by the manufacturer. The Blue fuse has over a 1000 hours on it and the Orange had a 160 hours (continuous playing time) on it before any listening evaluations. The Bussman was listened to for the first time immediately out of the box.

The Bussman fuse did a fine job. But going from the Blue fuse which I had been using to the Bussman, there was a definite change. With the Bussman the sound was now more two dimensional. Instruments were not as full bodied. The depth of the soundstage was compressed front to back. I was more aware that I was listening to a recording versus being in the room with the musicians. The music was less emotionally involving. I did for completeness sake reverse the direction of the new Bussman fuse several times. It did consistently sound better installed in one direction, not huge but it is there.

Comparing the Synergistic Blue Fuse to Orange Fuse was similar to my past tube rolling experiences with my 300B tubed amplifier (but cheaper to carry out). Different tubes change the sound and these different fuses change the sound. Both of these fuses brought out more of the music that the Pass Labs amp was playing when compared to the Bussman fuse. Before any serious listening was undertaken, the fuses were evaluated for best sounding direction - and they both were directional.

The Orange fuse really is exceptional in it’s ability to let me enjoy the music and who is playing what. The detail of Willie Nelson’s nylon strings on his guitar had much better dynamics and richer texture than I have previously heard using the Blue fuse. His Stardust album continues to impress me.

When listening to music that has more musicians playing, such as on Sierra Una Noche, I can more easily distinguish each instrument and it’s contribution to the musical whole. Also in this live recording that uses only two mics, I get a better feel of each musician’s distance from the microphones and that they move toward and away from the microphones while playing. These factors allow me to forget I am listening to a recording of an event. With the Orange fuse, I feel I am at the event as it is playing.

This fuse experiment was fun to do and educational.
Feel free to call.

David Pritchard
575-644-1462

128x128davidpritchard
I'm still waiting for a response to my "wire direction chaos" post...it's almost as if nobody cares...*sniff*...and to address Kaitty's comment...yes, georghifi and I are the same person. Anybody got a problem with that?
Gee, are there really high end amplifiers with crappy power supplies? Are there mid fi amplifiers with crappy power supplies? 
Imagine a world with no poverty so everyone can own a pet, no snide remarks about participants in a thread, and where audio is dirt cheap.

Now, back to the real world.

All the best,
Nonoise
I certainly welcome off line discussion about audio observations I have made and posted. My areas of interest are especially in fuses, wall outlet sonic changes, and Pass Labs amplifiers.

David Pritchard
575-644-1462
As the original poster I do think it is important to remember I few points that I wrote about the topic.

 This was an experiment to see if there were sonic differences using three different fuses - each installed and removed multiple times and in both directions. A well know respected amplifier brand ( Pass Labs) was used that has a reputation for having a excellent power supply. This was done on purpose to discount the experiment being devalued due to a "poor power supply being a factor in the observed results".

No other changes were made to the system for the past five months. So there are no other known major  variables going on. The humidity (measured), and room temperature (measured) were kept constant. The time of day for listening was kept constant - 8:00 to 10;00 at night. The Pass Labs amplifier was also chosen as it can and was left on 24/7 (except when it was turned off to change fuses). Since this amplifier has a screw in fuse holder, fuses can be easily and safely changed.

This was a serious attempt on my part to do a meaningful evaluation of three fuses and their sonic effect on a well respected amplifier. It is the first of several experiments I have planned pertaining to this subject.

It was earlier pointed out earlier  that testing - evaluating fuses is " by necessity a time consuming affair". That is absolutely correct and one reason I chose to  report this experiment. It is a lot of work. It takes a lot of time.

My observations indicating a change in sound have not and will not ever have a percentage number assigned to them. 

I have found it very helpful to watch all the You Tube videos posted featuring interviews with Nelson Pass and his co-designer Wayne Colburn of Pass Labs Inc. I will not attempt to condense what their approach to perfecting a design is but it involves both measurements and a lot of listening. Nelson also discusses the  subjective and objective  and their place in developing audio products.

Wayne Colburn of Pass Labs has been most gracious in his time and expertise to directly answer questions I had about Pass Labs's use of fuses and circuit breakers.  

David Pritchard
"That this site is the only place where so much time and effort is put into discussing how fuses sound (mostly by the same handful of people) says a lot...."

I wonder how many are associated/affiliated with SR?   
That this site is the only place where so much time and effort is put into discussing how fuses sound (mostly by the same handful of people) says a lot. 
It’s a wonder the rest of the world is able to function in lieu of expensive fuses. 
There are places in the world where people do not even consider having a pet because of poverty. 
There is also this place where people are encouraged to drop $100s of dollars on fuses based on a handful of opinions and total hearsay. 
Just saying....
It has been shown that some members here are notoriously bereft of anything new to contribute to a debate other than the same old, squawking points.

All the best,
Nonoise
It has been shown that witnesses to staged crime scenes are notoriously unreliable. And the validity of subjective reviews of aural phenomena are equally suspect!
Quick question, how do you know if it’s the Orange fuse breaking in or the eMats breaking in? Also, are they still breaking in? Does the system have to be ON for break-in to occur? How do you distinguish been what you hear with the Orange fuse and what you hear with the eMats? See 👀 where I’m going with this?
And in spite of all of the nay-saying, the new SR Orange fuses are still sounding exceptional in my system.

Highly recommended.

Frank
And it's the same old magic circle hater club every time, that come up with monotonous regularity.
georgieporgie
Even the non technical and gullible aren’t that stupid to be coned by this rubbish.

>>>>>Let’s see if we can figure this out. Did Georgie mean cloned? How about coined? Is that a contraction of corn pone? Is he referring to cone heads?🧑🏻‍🦲 👨🏻‍🦲
Let me guess.....is the one behind it upside down compared to most?

I guess that’s me, would be nice if I had that much influence from down here, I’d use it much more, with this malignant, snake oil, voodoo, rubbish.

And it's the same old magic circle fuser club every time, that come up with monotonous regularity each different color of the >$150 fuses sounds 100% better than the last.

Unbelievable they say, but make sure it’s around the right way, and had at least 100hrs burn in time, before you judge it!!

Even the non technical and gullible aren’t that stupid to be coned by this rubbish
Coriolis Force: "fictitious force that acts on objects that are in motion within a frame of reference that rotates with respect to an inertial frame." 😀
@oregonpapa Frank, I see your Orange Fuse Thread up... and now down, again. Do you know why?
Let me guess.....is the one behind it upside down compared to most?
  • @oregonpapa   Frank, I see your Orange Fuse Thread up... and now down, again. Do you know why?

Nope. Don't know and don't care. I have way too much music left to listen to instead of worrying about a couple of nay-sayers getting their panties twisted into knots.

The SR Orange fuses are another advancement in after-market fuses. I loved the effect that the SR Blue fuses had on the system, but the Orange fuses are even better.

Frank
@oregonpapa   Frank, I see your Orange Fuse Thread up... and now down, again. Do you know why?
Wolf
Useless in what way. If you do not have measurements and triple bypass blind testing on everything with a reputable company I can’t believe what you are saying is true. You know the bias factor also comes into play.. The first thing I would want to know is how big a pile is that you mentioned. You see something else could of been in that pile that you used for a fuse. So come back with extensive documentation and I just might start to listen.
I am being sarcastic. I do hope you are enjoying your system even without those terrific fuses.
A couple of years ago I tested a pile of SR fuses just to give my ranting some credibility (!) and found they were useless and somewhat dangerous as their ratings were suspect. You can look it up...also, note that nobody responded to my previous post regarding internal wire direction chaos which, to my thinking anyway, negates fuse influence as described by the Athletic Supporters of fancy fuses. 
At some risk of being flamed 🔥 can I point out that because of the rather long burn-in times required for fuses generally and the vagaries of fuse directionality, as well as possible fuse holder issues interfering, that any comparison or evaluation of fuses is by necessity a time-consuming affair fraught with all sorts of possible interfering conditions that might impose themselves on such a test and make conclusions questionable. Also, I think that it would be of value to select an amplifier with a reputation for a crappy power supply on which to experiment with fuses.
And we thank you for the thread and the information contained within David.
Confirms my findings but on a much more organized scale.
As the original poster I chose to perform an experiment that I considered fun and thought it was worth while to report the results.

 I chose the Pass Labs amplifier as their products do have the reputation of having a good power supply and being well built . I did not want to waste my time evaluating fuses in a product that has a questionable build quality. On all the Pass Labs amps that have fuses, the fuse is easily removed using a  screw in fuse holder which is next to the on -off power supply switch. I also considered this an important reason to chose a Pass Labs amp. I do consider safety to be important.

The experiment was not designed to be sales pitch for a new product but to examine if fuses in an amplifier might affect the sound. The test results I obtained revealed that three different fuses had three different effects on the sound, and that in each case simply removing the fuse and changing the direction of the fuse also changed the sound.

 I did not expect to hear a change in sound with the Bussman brand fuse. This alone made the experiment worthwhile to me. So for some audiophiles, simply changing the direction of the fuse may change the sound for the better. Fun to try if you have a fuse installed as the Pass products do.

 Since changes of fuse type and direction were made multiple times  an amplifier who's fuse  was easy and safely removable was a conscious decision that I made.
 
After spending many hours doing this, I thought it would be informative to the audiophile community to publish my results. I hope others will repeat similar experiments and report their results.

David Pritchard

I would like to David for posting his experiences on fuse swapping .

I like many others have experienced sound differences when swapping
fuses .  But before I did I was skeptical how could the power going thru a small wire ment to melt affect the sound ?  
( the same can be said with power outlets and cords )
hearing is believing !
When I experimented I didn't use $100 or $150 fuses ,
I used $2 , $10 and $20 fuses in both my amp and a guitar amp .
The first thing I discovered is that a ceramic fuse sounded better than a glass fuse , so I replaced all fuses in my system with ceramic ones 
for less than $25 .
I didn't like the sound of a gold plated cryro'd fuse or the audiophile directional one so I wasn't tempted to spend $100 or $200 on fuses .
I also discovered the HARD WAY that genaric cereamic fuses 
should be avoided both for reliablity and sound .
Spending a lot on a fuse was hard for me but when a 1/2 price sale 
on a Furutech fuse came along I had to try it .
Was it worth the price ? 
It did sound  better But for my pocketbook not enough to 
justify replacing the other 6 fuses in my amp .

In my opinion and experience fuses can and do affect the sound .
For me its a matter of the cost benifit ratio .





As opposed to a restaurant reviewer who with two plates on the table, tastes one, then denotes the other one to be the best they have ever tasted if they only add a bit more salt to it.
geoffkait ...

  • "Side note: Frank, never one to miss an opportunity to shill, jumps right into the fray."  

Geoff, if I said something really obvious like: "Hey it is raining." Or, "Gee, the sun is out." Would that be considered "shilling" for the weather? Stating the obvious isn't shilling, it is just stating the obvious.
-------------------------------------------------------------------------------------
gcdrum ...

Right, and these are the type of folks who will tell you that food is just a "fuel," and that sex is for procreation, never experiencing truly great food ... or ... 

Frank
Frank
Maybe if they find a new hobby it could be restaurant reviewer (without tasting the food); or book reviewer (without reading the books); or movie reviewer (without seeing the movie).
Perfect new hobbies!
I looks like I’ve picked up a new stalker. Welcome aboard, misogyn!

Side note: Frank, never one to miss an opportunity to shill, jumps right into the fray.
Anyone who can’t hear the improvement in SQ afforded by SR Blue or Orange fuses over stock fuses should find a new hobby.

Those who knock aftermarket fuses without trying them for themselves need to find a new website to whine in where a lack of credibility is more acceptable than it is here.

Frank
There sure is definite signs of toxicity on display today.
First time I have to agree with George!
Not likely to get better anytime soon.

Good to know which camp you fell into Mijo, I figured you for a little more receptive given your normal intelligent postings , even if they can be abrasive.
Oh well......
😇😇😇
Geoffkait with two f's. Do you ever say or do anything useful? This is a rhetorical question that can not be reasonable answered in English. Any one here speak Mandarin? Geoffkait , you need to audition for a Quentin Tarantino movie. 

As always, you are welcome to try Synergistic Research Fuses in your system for 30-days risk-free and return them to your SR dealer for a full refund if you are not completely satisfied.

Sold with a no-risk 30-day money back guarantee

Doesn't SR return policy take the risk out of trying them?  If you can hear a difference, keep them, if not, return them?  What's the problem?
George,

If you object to a post, just report the post. I don’t understand this need to censor people for their views, whether they are wrong or not. People are adults here. I think they all understand electricity can be dangerous.
georgehifi6,325 posts12-04-2019 3:40amMods!!
This thread, needs to be shut down, it’s turned toxic just like all other fuse threads have. None, not one, especially SR fuse manufacturers have come onto these forums to stand up to what BS they (and the magic circle club) say these fuses can do

And it’s very dangerous for non technical to be playing around with ac mains fuses, and trying them in different directions frantically, forgetting just once to unplug mains before touching the fuse.

Cheers George

No, it is like saying that someone who saw something in a scene a year ago, then saw the same scene today and claimed they noticed some minor change, has less credibility than someone who is comparing two pictures. Sort of like how people with "photographic" memory will regularly "remember" something in the scene they just saw that was not there.

That's like saying an actual witness to an event has no more credibility than one who hasn't. It's a word game now, and has been for a great while.



Boy this is fun. George and Wolf hang on. These guys are talking a bunch of innocents into wasting their money on silly fuses and other misc JUNK. We are on the right side of history. Thinking that a fuse is going to make a difference is s___y and s----d to be polite. But these are the depths to which these people will dive to make cheap incredible, fabulous, unquestionable, dramatic and huge improvements in sound quality when all they need to do is get a new set of loudspeakers and one of Ralph's amps to drive them:)
Somebody help me out. Are Georgie Boy and Wolfie the same person? Or do they just drink from the same water trough? Come on guys, lead, follow or get out of the way. 
C'mon now George, you can do better than that!

Maybe keep off the Dingo meat........
And it’s very dangerous for non technical to be playing around with ac mains fuses, and trying them in different directions frantically, forgetting just once to unplug mains before touching the fuse.
And this is getting so old, trite and worn out it needs addressing before it is regurgitated yet again by George.

Have you ever changed a fuse in an amp George?
You know, where you pull out the fuse drawer at the back WHICH DISCONNECTS THE FUSE FROM THE AC POWER NO MATTER WHAT?
Or screw the black cap container head off type?

Granted there are some amp and equipment around that entails opening up the casework to get at the fuse but do you TRULY think anybody who is going to do that will really have left it plugged in and switched on???

Not everybody is as dense as some people George......

Let me put it another way..

If I was going to choose between reading and believing posts from David Pritchard or Georgehifi.......
Well do not hold your breath George........
The ONLY reason any of these fuse threads turn "toxic" is because of people like YOU GEORGE!
Now why don't you be a good boy and run along , this is the big boys play pen.
😁😁😁
Mods!!
This thread, needs to be shut down, it's turned toxic just like all other fuse threads have. None, not one, especially SR fuse manufacturers have come onto these forums to stand up to what BS they (and the magic circle club) say these fuses can do
 
And it's very dangerous for non technical to be playing around with ac mains fuses, and trying them in different directions frantically, forgetting just once to unplug mains before touching the fuse. 

Cheers George
In a few of my posts regarding fuse mythology I've asked the question, are all of the wires used in a component sorted for directionality? Wait...I think I know the answer: the answer is no. Moving on...Is the wiring in that jumble of direction chaos possibly self canceling as regards directionality advantage? If a fuse's directionality benefit meets wire (and PC board traces) installed in this random order of direction, how does reversing it (remember, it's generally a tiny little wire relative to the wiring and traces in the component) audibly help things? The likely answer could be "somehow it does" if you spend 150 bucks or so...and remember when reversing the fuse to its supposed audibly "phase correct" position, you should reverse and test all the wire and PC traces (!) in that component as hey, ya never know. Now get busy...
I have enjoyed my experiment to see if three different fuses would affect the sound in my Pass Labs INT-60 amplifier. To my brain they did.

My next experiment will simplify things a a bit more. Today I ordered the Nelson Pass First Watt SIT-3 amplifier. This will be compared to the First Watt F-7 using stock fuses and boutique fuses. So two similar very low part count and simple circuit amplifiers will be used to compare the difference between two different type.output transistors. Then stock and boutique fuses will be tried in both. 

The SIT-3 amplifier arrives this Friday.

The test will be partially blinded in that my Mother will be the listener and she is legally blind. The new amp if she likes it, is her Christmas present.

This will be fun.
David Pritchard MD
The new SR Orange fuses are doing just fine in my system at the moment. They have provided more clarity, better dynamics, and more realism overall.

They put this lady in the room front and center:

https://www.youtube.com/watch?v=ukO46Fibzi4

Highly recommended.

Frank
Uh, nobody said the very small differences in voltage drop explained the differences in the sound. In fact, HiFi Tuning states that fact themselves in the fuse Data Sheets on their web site. Which every yahoo and his brother would know IF they had read the Data Sheets. 
People sure are dumb. - Gomer