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
Hi David,

Thank you for your report about the Synergetic Research Orange Fuses. As an owner of also a INT60 and about to replace the Main Fuse, which direction of the fuse have you choosen? I would love to hear back from you and thanks in advance - best regards from Germany klaus
 us wise old owl types that KNOWS these things are directional.
Yep, a one way brain, can't see the forest for the trees.
@David Pritchard. Can you post which way the fuse sounds better? On the Pass Labs, which end goes in first? Don't know, but would it be possible to post a picture? I just got an orange fuse for my X-150.8 and if somebody can just tell me which way is the right way, that would be awesome.
Thank you.

You really should listen to it, because it really does sound better one way than another, and then you will know. Also then you can come back here and say hey guys you were right, it really does sound better one way than the other! And george will have one more in the mountain of evidence to deny and deride and ignore. But more importantly you will no longer be one of these parrots repeating stuff other parrots squawked about, you won't be a bird brain like George either, you will be one of us wise old owl types that KNOWS these things are directional. 

What Peter can't you tell???? The other fusers, will be up in arms.

THERE IS NO RIGHT WAY. (it an ac mains fuse, mains alternates direction "60 times in a second" you'd have to pull it in and out and reverse it at the same rate to see if it's directional 😵)

Cheers George
@David Pritchard. Can you post which way the fuse sounds better? On the Pass Labs, which end goes in first? Don't know, but would it be possible to post a picture? I just got an orange fuse for my X-150.8 and if somebody can just tell me which way is the right way, that would be awesome.
Thank you.
Harbeth speakers are fairly respected by most and yet the designer alan shaw does not necesssarily recommend speaker stands for them.  He does not discourage it either.  He leaves it up to the buyer to decide if worth the money.

If alan shaw is saying you can put your speaker on a chair and it might be good enuf for you then please dont tell me that speaker stands dont make a difference.

The issue is does it make enuf of a difference to justify the cost.

Well if you buy 10K speakers to me $500 for a stand is not extravagant...plus seems more stable than a chair..

As for fuses, it sounds different and is worth $150 to me but can see someone feeling its too small and cannot be measured the improvement so not bothering to try.

I dont get why people get so upset though ...especially if they have not tried it.

If people are happy with it and it comes with money back guarantee what is harm...

Some people seem insulted here that others willing to experiment even if it makes no sense to them...

I think refusing to experiment where you can get money back makes even less sense..




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Merry Christmas and Happy New year to you and your family too George.

And too all Audiogon members old and new!
Telling it like it is, voodoo snake oil BS that’s become "almost accepted" in hi-end audio by the gullible.
That not even the manufacturers snake oil themselves will come on here and stick up for their own product, with some sort of EE proof to this ****, it’s up there with Scientology as a hoax. Happy New Year to you and yours!!
Merry Christmas George
You too Boxer, admin must have thought where there’s smoke there’s fire, they're not stupid, he was slapped on the wrist a couple of months back for doing the same thing and went quite for a little.
The proof’s in the fire sale of Orange voodoo fuses and his timely post. That was "oh so subtle" NOT!!
"Immediately there was a change in sound. Noted was and increase in dynamics, more precise localization of instruments, and increased depth of soundstage. There was a decrease in clarity in the midrange. A significant change was obvious."
What a load of snake oil voodoo BS.
Cheers George
Speaking of George how about unhinge? Orange. Unhinge. No, but it’s darn close.
And here they are the rest of the (shillers), errr I mean magic circle club.
Immediately there was a change in sound. Noted was and increase in dynamics, more precise localization of instruments, and increased depth of soundstage. There was a decrease in clarity in the midrange. A significant change was obvious.
This is just too obvious for words

Of course it did, as there must be new color coming and they have an over supply of "Orange" and have asked their shills "to push hard"
 
"For two weeks until end of December, we offer an ORANGE Quantum Fuse Special. BUY 2 ORANGE Fuses and GET another one FREE."
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Way back I was very skeptical of power cables.  I have not tried fuses myself.  I suppose the reason of improvement by fuses more or less the same along the line of power cables.  

The first time I've ever heard of "fuses", was when reading an article about YBA designer, a rather eccentric French man who believed fuses have a detrimental affect on the sound.  The best fuses is no fuses at all.  With all the beefy power cables, water hose size speaker cables, it is rather comical that the electrical current has to pass through such tiny wire in the fuses.  

I know a lot of very capable electrical engineers who don't believe in power cables, fuses and so on ... and think of them as crack pot science.  


uberwaltz:

I do hope you audition the Orange fuses in the Ayre EX 8. What a special amplifier. Put the fuses in and do a final evaluation after 14 days. If you like the sonic change - Merry Christmas !  Send them back if you do not think the are worth it. Please report what you hear. I am a big fan of Ayre products as well as Pass Labs products.

The last few days I have been watching "You Tube" videos after telling the search microphone on my TV - " Audiophile fuses".
Multiple interesting videos both pro and against.

    Magneplan Fuse Upgrade
    Audiophile Fuses
    Audio Magic Beeswax Fuse vs. Furutech Blue
    Fuse AMR
    Fitting More Internal Audiophile Fuses
    Upgrading to Audiophile Fuses
    Audiophile and Ceramic Fuses Tests and Thoughts
    Audiophile Snake Oil !
    Synergistic Research Orange Fuse

I hope readers of this thread will take time to watch some of these interesting videos. I continue to be impressed with the improvement the Synergistic Research Orange fuse has on the performance of the Pass Labs HP-1 amplifier.

 The HP-1 which is a   wonderful amp that was specifically designed for both low impedance and high impedance headphones is now performing at an even higher level of sonic enjoyment.

David Pritchard
Great review David.
And if I am not mistaken SR did a similar deal last year whereby you received a free Blue fuse upon purchasing a Blue duplex.
Pretty sure it was just before Xmas as now.
Intrigued as my Ayre EX 8 uses..... Three fuses....
🤔🤔
This is the second of three planned posts evaluating the effect of different fuses on three different Pass Labs amplifiers.

This evaluation is using the Pass Labs HP-1 amp. I enjoy this amp especially for night time listening. My favorite headphones were used, the Focal Utopias and the Sennheiser 800.. The source is a Marantz SACD player.

The amplifier and SACD player were kept on 24/7.

 The fuses evaluated were the stock fuse - wire around a ceramic rod enclosed in a glass case, a Synergistic Research Blue fuse, and a Synergistic Orange fuse. Listening was done at night,  room temperature was a constant 73 degrees, humidity 35-41 percent and all other electrical devices except refrigerator and heating system were off.

Listening was done with four cd's. Male vocals- Willie Nelson - "Stardust" (SACD disc), female vocals- jazz singer Nnenna Freelon- "Live", acoustic instrumentals featuring multiple instruments and complex percussion - "Sera Una Noche" and solo piano- "Mozart -Works From His Golden Age".

The last two Cd's are on the MA record label. MA owner Todd Garfinkle records using only two microphones in buildings that have wonderful ambient spacious sound qualities.


The Orange fuse's effect on the sound clearly gave the biggest improvement. Especially with the MA recordings, the ability to hear micro details during the decay portion of a played note made me forget I was listening to headphones. Many times I felt as though I was a solitary guest who was allowed to sit in during a performance.

 On the Nnena Freelon album ( Concord Records) , the live crowd ambience was not a distraction but added to the enjoyment of listening to the performance.

Willie Nelson's nylon guitar sounded more detailed and richer when the Orange fuse was in the system.

I found the Orange fuse to give a significant improvement to my Pass Labs powered headphone system. I think the cost benefit ratio is most excellent.

Both the Cable Company and VH Audio did announce a buy two and get one free Synergistic Research fuse special. This according to the Cable Company (E-mail which arrived today) is only for the next two weeks. 

David Pritchard
George
Dident Momma ever shout to you down in the basement that if you got nothing nice to say then say nothing?

There is a purchase 2 get 3 Orange Fuse promo on offer for a short time period.


Of course there is, people are starting to wise up to this voodoo snake oil BS and they have an over supply, wonder what the next color will be.  
FYI for those interested: There is a purchase 2 get 3 Orange Fuse promo on offer for a short time period.
The Title of this thread is Pass Labs Amplifiers and fuses, and so I will discuss at least some aspects of the title subject.

Yesterday Mother's new Pass Labs First Watt SIT-3 amplifier arrived from Reno HiFi. Enclosed was an informative manual.

"The amplifier requires about One hour of operation to reach full operating temperature. I personally do not see a reason to run the amplifier all the time, but you can do that if you want to. The power supply capacitors are likely to last 20 years or more, and while they will slowly dry out just sitting there, they will have a longer life if the amplifier is not run continuously. Practically speaking, it makes sense to shut the amplifier off if you are not planning to use it the rest of the day".

"I answer all questions, even if the answer is No.
and sometimes it takes a little while" - Nelson Pass


In the experiment I performed with the Pass Labs INT-60, I heard a distinct difference using three fuses. 

The newly acquired SIT amp is designed having a SET tube amplifier sound without using vacuum tubes or transformers. The goals of this amp are " to get transistors to sound like Triodes(vacuum tubes) and simplicity and minimalism of circuit design". I think this amplifier with a simple design will be a good test vehicle to further evaluate different fuse affects on sound. The amplifier will be left on 24/7 to minimize any "break in effects". This amp uses about 150 watts when on. And yes the Main circuit breaker is turned off when fuse rolling.
 
This amp is entirely designed by Nelson Pass and only 250 were manufactured. There are a few new units still for sale.

Out of the box with one hour warm up and the stock fuse, the sound is wonderful. For audiophiles with efficient speakers and wanting an amp that is sold state but sounds like a SET vacuum tube amp, this is a  compelling option.

I soon will also be posting the results of the interaction of fuses and the Pass Labs Headphone amp. 

I hope all readers will take some time to reflect that today is the date of the attack on Pearl Harbor.
David Pritchard
My apologies George.
I wrongly assumed there would be no mains voltage involved in a passive device.
Thank you for enlightening me.

Common mistake, if you can read a circuit diagram, you’ll see that the signal (green) from input to output of each channel only goes through one fixed passive "light dependent resistor" (LDR), that changes it’s resistive value via a chemical reaction, to the amount of light that is shone on it from a light emitting diode (LED).
The only active part is the LED’s and what powers and adjusts them, the rest where the signal travels, is totally passive https://ibb.co/cCbDC5c

There are no active parts, no volume control, no resistive wiper contacts, no switch contacts in the signal path as active preamps all have.
A CdSe photocell (and other photocells) attentuator may require little power, but definitely not a passive device. It is an active device. It is a semiconductor. Light induces more available charge carriers. 
Wrong again, do your homework, yes it’s passive, yes it’s mains powered or can even be battery powered.
My apologies George.
I wrongly assumed there would be no mains voltage involved in a passive device.
Thank you for enlightening me.
George.

Are you suggesting that Ayre do not sell their equipment cw Myrtle wood blocks?
Just peruse their website and go to the ex8.
Come back and tell me what you see.....

Oh and $6k is bare bones, fully loaded they are $8.5k.
Just for edification.

But alas I am afraid your increasingly irate posts are not on topic so could you please refrain from getting yourself all worked up and let us get back on point.
Thank you
Hence no fuses as no mains ac is used.
Wrong again, do your homework, yes it’s passive, yes it’s mains powered or can even be battery powered.
I rang them to confirm fuse size they were extremely enthusiastic about both aftermarket fuses and wooden blocks underneath the amp.
If the fuse made the kind of differences you guys say they do here, they would be in the  Ayre EX 8  from the factory, being already at $6K. And as for the wood blocks 🤦‍♂️
They were just humoring you, they would have          themselves laughing after that phone call🤣, as they are technicians first and foremost, not snakes oiler's. 
Boxer
What George is trying to explain is that the Lightspeed Attentuator is a passive product.
Hence no fuses as no mains ac is used.

The rest is just a little bit of extra vitriol for good measure.
Sorry george I thought you actually sold audio products.
Sorry, I didn’t say I didn’t, read again, I don’t have fuses in the Lightspeed Attenuator, (and if I did re my last post)

Cheers George
Sorry george I thought you actually sold audio products. 

uber, I agree that Ayre is certainly not close minded. Great company!
George,
Do you know if anyone has tried an SR fuse in one of your products? It would be interesting to hear if it made an improvement to the sound quality.
You obliviously don’t know that there is no mains fuse, the only AC mains fuse is the one inside the fuse box outside the house and the AC service fuse on the poles in the street.
And if there was an AC mains fuse then the answer would still be no, as a fuse is not a diode, it’s a piece of wire.
And to do any voodoo experiments, you would have to do all those other fuses as well, and probably the one/s back at the sub station. That’s why this fuse voodoo is such snake oil.

Cheers George
Thx Boxer.
Sort of wish I had a Pass amp so it might be a little more relevant to this thread of David's.

But I think my Ayre EX 8 is no slouch.

One interesting aspect of Ayre was when I rang them to confirm fuse size they were extremely enthusiastic about both aftermarket fuses and wooden blocks underneath the amp.
Indeed the ex8 is sold cw three Myrtle wood blocks right from Ayre.
That right there says a lot to me about an enlightened audio manufacturer.
Look forward to your opinion on the orange fuse uber. 

George,
Do you know if anyone has tried an SR fuse in one of your products? It would be interesting to hear if it made an improvement to the sound quality. 
I see George.
So now you are recommending that users( fusers?) should change the fuse while live?
That's not really a very good idea you know.

I am afraid I will have to decline to follow your recommendation in this instance but I do thank you.

Na just put your BS hat on, but don’t forget 100hr burn-in, as AC mains is not alternating, "so these fusers think", and then for an even bigger laugh they turn the fuse around and swear it’s better one way than the other.
What a crock of **** , maybe you should change the fuse without disconnecting from the mains for an even better sound/hit https://youtu.be/aC6S_VuRNGk?t=13
Well my SR Orange fuses were waiting for me when I got home from work travels and one is in the amp right now cooking a little.
The other one is for the CD player but I need to open that one up replace, gosh who do I need to call to make sure I do not hurt myself whilst performing this dangerous task?
Ah yes, Ghostbusters!
Uber, I had no idea you liked the old Whack a mole. Good job! Whack him good! 
Your negative cynicism is not helping the thread at all.
Really!! ya think!
They are totally positive to being correct, just negative to fuser snake oil voodooism.
Now George
Your negative cynicism is not helping the thread at all.

I will only report what I hear.

I hope it will be good but you do not know until you try.

Would not be the first tweak that I heard negative results as I did with solid copper core speaker cables that had to be returned as just plain awful in my system.

It will be a fair and subjective review of the effects in my system.
I do not know that yet George so I cannot comment yet.
But thank you for the enthusiasm!
Means a lot!

We all know what sort of answer that will be from one of the "magic fuser club", it’s almost written in stone.
And it will mean nothing!