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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

davidpritchard
tommyu
45 posts
 
Hi all, I almost never post but after many years of reading how some people say fuses don't make a difference or are not "directional" here are the facts they Do measure differently in either direction! also to those who don't believe they impact the sound of a piece of equipment read the measurements again they all measure differently...
I have tried fuses from 5  manufactures over the last 10 years and they all sound different and are directional.
Kind of amusing that people who have never tried fuses bash the concept like their life depends on it I just don't get it, and probably never will...
Please feel free to pass this link on to the other threads for the nonbelievers, the numbers and my ears don't lie.
Enjoy
Http://www.hifi-tuning.com/pdf/wlfr.eng.pdf
nutella
223 posts
 
To some people it is more important to think they are right than to experience and learn something.  Know it alls don’t accept things they may not understand.  
pokey77
1,272 posts
 
@tommyu 

@nutella 

x2

BTW, I’ve never tried fuses, but like all things audio, I expect they can and do have an effect on sound. People shouldn’t have such an aversion to trying it for themselves. I’ll get around to it myself some day.
bdp24's avatar
bdp24
10,493 posts
 

Modjeski actually did find the Tuning Fuse he tested measured differently than the Little Fuse brand he routinely uses. The difference was on the order of 120dB down ;-) . If your system can reveal that, and your ears can hear it, congratulations, you do indeed have a mighty fine system and golden ears.

Yeah, I know not everything that can he heard can be measured. But for a fuse to effect the tonality of a system? C'mon, man, you know that's not possible. A fuse doesn't know about tone, any more than an acoustical instrument knows about electricity.

As for fuse directionality in an AC application, that defies what used to be called common sense. Yeah I know, what about all the people who insist to hear a difference when the fuse is reversed? I have no idea (mechanical issues perhaps), but people also claim to hear God talking to them. Do you?

geoffkait's avatar
geoffkait
23,365 posts
 
That’s precisely what wrong with the “measurement is everything” approach. Even HiFi Tuning admits the relatively small measured differences don’t account for the relatively large differences in fuses and direction of fuses heard in listening tests. Oh, well, that’s the way it goes sometimes. It looks like it’s Modjeski’s opinion vs 90,000 aftermarket fuse users. No one really knows why cables sound so different yet measure the same, either, or sound so different in one direction vs the other. This not something new under the sun, anyway. Modjeski is a few paradigm shifts behind the power curve. The only debate about fuses and cables and power cords is in the mind of the dyed-in-the-wool skeptic.
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