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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

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Showing 5 responses by mijostyn

mijostyn's avatar
mijostyn
8,152 posts
 
David, you hit it right on the head,”less emotionally involving.”
Although I do not own one at this time, Mr Pass makes some of the best sounding amps. I think Beethoven proved that you don’t have to be able to hear, you just have to know what you are doing.
Some days my system sounds killer, other days not as good even with the same recording. The only things that have changed are the humidity and the barometric pressure. The real culprit is my state of mind, happy vs pissed off. If there is just one neuron in your brain that thinks something is going to sound better, it will. This does not mean that there are not meaningful changes you can make, there are. In my experience there is always a sound reason why something sounds better. In the case of the fuses there is not one. I use to bypass all the fuses in my system including speaker fuses. Then I started doing AB experiments with fuses, wire and switches. There was a slight improvement in bass bypassing speaker fuses. Otherwise the differences were hard to appreciate. I also always have a second set of ears participating. It would be better to have 100 sets but it would be hard to arrange for obvious reasons.
In most cases you are better off buying more music. 
mijostyn's avatar
mijostyn
8,152 posts
 
bdp24, thanx for making sense. Both Nelson and Roger have access to serious test equipment. I think over the years they have established which measurable anomalies sound bad (IM distortion) and which are euphoric (harmonic distortion). Nelson admits to adding small amounts of harmonic distortion to make his amps sound like tube amps. I suspect John Curl does the same thing. Having played with and measured hundreds if not thousands of circuits I am sure they are quite aware of what alterations do absolutely nothing like fancy fuses. 
I do not know what it takes for people to understand the power of our central nervous systems to modify perception. All our senses, hearing included are adjusted by our central nervous systems to perform well under various circumstances. Emotion can also make changes which are measurable. This is how lie detectors work. The fact is, if you think something will sound better or worse it will and it does. But the next time you are in a bad mood it will sound awful. 
mijostyn's avatar
mijostyn
8,152 posts
 
And Uberwaltz, I am not criticizing your hearing or the CNS behind it. I am just giving you the real reason behind what you think yo are hearing. The operative word here is, "think."
mijostyn's avatar
mijostyn
8,152 posts
 
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:)
mijostyn's avatar
mijostyn
8,152 posts
 
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. 
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