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What's going on with Synergistic Research fuses?

I live in California and a couple of weeks ago we had strange lightning storms that started the many fires burning in the State.  It also fried the fuse in my Pass XA30.5.  I got the amp second hand and it came with a SR Blue fuse.  I called Pass and they recommended a very cheap fuse which I ordered and installed.  Because I was curious, I took the SR sticker off the old burnt out fuse and found that it was a very cheap SIBA brand fuse underneath.  It is clear that SR is either not making the ceramic casing for this fuse or using the SIBA fuse and then doing stuff to it.  At the very worst, it's just slapping a sticker on it and charging a ton more

The thing is, I'm pretty sure I could hear a difference for the worse when I installed the cheap glass fuse post lightning storm.  Could it be that SR is modifying an existing fuse to make it sound better?  Maybe some more technically minded folks here on the forum could help me understand

thanks!
adam8179
glupson
7,842 posts
 
Impressive!
glupson
7,842 posts
 

cal91,

"The instruments started moving closer together and no longer went as far past the speakers. Coletrane seemed to fade a little further back and Haynes lost a little of the sharpness and clout."

It seems that you have mono version.

twoleftears's avatar
twoleftears
5,320 posts
 
@cal91  
If you ask them nicely, they'll do "It isn't real" for you.
https://www.youtube.com/watch?v=M0itI_H2wK0
cal91
233 posts
 
twoleftears...good one
atmasphere's avatar
atmasphere
12,116 posts
 
if a piece of equipment, let's say a CD player, has multiple fuses, let's say eight of them, how does the improvement go?
The voltage drop across the fuse is the issue. I seriously doubt you would be able to measure or hear anything in a CDP, since many of them employ regulators in the various power supplies, and also since the voltage drop is very slight anyway.
I connected a scope to the speaker outputs and used a 1khz sine wave input and I replaced the fuse with the following:

- straight silver wire 12 awg (no change in sound, no change on the scope)
- straight 99.9% pure OFC copper wire 10awg (no change in sound, no change on the scope)
- standard Romex wire used in the house installation (12 gauge 20 amp circuit) (no change in sound, no change on the scope).

Even with a complete short circuit of the fuse there was absolutely no change in the sound and/or signal.
I am not arguing the results of your experiment.

However there are some uncontrolled variables. In the measurements I've made, they only seem to show up with equipment that actually draws enough power that you can measure a voltage drop across the fuseholder. You did not mention what amp you used, but I suspect it does not draw much power. The less power drawn the less measurable the effect of the fuse is and likely the less audible. The areas I see it making a difference are total power output. You'll need a variac to do this, since as the amp makes more power it will make a bigger voltage drop. You want to be able to change the input AC voltage to compensate for that so you can see what the amp does if 120V is present at the output of the fuse as opposed to when the voltage is at the input to the fuse. So you have to increase power to clipping, then measure the voltage on the output side of the fuse, readjust the variac, then readjust for clipping and so on.

Also measure the output impedance and distortion. Don't bother if the amp only makes 5 watts- the effects will be too diminished.


Using this technique I've seen how a power cord can rob an amp of nearly 40 watts- slightly less than 1/3rd its total power. But that amp has a significant filament circuit; if you are trying to this with a 20 watt solid state amp you're going to have difficulties measuring anything!



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