What's going on with Synergistic Research fuses?

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!

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.

This is "maybe" a correct statement, but lets get the rest of it right, and may only apply to non regulated equipment.

What should be added is that it would be "impossible to hear" the difference. As the mains fluctuates much more every second, your measuring the same ***** thing, a minute voltage drop across the fuse or larger voltage drop in the mains every second!!!

It’s all fuser snake oil voodoo **, don’t try to make it anything else and give fusers even more fodder for the shilling of these >$160 fuses

Cheers George

but lets get the rest of it right, and may only apply to non regulated equipment.

Yes- I've been careful to mention this at least twice earlier. 

It’s all fuser snake oil voodoo, don’t try to make it anything else and give fusers even more fodder to twist around in their snake oil heads.

Using a generality like this is problematic- its better to say that *most* of its snake oil... the problem is that the effects are measurable. But there is also the Veblen Effect- that the fuse must make a difference because it cost so much (which is a subset of 'expectation bias').

So, you would consider an expensive aftermarket fuse a Veblen Good as opposed to a Giffen Good given that an argument could be made that they are nothing more than rebranded cheap fuses?
I personally have no opinion either way as to their efficacy as I have never used one.