Synergistic Red Fuse ...

Whoa! Hey, that’s exactly what they said about the Black fuse when a couple regulars reported hearing nothing on these very pages. (Say, whatever became of Mapman, anyway?) No matter how many audiophiles go bananas 🍌 over one thing or another you don’t have to look too far to find somebody who doesn’t hear a gol durn thing. It happens all the time. That’s why controversial audiophile thingamabobs abound. Maybe the dude got a dud. 😛

Joe (Jafreeman), yes, the reason I asked about the subs is that connecting a sub to the outputs of amplifiers that are balanced or bridged or monoblocks can be tricky, and I’ve seen a lot of posts here in which people have described doing that in an incorrect manner, at least from a theoretical standpoint. Although in many cases the results are still reasonably good, due mainly to the happenstance of the internal grounding configurations of the sub and the amp.

And in the case of your particular sub the issue is further muddled by inconsistent and misleading statements in the manual, which I found at this link:

https://relsupport.zendesk.com/hc/en-us/article_attachments/115015632767/REL-ST-Series-Manual.pdf

In various places the manual refers to using the sub’s balanced input for amps having balanced outputs or differential outputs or bridged outputs, or various combinations thereof. And in at least one case it refers to "differential output (bridged mode) amplifiers," which is completely misleading.

In this case, since it is a fully balanced amp it has a differential output, and the amp’s negative output terminal therefore has a full amplitude signal on it. By connecting the sub’s ground wire to that terminal you are creating a path for that full amplitude signal to the sub’s circuit ground, then through some unknown but probably low impedance within the sub to the sub’s AC safety ground, then through the AC wiring to the amp’s AC safety ground, then through some unknown but probably low impedance within the amp to the amp’s circuit ground. In other words, not quite a direct short of that full amplitude output of the amp to the amp's circuit ground, but a connection of that signal to the amp's circuit ground through what is likely to be a relatively low impedance. Which depending on the particular impedances that exist between circuit ground and AC safety ground in the sub and the amp might degrade sonics, cause hum, or even damage the resistors that probably connect those two grounds in each component.

The right way to do it is stated on page 18 of the manual:

For differential amplifiers using two subs, one for each channel: connect red to positive; yellow to negative; and black to chassis ground; plug the Speakon into the balanced high level input (Bal Hi Input).

The "chassis ground" connection can be to any screw on the chassis of the amp, assuming that paint doesn’t interfere with the connection.

As I indicated, compared to what you are presently doing there may or may not be all that much difference sonically, depending mainly on the internal grounding characteristics of the sub and the amp. But this is the right way to do it.

Finally, when you try this you may find (depending on the design of the sub’s balanced input circuit) that the output of the sub increases by 6 db, and if so you’ll have to reduce its level setting correspondingly.

Getting back to fuses, regarding your mention that...

... the front-panel display on each amp now reads at 120-121V, whereas at lower fuse ratings, the line voltage was at around 117V. The operating range of the ARC 210’s is 105V-130V.

That’s certainly surprising, but what I can say with certainty is that if the 7 or 8 amp fuses were dropping 3 to 4 volts, not to mention 3 to 4 volts more than the 10 amp fuse is dropping, while conducting the more than 3 amperes the amp draws even when idle, the fuse itself would be dissipating (consuming) upwards of 10 watts of power, converting it to heat, and promptly melting. Therefore I suspect that either the line voltage has changed, or the fuse holder has loose or corroded contacts, or the meter on the amp is erratic, or some combination thereof.

Best regards,
-- Al

I continue find some of the descriptions of the degree of improvement that "special" fuses provide in the systems of the proponents of these things unbelievable, especially since a new round of claims of MORE  wonderfulness is begat by the New Blues. It's a FUSE (a safety related device that's supposed to MELT if need be), and until some rational explanation is provided as to WHY and HOW these things "massage the juice" before it runs through the power supplies and all the other caps, resistors, transformers, rectifiers, tubes, transistors and every other part of an audio component's circuits, I'll continue to hold the opinion I've had since doing my own little test of the black version of these things…they're a silly and possibly dangerous (sketchy fuse ratings) waste of time and money when compared to less precious (like ultra reliable way less expensive Littelfuse products) "standard" fuses. Unbelievable. 

Jay ...

Notice that I said "Hope for." 

That is fine, but useless. That is what I was saying. You're more likely to meet God or the devil, than have it happen in your lifetime.

The new BLUE fuses have brought everything up to a new, and unexpected level. I was just listening to Charlie Mingus’ "Tijuana Moods." I don’t care what others are saying ... they were in the room. *lol*

...........

Frank

PS ... Has anyone else posting here ordered any BLUE fuses? It would be nice to compare notes

.

.......
I know what I hear and I hear what I know. The BLUE fuses are a major step up from the BLACK fuses .... as the BLACKS were from the RED fuses ... and the RED fuses were from the stock fuses.

Once again, without hearing for themselves, the naysayers are coming out of the woodwork in an attempt to throw ice water on a perfectly good thing. Gets a bit old, doesn’t it??

Frank

Hopefully I am not being lumped in with that group. I have one on order. I just hope it's not less transparent, like your writing indicates to me.