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HiFi tuning Foo-uses

naimsg said:
Does bypassing fuse in the speaker improve the sound? :)

Btw, AMA in the Naim forum mentioned that sarum cables are used in the kudo titan speakers. Is it worth investigating replacing the cables in the speakers? Maybe there should be another thread on this.
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Bypassing Ohm level resistances requires very large capacitors
 
rontoolsie said:
.....yet inconsequential when inline with the mains delivery?
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Inconsequential? Hardly ! As you've found out with chassis fuses as well, it seems, Ron. Mind you, I believe that different kit reacts differently in this respect; in my experience, at least.
 
Nobody's picked up on my total ignorance of fuses in passive m/coil speakers. I've had dozens over the decades, without being aware of any fuses; are these buried in inaccessible internal crossovers or something? If so, this seems counter-intuitive as it's a fuse.

The thought of fuses in passive speakers appalls me, though I'm only mildly disconcerted by their use elsewhere.;)
 
Mike they don't have inductance or capacitance, just resistance, which varies with current flow. Its the variance in resistance with load that makes them 'unsuitable' in speakers and perfectly suited for mains safety.
 
Arkless Repairs said:
Remove them altogether and bypass them. BIG improvement likely! Majority of speakers have no protection so they won't be any less protected than that!
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I assume this is real advice, not sarcasm?!! ;)

OK, how do I go about bypassing them? Do I replace them with a fuse of much higher rating for example?

Not sure I want to start taking the speaker apart to bypass the fuse holder if that's what you mean, but willing to do so if there really is a BIG improvement?

Thanks.
 
Sticking to just speakers, so no electrical safety issues, Bypassing the fuse fitting a much higher current part is OK, so long as you don't party the speaker. It is being a bit hopeful that the original fuse would go before the tweeter died anyway
 
I'm sure that the removal of fuses in Shahinians has been discussed previously and I can remember there being many opinions that the fuses used were too slow anyway and will do nothing other than degrade the sound. I'm seriously tempted to bypass mine, but the cost of a Titanium tweeter does worry me.

Other fuse news... For the past 2 nights of listening I have been swapping between the std 750mA chassis fuse in my tweeked LS7 and a 10A one. I'm sorry to report this, but the soundstage grows by at least 1m in every direction with the 10A fuse. This is quite a quandry as I really don't like the safety aspects of using a valve amp without a chassis fuse. For me there is something going on that is not understood. Perhaps it's noise due to the fuse holder contact, perhaps it's the tiny wire resonating... There's no accepted theory to support it, but there's clearly a difference to my ears
 
davidsrsb said:
In order to usefully protect the drive unit from excess power, the fuse current rating must be quite low and therefore have a fairly high resistance. This will be higher than a typical amplifier output resistance. It will also vary with music level as the fuse element gets hot, giving some power compression
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Spot on. It will give considerable compression and "envelope distortion".

vital. No I wasn't being sarcastic..... the difference is real and measurable, not foo, and can make quite a big difference. Best thing if you can get access is to solder a wire across the fuse holder.

Of course many speakers don't have fuses at all, some have internal one on the crossover board and some have an externally accessible one.

Some amps have a fuse at the output which is of course electrically just the same as having one in the speaker.... However, sometimes this fuse will be before the NFB take off point and so the fuses non linearity is by and large cancelled by the NFB.

Mains fuses have no effect on sound. leave them alone. They are there to stop your house burning down!

Amp internal power rail fuses can have some detrimental effect (depends on a few factors) but not as bad as in speakers. Again, leave them alone.... safety first! ;)
 
Arkless Repairs said:
vital. No I wasn't being sarcastic..... the difference is real and measurable, not foo, and can make quite a big difference. Best thing if you can get access is to solder a wire across the fuse holder.
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OK thanks :) It's probably hard for you to understand a level of DIY incompetence such as mine on these things (I don't even own a soldering iron), so I'm wondering if a higher rated fuse would at least show a difference that might spur me on to doing/getting done the bypass of the fuse holder?
 
Dan K said:
I'm sure that the removal of fuses in Shahinians has been discussed previously and I can remember there being many opinions that the fuses used were too slow anyway and will do nothing other than degrade the sound. I'm seriously tempted to bypass mine, but the cost of a Titanium tweeter does worry me.

Other fuse news... For the past 2 nights of listening I have been swapping between the std 750mA chassis fuse in my tweeked LS7 and a 10A one. I'm sorry to report this, but the soundstage grows by at least 1m in every direction with the 10A fuse. This is quite a quandry as I really don't like the safety aspects of using a valve amp without a chassis fuse. For me there is something going on that is not understood. Perhaps it's noise due to the fuse holder contact, perhaps it's the tiny wire resonating... There's no accepted theory to support it, but there's clearly a difference to my ears
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It is perfectly understood. No mystery. All due to non linear resistance. A 10A fuse is big enough to have little effect on the sound but it's so big it will give no protection at all so you may as well just bypass it....
I assume you mean Rogers LS7 speakers here and not some valve amp called an LS7.... leave chassis fuses alone!
 
Vital said:
OK thanks :) It's probably hard for you to understand a level of DIY incompetence such as mine on these things (I don't even own a soldering iron), so I'm wondering if a higher rated fuse would at least show a difference that might spur me on to doing/getting done the bypass of the fuse holder?
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Something like a nice clean 20 A fuse would be near as damn it like a wire bypass....the main resistance left would be the fuse holder but if everything is clean and tight you can ignore that... until it tarnishes eventually...
 
Arkless Repairs said:
Something like a nice clean 20 A fuse would be near as damn it like a wire bypass....the main resistance left would be the fuse holder but if everything is clean and tight you can ignore that... until it tarnishes eventually...
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Excellent - thanks again - that should be easy to try. Anyone happen to know the physical size of the fuse in the Obelisk? (I'm at work and keen to order some!)
 
I'm wondering about replacing my 750mA LS7 power rail fuse with a 1A RCD as there's space inside, or could I get an in-line one?

We could all just use power leads with built in RCD's - why not?
 
Dan K said:
I'm wondering about replacing my 750mA LS7 power rail fuse with a 1A RCD as there's space inside, or could I get an in-line one?

We could all just use power leads with built in RCD's - why not?
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If this "LS7" of which you speak is a valve amp (AR LS7 pre?) and not a set of speakers then there is nothing to be gained from messing about with fuses at all.... but a lot to be lost :eek:

BTW A RCD isn't a fuse and does not do the same thing as a fuse. It's completely different. As I've had to point that out to you, my advise is to not to ***k with things you don't understand in case you end up electrocuted.... or burn your house down :eek:

Safety first fishies! It's safe to bypass speaker fuses but leave well alone beyond that!
 
Dan K said:
Other fuse news... For the past 2 nights of listening I have been swapping between the std 750mA chassis fuse in my tweeked LS7 and a 10A one. I'm sorry to report this, but the soundstage grows by at least 1m in every direction with the 10A fuse. This is quite a quandry as I really don't like the safety aspects of using a valve amp without a chassis fuse. For me there is something going on that is not understood. Perhaps it's noise due to the fuse holder contact, perhaps it's the tiny wire resonating... There's no accepted theory to support it, but there's clearly a difference to my ears
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Why you're sorry to report this, AND be in a quandAry, is beyond me, Dan. You've just discovered what I. and a few others, have known about for yonks. Bless his engineering heart, but young Arkless is wrong when he says that chassis fuses do not affect s.q. ;) He's right on the safety risk, though (otherwise why have fuses in the first place?).

I've not had ARC stuff, so it's interesting to see that this is yet another make susceptible to this, as is my Meridian CDP, my E.A.R. valved monoblocs and all the Naim kit I've had. The jury's still out on my Lector CDP, though, so it's not a blanket endorsement. RCBOs (or possibly separate MCBs and RCDs) are very effective safety devices, especially when each is dedicated to just one piece of kit, but the chassis fuse is there for a very good reason (unfortunately).
 
The fact that this thread has now grown to eleven pages and counting suggests that the benefits of fuse uprating/replacing are at least contentious and should not be readily dismissed on purely technical grounds. Any more than suggesting that the voltage inputs of naim preamps are so cobbled that there will be no appreciable benefits moving from a Hi to a Supercap. I do admit that in the latter case the design of the preamps may somewhat lessen the differences between power supplies, which in my experience still can be *huge' and not marginal.

I think that chassis fuses do protect more than just the mains. They can also protect transformers, circuit boards etc from melting down if there is internal shorting. Of course in the thirty something years I have had legions of hifi, I have never had a single component go bad to a point where it was blowing fuses. Which is not to say that never happens.
 
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