Fine fuse ratings (unit vs manual)?

There’s quite a discrepancy between the fine fuse ratings indicated on the back of my units and what it says in the respective manuals. Which are correct? Thanks in advance!

Greetings from Switzerland, David.

David, if you mean the external fuses for the Vivaldi stack, it’s a 1Amp fast-blow (“T”), 20mm x 5mm, with appropriate voltage rating for your region (mine’s 250V).

By the way, if you’re consideringafter-market fuses, I’ve tried a few, subjectively, I’ve found the Synergistic Research’s Orange fuses to be the best thus far :slightly_smiling_face:


I need to throw this into the discussion so that our policy is crystal clear when it comes to fuse substitution.

  • The fuse is primarily a safety device and is there to protect life and property.
  • A blown fuse should always be replaced with the same value that shipped with your unit. Be absolutely certain that you replace a blown fuse with the correct value. PLEASE contact dCS if there are any questions here and we’ll get you the correct information.
  • Replacement of a fuse with anything other than the specified rating may result in damage to your unit, other property, or your life and may void your warranty.


Changing out your fuse for one that makes claims of better sound as its sole benefit is extremely dangerous. At best these items are just relabeled standard fuses so you’ve ended up spending 100x the actual cost of the item. At worst these items simply don’t work and pose a danger to you and the other members of your household (as well as your neighbors).

Furthermore, as many of these items lack any sort of safety certification (UL or otherwise) your insurance company may walk away from you and deny all coverage in the event of a claim.

Please don’t mess around with fuses or other mains tweaks. The risks simply aren’t worth the dubious rewards.

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Interesting topic, but not an answer to my question: what it says on the back of my units differs from what it says in the respective manuals. Why, and am I assuming correctly that what it says on the units is correct?

Greetings from Switzerland, David.

Am I going to get an answer to my question, please? It’s not about audiophile fuses, but about the fact that it says one thing in the manuals (T 1A L) and another (T 500 mA L) on the back of two of my 230V units. All I want to know is whether I have the correct ratings installed (yes, CE certified, that’s not the point). Thanks!

Greetings from Switzerland, David.

OK I am not Andrew but in an attempt to put you out of your misery, If you look in the black folder(s) that contain the documentation you should find a ziplock pouch with the correct replacement fuses therein. As Anup says earlier in this thread those for Vivaldi are 1 amp fast blow.

This agrees with the manual for nominally 230V countries ( e.g. EU/EEA) where the closest fuse voltage rating is 250V. Were your units originally from a region with a different voltage?

NB: I think that Andrew’s answer was actually to Anup’s response where Anup recommends an “audiophile” non-standard fuse and Andrew responds with a necessary caveat.

My units are 230V from the importer in the Netherlands (we no longer have an importer in Switzerland, or at least we didn’t for years). I got a reply from Martin Reynolds at dCS this morning. Apparently, it did say 500mA on the back of early Vivaldi DAC units, and since some occasionally blew a fuse at power up, the fuse rating was uprated to 1A.

As to audiophile fine fuses, there are certified ones available such as Hifi-Tuning Supreme and perhaps others, no need to use ones without CE certificate.

Greetings from Switzerland, David.

Doesn’t “T” stand for “time-delay”? That’s not the same as “fast-blow” or is it?

Greetings from Switzerland, David.

I’m just bowing to Anupc’s superior knowledge on such things. They are marked " F.T1AL250V".

It says

“Fuse type: 20 x 5mm T 1 amp L fuse”
“Fuse type: 20 x 5mm T 1A L fuse”

(same thing)

in all the respective online manuals.

Hence my confusion, as there’s a discrepancy between what it says on the units and in the manuals.

Greetings from Switzerland, David.

David, yes I understand the discrepancy that you have between what is marked on the fuse holder and what I shown in the manual. But I thought this had been explained by Martin Reynolds- early Vivaldis used a 500mA fuse which tended to blow in the field and so the fuse was re-rated to 1A.

The last point that you made earlier concerned the fuse speed marking. I agree with you. The T mark means slow acting ( slow blow). The L in the position cited means low breaking capacity.

Apparently, the preferred rating would be from a third category called “time-delay”, which I haven’t seen an equivalent of in the German literature.

Got the following information from Martin Reynolds:

  • Quick-blow – blows almost immediately the rated current is exceeded.
  • Slow-blow – can cope with a substantial surge current, eventually blows if the rated current is exceeded for more than a few seconds.
  • Time-delay – copes with a brief switch-on surge (0.3 seconds?) but then blows if the rated current is exceeded for longer. Better protection than slow-blow.

Greetings from Switzerland, David.

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May be of interest:

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Apart from all this, I’d like to emphasize again that “audiophile” and “certified” aren’t mutually exclusive in this context. There are lots of audiophile snake oil aftermarket products out there, but that doesn’t mean there aren’t ones that come with e.g. a CE certificate.

Greetings from Switzerland, David.

AFAIK, some popular aftermarket gadgets such as GigaFoil and Uptone EtherREGEN are not CE certified, which is why I’d hesitate trying them despite the promise of better sound. I’m not even sure the use would be legal in our country.

Goes to show how much I know… :man_facepalming:t2:

I always assumed the “T” was UL Class T which is a “fast-acting” fast blow fuse.