Fuses
What fuses are used in AVA products?
All AVA products are protected by one or more fuses. Preamplifiers generally have one protection fuse, but big amplifiers, such as our DVA 850, have up to six protection fuses.
AVA uses two physical sizes of fuses. Almost all are standard 0.25” diameter by 1.25” long. We do, however, use some much smaller 5mm by 15mm glass fuses in a few applications.
The fuses come in two types:
The first are quick blow fuses with a glass body and metal end caps. Quick blow fuses have a single small wire visible in the glass body. The wire may be straight or jagged or wiggly.
We use quick blow fuses for the internal power supplies, and as speaker fuses because they are designed to fail immediately at the first instant of overload. It’s important to note that quick blow speaker fuses protect your speakers and amplifier from excessive volume levels. They also protect your speakers from connection mistakes and protect against accidents such as a dropped tone arm, or disconnecting an interconnect cable or speaker cable when the system is on.
Quick blow fuses come in a variety of values, and the value is printed on the metal end caps, such as 1A, 3A, 5A. These numbers show the maximum current the fuse will pass before blowing in amperes. They are typically rated at 250 volts maximum.
Usually you can tell if one of these fuses has failed by observing that the fine internal wire is parted or even missing; however, double check with an ohmmeter or continuity meter to make sure.
The second kind of fuse is a slow blow fuse. These are identified by a much heavier spiral wound wire often connected to an internal heavier slug. Slow blow fuses are designed to pass a much heavier current peak for a short time before blowing. We use slow blow fuses where it is important to handle momentary current peaks, such as when electrical equipment is turned on.
Low amperage slow blow fuses are glass. The high amperage slow blow fuses have ceramic rather than glass bodies as they contain substances to prevent sustained internal arcing if the fuse blows.
You will need an ohm meter or continuity meter to test ceramic fuses as you cannot tell if it has failed just by looking at it. AVA only uses ceramic fuses for the main AC line fuse, and are only used in the large (400 Watts or larger) amplifiers.
SLOW BLOW FUSES SHOULD NOT BE USED AS SPEAKER FUSES because the speakers will blow on an overload before the slow blow fuses opens.
Please refer to the AVA fuse chart below for our recommended fuses.
Audio by Van Alstine Fuse Chart
| Mains AC Fuse | Speaker Fuse(s) | Internal Fuse(s) | |
|---|---|---|---|
| Preamplifiers | |||
| Solid State | 0.5 Amp slow blow | N/A | N/A |
| Hybrid | 1 Amp slow blow | N/A | N/A |
| Tube | 1 Amp slow blow | N/A | N/A |
| Amplifiers | |||
| SET 120 | 3 or 4 Amp slow blow | 3 Amp quick blow | 4 Amp quick blow |
| Synergy 200 | 6 Amp slow blow | 3 Amp quick blow | 5 Amp quick blow (4) |
| Synergy 240 | 6 Amp slow blow | 4 Amp quick blow | 6 Amp quick blow (4) |
| Synergy 300 | 6 Amp slow blow | 4 Amp quick blow | 6 Amp quick blow (4) |
| Synergy 450 | 10 Amp slow blow | 5 Amp quick blow | 8 Amp quick blow (4) |
| DVA M225 | 5 Amp slow blow | 5 Amp quick blow | 5 Amp quick blow |
| SET 400 | 10 Amp slow blow | 5 Amp quick blow | 5 Amp quick blow |
| DVA Set 600 | 12 Amp slow blow | 8 Amp quick blow | 6 Amp quick blow |
| Fet Valve 400R | 10 Amp slow blow | 5 Amp quick blow | 5 Amp quick blow (2) 0.25 Amp quick blow (2) |
| Fet Valve 600R | 10 Amp slow blow | 6 Amp quick blow | 6 Amp quick blow (2) 0.25 Amp quick blow (2) |
| DVA 850 | 12 Amp slow blow | 8 Amp quick blow | 6 Amp quick blow (2) 0.25 Amp quick blow (2) 0.25 Amp slow blow (1) |
| Ultravalve | 3 Amp slow blow | N/A | N/A |
| Ultimate 70 | 3 Amp slow blow | N/A | N/A |
| Miscellaneous | |||
| Humdinger | 10 Amp slow blow | N/A | N/A |
| Vision Phono Preamp | 0.25 Amp slow blow | N/A | N/A |