Variac specs?

[tubeswell]

I have found a new variac for sale (for the 230V 50Hz main system here)

The specs are:

* Rated power handling: 500 VA (fused)
* Input voltage: 240 VAC @ 50Hz
* Output Voltage: 0~260 VAC @ 50Hz

Do you guys (n'gals) think that would be sufficient for 99% of geetar tube amp work (in my neck of the woods)? Or would you use something beefier?

Any comments?

TIA

Cheers

Pete

(PS by way of comparison, there is another one for sale nearby in 'as new' condition, specifications:

* Rated power handling: 2000 VA (8Ampere)
* Input voltage: 240 VAC @ 50Hz
* Output Voltage: 0~280 VAC @ 50Hz

but it is 2 x as expensive)

[g1]

500 watts sounds a bit small for my liking, if you're doing anything big like PA power amps it's too small. For guitar amps, it may be ok but remember a 100W tube amp uses a lot more power than 100W when cranked. They are usually fused around 500W input so you would be right on the edge.
I think mine is around 1200W, the 2000VA one would be a lot better.

[Enzo]

Imagine having a 100 watt speaker and repairing 1000 watt amps. The thing is to use the speaker to determine if the amp functions or not, just don;t crank it looking for full out. MY variac is fused at 8A, but I use it on much larger amps. I am using the variac to bring something up slowly to see if it is going to start to draw excess current. I am not going to test high power stuff on the variac after getting it to power up without taking fuses. Once the amp is stable, then I remove it from the variac and continue the work powered from the mains.

SO it is up to you, tubes. If you want to play a Fender twin full out with it dialed way down, l;ooking for tones, maybe you will be stressing the smaller one. But if you use it like I do, just to power things up and watching, then that Twin won;t be drawing full powr and things will probably work out.

[soundguruman]

I think you want to wire the taps so it can't boost, but rather goes to line voltage, and no further.
Most variacs have the taps to set that configuration.

[Enzo]

I think that is a matter of taste. MY variac is still wired to go to 140v. I leave it set at 120v when not dialed lower. There are times when having a few volts of boost available comes in handy. No I am not going to stress an amp at 135v just to see what happens, but sometimes you want to know what a circuit does when the mains varies.

[1ampman]

Enzo is correct. Variac is for testing and repairing, not full output testing. If your blowing 8 amp fuses at idle, it still needs repair. So 8 amps is plenty for what we repair. That size it self takes up plenty of space on the bench.

[g1]

Sorry for the disinformation, I agree completely with the others that the variac should not be used for full power testing. I am guilty of using mine as a line regulator as our line voltage is kind of hot for my liking, 125 to 126VAC which can give 6.8 or more filament voltages. Then the electric furnace kicks in and it's down to 118V. So I tend to regulate as I get fed up with waiting for the line to come back up.