Another Airbrake Question

[Gibsonman63]

How many Watts can an AirBrake handle? Mine works fine on my Express build. I was playing around with my 100W Marshall JMP. The sound was incredible, but the AirBrake gets pretty hot and starts to smell a bit.

It may be time to drill a bunch of holes in the top and bottom of the enclosure.

[Reeltarded]

Should be 100 watts. It should also smell like a new toaster and get hot enough to bake cupcakes at full attenuation.

[martin manning]

The 25R 100W shunt resistor is the limiting item in the attenuator. WIth an 8-ohm speaker load you can put about 112W in at max attenuation. At min attenuation you could throw 400W at it, but you'd better have a 300W speaker connected. Note that the load this thing presents is not constant. WIth an 8-ohm speaker it looks like 20 ohms at max attenuation and 6 ohms at min.

[vibratoking]

Actually, I thought the limiting factor was the rating of the adjustable resistor. The max power dissipation is based on the minimum configured resistance that is used. The max power rating is for the device used at it full resistance. Anytime you use less than the full resistance, the power rating must be derated accordingly. For instance, if you use it as half it's total resistance, then the power rating is cut in half. At least this is how I remember it and I am too lazy to find a data sheet.

[Gibsonman63]

How about parallelling two adjustable resistors and doubling the resistance of each for every setting?

I'll be serving brownies tomorrow after rehearsal.

[Reeltarded]

This thing doesn't work like I was told, nor does it work like my other attenuators! They work as constant loads as if the box is a pair of 16ohm 4x12s.

After searching for a few minutes I am not sure there is any good info on the web about it until Martin's post above. With an AB, how do you set the amp output imp? It has to change with settings changes at the brake?

I think I still like variac as an attenuator best. At least I understand that!

[Gibsonman63]

I think I still like variac as an attenuator best. At least I understand that!

I am thinking a little bit of both would work well. I find the most useful settings at -6, -9 and -12 dB on the attenuator. Anything more starts killing the tone and -3 doesn't do much.