Bad L-Pad SWR?

[lowell]

This cab's tweeter is sounding quite bad. I removed the crossover board from the cab and am measuring the rheostat. This should measure like a pot right? It is measuring 0ohms no matter where it is set to. The tweeter driver is fine.

Aside: Is this REALLY a true L-pad in ss amp cabs? I read that an L-pad was 2 rheostats that worked together to maintain a constant load impedance regardless of how much power was attenuated to the speaker. Technically these attenuators in bass cabs do not seem like true L-pads.... is this correct?

[52 Bill]

Is this REALLY a true L-pad in ss amp cabs? I read that an L-pad was 2 rheostats that worked together to maintain a constant load impedance regardless of how much power was attenuated to the speaker. Technically these attenuators in bass cabs do not seem like true L-pads.... is this correct?

Yes, you would use an L-Pad to control the volume of a speaker connected directly to an amplifier, thereby keeping the load seen by the amp at a constant level.

The tweeter is isolated from the amp output by the crossover cap and the wirewound control just sets level of the signal going to the HF driver.

[lowell]

Not being familiar w/ L-Pads I tested this one w/ my ohmmeter and the ohmmeter reads shorted no matter where the l-pad is. Do L-Pads test like a normal pot? I have a feeling they don't.

[Enzo]

Did you rewmove it from the circuit to measure it? All it takes is an inductor across it to make it read short.

[lowell]

I just remeasured and it is reading something but if I push on the knob at all there is a short... where can I get one of these for replacement? I emailed SWR but never done this so don't know if they'll get back to me.

[Enzo]

L-pads are generic. Most places that sell speaker stuff sell them.

MCM sells several


Stock number 50-080 is a 50 watt, they also make 100 watt.

Parts Express sells all kinds of speaker related stuff

They seem to have a larger selection than MCM check out stock 260-252

They come in various wattages and in varous impedances, mostly 8 ohm but also 16.

[lowell]

nice thanks!

[Regis]

I've built a couple of amp attenuators using Parts Express L-Pads.

Here is one.

[lowell]

very cool! like the fan too!