cab blend box?

[flateric]

Idea for a small project - I have a Peavey Tour 450 bass amp head driving 2 hartke XL cabs in parallel - a 200W 1x15 cab (8ohm) and a 400w 4 x 10 cab (also 8ohm).
The cabs have quite different tonal characteristics, if I wanted to be able to change the balance of signal fed to each, how would I go about it using a simple passive box? Some sort of blender or level control to allow me to get the right blend of output from each cab, and to take into account the power difference between the two.
Any thoughts?

[newey]

Sounds like a box with 2 L-pads would do the trick, one for each cab. Then you could mix in any desired mix of the 2.

Problem is, I don't know if you can find them to handle 200+ watts.

[flateric]

thanks for the steer - there's more:
www.bcae1.com/lpad.htm

Need to get some beefy resistors

[flateric]

After some more L-pad investigations it seems this is not a viable way of attenuating a powerful amp/speaker. It might be ok as a power-soak type app for 15 - 30W amp but any higher than that and you need a really big, expensive rheostat.

[sumgai]

♭eric,

Whoa, not so fast there, bunky!

When I think of power resistors, I tend to dream of things from a bygone era, like these:




Dgikey (in the UK) has some prices, but the chart is not directly linkable. Go here, pick appropriate values, and see what they have to offer.

Interestingly enough, even though I was logged into the UK site, the prices quoted were still in US dollars. They ranged as expected, from under $20 to around $30.

Now, a couple of those can get a bit expensive, and a bit bulky, but they will do the job. And looking at them in the flesh, you can understand why they don't make adjustable high-power units that look like rheostats or potentiometers - things like that would be huge, and very expensive. (You can get them, but only if you have a budget like as if you're a company that supplies power to the national grid.)

.................................

But even after I give you all of that, I have to say that today it's faster and much cheaper to simply trot down to Radio Shack and snatch up some of these:

Ignoring the printing on the device in that picture (they use the same image for all their power resistors), you can snap up some 10 watt 50Ω or 10 watt 100Ω resistors, and assemble them into your own configuration. At a buck apiece, that's a pretty good way to get what you want.

For example, 12 ea 50Ω resistors in parallel yields 4.17Ω, and at 10 watts apiece, that'll soak up 120 watts. But wait.... you suck up as much as 240 watts with just 24 ea 100Ω resistors in parallel. And you're still under $25 (USD). Just remember to use Ohm's Law, and you're pretty much unlimited in getting the values you want.

And of course, it goes without saying that you can tap anywhere along those connections to do your intended job, which is to set up an L-pad.

Now, being as you live "over there" , I tried Maplin's website.... sadly, they are very user-hostile. I can't get them to come up with anything resembling what we want/need here - they just keep giving me everything in the store that includes the word "power". Not an ideal situation. But I'm also under the impression that there are other outlets of that type in GB, aren't there?

And as usual, if you can't easily procure them in your neck of the woods, then I'll get them for you, and forward them along at a more friendly shipping cost. ;D

HTH



sumgai