4 Webber Speaker Motor Load

[emmjaydubya]

You wire it and fire it yet? I'm very curious...

[vanhalen5150]

Yeah, it works awesome. I finally have a decent room volume with the 12000. Still taking it slow to see how much heat build up if any. Really need to have it playing for a few hours to see how it holds up.

I have it in combo with a Faustine Phantom , and it really brings out the true sound of the amp at much lower volumes. If it stays as it is I'll add the line out circuit as well.

Cost me a few hundred bucks to put together, but its well worth it for the sound.

[emmjaydubya]

So is this eating more juice than say, another 4x12? And you're using the Faustine with a 4x12 in the other speaker jack, right? Is this with or without a Variac?

Inquiring minds...

I know I will have to run an attenuator (probably an Alex) and most likely a Variac, and I have two 4x12 cabs with 25 watters. I guess this setup is one more way to bring the volume down, i.e. less speakers, since you only use one 4x12?

Hmmmm....

[vanhalen5150]

It sucks the same amount as another 4/12. It brings down the volume but it allowas you to use less attenuation from the attenuator itself. You get the same low volume but the sound quality is much better because your not making the attenuator do all of the work.

Yeah I have a variac at 90v with the bias cranked.

[Roe]

Like I said, the big question is how much heat will these things produce. At 400w total, it should be a nice little experiment. Hopefully not a costly one. Should have it up and running this weekend.

they will see max 100w, something that should be fine. however, I wouldn't try much more

[vanhalen5150]

Like I said, the big question is how much heat will these things produce. At 400w total, it should be a nice little experiment. Hopefully not a costly one. Should have it up and running this weekend.

they will see max 100w, something that should be fine. however, I wouldn't try much more

You mean a more powerfull amp? Or a higher load?

A bit of testing this week. I could feel the coils get a little warm but nothing major. The attenuator runs much cooler as the load is spread out I guess.

[Roe]

Like I said, the big question is how much heat will these things produce. At 400w total, it should be a nice little experiment. Hopefully not a costly one. Should have it up and running this weekend.

they will see max 100w, something that should be fine. however, I wouldn't try much more

You mean a more powerfull amp? Or a higher load?
.

the former

[vanhalen5150]

I guess what Im saying is its ok for the OT?

[Strat78]

Grabbed a quad of 100w 16ohm motors, think I'll mount them in one of my extrat 4X12's with some sort of fan set up to keep'em cool. Can't wait to give this a try, or at least use them for silently testing builds. Thanks Shannon!

[demonufo]

I guess what Im saying is its ok for the OT?

Will be fine. As long as the attenuator is working correctly. You seem to be presenting the correct load to the OT, and no mismatch. The OT won't even care if it is a reactive load or a resistive load (but you will hear the difference between the two quite often).

[vanhalen5150]

Grabbed a quad of 100w 16ohm motors, think I'll mount them in one of my extrat 4X12's with some sort of fan set up to keep'em cool. Can't wait to give this a try, or at least use them for silently testing builds. Thanks Shannon!

I have a another pair of 50watt 16 ohm I put into a 2/12 cab with 2 25 watt 16 ohm GB 6402 cones.They are wired like a 4/12, that way I still have 16 ohm total on the cab with 2 speakers. I use it with a 50 watt Variplex. Sounds great. Many cool little tricks with these things.

[stratonenator]

Where did you guys pick up those speaker motors?

[vanhalen5150]

Where did you guys pick up those speaker motors?

Webber speaker site. Its under "amp tech tools" on the left.

https://taweber.powweb.com/amptechtools/truload.htm" onclick="window.open(this.href);return false;

[ampSnob]

These things are fun. I have 2 (16 ohm each) in parallel which I'm using in a Marshall powerbrake instead of the internal 8 ohm. Sounds much more natural than the resistor. 

I have found they get really fricken hot. Definitely some holes are going to be needed for cooling in an enclosure. I have mine out in the open which is causing all sorts of squealing which isn't good final design either.

These things are simply inductors, not really 'motors' as they don't move or do anything. The initial resistance comes from copper wire length only. The soft iron core is simply there to mimic the inductance of a speaker mechanism more closely.(permeability, hysteresis, etc.) According to reports, some of these units shipped with little magnets attached to the iron cores. This would cause the coils to move just a little and more resemble the functioning of actual speakers. Of course to get the true response of a speaker it needs to hooked up to a cone that moves air so that resonances and induced reflected signals or whatever it's properly called (the sound of the speaker itself) make it actually sound more natural but then it isn't silent and you might as well use an actual speaker. I have a 200watt celestion I'm someday gonna build an airtight enclosure for for this exact purpose.

Anyway, if you like to experiment, these things are definitely worth picking up.

[ampSnob]

How much voltage is generated from the OT to a speaker?

Never scoped it but in theory it should be:
voltage = sqaure root(wattage * resistance)
40v=sqr(100w*16ohms)
or
50v=sqr(160w*16ohms)