4 Webber Speaker Motor Load

[bmf5150]

Anyone incorporate with an attenuator circuit?

[vanhalen5150]

Anyone incorporate with an attenuator circuit?

I use them in parallel with an attenuator. For lower volumes it allows you to keep the attenuator up a notch but still have a nice lower volume. I just have the attenuator at 16ohms and the speaker load the same. Amp drops down to 8 ohms.

[rgorke]

Could also use the Aiken dummy load for similar results, no?

[vanhalen5150]

Yeah same thing. Your amp is seeing both resistive and reactive.

[jnew]

Very cool looking little motors. I'm doing a slave setup right now but using a resistive only load. I don't think it's as good as it could be and am interested in a more reactive type load. Does anyone else have experience with using these as a load in parallel with a line out for slaving?

[rgorke]

While these clips aren't specifically using the Weber motors, they are using a reactive load - the Aiken designed load.

http://soundcloud.com/ilya-v/straight-vs-reactive-vs" onclick="window.open(this.href);return false;

To me, there is a significant improvement to warrent going this route.

[jnew]

OK, so to clarify here, if there are no moving parts, then this would still remain as more of a resistive load then. Where does the reactive happen here? These things are super cool looking and I'd love to build one but I don't want another resistive load.

[rgorke]

Don't ask me to explain it scientifically, but the inductors and even some transformers mimic the moving parts thus the amp "feels" a speaker type load. The Marshall Power Brake is based on either an inductor or transformer and that is why it sounds better than some other attenuators.

[jnew]

Aah. I see. Good to know. Probably a worthwhile project then.

[Strat78]

I mounted my weber motors inside an empty cab and it seemed to be doing the trick, though I didn't notice an improvement in the amps performance or tone. In fact a strange very loud whistle began to appear to the point where it became unbearable. I noticed that if I jiggled the plugs at the power strip the sound would go away briefly but it increasingly would come back with more frequency. Finally, after switching to a different variac and actually replacing the power chord to my Echoplex (those two plugs seemed to be the source of the noise when jiggled), I unplugged the motor load cab and the problem was gone!
Maybe I'll put the motor load cab on the other side of the room and see if that works.

[demonufo]

Were the motor units near anything that could induce noise into them? Transformers etc...

[vanhalen5150]

Thats weird, mine have never done that. What combo of loads/total do you have? Enclosure?

[Strat78]

Perhaps I spoke too soon. The motors are wired series parallel into an open 1960B cab in parallel with a power brake into a regular cab. The open chassis is on top of the cab, the variacs are right next to the cab and the Echoplex's were right in front of the open part of the motor load cab. I think somehow the motor load cab was compounding a problem that was already there. Now I recall having to jiggle the plugs and even the cable going into the power brake to make an annoying buzz go away. Perhaps the echoplex is causing a ground loop like I've heard they can do.

[dirtycooter]

So what would happen IF

I have 3 total 16 ohm 100 watt resistors and a 16ohm 4x12..... each 16 ohm load here is wired series parallel like a giant 4x12 with a 4x12 acting as one of the 4 total 16ohm loads....

This would be a total of 400 watts of load with a quarter of it being reactive still at 16ohms.

Anyone try this???? Wouldn't this show the 4x12 only a quarter of the wattage output from the head??
It would be like the whole 4x12 takes the place of the 4th resistor and spreading out the load and output wattage.
It would be more like the 2 weber motors with two speakers on a 2 to 2 scale but only on a 1 to 3 scale wouldn't it? The reactive part being the cab fluctuating while the reisistors eat up some wattage?
I mean a whole 4x12 is acting like one speaker really though there is 4 speakers in it it equates to basically 1 as far as the amp knows. The other three speakers are resistors here in the series parallel scheme.
The 2 weber motors and 2 greenbacks got me thinking.
Or even this.. but it would be costly
3 banks of 4 speaker motors wired series parallel to equal a 16 ohm load each and the fourth is a full 4x12.
That would be like running 4 4x12's and only one makes sound. Am I onto something or is it simply gonna follow the path of least resistance and do nothing to attenuate??

[demonufo]

There will be no benefit of running three banks of motors and one cab. May as well use three high watt motors and one cab. The losses would be immense otherwise and unnecessary expense for no gain.

Running three resistors and one cab as described would end up with the cab seeing one quarter of the power load ON AVERAGE, but that will vary with frequency and volume as the load of the speaker is less even due to it's reactive nature.

A resistive load will be more even in it's attenuation on an electrical basis, but that's not necessarily what our ears want to hear, due to the nature of both speaker behaviour and our hearing response.