Multi Purpose Load Box and LineOut

[briango]

I'm thinking about building one of these as well and I think if you don't go with active cooling then I might try a piece of copper that is suspended off the bottom a bit and use some dielectric grease on the bottom of the resistors. I think some holes around the sides of the case would be good as well. I did something similar on my homemade attenuator and it seems to stay pretty cool.

BFG

[vh junkie]

Finally got to try the sah5150/Egnater/Rockstah lineout today!
Reminds me of why I love slaving!

I tried 8ohms(amp) into 8 ohms(load), then on to the slave amp... then 8ohms(amp) into 16ohms(load), then on to the slave amp... both sound great!

The resistors are "3 seconds hot" which is acceptable... I suspended the resistors on an aluminum plate, with heat sink grease... but now I'm thinking of adding copper or aluminum plates in a couple of spots underneath... really don't need it (I think)... especially with a little air flow...

[Beavis]

Are carbon film resistors the ticket for the line out side? With the exception of the "Ralle" resistor?

[vh junkie]

Are carbon film resistors the ticket for the line out side? With the exception of the "Ralle" resistor?

That's what I'm using...

... the Ralle resistor is way overrated(25w!)... but if you look at its importance, it's "too big to fail"!

Here's a pic of the Egnater/SAH5150/Rockstah line-out:
Click pic for larger view.

[vh junkie]

OK, lets wrap this thread up!

Final gut shot!
Input, impedance selectors on the left side. Line-out components on the right side.
Match the wire colors to those shown on the previous schematic to figure out the layout.
NOTE: The Jose line-out will be added externally via the center connector on the right.




The line-outs hooked up!
Left: The Egnater/sah5150/RockStah line-out with volume control, with switch to isolate it from the extension jack.
Middle: Extension jack for the Jose line-out which will be added externally via the connector in the center.
Right: Ralle line-out with volume control.


Line-out side of the amp:
Left: Ralle line-out with volume control.isolate it from the extension jack.
Middle: Extension jack for the Jose line-out which will be added externally via the connector in the center.
Right: The Egnater/sah5150/RockStah line-out with volume control, with switch to


Jose line-out:
Jensen JE-6110-PC transformer and 250k pot. I got the Jensen used off ebay for about half the price of a new one.
I'm keeping this external for now because I like to use it for re-amping.

[vanhalen5150]

I have a small fish tank water pump. I'm thinking water cooled. I'm just trying to outdo you Vhjunke!

[vh junkie]

Awww! Thing big!

Liquid Nitrogen!

[502_6speed]

vh, that looks great and what attention to detail. I sure would like to try something like that one day!

[vh junkie]

Given the interest in load boxes on other threads, I figured I might a well resurrect this one. I built two of these... one like you see here and the other with smaller resistors (basically each resistor you see here is replaced by 4 smaller ones).

[rgorke]

12x10x2 Enclosure: Hammond 1444-29
tubesandmore.com P1444-29
mouser.com 546-1434-29

12x10x2 Lid: Hammond 1434-29
tubesandmore.com P1434-29
mouser.com 546-1434-29

Typo - the Mouser.com number for the enclosure should be 546-1444-29

[rgorke]

Thanks for reviving this thread!!!

What about using the Aiken dummy load?

http://www.aikenamps.com/spkrload.html" onclick="window.open(this.href);return false;

Seems that with just a resistive load, the tone is a bit flat - from the clips I have heard versus using a reactive/resistive load.

Do you have any clips for each of the line outs? Does one sound better than another?

[vh junkie]

As far as the hammond enclosure, one might just want get a rack tray to do this with. If you are going to enclose the thing it will need ventilation and a fan. A lot of racks already have this built in.

This is easy to build, but the resistors have to be mounted on aluminum to disspate the heat. The hardest part is drilling all the holes!

This is essentially the Aiken Dummy Load
http://www.aikenamps.com/DummyLoads.htm
http://www.aikenamps.com/DummyLoad.pdf

http://www.aikenamps.com/spkrload.html

I think this is a link to his reactive loads page(s).

The pics of Mark Cs old loadbox showed just resistor and a tranny so that is one of the things I was going for here.
I don't think the tranny coupled version necessarily sounds better than the Rockstah line-out, but the tranny helps with isolation. Sometimes you get a bunch of oscillation with the Rockstah line-out... the decoupling provided by the tranny fixes that right up!

[rgorke]

I am just hearing a benefit of going the resistive/reactive load route. What you go through after the load is a different discussion.

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

[emmjaydubya]

Wow the difference is dramatic!

So if one were to build a reactive load box, would it be with speaker motors like the kind Weber makes? Maybe a blend of vanhalen5150's cool 4 speaker-motor-dummy-load-in-the-ammo-case setup (see below) with this type of load box circuitry? That might be the ultimate slave rig!

Here's Shannon's awesome speaker-motor thread, if any of you haven't seen it...

http://forum.metroamp.com/viewtopic.php?f=14&t=39807

[rgorke]

I too was surprised at the difference.

I have been looking into this type of load.

http://www.aikenamps.com/spkrload.html" onclick="window.open(this.href);return false;

Here is a thread where I found that clip.

http://www.thegearpage.net/board/showth ... ?t=1072793" onclick="window.open(this.href);return false;