Author Topic: Anyone build an amp load box  (Read 297 times)

BryGuy

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Anyone build an amp load box
« on: January 11, 2018, 07:49:57 PM »
Friend of mine asked me if I could build an amp load box for his amp. He basically wants to run the amp silent and just use the direct out. So anyone have any advice or a goby designs/schematic? Can it be as simple as a resistor in a box? I guess the biggest concern is getting rid of the heat. He says it's a 15 watt amp but I should know more when he sends me all of his gear info.

gordo

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Re: Anyone build an amp load box
« Reply #1 on: January 11, 2018, 09:22:32 PM »
It can be, but the results are sometimes under-whelming.  I have a simple resistance load box that's switchable for 4/8/16 so I can bias tube amps without blowing out a speaker.  I also have load resistors built into most of my "public" amps I leave at church so that if someone fires it up without plugging in a speaker cab it won't smoke an OT.

If looking for recordable line out it's hard to beat the Weber/THD/Riviera boxes but they're pretty pricey and in that order.

flanagan0718

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Re: Anyone build an amp load box
« Reply #2 on: January 12, 2018, 09:07:41 AM »
I'm building one for a friend (hopefully) this weekend. The resistors are kind of pricey. I got 4 ohm 50 watt resistors. He has a 30 watt head so 50 will be more than enough. I'm putting a 4 / 8 / 16 ohm selector switch in it so he can use it for other heads too (50 watt max). I'm also going to see if i can get an output volume control for his headphones.

gtr2

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Re: Anyone build an amp load box
« Reply #3 on: January 12, 2018, 10:07:43 AM »
I have a weber mini mass that wasn't too much more than what it would have cost to make it.  It has a reactive load.
It works great but if you want to use the line out you'll need some sort of speaker sim to run it through.

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HamSandwich

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Re: Anyone build an amp load box
« Reply #4 on: January 12, 2018, 11:22:37 AM »
I have a weber mini mass that wasn't too much more than what it would have cost to make it.  It has a reactive load.
It works great but if you want to use the line out you'll need some sort of speaker sim to run it through.

Josh

I have their mass lite, 100W. Highest wattage amp I used it for was a JTM45, which has varying wattage estimates, but certainly not over 50W. I can run it silent into cab sims on a computer with really great results. I've read you're supposed to shoot for 2x the wattage if you're going to turn the amp down to silent, FWIW.

OTOH, I have tried a resistance based load and while I'm sure you can find a sound in there with enough processing afterwards, the Weber product blows it out of the water (based on my amazing and unbiased memory  :P :P :P :P :P )

I believe it was FSB that had schematics of the Weber load boxes. Quick search has this one with the reactive loads on the front page, might have to search a little deeper for the resistor ones,  but I'm sure I've seen them on there somewhere.

http://www.freestompboxes.org/viewtopic.php?f=2&t=2287
« Last Edit: January 12, 2018, 11:24:27 AM by HamSandwich »