New dummy load

DankStar

DankStar

Her Little Mojo Minion
Made this to try and capture the speaker signal from my amps then realized I have the crappiest DI ever and couldn’t do a proper test so a new one (Warm Audio WA-DI-P) arrives tomorrow.

i used this YouTube vid but with a female jack instead of male

https://youtu.be/8jFKa8AJkFo

switchable 4 ohms/50w or 8 ohms/100w
 

Attachments

  • 07D02634-437E-4BAF-BB1C-2C4FD15CD4C9.jpg
    07D02634-437E-4BAF-BB1C-2C4FD15CD4C9.jpg
    49 KB · Views: 0
Last edited:
Just a heads up, if you dump 50W or 100W into it (depending on the setting) wear gloves to pick it up and don't let it sit on anything that's not heat resistant, and I wouldn't do it for long, not sure how long those resistors will last at maximum power without proper heat sinking.

FYI, first comment:
"This would be extremely unsafe to use with any amp more powerful than 5w. The 25w rating of those power resistors is assuming they are correctly mounted to a metal surface, preferably with thermal grease. And it is also hazardous to leave them in the open air, because they will become very hot if any appreciable amount of power is run through them for more than a couple seconds. This is a serious burn hazard if anyone were to touch it. The switch and zip tie may very well melt. It looks clever, but it's not well considered. The same circuit could be built into a small ventilated metal box and be 1000% safer."
 
Last edited:
Thanks for the heads up. I guess most people use these for blasting their amps or something? I'm mainly using this to capture the signal of two SS low-wattage amps (10 & 20 watts) that don't have line outs that I put speaker extension jacks on. I'm literally on like volume 1-2. I probably don't need it with the SS amps but I want the amps to react as if there's a speaker connected.

I had it running for a bit with my other crappy DI and the box didn't even get warm tbh. I'll watch it when I test my tube amps (also low wattage, 10-20 watts) as I'm sure they put out more juice, but again, my goal is not to crank them up at all (I have dirt pedals I really like the tones of for OD), just capture a signal to see how it sounds (with speaker IRs) versus using only a guitar into an interface with virtual amps (and versus reamping into a real amp with a mic) - tests that have been on my to-do list for quite some time.

I like the idea of vent holes in the case in the event that the resistors do end up getting hot, but if it gets so hot I can't even touch the case I'll most likely not use it out of fear of part failure/amp damage.

Yeah, I thought it was a bad idea for him to zip tie two together like that, but he appears to be a farily knowledgable electronics guy (more so than me)
 
Last edited:
I just skimmed the video but looks like he is just using it for setting bias, not running them for a long time, but still, I would have at least doubled the power ratings of the load resistors, probably shot for closer to 5 - 10X. FWIW, to run those resistors near maximum they should be properly mounted to heat sinks (not just a box) with thermal grease, and there should probably be forced air cooling on the heat sinks (a fan blowing across them).

FWIW, this is coming from someone who did play with some of these back his younger days and has burnt fingers!
 
explosion-explode.gif


That's one of the most piss poor designs ive ever seen.
Great way to F up an amplifier.
That would melt a Cliff jack for sure.
So much for the "internet generation".
 
Didn't Lynyrd Skynyrd write a song about this stuff? "Ooo ooo, that smell. Can't you smell that smell." :D
 
DankStar said:
Made this to try and capture the speaker signal from my amps then realized I have the crappiest DI ever and couldn’t do a proper test so a new one (Warm Audio WA-DI-P) arrives tomorrow.
Click to expand...

How do you like the DI? Why did you get the passive one and not the active? Conventional wisdom is that passive pickups match best with active DI. And vice versa.
 
Not here yet unfortunately. I mainly just need it to handle an amp signal, otherwise I plug right into the interface. The level pot should come in handy. Ideally I’d have gotten the active (since it can also run passive) but got budget-conscious.
 
DankStar said:
Not here yet unfortunately. I mainly just need it to handle an amp signal, otherwise I plug right into the interface. The level pot should come in handy. Ideally I’d have gotten the active (since it can also run passive) but got budget-conscious.
Click to expand...

If you are just taking signal from a loaded amp, what I use $40 is Behringer Ultra G. It has pads and ground lift for dealing with hot signal from amp. Defeatable cab sim is good too.

Amazon can get it to you overnight.
 
The Ultra G is cool but it does not provide a speaker load. You still need to connect a speaker cabinet to the "thru" jack to avoid damaging the amp. I had one for a while. Then it died and became a door stop.
 
That’s what I was replacing - mine got all goofy, cutting in and out. Decided to upgrade rather than troubleshoot. I liked the cab sim on it.
 
I use a simple "reactive" loadbox I got off reverb a few years ago ("Julius Loadbox") along with a Behringer Ultra G DI. Never had a problem. i've often run the thing for upto 2 hours hooked up to a wide open 120 watt tube amp and no problem. It never gets too hot ..just kinda warm. Mine is rated at 200W though.......

Julius-Load-Box-1.jpg



Julius-Load-Box-2.jpg



Julius-Load-Box-Gutshot.jpg
 
^^ $69 + $20 shipping.. :D

This was just a quick test w/ the amps into the DI/Loadbox and out to my digital recorder (No bass/ delay/reverb or any other FX/processing..)

 
Last edited:
Very cool! Thanks for sharing phantasmagoria

played around last night with the warm audio & dummy load with my SS combo.

the pedal I thought I was going to use (Ross distortion) into my amp sounded a bit weak in the mix but when I changed to an AMT M1 with a TS it livened up a lot. The warm audio works perfect and my dummy load doesn’t even get warm at such a low volume.

gonna do a tube amp test later…
 
Last edited:
Apparently the coil is the middle is a simple inductor which does make it a "reactive" load as the listing says. That's what a couple of the more electronics savvy guys on here said when I posted up the gutshots soon after I bought it..

Julius-Loadbox-Reactive.jpg
 
DankStar said:
Very cool! Thanks for sharing phantasmagoria

played around last night with the warm audio & dummy load with my SS combo.

the pedal I thought I was going to use (Ross distortion) into my amp sounded a bit weak in the mix but when I changed to an AMT M1 with a TS it livened up a lot. The warm audio works perfect and my dummy load doesn’t even get warm at such a low volume.

gonna do a tube amp test later…
Click to expand...

No problem Dank. All I can say is I've personally had no problems with my box (overheating etc) and it works /sounds great for being as cheap as it is..no complaints :bigthumb:

Post up the results of your tube amp test if you can :)
 
Funny fact. If I put my ears kinda close to the loadbox I can actually hear what I'm playing really softly w/o it being hooked up to a speaker....the coil thingy I'm guessing?
 
Phantasmagoria said:
No problem Dank. All I can say is I've personally had no problems with my box (overheating etc) and it works /sounds great for being as cheap as it is..no complaints :bigthumb:

Post up the results of your tube amp test if you can :)
Click to expand...

Here's a quick test with a tube amp (bogen challenger 20-watter) with an AMT M1 and a TS in front. Speaker out to DI, thru to my dummy load

Processing: ignite power amp, ownhammer IR, and SSL channel strip with some filtering and compression

https://youtu.be/ak7AJuEJ7_E
 
You must log in or register to reply here.

Similar threads

Kamanda~SD
Recording gurus I need your help, sound card! (Long post)
Replies
5
Views
2K
Kamanda~SD
Kamanda~SD
Back
Top