Anybody done DIY Load Boxes

[koshikas]

Now ppl i know there are no junk replacements for proper load boxes.

But for some experimentation, i would like to try out taking a DI'ed signal from inbetween the amp and the speaker, and also not fry the OT and the output tubes in the process. Just dont want to spend dough on my wise weasel activities either. I do have a Radial JDI, which has pads and speaker emulation so no problems with DI.

from the brief research i did, a proper load box should be a reactive load, simulating a speaker and impedance loading between it and the OT. i found schematics here for that. But i m thinking of going ahead with a dumb static load (resistor, with heat tolerance), cos this really would only be a experiment.

What are ur thoughts?

[jon the art guy]

Re: Anybody done DIY Load Boxes

While you're at it you may want to try a bridged T load. Its a pretty sophisticated design in comparison to a regular dummy load, but at like 6 parts its.....not complicated.
Nope, I haven't built one, or any one of them. I'll worry about it when I get a tube amp or a friend I can experiment on.

[koshikas]

Re: Anybody done DIY Load Boxes

While you're at it you may want to try a bridged T load. Its a pretty sophisticated design in comparison to a regular dummy load, but at like 6 parts its.....not complicated.
Nope, I haven't built one, or any one of them. I'll worry about it when I get a tube amp or a friend I can experiment on.

bro i m not sure i got what u said right.

bridged T load; the closest thing that i could find with some relevance was http://www.electronics-tutorials.ws/...ttenuator.html

it is explaining about how to reduce db, perhaps quietening the speaker, whereas i m much more searching for a load that will totally take out the speaker from the output path.

[jon the art guy]

Re: Anybody done DIY Load Boxes

Ah yea you're right. I was looking at db reducers when I was looking hard at Carvins but not dummy loads.
The concept isn't far off though. Many loads out there are resistive loads. I'd suggest a Weber if you can, or a Palmer dummy load. So many bands have Palmers going to front of house.

[koshikas]

Re: Anybody done DIY Load Boxes

There is a poor man's reactive load solutions that does the job, but not as properly as a speaker load. PremierGuitar recently featured one such solution which actually got me going on this. Their solution, like jon's is more about reducing decibels of the speaker. The solution is actually putting a incandescent bulb in series with the speaker, although I m sure the bulb on its own will still function as an adequate load.

From what i ve read the speaker is a reactive load that varies its load based on the signal frequencies sent to it. Whereas a make-shift bulb load will only be a different kind of reactive load based on how much current passes through it.

I quote the part where this is described:

Not quite understanding the science behind how the device functioned, I asked Clark to explain. I learned that the light bulb’s load is always changing due to the fluctuating temperature and brightness of the bulb. The bulb is in series with the speaker, so as the bulb absorbs power and its impedance increases, it decreases the amount of power that goes to the speaker. When a light bulb is cold, it only provides 1/10 to 1/15 the amount of resistance as it does when hot. On a 40-watt bulb, for instance, a light bulb measures 26 Ω cold, but it will be over 300 Ω when lit up correctly. Brett and I tried different bulbs with different wattage ratings and found that each bulb changed the tone, feel, and sag of the amp.

We began our experiment with an 11-watt bulb. It reminded me of the guitar tone on “Wild Thing” from the Live at Winterland album by the Jimi Hendrix Experience—it was very compressed and low volume. Using a 100-watt bulb with the 100-watt head was interesting because the volume was still lowered and compression was present in the tone once again. But the 100-watt bulb didn’t compress the attack like the 11-watt bulb did—it instead compressed only the bloom of the notes and added an unbelievable amount of sustain. Not only did the light bulb experiment provide interesting tones, it also entertained us with a bonus light show. The light bulb’s brightness increased when I hit the strings with more force, but when I wasn’t playing, the bulb was completely dark.

- PremierGuitar - Paul "TFO" Allen http://www.premierguitar.com/articles/Light_Bulb_Gear

[jon the art guy]

Re: Anybody done DIY Load Boxes

Oh yea, the light bulb trick is something I'd totally love to try.
I did a search and there's a little more trick as part of the load is the physical movement and the force the speaker has to push. It turns out a gutted speaker will be less than the ohm rating it used to have. You may want to string what would have been a 16ohm load for an 8 ohm out. Use old car speakers; remember its not for tone, its for load.

[koshikas]

Re: Anybody done DIY Load Boxes

I did a search and there's a little more trick as part of the load is the physical movement and the force the speaker has to push. It turns out a gutted speaker will be less than the ohm rating it used to have. You may want to string what would have been a 16ohm load for an 8 ohm out. Use old car speakers; remember its not for tone, its for load.

bro i m all into this gutted speaker thing. i thought though how trivial it is, it is the sh!t. tell me, how gutted do u think the speaker should be. i think the cone should still be intact for the voice coil to work. thinking of that i might as well get a cheap speaker. less see if i can do the impedance math right.

[dominus]

Re: Anybody done DIY Load Boxes

Just pick up a used Tom Scholz Power Soak. Sure, you can make one, but the nice thing about the Power Soak is that you can hook it up to any tube amp. (Switch-able 4/8/16 Ohm.)

[koshikas]

Re: Anybody done DIY Load Boxes

Just pick up a used Tom Scholz Power Soak. Sure, you can make one, but the nice thing about the Power Soak is that you can hook it up to any tube amp. (Switch-able 4/8/16 Ohm.)

it certainly appears to be one heck of a stable power soak too. http://www.rockman.fr/Reviews/Power_Soak.htm. i ll be on the lookout. although i m not really sure whether i wanna pull the trigger for something going around $200-$250 + shipping for an experiment.

the internals suggest this is based on static load consisting of power resistor network.:

[TwilightOdyssey]

Re: Anybody done DIY Load Boxes

I've heard of the light bulb attenuator before; would love to try it some day but am too scared lol. Basically an optical limiter.

[koshikas]

Re: Anybody done DIY Load Boxes

I've heard of the light bulb attenuator before; would love to try it some day but am too scared lol. Basically an optical limiter.

it is scary, because no one knows the long-term implications of running this with tube amps, which is very sensitive specifically with its speaker loads. for experimentation i will be running these on the solid-state amps i ve got. from that, if the enthusiasm kicks in (with results), i m also hoping to jump onto my sole tube amp. few hours wont hurt i hope.

but the '****ty speaker' dummy load thing is also something i m really interested now. doing the impedance/wattage calculations with www.duncanamps.com tools.