(Mods: feel free to move this post to the most appropriate sub-forum if this one is wrong.)
I've been wanting to have a means of hooking my Vox AC4 directly into my Behringer UMC202HD for computer recording. This would be to bypass the amp's speaker. Obviously, I shouldn't just send the 1/4" cabinet output to the AI as that would likely melt something. The answer seems to be "loadbox", but all the commercially available ones seem extremely expensive given what they're actually doing (tapping the characteristics of the speaker drive signal to a safe, line level). I tried searching the forum, but when dealing with stomp box electronics the words "load", "tube", etc are very common.
Also, I apologize for some of my ignorances, I'm a EE by training but I don't work with tubes, audio signals or speakers (I design high speed serial buses and automotive computing platforms). I know that the load of a speaker is not constant over frequency because of many things (magnetics/inductor/transformer, cone and enclosure characteristics, etc).
So, for those that have made their own loadboxes:
- How much difference is there in using a (almost purely) resistive load from as compared to an inductor + resistor load?
- How do you size the inductor to handle the power from the tube amp?
- Can you resistively divide down the signal then add a small inductor in parallel?
- Are there any other considerations to allow flexibility between my little 4W class A and a ~50W amp? Obviously matching the speaker/cab impedance, but what else?
- Would it be wisest to cut the signal power down to line levels or below then redrive them with a non-distorting opamp circuit?