advertisement


Dummy Speaker

BTW If you want to use a resistor with wideband audio, check that the resistor is 'non inductive' - i.e. has a low inductance. Partly so it *will* then be X Ohms (for your choice of 'X') over the audio band.. Partly because some amps may not take kindly to some values of inductance on the end of some cables.
 
tmhutch said:
Yikes. OK. Does anything else come to mind that I might use besides speakers?
Click to expand...

Why not just sit back and play some music and enjoy it as your cables 'burn in'?

Here's an example of one of my 2 channel dummy loads.



 
Last edited:
mark121211 said:
Here's an example of one of my 2 channel dummy loads.

Click to expand...

Very close to what I did back in the day when I had a 50w Marshall guitar amp and wanted to take a recording/headphone feed direct from the speaker output.

I didn't make the mistake of touching the heatsink more than once...... could have fried breakfast eggs on that thing.
 
If you really must burn a cable in , wire it to something that isn’t expensive, like a bulb!
 
Back at Uni in the 70s a group of electronics students built a 600W per channel amp. A massively parallel output stage, ideated from a Mcintosh unit I think. I was somewhat on the fringe of said group. You can imagine the size of the dummy load I helped build to get it tested properly!

We then used the amp for student discos.
 
awkwardbydesign said:
Compared to the inductance of a speaker? Surprised.
Click to expand...

Its because in the well-ultrasonic region the connecting cable can act to convert the load's inductance to something quite different as presented at the speaker terminals. When using a dummy load you probably *won't* have the speaker also connected. i.e. in tests with the load you are generally *only* using the load via cable. Not a speaker.

But, yes, some speaker+amp+cable combinations also would lead to problems like RF oscillations. Seen it happen. And something some makers are wary about having perhaps been bitten!

You can find measured results on this on my webpages.
 
I had a set of 'quite big' loads when developing the Armstrong 700 range. (>200Wpc 8 Ohms, and about 400 Wpc 4 Ohms.) Bigger than that on peaks for music.

I used some big non-inductive loads on big heatsinks. They stil tended to melt the top of the bench if used for a long time! 8-]

FWIW I used individual 8 Ohm loads as I could then use series or parallel to get 4 or 16 Ohms for tests without needing lots more loads.
 
Have you actually done a comparison yourself? Or are you just repeating the mantra?
I have just been reading "Quantum", by Manjit Kumar, a history of quantum theory, and even there theoretical physicists fell into the same trap of assuming that just because some authorities claimed to have found the definitive theory of quantum mechanics, they stopped experimenting for themselves. An absolutely brilliant book, BTW. I now understand just how much I don't understand! :D
I have compared before and after cables, and made up my own mind.
 
awkwardbydesign said:
Have you actually done a comparison yourself? Or are you just repeating the mantra?
I have just been reading "Quantum", by Manjit Kumar, a history of quantum theory, and even there theoretical physicists fell into the same trap of assuming that just because some authorities claimed to have found the definitive theory of quantum mechanics, they stopped experimenting for themselves. An absolutely brilliant book, BTW. I now understand just how much I don't understand! :D
I have compared before and after cables, and made up my own mind.
Click to expand...
Here we go again, you can't know until you've tried it. First question, if you are comparing something, is your measurement system accurate, reliable, and repeatable? If your measuring system is your ears, then the answer is "No". If your measuring system isn't reliable then your findings are meaningless.
 
You must log in or register to reply here.


advertisement


Back
Top