So I am buying an oscilloscope....

Well after my setting gains with a DMM thread I have decided to just buy an oscilloscope. It is more accurate and easier than setting with a DMM with a load on it. I also can not get the mini speaker locally. So a PCs based scope is my go to now. Not much more than a shop setting them and then I have the gear to do it if/when I ever do another build.

Here red is my question, what is a good one to get? Amazon has the sain smart.....

http://www.amazon.com/gp/product/B00...140_em_1p_0_ti

and the Hantek...

http://www.amazon.com/gp/product/B00...140_em_1p_1_ti

but what's the difference?

You still need a load with an oscilloscope.

Quote:

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Originally Posted by ca90ss

You still need a load with an oscilloscope.

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yes thanks. I will just leave the speakers hooked up and use ear protection.

A dummy load is a whole lot cheaper than new speakers.

Quote:

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Originally Posted by ca90ss

A dummy load is a whole lot cheaper than new speakers.

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But it with a scope I should be able to set gains accurate so the speakers don't blow, no?

To set gains, you hook the o-scope to the outputs of the radio and play a test tone. You then watch the scope as you slowly turn up the volume. When you see the signal start to clip, you back it down a bit and record it as your maximum unclipped volume. You then move on to the next component down the line (EQ, processor, etc.), play the same test tone at full unclipped volume, and adjust the gain on the second component intil it starts to clip...back it down, and now it's set. You keep doing this until you get to the amp. The problem is that the amp puts out more power than the oscilloscope can handle, so you need a voltage divider. Again, play the test tone at full unclipped volume and turn up the gain until it clips and then back down a bit. Now everything is set.

If you wanted to use your speaker as your voltage divider, know that you will be running a fully-amplified test tone thru it to the point of clipping. If the speaker can handle more power than the amp produces, you might be okay. However, if the amp put out more power than is actually needed, you could fry the speaker during the setup. I would recommend either a dummy load from the eBay link I provided on the other thread, or using the coil of an old speaker.

An oscilloscope won't keep you from blowing speakers. Clipping doesn't blow speakers, power kills speakers. If you start playing test tones at full power, clipped or not chances are pretty good you'll end up with some nice expensive paper weights.