foreverstrung wrote: ↑
Thu 12/22/22 4:05 pm
So I swapped out my Siglent scope for a 1104x-e. I'm getting ready to fire it up for the first time and trying to get motivated. I've watched tons of videos on scopes but still really don't have a line on what I'm doing. I'd sure appreciate some very basic 1-2-3 direction for setting the unit up correctly and then chasing down the circuits. Like your explaining to a child, because I feel about as smart as one right now with this thing. I know the black wire with the 3 prongs plugs into the wall, but that's about it. lol
Josh mentioned to use a guitar in place of a signal generator a while back? Do I need that sound ever present?
A signal generator is required. To really test, you need a 1kHz sine wave being fed into the amp. This is the cheapest/decent signal generator I've used: https://www.newark.com/tenma/72-505/han ... dp/66F3575
(though I have a couple nicer ones I don't need anymore if you feel like wasting money
You can also get a signal generator app on your phone, but that's trickier to calibrate sometimes. Look for the "function generator" app.
Follow the directions to calibrate your scope probes. You'll be connecting the probe(s) to the calibration terminal on the scope. Press the "auto" button, and it will show you a square waveform. Adjust the screw on the probe as per the directions.
After you've calibrated your probes, leave them set to 10x. Then connect them directly to your signal generator, and set the generator for a 1kHz sine wave. Adjust the output of the signal generator to somewhere between 150 to 300mV (millivolts). That's a relative range for guitar, low mV being lower output pickups. You'll need to hit that "auto" button again to acquire your signal (at least until you get good at messing with the knobs).
Once the signal generator is calibrated to the correct range, you can then plug it into your amp's input jack.
Doing this test with the scope is much easier (and safer for your ears) with a "dummy load." Personally, I use an attenuator on my workbench as my dummy load (it has a speaker cone in it). Alternatively, you can google making a dummy load yourself with a high-wattage 16ohm or 8ohm resistor. NEVER turn your amp on without a speaker or dummy load connected.
This page has some great info on using an oscilloscope for an audio amp: http://www.r-type.org/articles/art-125.htm
You can start by connecting the scope probe to your speaker jack. Chances are, that may look normal if you're just troubleshooting your reverb. So you will need to look at the schematic and what points bring audio signal into, through, and out of the reverb circuit.