I'm setting up to do some amplifier measurements. I think it would be great to have measurements taken like Langston Holland has performed in the past. Seems like there hasn't been any consistent measurements being taken in some time since Chasw98 stopped.
I have a scope to measure peak voltage, and in turn, power. I have parts coming to setup a resistive load bank.
Unfortunately, my scope is not the greatest and doesn't provide THD numbers. I'll be using it to measure max output, but I'm thinking of using ARTA or REW to measure distortion with stepped sine waves. If anyone has experience with this, please share. I may get a nicer scope before starting this. Update: looking at Rigol DS1074Z, upgradable to DS1104Z via software.
I'll be setting up a webpage sort of like data-bass to compare and graph various results. I'll also be outlining the test procedure, so if anyone else with comparable equipment wants to take measurements, there will be a standardized procedure.
The first data collected will be CEA2010 bursts at various frequencies, I'm thinking: 5,10,20,30,40,80,100,200,500,1000,2000,5000,10000, 15000,20000 hz
I'll capture the input and output waveform until distortion becomes significant and use this as peak voltage. From there, wattage can be calculated with with Vrms^2/R.
The next tests would be sine sweeps at various levels to measure FR and THD. This is where I think REW or ARTA will be needed with a voltage divider. Any suggestions for a good low noise audio interface to use for this? Not looking to break the bank here. Update: Looking at the Scarlett 2i2 for now. Seems to measure well.
Ideally I'd like to perform these tests at 2, 4, and 8 ohms, with one channel, both channels, and bridged if possible. Once I get my heating elements in I'll see how I can wire them up to attain this.
I'll also post hi res pictures of the amps internals. It should be a nice repository if I get it going.
Also going to measure idle current draw, noise at 1 foot, and possibly RF noise.
I have a few amps to start testing with to get the procedures ironed out and the website built, then I'll start testing amps for anyone who wants.
If anyone has any feedback, I'd like to hear.
Got my heating elements. About 13.4 ohms each. Impedance in parallel should be about 4.45 ohms.
Got my audio interface. Scarlett 2i2. Measures well. I should be able to sufficiently test amps with this.
Sweep, nice and flat..
Intermodular distortion nice and low
Waveform from IMD test
CEA 2010 burst
Took some pics...