How to test amplifiers properly on a budget (gear overview)
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- Опубликовано: 27 авг 2024
- No audio precission needed. I would like to test my amplifiers and compare them. After some digging around and some cheap purcheses I think I am ready. No amp dynos! I will be testing the stuff that really matters.
Bare in mind the voltage divider used in this video can be used ONLY with half bridge amplifiers. Full bridge amps require a differential probe. The construction of such probe is covered in DOG-BUT guide that you can find here:
drive.google.com/file/d/14agZOyeIl3fCKqwDgHtrFqZ58bF7gJ9f/view?usp=drivesdk
Lovin this stuff. Tinkering into retirement. Lord-willing, I will be an old man with great car audio.
At this point you can make a cooking video and I'm here for if :D Very cool setup man!
🤣🤣🤣
Wow, I fell asleep here on the couch last night, I've just woken up and flicked on the tv, then BOOM there it was, like waking up next a to semi hot woman, but without the hangover😏. what an amazing setup mate, plus the informative walk through, just what I needed. Now I know what I'm gonna do today. I'm subbin' and 👍. Cheers
Great video!! Looking forward to test mine.
Your first test with signal noise i dont believe will work, as the noise we all know of is from the alternator which is AC hum which you don't get from a DC battery.
Well, it's very easy to connect the whole rig to car battery instead of lithium🙂 Just run the engine and measure.
Exactly, you need an alternator and other stuff running to test for noise. From a battery will always be clean.
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Agreed regarding being connected to the car's electrical system (or not).
It is usually a dirty noisy or failing rectifier/power diode in the alternator that causes the infamous alternator whine. The rectifier in the alternator converts its generated A/C voltage to DC.
Noise can also be caused by other electrical system modules in a vehicle...I've had an ABS module (anti-lock brake system) and fuel pump cause noise. Or any type of ground loop.
Does this particular Alpine amplifier have Differential RCA Inputs like the 2nd Gen PDX, the X-series that you have, and the STATUS amps? That can make a big difference on whether or not you have inducted noise from RFI & EMI sources.
@@bbfoto7248 my understanding is that all of these Alpine amps have single ended RCAs.
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Nerijus, I also wouldn't totally dismiss the Amp Dyno power ratings, as they are determined by or based on a few things which are useful to know:
# 1. The car's electrical system or power supply DC voltage Level that is fed to the amp's power connections during the test.
# 2. The Power Rating Numbers that the AMP DYNO provides are based on at what point a certain Distortion Threshold is reached...usually 0.1% THD+N, 1.0% THD+N, or the onset of Clipping.
Both the Voltage and the Distortion Threshold are visable in the Amp Dyno's Display when the test is completed.
So IMO it is useful information.
As a point of reference, with speakers it is generally accepted that we cannot begin to detect Distortion until it reaches ~3%. And that threshold is even higher for subwoofer frequencies...closer to ~10%. It depends on the type of distortion as well as at what frequency.
Generally you fuse for the wires amp capacity not from what the source can put out or demand.
Great fan of you productions, looking forward to see some results! The fun factor of amp dyno's is good, but I'm really curious about the actual performance of these amps too.
Since you're open for comments: please pay some attention to using balanced and unbalanced signals. The focusrite has 4Vrms balanced output, but you cannot use that for a RCA directly.
You could indeed use the +output only for 2Vrms, but make sure not to short the -output AND check if the performance of the + vs GND output is OK: A balanced output is designed to have a good differential performance (between + and -), not mainly referenced to GND.
The same goes for the input, I'm not sure if you've shorted the - input to GND? Which is OK, but it could also be used as a floating input for the negative amp output (with split the 22k into 2x10k towards each input and the 330R between + and -). This will either avoid a GND loop for half bridge amps and give the opportunity to measure bridged outputs, as now one of 2 bridges would be shorted to GND? Also most factory and low power channels are already bridged designs and that some amps drive the - output of CH2 to avoid supply pumping in normal use and don't need channel inversion for BTL use between CH1+ and CH2-, which would also be shorted. (or maybe I assumed wrong but please check!)
Some car amps dont connect the RCA GND to GND and sneaky make a differential input of that to avoid GND loops, in that case it may even be wise to properly connect the GND of the amp to the GND of the interface to avoid common mode issues, but still: make sure you only create intended loops!
Hey man, this is very cool stuff and I confess that after reading it 5 times it still confuses me🤔 Any chance you could contact me directly, as I have questions and you seem to know the answers🙄
I Had the Gen2 scarlett. Maybe something was wrong or fried on it, but Something was actually off with the output. You could see it in the measurements. I got a Gen 3 and it cleaned up. Surprised you are only 1v out? I was pretty sure it gave 2v. I'm 2v out on the 3rd gen (at 0db)
Sometimes I get a bad signal due to poor USB connection. Unplug, plug back in or use a different USB port on the laptop and all is good.
Plz make a video helix DSP autotuning step by step and comparing with REW MASUREMENT
Unfortunately I don't have a Helix procesor with the new features.
@@RAW-CAt almost helix give auto tune in every DSP
@@surajbhan6549 auto tune is only for 5.0 software and ACO processors. Older non ACO processors cmdon't have that.
@@RAW-CAt ok thanks
I could do with this for testing my amps 😂 still not got to the bottom of my noise issues lol
Where are you at? I could measure your amp🤔