My New Oscope Edit! Its Here! Pics Inside!

[ISO]

you will be happy i got mine last week. i am ready to throw the thing threw a window when i couldnt get it to work. i managed to figure out how to check the clipping but i still cant figure out how to get the wattage readings from it.

...you can't get wattage readings from an o-scope...

I was kinda wondering why people were saying this...not sure how it would have worked.

I see it listed on the product sheet, but I've never seen an O-scope that did that. How exactly does it calculate wattage?

That's still just a 'guess'

You really need a true RMS AC clamp meter to measure current, o-scopes just read voltage so you're missing one side of the P=IV triangle (or the P=V^2/Z one)... speakers are a reactive load so just telling it that it has a 2 ohm load is not much good...

Like Boon say's theres a little more to it than setting an O-scope to some non-variable load.

I'm afraid everyone will have to do alittle work to find out anything else they want to know except were clipping is at with a scope.

Start here and scroll up to learn how to find your real world wattage.

http://www.stevemeadedesigns.com/board/ind...st&p=352723

You'll need:

Ohm's Law

O-Scope

AC clamp meter

Digital multi meter

Paper and pencil

Calculator

Have fun!

[fritosaregood]

mine should be here today. i gotta sit and wait

[SundownTL3.2]

found out how to use this yet roscoe?

[fritosaregood]

mine showed up today. I got it from PartsExpress. I opened up the box and i came with a free DMM. to bad i already have a ton of them.

[brewer_brewer]

mine showed up today. I got it from PartsExpress. I opened up the box and i came with a free DMM. to bad i already have a ton of them.

nice. freebies. was it just a lil cheapo dmm?

you still going to show up at the comp on the 25th. i'd like to see hows yours is before i buy one.

[fritosaregood]

nice. freebies. was it just a lil cheapo dmm?

you still going to show up at the comp on the 25th. i'd like to see hows yours is before i buy one.

im not gonna be able to make it. gf's prom

I gotta wait to use the oscope too. its a bday present, ill get it on the 25th, i can wait the 10 days since its free to me.

after i get it all figured out i can meet you up at harbor freight again.

it looks like a cheap dmm,

[brewer_brewer]

im not gonna be able to make it. gf's prom

I gotta wait to use the oscope too. its a bday present, ill get it on the 25th, i can wait the 10 days since its free to me.

after i get it all figured out i can meet you up at harbor freight again.

it looks like a cheap dmm,

thats cool.

i'll be there. most likely just helping out chris and jeff. i don't think i'm going to compete because i already know what i do with this setup. just gonna watch.

[ISO]

found out how to use this yet roscoe?

So far the best way to use the Velleman is to calibrated it properly first.

Then I found that the auto setting with the probe set to x10 works the best so far.

I have messed alittle bit with all the settings on the HPS10SE so far and it just seems like auto seems to work best.

It also seems that the HPS10SE is about .7 volts to 1 volt off from my Fluke 112 True AC DMM.

I forgot to turn on the x10 function in a few of the pics so to compare the AC voltages between the Velleman O-Scope and the Fluke 112, move the decible point to the right on the Velleman O-Scope when the x10 function is not activated in the pics.

This is what the screen should look like when you have the O-Scope properly calibrated.

I used a 50 hertz test tone from the 2006 DB Drag Competition Disc for all testing done here.

Hook the O-Scope to the RCA outputs of the H/U and leave all the settings to flat to find clipping on the H/U(Head Unit). That means shut down all signal processing that the H/U has to offer.

My example is a Panasonic CQ-C8300U Head unit and it will not clip no matter what and I did everything I could to try and make it put out a clipped signal and it just won't put out a dirty signal.

Great unit Panasonic! 4.69 volts of clean output.

My test unit is a Rockford Fosgate 1501BD with no load on it and I wanted my Fluke hooked up so I could compare the AC voltage accuracy of the Velleman O-Scope.

This is what it looks like when setting up such a test.

If you are able to zoom in on this pic, then you will beable to see were I forgot to turn on the x10 function. The Velleman says 7.71 Volts AC and if the x10 function was on the Velleman would say 77.1 volts AC and as you can see the Fluke says 76.3 volts AC.

This in my opinion is a beautiful unclipped signal from the RF 1501BD. This was done with the crossover turned all the way up to 250 hertz since the crossover on this amp is not defeatable and since I use the Punch Bass I probly would leave the gain at this setting.

For most people you might want to set the gain with just alittle bit of a clipped signal. Something close to this should be great.

(Note I have the x10 function activated on the Velleman and is now a little more easyer to check the output voltage against the Fluke.)

In this pic I left the Gain control set the way the O-Scope told me to set it at but now its time to adjust the crossover.

I used 75 hertz as my crossover point and you can see that the AC voltage has dropped some but I feel that the gain on the amp should not be changed.

Hope this helps some of you guys and good luck and happy tunning.

LOL Don't forget to turn on the x10 function on the O-Scope.

If you are useing this scope to set the gains on alot of the same amps I recommend useing a very acurate DMM inline with the Velleman so you can write down the actual AC voltage from the DMM.

This will allow you to use the DMM to set the gains on the rest of the amps so you won't have to hook the Velleman O-Scope up to every amp that is the same.

Nice little trick to know if you are putting 4 amps on one Quad Coil Subwoofer, 2 amps on a dual coil subwoofer or just plain have alot of amps to set the gains on before you go into the DB lanes.

Write down your AC output voltage you got from the first amp. Then use that as your reference AC voltage to set up the rest of the same type of amps in the vehicle with a Digital Multi Meter.

That should help you move at a faster pace than useing the O-Scope on every subwoofer amp before every competition.

[zfrerichs]

so how do you calibrate it first?

[moh.vze.com]

So Boon, is it true that it's bad to have a long ground lead on a scope probe? I heard if you keep the ground lead as short as possible, you'll be able to get a more accurate reading as far as over shoots and under shoots go.

I remember when I bought a cheap $50.00 10x scope prob for one of my Transmissions Lines class and it came with a stock dangling ground lead. It seem to show more of a detailed graph when I took the dangling lead off and used a shorter wire.