Looking For a Portable Oscilloscope

Hi guys,

I'm going to be upgrading my system to a more powerful one and will be using 3 amps, the installing I'm comfortable with, but it's come the time where I feel I want to de the audio setting myself, thus needing an O-scope to set the gain levels. Due to me being a student I want a portable one, because I live on campus and outside plug points are not available for power supply. The options I've been looking at are:

Velleman HPS10
Velleman PPS10

To me they seem very similar, how are they purely for car audio application? I'm not going to be doing any high level competition installs (yet), so I'm just looking for a basic easy to use unit.

Would a laptop option such as the:

Velleman PCS100

possibly be a better option?

Also I'm not managing to figure out as to why these o-scopes have only one probe, don't you need two, one to connect to + wire / terminal and one to connect to - wire / terminal??

I live in South Africa, so setting a budget is difficult, but looking online it seems $100 to $150 is the equivalent price range (not directly converted).

Any alternatives to the ones listed above would be considered and any assistance would be, much appreciated!

 

I was also thinking about this. I need to set the gain levels for:

a sub amp (You use 40Hz test tone right?)
a front split system amp (what's this test tone's frequency?)
and a rear 6x9 amp 3,4or5 way (again not sure of this test tone frequency?)

I'm just also struggling to understand as to how you find the head units distortion point (can't remember the official jargon name for this, apologies)

 

The problems is although I'm not competing in comps my system is basically competition ready, I'm going to use it for parking lot and pavement pounding, so the loudness of the system makes it hard to tune by ear without playing a test tone or something like that (in which once the test tones frequency slightly alters the gain should be turned slightly down and left at that level), the reason for me wanting to go in depth with the setting of my gain levels is that I don't want to spend all this money on such a powerful system, and not fully utilise it (but at the same time not over use it to the point of blowing my speakers)