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I'm looking to pick up a portable scope-meter. I was recommended the TPI 440 which I saw in action and looks pretty nice.
I also came across this Owon HDS1021M unit which seems to have better specs and a nicer (color tft lcd) screen. http://www.testequipmentdepot.com/ow...s/hds1021m.htm
Anyone have feedback to offer on these (or others?) Looking to keep it under $300.
Thanks !
IIRC, Glenn has the Velleman SA-HPS140I and seems to like it a lot...but that Owon does look cool, and the reviews are favorable.
BTW...Amazon has a better price http://www.amazon.com/HDS1021M-Handh...m_sbs_indust_4
Thanks Al, yeah I had seen that price on Amazon as well- very nice. I linked the other site since it had actual specs. As for the Velleman HPS140i, check out this price :) http://www.scopemetrics.com/cart/ind...ct_detail&p=10
If it can do what I need, that would be an excellent choice as well. Waiting for some feedback from Glenn since he has used it. It doesn't look like it has DMM features, but at that price, I could always buy a separate DMM if I wanted to.
We have the HPS10 in our workshop and that's also a nice device..
Thanks!
I ended up ordering with the OWON HDS1021M unit. Very nice specs and a great color tft lcd screen to make viewing much better. It was only $205 on Amazon so tough to pass up.
I had this scope http://www.vellemanusa.com/products/...=enu&id=351263
I found that I was as close with a scope as I was by ear so I rarely used it. I usually adjust by ear and then use a DMM and a 60Hz test tone to get the gains as close as possible.
Why not the DSO Nano?
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I wanted good multimeter functions as well in one unit. ;)
BTW, the screen resolution on the OWON makes it much easier to determine a clipping point, not to mention it's just much easier to see/read period (than the TPI). I was just out checking output on the scope to test it and it looks great.
http://i61.photobucket.com/albums/h7...tertest005.jpg
http://i61.photobucket.com/albums/h7...tertest006.jpg
And a quick vid of it reading the waveforms of sine waves on a test cd. They change every ten seconds (and i'm playing with time and sensitivity here to get a larger view of the waveform for ease of identifying clipped signal...didn't see any though). Sorry for the motion, trying to adjust scope, hold camera and operate the remote control at the same time- doesn't work well.
http://i61.photobucket.com/albums/h7...tertest004.jpg
You might also consider getting one or two of these braking resistors to make a voltage divider for testing amplifier outputs
PS...I ordered the 4-pack that he sells, only to find out that I would have saved $20 by ordering them individually :doh:
That's WAY easier than trying to build a resistor load bank. Thanks for the heads up Al :)Quote:
Originally Posted by AL9000
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BTW- Why a four pack? Do you need to actually load all 4 channels at the same time to get an accurate reading on a 4 channel amp?
Ooh! Good kweshun!Quote:
Originally Posted by captainobvious
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What if you want to test it on a 1-ohm load, how would you do it? If the amp has a single power supply, loading all the channels might affect the reading. Also, if it's extremely high power, you might want to run the resistors series-parallel to dissipate the power across them.
Maybe Chad could chime in on this.
I use bigass dales, I have them hanging over my bench.... I had another rig that was fan cooled. And the mother of all loads was modified water heater, radiator, water pump, and radiator fan.
But that was for testing some big fucking amps....
FWIW, liquid cooling resistors in ATF works great.... Heath made a RF load called the cantenna.... I use one as my RF load but have cooled big hollow ceramics equally well.
Quote:
Originally Posted by chad
Chad, can you comment on the single vs all channels question? If you have a multi-channel amp, are you required to load all channels in order to get the proper voltage output at each individual channel, or can you simply load each channel one at a time?
Thanks
If you are measuring for max power and want to be accurate then you load them all. However, keep in mind that on say, a 4 channel amp you may have 2 channels running tweets and 2 running midbass so overall output per channel pairs could be quite different in the real world.
Also keep in mind that music is not a 100% duty cycle sine wave. Pro audio manufacturers are adopting new power ratings standards one by one that depict actual output for music uses. like EIA "33/66"
Can you explain the EIA ratings to me?
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X amount of time at WFO, X amount of time off.... 33mS and 66mS respectively for the 33/66
But there are many different "EIA ratings"
anyone likes the CEA 2010 specs for subwoofer distortion?
was reading about that a couple days ago, looks like a graphical representation of an audible distortion curve threshold, I guess some manufacturers won't like it too much...
the way I understand it, is there's a musical representation of a note, which is better than test tones.
it sounds like an advancing method, because test tones and music are so different that this new test would reveal more about a speaker's non-linearity relating to real world conditions in comparison to the old way.
I think they said it was a 6.5 cycles long, test impulse.
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okay, that's off topic for 'scopes, disregard...