Real Scoop on meters for tube amp use

[52 Bill]

I guess whether or not you've ever been annoyed by an auto-off feature would depend a lot on how you use your meters.

On my own bench, when I turn on the light I turn on my meter. When I turn off the meter I turn off the light. When I grab the meter leads, I want the meter to be ready to read whatever I'm working on.

At work we have a number of smaller meters and mine has an auto turn off feature that you can't defeat. The problem that I have with it is that I never know what part of the time on function it's at when I grab the leads. So I grab the leads to read the voltages in an amp, and after my first couple of readings the meter hits the time off point and powers down. Not a big deal, but then I have to wait to reboot the meter and then make my next reading. It can really interrupt your train of thought by being distracted by the meter.

So I have to try and remember to reboot the meter right before I start taking readings.

[Enzo]

A couple thoughts. What I meant by never see duty cycle on a meter was that you will never see it on an analog meter by looking at the needle. yes, modern digital meters can include it, and a useful feature at that for some applications. But the sense of my point was that a meter needle won;t move fast enough to see visually a duty cycle happening, unless you are looking a 2Hz waveforms or something. My additional note about you might be able to peak it was that if you go from thin spikes to even square waves and on to thin spikes again, you might be able to put the meter on AC RMS and peak the reading as I suspect the thing would max at about 50%. Like you can do audibly on an old synth turning the duty cycle knob on square wave. The OP was looking to decide analog versus digital, and mentioned duty cycle as an application wherein he might need a fast response.

To be clear, my meters time out all the time, but it has never shut off while in use. I can believe some cheap models pay attention to the switch, but every one I ever had or used only timed out if no readings were taken. Any reading I took would reset whatever internal timer was going. I may be a pretty good troubleshooting, but believe me there can be LOTS of head scratching time involved. I have just spent a couple hours buried in an old Heath TA-17 doing just that.

I can see if there are relatively long periods of inactivity, like setting up the bench rig or whatever, that you might be timing out.

Just academically, I wonder if one could make a holder-onner so to speak. Like stuff the probe into an outlet so it continuously reads the main voltage while not in use. Sorta Rube Goldberg, but it might hold it on for you. Like the thing you stick your soldering iron in while not using it, you'd have a thing for your meter probe. Of course we'd rather not have to do that, but it might work. Problems are for solving.

[52 Bill]

I can believe some cheap models pay attention to the switch, but every one I ever had or used only timed out if no readings were taken. Any reading I took would reset whatever internal timer was going. I may be a pretty good troubleshooting, but believe me there can be LOTS of head scratching time involved. I have just spent a couple hours buried in an old Heath TA-17 doing just that.

I only wish that this was the case with this meter, taking any kind of reading does not keep the meter running. This can be really frustrating at times.

I used to bring my own meter into the shop, but I would find that it was being used and abused while I was out. I got tired of replacing fuses and test leads so I just started using the meters in the shop. Now I'm getting too old to make this an issue, so soon I'll retire and just enjoy having my own bench and my own rules.

[bob p]

Good points Enzo. Sorry if I took things on a tangent by misunderstanding what you meant.

Back to the OP's question -- whether a meter has a non-defeatable auto-off function may or may not bother you. If it's something that bothers you, then pay attention to that feature when shopping for a DMM. When shopping I think you can expect that cheapo meters with an auto-off feature will base their timeout counter on switch rotation rather than elapsed time since last measurement. The problem is that buying a more expensive meter won't necessarily get rid of the problem for you, as you are also likely to encounter pricey meters that have the same problem. In general I'd say that the high end meters targeted toward electrician and HVAC applications are more likely to have auto-off based on switch rotation than are high end meters targeted toward bench work. If defeatable auto-off is important, then it's probably worth putting that on your features checklist when you go meter shopping. the last thing that you want is to spend a lot of money on a meter only to find out after you start using it that it has a behavioral quirk that annoys you.

The auto-off problem has been enough of an annoyance for me that it will definitely shape my meter buying in the future, but the problem is that I already have enough annoying meters on-hand that I don't see myself replacing all of them. For now I just deal with the problem that I wish I had avoided by more careful shopping.

[Tom Phillips]

...The auto-off problem has been enough of an annoyance for me that it will definitely shape my meter buying in the future, but the problem is that I already have enough annoying meters on-hand that I don't see myself replacing all of them. For now I just deal with the problem that I wish I had avoided by more careful shopping.

I avoided that problem by using line voltage operated bench top meters. I have battery operated meters too. They are used for backups and remote work. Used high quality bench meters are not much more expensive than many of the good battery operated handhelds and they often have superior specs. Works for me.
YMMV,
Tom

[bob p]

I've got a 4-wire 5-digit Fluke kelvin meter for benchtop work. I love it. It doesn't have the annoying auto-off feature that the hand held meters have. The problem though, is if I want to follow several parameters concurrently, I don't have enough benchtop meters to do that, so I have to use portables on different monitoring points. Then they start shutting off asynchronously. It's quite a pain.

[big_teee]

It's not that way at all, Terry. Sometimes I just have an opinion that doesn't align with yours. You need to be ok with that.

Not really!
That's why I put you on my ignore list!

[bob p]

Bob mainly just likes to try to discredit whatever I say or like.

It's not that way at all, Terry. Sometimes I just have an opinion that doesn't align with yours. You need to be ok with that.

Not really!
That's why I put you on my ignore list!

My apologies -- I thought that you were selected as a moderator because you had a scope of vision that would allow you to tolerate opinions that differ from your own. My bad.

[DrGonz78]

I have the Fluke 189 and an Extech EX430 as my primary meters. The fluke 189 and 187 are nearly the same and the auto off setting defaults to 15 minutes. On these models you can program them to max auto off time up to about 24 hours. If you put the value of time as zero it will disable the auto off feature. The Extech defaults to auto off by 15 minutes, but if you press the light on button it resets the timer again. I hate the auto off function and personally if they are sophisticated enough meters to have auto off then they should be programmable too.

[jbltwin1]

I still have and still use my old simpson 260. It hangs right in front of me on the bench wall and it's right there for simple continuuity testing mostly. Mostly gets used when fixing or making mic cords, guitar cords and the like. It's just easy and RIGHT there. The DMM's sit off to the side and get turned on when needed. They're usually in the base of the scope stand that elevates my scope to eye level. Mike