Bests & Worsts Reviews from Amazon

Just to give a heads up, I'm an electrical engineer. I have the standard workhorse Fluke 87V on my bench at work and absolutely love it. However, it's pretty pricey. My cheap ~$35 R.S. DMM for hobby use and occasional electrician work at home finally broke after ~16 years. So I wanted to purchase a fairly good quality meter that didn't cost as much as the Flukes. I probably spent, on and off, about 8 hours searching through various DMM spec sheets, user manuals, and product reviews, trying to find one that had all of the functions that I wanted, had fairly decent accuracy, and was also built with quality to last. My price range was around $50 to $70. However, I couldn't find one that fit all of these criteria in this price range. The Extech's 400 and 500's kept coming up, but there were just some real quirks found in the reviews that didn't sit well (bad fuse placement, knob functionality was intermittent, etc.). When I increased the price range I found this Amprobe AM-570 DMM. Overall, I'm generally impressed with the general quality of the meter. The rubber overmolding is good quality. The feel of the knob is good. Taking the meter apart, I was impressed with the quality of the design on the PCBA. (I read that some meters were pretty poor in design and soldering quality). Overall, I really like this meter. However, there were two REALLY HUGE ISSUES that stuck out immediately. The input terminals and the NCV feature. THE INPUT TERMINALS! The probe was EXTREMELY hard to push into the V+ input terminal, almost like there was something obstructing it. It has gotten a little better after ~20 insertions. So I'm thinking this terminal will eventually be fine. The COM input terminal felt more like what it should feel like (like the Fluke 87V). However, the biggest gripe is the A and mA input terminals. The leads slide into them fine, but their holding force is extremely light. They aren't necessary loose, there is just minimal force to hold them in. It seems, while sliding the lead in, that from the initial contact to the final seating is only about 1.7mm. If you insert the probe lead into either the A or mA input terminal, tip the meter face towards the ground, let the lead dangle, and shake the meter even mildly, the lead will come out in 2-3 seconds. On taking apart the meter, it is apparent that the V+ and COM terminals are built differently than the A and mA inputs. The A and mA inputs hold onto the lead by only two side bent out contacts each. Looking at the lead insertion of these terminals with the case taken off, sure enough, the probe pushes past these bent out contacts by about 1.7mm before stopping. I'm not sure why Amprobe made these terminals so loose, perhaps as a result of the design to implement the "wrong input terminals warning" feature. If you are the Amprobe sales person, reading this review, PLEASE FIX THIS PROBLEM, as its a huge black mark on an otherwise WONDERFUL meter. The only reason why I'm not sending it back for this reason is because I took the unit apart and saw that there was at least some good electrical connection between the input terminals and the probes. Also, on performing current measurements, there didn't seem to be any intermittency in the readings while jiggling the lead connection, as long as I didn't pull the lead out by that 1.7mm. I've never used a NCV feature on any meter, so I'm not sure if there is any correct method to use them. But I'm pretty sure the NCV FEATURE SUCKS on this meter. Placing the top facing part of the meter (where the light is located), it would register voltage on a 115VAC outlet maybe 1 out of 8 times, and then only intermittently. It didn't have much better success with a 220VAC outlet either. I tried touching the meter (where the Velcro strap loop is) right onto the outlet, rotating the meter and also moving this top face around, trying to see if maybe the sensor was in a certain spot. But nothing seemed to help. The only time it worked well was while running it along a power cord that was plugged in. Then it would work 100% of the time, with a response time of ~0.25s. So if the NCV feature is only meant for new installs, in which the dry wall is off, and the electrical wiring is exposed, this feature works great. But, if you're using it on outlets, it functions poorly. For me, this was not a deal breaker, as I wasn't going to use it much anyways. I can always use the probes. After purchasing this AM-570, I took it to work and performed a bunch of comparison measurements with it versus the Fluke 87V. Doing these tests with these two meters side by side, I was very impressed with the AM-570's accuracy, response time, and functionality. Granted the Fluke 87V has ± tolerances of its own, and is not really meant to be used as a measurement reference. But, overall it does have tighter tolerances than the AM-570. I also used an Agilent 33210A function generator for the frequency and duty cycle tests. So, for what its worth, the Vdc, Vac, Idc, resistance, diode/continuity, capacitance, frequency, and duty cycle measurements seemed to meet the AM-570 published specifications. There were a few measurements that seemed to be slightly out of spec, but they might have been because the Fluke 87V was measuring on one end of the tolerance, and the AM-570 was measuring on the other. I was not able to compare the temperature readings. Some specs that I measured, that I was looking forward to finding out, but which were not in the specification sheet were the following: Frequency measurement sensitivity (measured with sinusoidal waveform input): Frequency Range>Sensitivity: 60 Hz>150mVp-p. 600 Hz>150mVp-p. 6kHz>150mVp-p. 60kHz>170mVp-p. 600kHz>200 to 400mVp-p. 6.0MHz>400 to 500mVp-p. 10MHz>600mVp-p. Unfortunately function generator only went up to 10 MHz. Duty Cycle Sensitivity (for ±2% error): 4 Hz to 3kHz > 400mVp-p 3kHz to 10kHz > 400mV to 1.5Vp-p 10kHz to 60kHz > 1.5 to 2.2Vp-p 60kHz to 600kHz > 2.2 to 3.9Vp-p 600kHz to 1MHz > 3.9 to 5.0Vp-p Error started to be >2% above 1MHz Unfortunately the function generator's duty cycle range was from 20% to 80%. So I didn't get to test the full range of the AM-570. Response times: - Vdc: Auto: ~0.5 sec. Manual: ~0.25 sec. - Vac: Auto: ~1.0 sec (1.5 sec to stabilize). Manual: About the same. - Idc (10A): ~0.25 sec. - Idc (mA): Auto: ~0.5 sec. Manual: ~0.25 sec. - Iac (10A): Not tested. - Iac (mA): Auto and Manual: 1 sec (2 sec to stabilize). - Resistance (until reading stable): Auto and Manual: 1 to 3 sec (depending on value). - Analog scale is very fast (20/s) and is useful in catching faster transit signals. Overall, I really like this meter. It's a great meter for the more serious hobbyist as well as for probably most professional test bench uses (as long as you don't mind slightly longer response times and as long as you don't mind the current meter probes coming out). It would probably be fine for use in the field too, as long as you're not using it for current measurements (with those leads coming out). I could see how it would be very useful for the HVAC guys. Here are the pros and cons I found: Pros: - Quality designed and built. Nice overmolding work. Good sturdy feeling case and knob. Buttons have good tactile feedback. Waterproofing is good. Feels good in hands. - Really like the side grip texturing. Makes it really easy to hold with minimal chance of slipping out of your hands. - Response time is adequate for most uses. There were some reviews stating that the response was slow. But I think its useful for most applications. Putting it into manual range will give you faster response times if needed. Also, once measurements are started, the display updates 3 times/sec with any further measurement changes. - When in Vac and Iac mode, frequency is shown in upper corner as well. - Analog scale is fast and also gradiations on it are fairly accurate. - Has Min/Max features. - Flash light will definitely come in handy for electrician type work. Light is single white high brightness LED. Not super bright, but bright enough to help see what you're doing in the dark. Stays on for entire 15 minutes. - Auto shutoff is 15 min. My last meter annoyed me to no end with the auto shutoff around 2 minutes. - Backlight stays on indefinitely, until meter powers off after 15 mins. - Dual temperature probes. Can see how this would be really handy for HVAC. - Back stand is wide, so meter doesn't fall over as easy as other meters. Stands at a good angle. - Probe holders on the back of the case positively hold the probes tight. - Battery is easy to replace. Battery door is separate from taking rest of case apart. Battery door screw is metal machine thread. - Decent Cordura bag that fits all items that come with meter. - Probes come with safety tips (with smaller exposed metal areas). - Fuses are readily accessible upon taking case apart, and are clearly labelled, so finding replacements should be fairly easy. - Manual, comes on mini-CD. Is fairly helpful, especially with specifications. Cons: - Fit of leads is WAY TOO LOOSE in A/mA input terminals. - The NCV feature is poor. - Response for resistance could be just a little faster. But not a big deal for me. - Response time of continuity function could be a tad faster. - Min/Max feature forces meter into manual range, resulting with stated minimum and maximum values being only in that range. So if there is a transient minimum or maximum value outside of that range, it will only be shown as 'OL'. - Doesn't display frequency and duty cycle at same time in these modes. Overall, I would give this DMM 3.5 out of 5 starts.