Best bang for the buck bench multimeter new or used what do you recommend?

[mtdoc]

For pure bang for buck right now, it's hard to beat one of the like new GW Instek GDM-8251As from the ITT liquidation that are currently selling on eBay. The seller has been accepting offers as low as $90.

[EEVblog]

For pure bang for buck right now, it's hard to beat one of the like new GW Instek GDM-8251As from the ITT liquidation that are currently selling on eBay. The seller has been accepting offers as low as $90.

Complete no-brainer at that price. Even $110 is a bargain.

[whipaway]

That Instek has a basic DC accuracy of 0.012%, and is a hard sell to me at the prices that they want on Ebay... And if I'm going to get another meter to complement my Fluke 8800A's 0.005% accuracy, I'd rather go in the other direction.
Are there any DMMs that are similar in functionality/accuracy to the Fluke 8800A, but without an internal battery, or else an easily accessible battery door./compartment?

[Wytnucls]

The Fluke 8800A has a basic DC accuracy of 0.01% over 90 days only.
Fluke recommends a calibration every 3 months to maintain that rating.
The Instek basic accuracy is valid for 1 year.

[Housedad]

Fluke 8800A - approx 1974
Instek 8251A- Approx 2008

Difference of 34 years. 

[Wytnucls]

The Keithley 191 may be what you're looking for:
5 1/2 digits 0.007 accuracy
No internal batteries

http://www.ebay.com/itm/Keithley-Instruments-Inc-Model-191-Digital-Multimeter-/232280737125?hash=item361502c565:g:VUAAAOSw4A5Yq2-z

[whipaway]

HI Wytnucls,
Thank for the info in the Keithley. Yes, that is the type of instrument that I am looking for. I have a Keithley 179 that I picked up for  $10, and it is a good, solid performer, so most likely any other Keithley from that era should do the trick.

[rsjsouza]

I sent you a private message with an offer for a Keithley 191. Let me know if that interests you.

[whipaway]

Sorry, I don't see any PMs.

[rsjsouza]

I resent it.

[whipaway]

So, sorry for reactivating an old thread.
My dilemma was that I was looking for a DMM that would be similar in functionality/accuracy to the Fluke 8800A, but without an internal battery, or else an easily accessible battery door./compartment?

I am surprised that no one mentioned the Fluke 8810A, same as the 8800A, but has a nice, isolated dc-dc converter replacing the internal batteries for the ohms converter board.

The 8810A is exactly what I was looking for.

Thanks for all of the advice here in the forum.
I will be stocking up on these units, plus I would like to retrofit my 8800As with the newer ohms converter board, so if anyone has spares, let me know.

Thanks again,
-Paul

[lowimpedance]

So, sorry for reactivating an old thread.
My dilemma was that I was looking for a DMM that would be similar in functionality/accuracy to the Fluke 8800A, but without an internal battery, or else an easily accessible battery door./compartment?

I am surprised that no one mentioned the Fluke 8810A, same as the 8800A, but has a nice, isolated dc-dc converter replacing the internal batteries for the ohms converter board.

The 8810A is exactly what I was looking for.

Thanks for all of the advice here in the forum.
I will be stocking up on these units, plus I would like to retrofit my 8800As with the newer ohms converter board, so if anyone has spares, let me know.
Thanks again,
-Paul

You are aware that the ohms converter and AC are options, and may be not installed. So check with any sellers that these options are installed (ie actually present and have not been removed) despite the option box being marked.
 The newer ohms pcb are quite rare beasts, good luck with the hunt.

[Pinkus]

Let me share you my thoughts of my last DMM purchase. It might help you (or others).
I ordered a Siglent SDM3045X for <300 Euro in China including UPS shipping which is a quite useful instrument for this price. It has decent quality and has 60.000 counts with 4.5 digits. Thus in the range of e.g. 3V or 5V it has the same resolution as  5.5 digit DMMs with e.g. 120.000 or 240.000 counts. Both will show e.g. 3.3000V - the 5.5 digit version will not show a digit more if the value is >1.2V or >2.4V. This is why I liked the 60.000 counts 4.5 digit Siglent. It will show the same amount of digits up to 6V.

Other reasons I chose this: My budget was 300 Euro and I knew I can sell it anytime - same functionality as the 5.5 and 6.5 digit (SDM3055X and SDM3065X) units (and maybe the 4.5 digit version can be hacked to 5.5 digits - but for me there is no need to do this). And I wanted a visible logging functionality without the need to use any PC  software or to add my scope. And Ethernet and USB / copy data/screenshots to USB were on my checklist.
I had a Rigol DM3058 before and I did not like the small and crowded display. I am getting older and like large numbers
Practically I didn't need/used the 5.5 digits of the Rigol - 4.5 digits are fine for me until the count is >50.000

What I excluded right from the beginning were these used VFL display units (Agilent, Keithley) as you never can trust the photos, and I did not want to end with a dimmed version, where I have to invest a lot of money and (more important) time to change the display unit. And I also did not want a unit with LCD display (like the older HP units) as the LCDs are slow and often difficult to read.
Of course I know, the precision of this Siglent unit will probably not match up after 10 or 20 years with a Agilent unit, but then I probably do not want the unit anymore anyway (I tend to exchange my gears after a few years). I am very pragmatic and to be honest: I do not need to measure 1 picovolt differences on a 3V systems, so I do not need 6.5 digit units.

[frozenfrogz]

Right now, I have a Fluke 8800A, which I paid $50.00 for, which meets almost all of the above criteria, but the only thing I don't like is the need for the internal batteries

Why not just retrofit a PSU?

[whipaway]

Right now, I have a Fluke 8800A, which I paid $50.00 for, which meets almost all of the above criteria, but the only thing I don't like is the need for the internal batteries

Why not just retrofit a PSU?

Yes, I have considered that option, but it is hard to find a low-cost isolated DC-DC converter with an output of 3 volts.

[nctnico]

It will probably work from 3.3V as well if it is battery powered.

[whipaway]

It will probably work from 3.3V as well if it is battery powered.

I just checked a new AA alkaline cell on my 87V, 1.68 volts, times two would give me 3.36 volts, so yes, absolutely it looks like 3.3 volts would be fine to use.
Thanks for your input.

[whipaway]

Let me share you my thoughts of my last DMM purchase. It might help you (or others).
I ordered a Siglent SDM3045X for <300 Euro in China including UPS shipping which is a quite useful instrument for this price. It has decent quality and has 60.000 counts with 4.5 digits. Thus in the range of e.g. 3V or 5V it has the same resolution as  5.5 digit DMMs with e.g. 120.000 or 240.000 counts. Both will show e.g. 3.3000V - the 5.5 digit version will not show a digit more if the value is >1.2V or >2.4V. This is why I liked the 60.000 counts 4.5 digit Siglent. It will show the same amount of digits up to 6V.

Other reasons I chose this: My budget was 300 Euro and I knew I can sell it anytime - same functionality as the 5.5 and 6.5 digit (SDM3055X and SDM3065X) units (and maybe the 4.5 digit version can be hacked to 5.5 digits - but for me there is no need to do this). And I wanted a visible logging functionality without the need to use any PC  software or to add my scope. And Ethernet and USB / copy data/screenshots to USB were on my checklist.
I had a Rigol DM3058 before and I did not like the small and crowded display. I am getting older and like large numbers
Practically I didn't need/used the 5.5 digits of the Rigol - 4.5 digits are fine for me until the count is >50.000

What I excluded right from the beginning were these used VFL display units (Agilent, Keithley) as you never can trust the photos, and I did not want to end with a dimmed version, where I have to invest a lot of money and (more important) time to change the display unit. And I also did not want a unit with LCD display (like the older HP units) as the LCDs are slow and often difficult to read.
Of course I know, the precision of this Siglent unit will probably not match up after 10 or 20 years with a Agilent unit, but then I probably do not want the unit anymore anyway (I tend to exchange my gears after a few years). I am very pragmatic and to be honest: I do not need to measure 1 picovolt differences on a 3V systems, so I do not need 6.5 digit units.

Thank you for sharing your thoughts.
My opinion is similar to yours, I would shy away from a meter that uses a VFD, due to dimming issues over time, and also LCD, hard to read in the dark, and overhead lights put a glare on the screen,again, making them hard to read. A(n) LED display is most certainly my choice.

Quick question about you meter: If you are able to read 3.3000 on the display, doesn't that make it a 4.75 digit unit?

[Pinkus]

Quick question about you meter: If you are able to read 3.3000 on the display, doesn't that make it a 4.75 digit unit?

You are right, some other manufacturers are using the term 4 3/4 or 4 2/3 digits for this.
I just made a screenshot for you: in 6V mode this is almost the maximum (6.5999) it shows with 4 digits after the decimal.
Thus it is even with all 5.5 digit meters with 120.000 or 240.000 (or more) counts as they have to drop one decimal when measuring more than 1.2 or 2.4 Volt, thus not showing more detail.

[whipaway]

Quick question about you meter: If you are able to read 3.3000 on the display, doesn't that make it a 4.75 digit unit?

You are right, some other manufacturers are using the term 4 3/4 or 4 2/3 digits for this.
I just made a screenshot for you: in 6V mode this is almost the maximum (6.5999) it shows with 4 digits after the decimal.
Thus it is even with all 5.5 digit meters with 120.000 or 240.000 (or more) counts as they have to drop one decimal when measuring more than 1.2 or 2.4 Volt, thus not showing more detail.

Now I see that the first digit is a 6, so that makes it a 4.8571428 digit unit    (4, 6/7).
How high does the first digit go?

[Pinkus]

The first digit will not go further than '6' (with 4 following decimals).
Thus it can officially show up to 6.0000 (in 6V mode) but in real you get a few hundred mV more, thus not before approx. 6.5 Volt (or so - I did not check in detail) it drops a decimal.
7.5V is then showing as '7.500'.