Voltmeter or multimeter recommendation?

oneinthepipe · « **on:** 5 Jul 2008, 10:52 pm »

After a long hiatus, I have returned to audio and am rebuilding my systems. I recently acquired a Super 70i, and my old analog voltmeter's display is too small (or the problem is my middle-aged eyes) for me to measure the tube bias. Could someone recommend a reasonably-priced voltmeter or multimeter?

tonyptony · « **Reply #1 on:** 5 Jul 2008, 11:09 pm »

What's your price point?

I've used Fluke meters both at work and at home and have always been pleased.

oneinthepipe · « **Reply #2 on:** 5 Jul 2008, 11:44 pm »

In the 50.00 to 150.00 range, if practicable, with measurements for voltage, capacitance, and resistance (and maybe diode check function).

mgalusha · « **Reply #3 on:** 6 Jul 2008, 02:55 am »

I've had a Meterman DMM for a number of years and it's been very good. It's not as accurate as my bench model Fluke but I don't expect it to be, however it's not far off either. MCM sells the Meterman line for a decent price and the bonus is the Meterman is made by Fluke. The "33XR" model is $79.99 and has the following features:

33XR

* Frequency to 40 MHz, temperature to 1832 °F, capacitance to 4000 µF
* Input warning tone when test leads are in wrong jack
* 1000 V/750 V dc/ac
* 10 Amps ac/dc, fully safety fused
* DC microamps for low current levels
* Resistance to 4 MΩ
* Continuity beeper
* Min/Max, Relative, Peak and Data Hold
* Auto power off to save battery life
* Separate door for easy battery and fuse access
* Magne-Grip™ Holster with magnetic hanging strap
* CAT III 600 V, CAT II 1000 V rated
* UL (CULUS) listed
* One-year warranty

mike

Listens2tubes · « **Reply #4 on:** 6 Jul 2008, 03:48 am »

A simple inexpensive digital multimeter from RS or your favorite discount mail order catalog is all you need for biasing your S70i. Keeping one near the amp keeps it handy.

oneinthepipe · « **Reply #5 on:** 1 Aug 2008, 02:42 am »

Quote from: mgalusha on 6 Jul 2008, 02:55 am

I've had a Meterman DMM for a number of years and it's been very good. It's not as accurate as my bench model Fluke but I don't expect it to be, however it's not far off either. MCM sells the Meterman line for a decent price and the bonus is the Meterman is made by Fluke. The "33XR" model is $79.99 and has the following features:

33XR

* Frequency to 40 MHz, temperature to 1832 °F, capacitance to 4000 µF
* Input warning tone when test leads are in wrong jack
* 1000 V/750 V dc/ac
* 10 Amps ac/dc, fully safety fused
* DC microamps for low current levels
* Resistance to 4 MΩ
* Continuity beeper
* Min/Max, Relative, Peak and Data Hold
* Auto power off to save battery life
* Separate door for easy battery and fuse access
* Magne-Grip™ Holster with magnetic hanging strap
* CAT III 600 V, CAT II 1000 V rated
* UL (CULUS) listed
* One-year warranty

mike

I purchased a Meterman 33XR "promo kit" from ITC Electronics for 59.99 plus shipping (about 11.00). The kit includes a cheap plastic carrying pouch, a temperature sensor, and a non-contact voltage detector.

The meter has a lot of features, appears to be well-made, is simple to use, and was inexpensive. I've had the meter for a couple of weeks and am very satisfied.

Thank you for the recommendation.

Wayner · « **Reply #6 on:** 1 Aug 2008, 08:41 pm »

Vellamen has a nice vom for about $15 (model DVM850BL) that has digital readout, back light and sound alarm for continuity.

Wayner

trebejo · « **Reply #7 on:** 27 Jul 2010, 09:21 pm »

Hey, it's been a couple of years. I am a little slooooow...

I've been "needing" a multimeter for a while now, just to explore what all these electrical gadgets around the house are actually doing rather than just hoping that nothing drifts with usage. Yesterday I got a Mullard 5ar4 for the U70 and I really like what I hear but I also hear that it's naughty to just put that thing in there without checking to see if the bias needs to be recalibrated (and, darn it, I think I hear a liiitle bit of non-euphonic distortion that wasn't there with the previous "inferior" tube). Going by the reviews of the punters on amazon, this one seems to be a good one,

http://www.frys.com/product/5213787?site=sr:SEARCH:MAIN_RSLT_PG

The thing that stopped me from just getting one of these is that in the notes that came with the U70 from Frank, he says that the dc meter should have a rating of 1000 ohms per volt or higher ("higher", I interpret to mean "more ohms per volt"). Now 1 volt/1000 ohms = 0.001 A, or 1 mA. So I interpret this as saying that the dc meter should be accurate to 1 mA.

In the same notes, he writes that the pair of tubes in each channel should put out 100 ma. This current will be measured as a 1.56 volt drop across a 15.6 ohm resistor, not as "100 ma" per se. But I still find reason to worry.

According to one of the numbers on that page, that would be cutting it kind of close:

DC amps Range/Resolution: 6.000 A / 0.001 A
Range/Resolution: 10.00 A / 0.01 A

You guys think this is good enough for this task? How about for general testing purposes for other things that one might want to know about the dacs, amps, preamps, etc.?

avahifi · « **Reply #8 on:** 27 Jul 2010, 10:46 pm »

Harbor Freight Tools has a little digital multimeter available right now for all of $2.00!

I picked one up but have not had time to play with it much yet. It should be accurate enough for setting the bias in an Ultravalve. I will test it against my much more expensive Fluke meters and let you know.

Frank

adydula · « **Reply #9 on:** 27 Jul 2010, 10:51 pm »

Funny,

How time revisits us...

I can remember being interviewed for a electronics tech job many years ago and one of the questions the interviewer asked me is:

"Son, do you know the difference between a VOM and a VTVM"

If you could not answer that you did not get the job!

Oh..by the way "I got the job!"

Alex

trebejo · « **Reply #10 on:** 28 Jul 2010, 07:15 am »

Well I thought about getting the $3 wonder but in the end I just got the Fluke, once I saw the sloppy arithmetic thing there.

So I plug in the Fluke and darned Mullard, the bias was around the 1.30somethings.

It goes up and down from the initial value at turn on, but it eventually settles down, I hear. I set it at 1.56something on both channels with the ol' screwdriver. Mild occasional distortion gone.

The sound? Fffffanstastic. Oh, what an amp.

avahifi · « **Reply #11 on:** 28 Jul 2010, 04:00 pm »

Well I used my Cen-Tech #90899 digital multimeter to check the bias on an Ultravalve amp this morning and it works just fine, giving the same readings as my Fluke meter.

This meter tests bipolar transistors, 1.5V and 9V batteries under load, DCV, ACV, DCA, Ω, and diodes.

The price is about $2.00 from Harborfreight.com. Buy two of them to set bias on both channels at the same time.

Note that there is no way we could have built a bias test meter or indicator lights into the amp itself for the $2.00 price of this nifty little meter.

Recommended.

Frank Van Alstine

jtwrace · « **Reply #12 on:** 28 Jul 2010, 04:08 pm »

I really like my super accurate calibration quality meter.

It's ~$1,000 but worth every penny IMO.

http://www.martelcalibrators.com/process_calibrator.html

AVnerdguy · « **Reply #13 on:** 28 Jul 2010, 04:11 pm »

Quote from: avahifi on 28 Jul 2010, 04:00 pm

Well I used my Cen-Tech #90899 digital multimeter to check the bias on an Ultravalve amp this morning and it works just fine, giving the same readings as my Fluke meter.

This meter tests bipolar transistors, 1.5V and 9V batteries under load, DCV, ACV, DCA, Ω, and diodes.

The price is about $2.00 from Harborfreight.com. Buy two of them to set bias on both channels at the same time.

Note that there is no way we could have built a bias test meter or indicator lights into the amp itself for the $2.00 price of this nifty little meter.

Recommended.

Frank Van Alstine

I also bought 3 of these from Harbor as they were so cheap and at that price I figured if they were even close on DC measurements (like power supply verification) they'd be worth it so I don't have to search go get my Fluke or Simpson true RMS meters. I leave one in the house, one in the garage, and one floating around my tech tool box (with my expensive Fluke Scopemeter).

It's very surprising how accurate this little meter is. I've compared it directly with my $2K Fluke scope - minimal differences for typical AC/DC measurements and good for bias settings and PS verifications.

avahifi_lj · « **Reply #14 on:** 28 Jul 2010, 05:22 pm »

The Harbor Freight Cen-Tech #90899 meter sells for $9.99, but is often on sale in their stores in the $2-$5 price range. They also have a Cen-Tech #92020 that is basically the same meter with a back light but sells for $11.99 (again on sale in the $2-$5 price range).

FYI: You can purchase the meters on the Harbor Freight Web site. Today, July 28, the Web site shows #90899 "on sale" for $3.49 plus 6.99 for shipping. The more expensive #92020 is "on sale" for $2.99 plus $6.99 shipping.

The wonders of Harbor Freight pricing....

Larry

whubbard · « **Reply #15 on:** 28 Jul 2010, 05:38 pm »

If you're willing to go on Ebay you can get a Fluke 77 for a steal.
Fluke 77-III
Fluke 77-IV

The 77-IV is better than the 77-III but not by the current price difference. I have the III and it is a charm to use.

-West

turkey · « **Reply #16 on:** 29 Jul 2010, 05:18 pm »

While I would certainly rather have a Fluke meter, I can't justify the expense.

I got an inexpensive Taiwan meter for about $20 a few years ago and it does everything I need. If it dies in 5-10 years I will just buy another one.

I'm sure I'd feel differently if I were using it for business purposes, and indeed, when I worked in live sound I carried a sturdy Simpson meter. It wasn't worth fiddling with the stuff like Micronta when you needed something reliable that would survive riding in a toolbox in the back of a truck.

Wayner · « **Reply #17 on:** 29 Jul 2010, 06:17 pm »

I just talked to Frank and Dean at AVA headquarters and they were all excited about the meter. Dean bought 2 of the lighted ones If I heard him right. Perfect for setting bias on the U70 or Ultravalve (better using 2 meters).

Wayner

jtwrace · « **Reply #18 on:** 29 Jul 2010, 06:27 pm »

Quote from: Wayner on 29 Jul 2010, 06:17 pm

Perfect for setting bias on the U70 or Ultravalve (better using 2 meters).

Wayner

As long as they match each other. I would suggest checking to make sure that they both read the same with a given value.

Wayner · « **Reply #19 on:** 29 Jul 2010, 06:57 pm »

Yes of course. Easy to piggy back the test probes and see if both meters give the same reading.

W