Quality and brans on LCR meters

[mickmutante]

Hi everybody.
I have been reading a lot here in the M.E.F about all the variables that a pickup maker has to consider on making pickups, measuring Inductance, AC resistance, Q, etc... And learning about the different devices... LCR meters...
So about LCR meters... what I read, some of you use Extech 380193 LCR meter.
Measures Inductance, Capacitance, and Resistance,
Test Frequency: 120Hz and 1kHz.
+- 0.7% basic accuracy
Average price: US $ 199.

I found another similar, the MCP BR2822 Professional 10KHz Digital LCR Meter.
6-function LCR meter: Inductance, Capacitance, Resistance, Impedance, dissipation & quality factor.
4 testing frequencies: 100Hz, 120Hz, 1KHz, 10KHz.
0.3% basic accuracy
Average price: US $ 299.

And I found on eBay a chinesse one, similar to the MCP, it is the TONGHUI TH2821 Portable LCR Meter.
6 basic parameters: inductance L, capacitance C, resistance R, impedance Z, dissipation factor D and quality factor Q.
4 testing frequencies: 100Hz, 120Hz, 1KHz, 10KHz.
0.3% basic accuracy
Average price: US $ 172 (plus shipping from HongKong).

I want to buy one LCR meter, I want to know what I am doing with my pickup prototypes, for me they sound good, but if I want to improve them, I need to know which could be the next step or at least have detailed record of my prototypes.
Do you guys would buy the Extech? the MCP..? the Tonghui..?

[mickmutante]

I made one error spelling on the tittle... It is BRANDS , not BRANS... sorry...

[mickmutante]

I just found that the MCP Lab Electronics, is from Shanghai, China too.

[Possum]

...

The Extech has been around awhile and is generally what pickup maker use, there's an ad in Vintage Guitar showing Bill Lawrence testing a pickup.......with an Extech. I've had mine about 3-4 years, never a problem, highly recommend it....

[dpm]

I've got the Tonghui. It seems to be identical to the MCP. Works well IMO, though I've not directly compared it to others.

[Chadheckler1]

I also have had the extech for a year and have no problems with it. I found it on ebay one day for $135 brand new.

My thinking is that if all pickup makers use the same one then we can be comparing "Apples to apples" when troubleshooting or sharing info...on the other hand, different brands "should" give the same readings...but I would be interested in playing with all 3 at the same time to see how they compare.

Having more test frequencies would be nice, but necessary? Probably not...I vote Extech.

[salvarsan]

Hi everybody.
I have been reading a lot here in the M.E.F about all the variables that a pickup maker has to consider on making pickups, measuring Inductance, AC resistance, Q, etc... And learning about the different devices... LCR meters...

With a $200 Extech 380193, you also get a serial link cable and PC reader software (finally).
Previously, you had to beg ExTech and pay $70 for the cable+software.

The MCP BR2821 is roughly equivalent to the ExTech but without the cable and,
at $175, sells for what the ExTech cost without the cable.

The MCP BR2822 is more interesting because it can test at 10kHz.
For this high frequency capability the price is roughly double the BR2821 at $300-$350.
Details for both are at http://www.mcpsh.com/BR2821.html although there is no
downloadable manual and neither one has a data port.

You must decide if you want a basic LCR meter, a data port, or one with 10kHz testing.
They're all made in the same Shanghai area anyway so it comes down to features/price.

-drh

[Possum]

...

Joe Gwinn used to harp on the fact that 10khz in an LCR meter would give meaningless results with a guitar pickup, if you get one that will read at that frequency let us know what kinds of results you get, it sure would be awesome if its a useful feature, 1khz is so limiting....

[mickmutante]

I've got the Tonghui. It seems to be identical to the MCP. Works well IMO, though I've not directly compared it to others.

Do you have comparative measurements with 100Hz, 120Hz, 1KHz, 10KHz on the same pickup.? Can you wrote some measurements.?
Is it worth it to have 10Kz on the LCR..?

[Joe Gwinn]

Joe Gwinn used to harp on the fact that 10khz in an LCR meter would give meaningless results with a guitar pickup, if you get one that will read at that frequency let us know what kinds of results you get, it sure would be awesome if its a useful feature, 1khz is so limiting....

Still do. The problem is that with many pickups, 10 KHz is above resonance, so the coils will appear to be a capacitor. The meter will give a number for sure, but what does it mean?

[dpm]

Yep, at 10k you get a capacitance reading. I'm still getting a feel for what it means though

[David Schwab]

Yep, at 10k you get a capacitance reading. I'm still getting a feel for what it means though

It means you aren't getting an inductance reading!

[dpm]

It means you aren't getting an inductance reading!

lol I think I grasp that much

How the capacitance at 10k relates to what I'm hearing, and the inductance at lower test frequencies, that's what I meant

[Possum]

....

Well, will it read AC resistance at 10K? That alone would be real useful.

So, what about the readings it WILL give, will these be useful if just doing comparative readings, say you pop in an alnico 3 magnet instead of 5, even though its not a correct reading will it give a relative reading from changing one thing to another just for comparison purposes?

[Mike Sulzer]

What does it all mean?

If measurements you make on a pickup have a significant meaning, they must relate to the operation of a pickup in place in its circuit consisting of volume and tone controls, cable capacitance, and amplifier load.

There is a frequency range where this circuit has the most impact on the sound of the pickup. Measurements in this range are most useful. Measurements outside this range are still useful because they still tell you something about what happens in this range.

What is the most useful range?
1. Guitar speakers fall very quickly above 5 or 6 KHz, some even lower.
2. Most pickups in the circuit resonate between about 2.5 to 5.5 KHz, roughly. The resonance provides a tonal emphasis. Ah ha! This tonal resonance falls within the range of a guitar speaker.
3. The pickup impedance is low at low frequencies, much lower than the load provided by the other circuit elements. Therefore these elements do not affect the pickup much at low frequencies. Therefore, the exact value of the inductance of the pickup does not have a big impact on the sound at low frequencies. (An exception is the tone control on zero. The tone cap is very important at frequencies much lower than the other elements affect.)

Example: Measure at very high frequencies. This gives the capacitance of the pickup. Add this to the cable cap in determining the resonant requency.

Example: Measure the inductance at low frequencies. Due to losses from eddy currents in the cores, this is different from the inductance near resonance (what really matters). But it still is a useful indication of the resonance, especially relative to other coils using the same magnetic structure.