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Testing a Cartridge with a multimeter

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Over the passt couple years I have picked up some very nice cartridges all of them with broken stylis. I would like to bring a couple of these into rotation by buying stylis but don't want to spend the money only to find the cart is no good.

How do I test a cartridge with a multimeter?

Shure type III or IV
Rat Shack/Shure RKT5
Shure M93E to name a few
 
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Let me take it up a notch...

part of the Quality of a cartridge (how good it is) is related to how well balanced the two channels are....

So a cartridge with both channels reading an appropriate value is a working cartridge - but not necessarily a "good one".

I specifically purchased a digital multimeter with capacitance and inductance capabilities (and made up some aligator clip leads to go with it)...

I measure each cartridges left and right resistance first (as per the Shure instructions).

Then I measure the left and right inductance.

Having both channels matched for resistance will match overall output level.
Having them matched for inductance will match the two channels frequency response.

The first is easily fixed with the balance control on your amp.... the second is a pernicious sneaky thing which smears tone surreptitiously, is hard to identify and is a possible reason why some people don't like some cartridges....
You don't generally get to hear multiple cartridges of the same sort.

Companies like Audio Technica made the cartridge bodies and would then rank them in order of channel matching (both resistive and inductive) before labelling them as AT10/11/12 etc... their quoted specs are identical - but the channel matching as you go up the range gets better and better.

It is worth while sometimes picking up a "cartridge lot" on ebay - so you can test a bunch of them, pick the real gem(s), and resell the rest.

bye for now

David
 
WARNING - Never test a cartridge with an older analog meter without a current limiting resistor in the line. The base current will smoke the fine wires in the coils.

Most digital meters are OK as they are delivered :)
 
Yep do it with the stylus out ...keeps the stylus safely protected!

I have heard there are possible issues with coils due to higher voltage/currents used in earlier analogue multimeters - but have had no problems with my older (5 yrs old) digital multimeter or my newer (6 months old) digital multimeter with inductance capability.

Some previous discussions on this topic ended up saying that the problem was with Low Output moving coils having coils made of very very fine metal, and being able to handle only a low current, apparently some older multimeters would put too much through these types of coils.

I don't believe I have heard of anyone having problems like this with moving magnet/moving iron cartridges or with more recent digital MM's

bye for now

David
 
I smoked a Shure V-15 with an analog meter. Never again :( That's not an MC cartridge.

I have also popped one leg of a GRADO GT with an analog meter. In that case it didn't matter, because the other side was already blown.

Be careful :smoke:
 
Ouch!!

My condoleances...

I've tested well over 100 cartridges to date - without a problem...

So it seems the Digital Multimeters with their lower voltage/current and more sensitive circuits are probably the way to go!

I hate to say it on this particular type of forum but - Avoid Analogue! Go Digital! :D

Bye for now

David
 
dlaloum said:
Ouch!!

My condoleances...

I've tested well over 100 cartridges to date - without a problem...

So it seems the Digital Multimeters with their lower voltage/current and more sensitive circuits are probably the way to go!

I hate to say it on this particular type of forum but - Avoid Analogue! Go Digital! :D

Bye for now

David
Click to expand...

A true analog devotee would use a Vacuum Tube Volt Meter (VTVM):D
 
BrocLuno said:
WARNING - Never test a cartridge with an older analog meter without a current limiting resistor in the line. The base current will smoke the fine wires in the coils.

Most digital meters are OK as they are delivered :)
Click to expand...

dlaloum said:
Yep do it with the stylus out ...keeps the stylus safely protected!

I have heard there are possible issues with coils due to higher voltage/currents used in earlier analogue multimeters - but have had no problems with my older (5 yrs old) digital multimeter or my newer (6 months old) digital multimeter with inductance capability.

Some previous discussions on this topic ended up saying that the problem was with Low Output moving coils having coils made of very very fine metal, and being able to handle only a low current, apparently some older multimeters would put too much through these types of coils.

I don't believe I have heard of anyone having problems like this with moving magnet/moving iron cartridges or with more recent digital MM's

bye for now

David
Click to expand...

Something to bear in mind is that higher resistance scale = higher voltage and current from the tester, so always use the lowest range possible, such as 1000 Ohms rather than Megohms.
 
This is a very handy thread, as it has enabled me to make a note of people I will NEVER buy cartridges from!

Even the most modern digital multimeter will output a volt or two for resistance measurment and by sticking the probes across a cartridge you're directing this through a set of coils designed to generate millivolts, or in the case of MCs, microvolts.

Still seem like a good idea? :no:
 
Well from my perspective it has allowed me to select the best from many many cartridges...

The end result is much more balanced sound, with steadier imaging...

The fact the the Frequency response is almost identical across both channels on well matched cartridges means that there is no smearing of tone....

In theory you would think that top end cartridges like V15V would be well matched.... not so - I have a V15V measuring 328/320mh left/right - that is a 3% (2.5% actually) difference and quite audible at certain frequencies

I also have a V15VP (same cartridge in a p-mount version) 312/317mh - 1.6% variation... much better.

I also have one of the hand picked AT20SLa cartridges - 453mH both channels - my instruments are not sufficiently precise to identify the difference between the channels! (and frequency response plots are also better matched...)

All cartridges have to be tested electrically at the factory before they get boxed - one wonders how this is done and what voltages are used?

In any case it has been a boon for me... and has not harmed any of my cartridges.
But like I said before - my units are current generation DMM's which use much lower voltages than earlier generation models.... so YMMV

bye for now

David
 
Beobloke said:
This is a very handy thread, as it has enabled me to make a note of people I will NEVER buy cartridges from!

Even the most modern digital multimeter will output a volt or two for resistance measurment and by sticking the probes across a cartridge you're directing this through a set of coils designed to generate millivolts, or in the case of MCs, microvolts.

Still seem like a good idea? :no:
Click to expand...

Not to be pedantic, but it's current that burns things up/out not voltage (unless we're talking voltage high enough to cause arcing, which is a different subject). Therefore, I would put a suitable resistor in series with one probe of the meter. This will ensure that excessive current does not flow through the coil. You could measure the resistor first and then measure the coil plus the resistor. The difference would be the coil resistance.

I believe this would also work for inductance measurements as stray inductance of the resistor would be small compared to the inductance of the coil.

I believe that the better digital meters are designed to measure resistance with very little current to begin with, but I would use the series resistor anyway as a further precaution.

Best,

Dan
 
Yes, it's current that matters. So let's not spread misinformation here. Dan, you are not being pedantic at all.

If it were really true that it's so easy to destroy a cartridge by measuring its DCR with a modern digital meter, there would be hundreds of cartridges laid waste by the procedure.

Let's say you have a typical cartridge with windings of about 1kOhms. Even if the voltage is 1 volt, the current is a milliamp. It's that simple.

Many of us have tested hundreds of cartridges collectively, in this manner, without dire consequences.

Doug
 
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Heaviside said:
A true analog devotee would use a Vacuum Tube Volt Meter (VTVM):D
Click to expand...

I know this was said as a joke, but my analog meter is a VTVM -- the venerable RCA VoltOhmyst. These are precisely the types of meters that could potentially put a sizable current across the cartridge. This is the meter I learned electronics on back in the 70s. For many of us, an analogue meter = VTVM.

For other purposes, it's a great meter. Measures very small resistances that a digital meter would have a hard time with. Also has a much wider frequency response for measuring AC than most digitals. Plus, sometimes an analogue meter (with a needle) can show you things that numeric meters can't.

Just to be clear.
 
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