Author Topic: need help re testing cartridge  (Read 147 times)

Offline Nick B

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need help re testing cartridge
« on: August 05, 2020, 10:05:26 AM »
I found an overseas buyer for another mm cartridge I have, but he would like me to test it before shipping. As he didnít include the picture he promised, can anyone tell me what settings to use and how to confirm each channel works? Heíd like me to advise the ohm readings.

I was able to locate my Micronta tester.

Thanks,
Nick
ICEpower 1200as2 amp
Audio Hungary APR 204 preamp
Fritz Carrera 7 BE speakers
Border Patrol SEi dac
Auralic Aries Mini & Mojo Audio lps
Audio Envy cables
Roon, Tidal, Qobuz
PI Audio UberBUSS

Offline steve

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Re: need help re testing cartridge
« Reply #1 on: August 06, 2020, 05:13:30 PM »
I found an overseas buyer for another mm cartridge I have, but he would like me to test it before shipping. As he didnít include the picture he promised, can anyone tell me what settings to use and how to confirm each channel works? Heíd like me to advise the ohm readings.

I was able to locate my Micronta tester

Thanks,
Nick

Hi Nick,

I will write from the stand point of newbies out there reading this, and may wish to use this information later.

I have a diagram, below, that I hope will help explain.

1. For MM DC resistance measuring, I would do an initial measurement of a very large resistor, say 100,000 ohms (100k).
"A" diagram show this. Digital meter leads either way to measure 100k resistor.

2. Set the digital meter to 200k ohm scale. The actual measurement will be a little off that, say 99,500 ohms, or it might read 100,100 ohms. A resistor never seems to read perfect 100,000 ohms. That is ok.

3. Write that reading down so as to remember the resistance. Let's say the meter reads 100,100 ohms.

4. Now look at "B" diagram. Using a clip lead, place a 100k resistor lead to the center pin as shown. Either lead is fine.

5. Now connect the other resistor lead to either meter probe with a clip lead as shown. Don't worry about which meter probe.

4. Now connect the other meter probe to the outside of the ic plug with a clip lead as shown in "B".

5. Set the meter to 200k scale and measure the resistance.

The resistance should Not measure 100,100 ohms, but some other value. As an example, my Accutex 320III STR moving
iron cartridge coils are 580 dc ohms. So the total DC resistance would be 100,100 ohms plus 580 = ~ 100,700 ohms.

What is important is that the total resistance changes from 100,100 ohms to 100,xxx ohms. If the meter reads infinite, then
either the cartridge coil is open, a bad solder connection, bad clip lead, or the ic itself.

I use a very high resistance in order to minimize the current through the coil. With my digital meters, and 100k ohms, the
current through the coil is 3 microamps (3 millionths of an amp).

6. Do the same for the other channel's ic.

Hope this helps all.

I just added the diagram in .jpg . Keep all diagrams and explanations in one post.

steve
« Last Edit: August 06, 2020, 08:02:54 PM by steve »
Steve Sammet (retired, owner, SAS Audio Labs)
"V" Very Low Capacitance ICs, 40pf 1 meter
SAS Audio Labs Test Phono Stage
SAS Audio 11A Tube Reference Preamplifier
SAS Audio Labs 25 W Triode Reference Monoblocks
2 way test Spkrs, 28 - 20khz  -3db (28hz)

Offline Nick B

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Re: need help re testing cartridge
« Reply #2 on: August 06, 2020, 06:50:44 PM »
Thanks, Steve. The pdf didnít display, but I was able to get ohm measurements and they were consistent for each channel. All I had available was a RX1K ohm setting. That Micronta is at least 25-30 years old. Had to clean those leads a bit :)
Nick
ICEpower 1200as2 amp
Audio Hungary APR 204 preamp
Fritz Carrera 7 BE speakers
Border Patrol SEi dac
Auralic Aries Mini & Mojo Audio lps
Audio Envy cables
Roon, Tidal, Qobuz
PI Audio UberBUSS

Offline steve

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Re: need help re testing cartridge
« Reply #3 on: August 06, 2020, 07:53:38 PM »
Thanks, Steve. The pdf didnít display, but I was able to get ohm measurements and they were consistent for each channel. All I had available was a RX1K ohm setting. That Micronta is at least 25-30 years old. Had to clean those leads a bit :)
Nick

Hi Nick,

May have to contact Folsom about it, as the .pdf opens for me. I am using Firefox, do you have .pdf or firefox .pdf applications?
I could go .jpg and see how that works.

I used the Rx 200k, much higher ohmage to as to limit the current through the coil and movement of the cantilever.

Below is same diagram in .jpg .

cheers

steve
« Last Edit: August 06, 2020, 08:01:13 PM by steve »
Steve Sammet (retired, owner, SAS Audio Labs)
"V" Very Low Capacitance ICs, 40pf 1 meter
SAS Audio Labs Test Phono Stage
SAS Audio 11A Tube Reference Preamplifier
SAS Audio Labs 25 W Triode Reference Monoblocks
2 way test Spkrs, 28 - 20khz  -3db (28hz)

Offline Nick B

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Re: need help re testing cartridge
« Reply #4 on: August 06, 2020, 11:12:17 PM »
Thanks, Steve. The pdf didnít display, but I was able to get ohm measurements and they were consistent for each channel. All I had available was a RX1K ohm setting. That Micronta is at least 25-30 years old. Had to clean those leads a bit :)
Nick

Hi Nick,

May have to contact Folsom about it, as the .pdf opens for me. I am using Firefox, do you have .pdf or firefox .pdf applications?
I could go .jpg and see how that works.

I used the Rx 200k, much higher ohmage to as to limit the current through the coil and movement of the cantilever.

Below is same diagram in .jpg .

cheers

steve

Steve,
I sent my results to the buyer. Will see what he says.
Thanks much,
Nick
ICEpower 1200as2 amp
Audio Hungary APR 204 preamp
Fritz Carrera 7 BE speakers
Border Patrol SEi dac
Auralic Aries Mini & Mojo Audio lps
Audio Envy cables
Roon, Tidal, Qobuz
PI Audio UberBUSS

Offline steve

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Re: need help re testing cartridge
« Reply #5 on: August 07, 2020, 01:45:37 PM »
Thanks, Steve. The pdf didnít display, but I was able to get ohm measurements and they were consistent for each channel. All I had available was a RX1K ohm setting. That Micronta is at least 25-30 years old. Had to clean those leads a bit :)
Nick

Hi Nick,

May have to contact Folsom about it, as the .pdf opens for me. I am using Firefox, do you have .pdf or firefox .pdf applications?
I could go .jpg and see how that works.

I used the Rx 200k, much higher ohmage to as to limit the current through the coil and movement of the cantilever.

Below is same diagram in .jpg .

cheers

steve

Steve,
I sent my results to the buyer. Will see what he says.
Thanks much,
Nick

Your welcome Nick. Glad all worked out for you.

I hope the newbies will save or print out this info for a later time.

cheers and great weekend Nick.

steve
Steve Sammet (retired, owner, SAS Audio Labs)
"V" Very Low Capacitance ICs, 40pf 1 meter
SAS Audio Labs Test Phono Stage
SAS Audio 11A Tube Reference Preamplifier
SAS Audio Labs 25 W Triode Reference Monoblocks
2 way test Spkrs, 28 - 20khz  -3db (28hz)

Offline Nick B

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Re: need help re testing cartridge
« Reply #6 on: August 07, 2020, 02:06:43 PM »
Thanks, Steve. The sale isnít quite concluded yet. Yes, enjoy your weekend as well. Am enjoying the cooling trend locally.....only 100 degrees today 🥵
Nick
ICEpower 1200as2 amp
Audio Hungary APR 204 preamp
Fritz Carrera 7 BE speakers
Border Patrol SEi dac
Auralic Aries Mini & Mojo Audio lps
Audio Envy cables
Roon, Tidal, Qobuz
PI Audio UberBUSS