How to Identify ADC Carts

the thin end of the wedge
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r.armoneit
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How to Identify ADC Carts

Post by r.armoneit » 04 Dec 2018 22:30

Hi,
I have a ADC cartridge and have searched for clues to what type it is! It's a gold or brass color with black plastic with Omni Pivot Improved on top of cart with etching on the black plastic 785373. It currently has a gray QLM32 MKIII stylus that sounds very good to me. I have seen ADC charts that indicate what I have is down to 3 improved carts,XLM,VLM orZLM. I have read that a Multi Meter reading will help,here is the reading .934. The questions would be ,What do I have so I can get a stylus comparable to the cart!
Thanks,
Bob

audiodk
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Re: How to Identify ADC Carts

Post by audiodk » 05 Dec 2018 04:48

Open screw holes: The XLM and XLM MK II have the patent number on the top. XLM MK III has a blank top. The inductance/Resistance of the XLM, XLM MK II is 300/625 while the XLM MK III is 580/820.
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Open screw holes back view: XLM, XLM MK II, XLM MK III. The MK III has color-coded pins.
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Closed screw holes: MK II Improved, MK III Improved, XLM Improved.
Top has "Omni Pivot Improved" on the MK II and MK III; "ZLM Improved" on the ZLM. Inductance/Resistance is 580/820 for all 3.
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Closed screw holes back view. All three have color-coded pins.
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In Summary:
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GOLD BODY I GOLD BODY II GOLD BODY III

Body I: 1971 - 1976 Used in the XLM, XLM MK II, VLM, VLM MK II. Resistance: 625 ohms. Inductance: 300 mH

Body II: 1977 - 1978. Used in VLM MK III, XLM MK III. Resistance: 820 ohms. Inductance: 580 mH

Body III: 1978. VLM MK III (rebranded as XLM MK II Improved), XLM MK III Improved. Resistance: 820 ohms. Inductance: 580 mH.

audiodk
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Re: How to Identify ADC Carts

Post by audiodk » 05 Dec 2018 04:51

ADC-XLM-SPECS1X.jpg
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donovan
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Re: How to Identify ADC Carts

Post by donovan » 05 Dec 2018 19:44

I have a Silver body with Blue open screw holes and Patent Number 3.294.405.
Ohm resistance reading about 460.
Any idea what model this is?

audiodk
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Re: How to Identify ADC Carts

Post by audiodk » 05 Dec 2018 20:27

donovan wrote:
05 Dec 2018 19:44
I have a Silver body with Blue open screw holes and Patent Number 3.294.405.
Ohm resistance reading about 460.
Any idea what model this is?
The silver body with blue molding are the 1971 QLM30 and QLM32 models.
The QLM30 has a spherical stylus tip .7mil radius with a tracking force of 1 to 2 grams.
The QLM32 has an elliptical tip .3x.7mil with a tracking force of 1 to 2 grams.
Later models changed to a silver/grey body with an increase in resistance to 820 ohms which provided a flatter frequency response with the newer stylus assemblies.

BMRR
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Re: How to Identify ADC Carts

Post by BMRR » 05 Dec 2018 20:51

Some of the K-series cartridges also came in blue. I've got a K8E that's blue and a K8C that's grey. I've also seen photos of blue K8Cs, K5Es, and K6Es.

That patent number was used on a lot of different ADC cartridges, by the way.

donovan
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Re: How to Identify ADC Carts

Post by donovan » 05 Dec 2018 21:23

audiodk wrote:
05 Dec 2018 20:27
donovan wrote:
05 Dec 2018 19:44
I have a Silver body with Blue open screw holes and Patent Number 3.294.405.
Ohm resistance reading about 460.
Any idea what model this is?
The silver body with blue molding are the 1971 QLM30 and QLM32 models.
The QLM30 has a spherical stylus tip .7mil radius with a tracking force of 1 to 2 grams.
The QLM32 has an elliptical tip .3x.7mil with a tracking force of 1 to 2 grams.
Later models changed to a silver/grey body with an increase in resistance to 820 ohms which provided a flatter frequency response with the newer stylus assemblies.
That makes since. I also have a "later model" silver body that reads 820.

r.armoneit
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Re: How to Identify ADC Carts

Post by r.armoneit » 06 Dec 2018 00:29

I want to thank AudioDK,BMRR for your input.
I know I have a ADC Improved Cartridge!
I believe the different improved model numbers were determined by the type of stylus,and the cart will accept(at least) any improved stylus.
I have also learned to remove the tonearm wires from the cart to get the 820 ohm reading! Unfortunately I am unable at this time to provide the Inductance reading. I was amazed to see the extremely high compliance rating that I want to try it on a couple of Dual TT with Low Mass Tonearms...
Best Regards,
Bob

wolfie62
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Re: How to Identify ADC Carts

Post by wolfie62 » 06 Dec 2018 23:12

Exceptionally good info here!

I just got (today) an ADC cart that I can’t identify. I’m guessing it’s a mid-80s cart, low budget. I have 3 Integras (1 ST and 2 for curved arms), 3 XLMs (MKII and MKII Improved). I have 2 PSX carts, a 30 and a 40. I also have 2 QLM bodies. So I’m not a complete novice to ADC carts. But this one has me stumped.

Any help?
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