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Cartridge Resistance (Ohms)

Posted: Wed Apr 23, 2014 8:11 pm
by carl_694
Hey all,
So I've noticed folks on eBay putting a digital multimeter across the pins of cartridges they're selling. Is there any science to this? I presume they're trying to show that the cartridge is not "open," but is there any reason to prefer a cart with higher resistance over one with lower resistance, or vice-versa? I spoke to a local guy, and he thinks it's voodoo, but it's certainly prevalent.

Re: Cartridge Resistance (Ohms)

Posted: Wed Apr 23, 2014 9:34 pm
by carl_694
A related question: My "R" has a 253781 Cartridge (and 4 prong-to-2 prong adapter) on it, which I gather is the one that came with the SS160 onward. I'm reading good things about it, but one guy advised it was better to switch to a redhead with the stereo-compliant needles on it? Yet I'm also reading this cartridge is very similar to the coveted 345-03. Any thoughts?

Re: Cartridge Resistance (Ohms)

Posted: Wed Apr 23, 2014 11:53 pm
by Rob-NYC
Carl, stay with the newer cart. The redhead will always be a mediocre cart no matter who makes the styli. The design of the cartridge precludes anything more than a modest improvement in compliance, so wear and distortion will always be greater on those.

The only tangible improvement is in possible higher output and that depends on styli design and material. It also will will result in somewhat greater record wear

The folks who are offering these new styli are supposedly producing a superior product as compared to the recent offerings. That maybe true, but for how long will they be offered? IF you have a redhead installed and don't want to mod the machine, go with the new styli for it. Otherwise, don't bother.

The 345 uses a type of shank/cantilever that was used in millions of phonos world-wide. Although you would have to cut away some plastic to adapt the home version, its popularity means that it has a good chance of being available far into the future.

Rob/NYC

Re: Cartridge Resistance (Ohms)

Posted: Thu Apr 24, 2014 3:13 am
by carl_694
Ok. Thanks! Do you think I need to modify the tone arm? Or replace it? Still has the original, so I need to use the adapter. Also read that I might need to change the springs is it has less pressure on the records?

Re: Cartridge Resistance (Ohms)

Posted: Thu Apr 24, 2014 11:46 am
by Rob-NYC
Carl, the options range from using it as-is with leaving the springs at their lowest position and weight, to replacing the entire tonearm with the later stereo model. It depends on your own skill and intentions here.

If the existing arrangement is able to properly balance without biasing inward or out, just set the "ears" on the tonearm where the springs hook at their lowest level and leave it at that.

Here is a pic of what I'm writing about:

http://s1192.photobucket.com/user/Rob-N ... ort=3&o=14

As you can see I've also slightly stretched the springs to weaken them. I don't recommend doing this unless you have access to a Neuses gram gauge:

http://www.pkneuses.com/www.pkneuses.com/spri.htm Number 10 is the one for this application. they cost around $30 and that may not be justifiable for just one phono. A tracking weight of 2-4 grams is ideal for that cart, but it will track "ok" at 4g too.

Beyond that involves getting the 345-03D retro cart. Be prepared to spend upwards of $200 even for a used one. You'll also need to cut the tonearm weights or add weight to the top of the cart to properly balance it.

Or replacing the existing tonearm with the later one designed for your cart.

There are two approaches to this;

1) Replace just the arm. This requires cutting off the new arm's tailpiece and cutting down the original counterweights to balance the new lighter arm.

2) Try to use the entire tonearm assembly from a later machine:

http://s1192.photobucket.com/user/Rob-N ... sort=3&o=7

Two problems here, as you can see there is a counterpoise weight at the side of the arm assembly. This will generally not fit under the mech cover although it will fit in V-VL.

On the elder electromechanical machines B-R a relay must be added in the mech as the reed trip switch can not withstand the current needed to directly operate the trip coil.

This may be more info than you bargained for, but at least you and other readers now have an idea of the options.

Rob/NYC

Re: Cartridge Resistance (Ohms)

Posted: Fri Apr 25, 2014 12:42 am
by carl_694
That was very informative. Thank you!