Tone Arm Weight –<P>I have a Seeburg Model K-46 (1946) record changer that was repaired and had its magnetic cartridge replaced by a ceramic unit. It only plays 78 rpm records. When buying needles for the ceramic cartridge, they state 2 to 6 grams for their use.<P>The changer has had its tone arm adjusted to allow minimum weight. It now measures about 13 grams with the cartridge. Since this is an older changer, it might be their tone arms were somewhat heavier than today’s players.<P>I would like input on using this changer with a 13 gram tone arm weight. Is this normal with these older record changers and will the needle work?<P>Thanks,<BR>Jerry <BR><P>------------------<BR>

<P>It must be a late ceramic cartridge with a half volt output right ? Do you experience overload with the new ceramic cartridge ? I would suspect the magnetic one to put out maybe 1/10th the voltage of the replacement ?<P> <P>Yes. The older cartridges were tracking much heavier. You are lucky the tone-arm has a weight adjustment at all.<P><BR> <P>I don'T think this is a good idea. If the cartridge is designed to track at a maximum of 6 grams, using double that will not only damage the cartridge/stylus, it will also seriously damage your records. Why ? Simple because the compliance of the stylus will be lost. Without compliance, it will be like using a nail in the record's grooves, causing serious damage on every pass. Even a single pass is often enough to cause serious damage.<P>I suggest either to find a proper cartridge or have the original restored, or find a way to bring the tone-arm within the replacement cartridge's specs.<P>Syl<P>------------------<BR>

Syl <BR>Thanks for your comments.<P>1. The output of my cartridge is rated at 650 mV. In fact two of its terminals are soldered together for more output. In the radio that the changer plugs in to, the magnetic cartridge required a separate amplifier. So, with this extra cartridge output, the amplifier is not required, and I do not detect overload. <P>2. I understand your concerns about my 13 gram tone arm weight and they seem reasonable. You also mentioned older units had heavier tone arms, so I assumed they may have measured somewhere near my number or more. I wonder if the older cartridges were as compliant so not to cause the damage you mention? <P>Jerry<P><BR>------------------<BR>

</B><P>Ok, that makes sense. I was wondering how'd you achieve the output matching.<BR> <BR> <BR> </B><P>In ounces rather than grams !<BR>1 to 2 ounces would be a reasonable assumption...<P><BR> <P>In a sense they are equivalent to the new types. Although lighter cartridges are nicer to records in terms of wear, obviously.<P>Take this analogy: Look at a large truck suspension. Use it on a light automobile, the passengers will bounce all over the place because the suspension isn't compliant enough for the weight of the car. Now install that same suspension on a heavy truck, the ride will be almost as smooth for it's passengers as in the smaller car with it's own adapted suspension. Yet, both ride over the same bumps and holes. Eventually the bumps will get flatten faster with the truck then with the smaller car and that's what happens to records. The grooves will see more wear with the heavier cartridge then the lighter one, but that doesn't mean that "damage" is done to the record per se.<P>Now remove the compliance to BOTH car and truck, and passengers will suffer the same bumping around. It's all a matter of compliance vs weight.<P>Oh, a good stylus is also on order here. A damaged, worn or mis-adapted stylus will cause greater damage to the record than weight alone.<P>When I restore cartridges, I modify the compliance of the rebuilt cartridge and warn the owner to remove all excess weight, like in some Capehart. The benefits are obvious; less wear on the records and a better, extended frequency range. A more compliant stylus/needle will react faster and conform better to the recording grooves.<P>That would be a benefit of a lighter cartridge alone, extended frequency response. All things being equal, you need a good quality replacement cartridge to achieve this.<P>Syl<P>------------------<BR>

Look underneath the arm near the pivot point for a spring or the holes where one might have been installed.<P>Many times there is a series of holes in the arm. Using holes farther from the pivot applies more tension from the spring, this reduces the tracking force. The spring may be missing entirely or in the wrong hole.<P>Not all of them use springs. I've also seen arrangements that have the counterweight or tensioner installed on the rearward side of the tone arm or going through to the underside.<P>If the cartridge has wires soldered together, perhaps it is a stereo cartridge converted to monophonic.<P>-Ed<BR><P>------------------<BR>

Syl –<P>How nice of you to detail your answers for me. You would make a great teacher (maybe you were).<P>When I received the changer from the repair shop, the tone arm measured about 17 grams. With the adjustment on the changer, I was able to reduce that to 13 grams. As for getting another type of cartridge, I am not aware of any that would be any better in terms of output and weight. Or, one that would allow a heavier tone arm. So, it seems the only correction is to do something more drastic to the changer than readjustment.<P>I did try tying together some of the spring rings that control the tension and was able to lower my weight to about 10 grams, but with what I had to do to accomplish this, I did not think was worth the gain of only 3 grams.<P>You mention when you restore cartridges, you modify the compliance. Is that a process you can share with me?<P>Jerry<BR><P>------------------<BR>

Hello Ed -<P>Yes, I do have a spring and connected to that spring is a metal lever (arm) that allows you to adjust the tension. And, I have adjusted it for best tracking (less weight). However, the adjustment was not enough to get me to six grams. And, as you said, if you get the spring farther from the pivot arm, you have less tracking weight.<P>So, I thought I would be creative and I made myself another bracket that is a little longer than the bracket that holds the spring. The bracket on the changer has two holes that will allow me to attach my extended bracket too. If I am successful, that should place the spring farther back from my pivot point and hopefully I can see less tracking force. I need to go to the hardware store tomorrow to pick up some very small machine bolts and nuts and then I will give it a try.<P>Jerry<P><BR><P>------------------<BR>

<P>Thanks.<P>I did for about a year. Basic and advanced digital electronics. The I started my business in software dev. I should have continued teaching...<P><BR> <P>Can you add weight to the back of the tonerarm "behind" the pivot point instead of "cheating" the spring ? It's hard to visualize if it's possible to do at all without a picture of your TT. <P>Although anti-skating isn't much of a concern in old TT with heavy arms and 78s, I wonder what will be the results with a much lighter tracking weight using an older tonearm ? No so much for minimizing distortion because the stylus has much more to do about this, but to keep it from skipping on not so pristine records. <P>An added benefit with a heavier tone-arm and lighter tracking is warped records will play better than using a lighter tone-arm found on newer TT. Physics...<P><BR> <P>Mmm...No offense here but that would be giving away part of the process that makes my restoration so different from others, so far.<P>You wouldn't find any benefit as it only applies to older cartridges rebuilding anyway. There isn't much you can do with a newer cartridge, short of re-designing the cantilever, damping etc.<P>Syl<P>------------------<BR>

How about a stronger spring instead of stretching the old one farther? Rubber band and a spring?<P>I've taken old pen springs, shortened them a bit and made a hook out of the ends.<P>Syl makes a good point, the old tone arms had more friction in the pivots and changer mechanism. Making the arm track too light may mean the stylus will skip more easily rather than stick in the groove and track the record. Well, it shouldn't be a problem to increase the tracking if you actually succeed in getting it to track too lightly.<P>-Ed<P>------------------<BR>