Phonoland

I just installed a Pfanstiehl P-132d cartridge in my AMI D-40, and need to lighten the tonearm to around 4 grams. There is very little room to add anything to the tonearm behind the pivot because of the close proximity of the records. Any tips?
This is set up for 45's.

My first post here.

Four grams is kinda pushin it.
For juke use, I'd recommend 5-6 grams with that specific cartridge.

Not familier with that particular arm setup, but isn't there a counterweight spring?

If there was a counterweight spring at one time, I sure don't know where it would go.

Got the parts book--that should "tell" you --Ron Rich

Todd, you are pretty much stuck with trying to add weight to the existing counterweight. I've seen those machines at shows and don't recall seeing any form of adjustment.

That arm was the same as used for the C and probably earlier. The 12+ g weight was not that bad when used with a 3 mil stylus as intended for 78's this would be the equivalent of 4 g on a 1 mil stylus.

Adapting those machines for 45 was, at best, an act of desperation.

Rob/NYC

Hello Todd,

Welcome to the forum. I assume that the jukebox has been converted from a 40 play 78rpm mechanism!

As the other forum members have said that 4 grames would seem somewhat light on these early mechanisms and they were adjusted for the height above the record, they did have some form of counterbalance which tended to be adjusted by a screw and there was a small biasing spring to stop the needle skating across the record.

Hopefully someone will offer advice who has indeed worked on these mechanisms.

Regards
Alan

Alan Hood
ami-man
UK

Todd, for what little good it will do in this case, here is a link to the 4 sel AMI mech manual of that era:

www.flippers.com/pdfs/AMI_Mechanism_R-2 ... ePaper.pdf

There is no mention of tracking weight adjustment though the arm appears slightly different.

You are going to have to improvise here. In several older Rock-Olas I angled the threaded bolt that I placed the new counterweight on upward so as to clear the dress cap over the records.

Rob/NYC

Between the pivot and the cartridge, there is a height adjustment screw that the tone arm rests on. What if I put a super light compression spring there? Not strong enough to lift the tone arm from it's resting point, but to help support some of the weight. Just trying to think outside the box...

There isn't any harm in trying that, but there are two problems associated with these primitive arms.

Aside from a lack of adjustment for tracking weight there are the problems of a crude trip switch, crude vertical bearings and the fact that the arm is unbalanced. A spring won't help that situation.

The reason I recommend going the route of a counterweight is that it puts the arm in better balance and, to a degree, mitigates the friction of the crude vertical bearing.

Here are two shots of the arm in my I-200:

http://s1192.photobucket.com/user/Rob-N ... ort=3&o=42

http://s1192.photobucket.com/user/Rob-N ... ort=3&o=41

This is how I've dealt with the problem of integrating a newer pickup cart into the older arms. When properly set-up even these can use a decent magnetic cart and track at 2-3 g with no stylus wobble or hopping.

The only AMI I've owned earlier than an H-200 was an E-120. That was in 1988. On that machine I did add a Pickering magnetic (Dat series) and a counterweight. Along with a preamp and tweeter, that ugly duckling did at least sound very good.

If practical a pic of your mech might help us give some suggestions.

Rob/NYC

I don't know what the original cartridge was, or what it actually weighed, but a P-132D is a very lightweight plastic cartridge compared to older ones.
Perhaps the end result could be lower stylus pressure in the acceptable range?
If need be, on top of the arm, behind the vertical pivot, a lead weight could be fixed, to counterbalance it.
A lead fish weight, sliced to the appropriate size/weight (trial/error)?
And of course a drop of oil on those pivots helps reduce friction.

This is what I came up with. It is not pretty, but it is functional.

Todd,
I am sure you have heard the old saying: "Beauty is in the eye of the beholder"--well,
I think it IS "pretty"-- Ron Rich

WOW.... is all I can say!