Seeburg tonearm dampening

[jukeboxmarty]

Lately I've come across many Seeburg tonearms that have lost their dampening.

Apparently some of these tonearms have been in service like this for years.

What weight oil was used to dampen the tonearm?

What are the pitfalls of a tonearm without dampening?

Do some cartridges/needles hold up better without it?

Any tips for reworking these?

Thanks!

[Ron Rich]

Hi Marty,
Well, there is a basic dis-agreement here on this subject--one person believes that Seeburg engineers were incorrect to damp the tone arms, I don't, as needles, and records, take a "beating", if not properly damped.
IMHO tone arms need to be damped, for two reasons. 1. So that "set-down" needle pressure is light,and 2., mostly to absorb any external shock the jukebox may suffer. The older tone arms were filled with a different weight then the newer (1967-up-"wedge" type stylii). The older arms had a retaining nut on the tone arm shaft, that often I have found to be loose- just tightening it, and the screw, will renew the dampening function. On the newer type SS-160's, and up, the tone arm was locked into it's spot without a lock nut. This screw needs to be "torqued" till the frame is slightly bent. If a red colored tone arm of this vintage is found, it should be changed for one painted blue-green as the chamber which held the lighter type fluid leaked--badly ! Ron Rich
As for the weight of the silicon fluid used--I never thought to check on this at the factory--and don't know.As for a process to re-fill the tone arms, I have attempted several ways. Best one I have found is to drill a small hole into the upper side of the round casting, use a needle injector to re-fill it close the hole with JB weld--and re-seal the edges with Red Glypt.  Ron Rich

[jukeboxmarty]

Nov 4, 2017 17:53:22 GMT Ron Rich said:

Hi Marty,
Well, there is a basic dis-agreement here on this subject--one person believes that Seeburg engineers were incorrect to damp the tone arms, I don't, as needles, and records, take a "beating", if not properly damped.
IMHO tone arms need to be damped, for two reasons. 1. So that "set-down" needle pressure is light,and 2., mostly to absorb any external shock the jukebox may suffer. The older tone arms were filled with a different weight then the newer (1967-up-"wedge" type stylii). The older arms had a retaining nut on the tone arm shaft, that often I have found to be loose- just tightening it, and the screw, will renew the dampening function. On the newer type SS-160's, and up, the tone arm was locked into it's spot without a lock nut. This screw needs to be "torqued" till the frame is slightly bent. If a red colored tone arm of this vintage is found, it should be changed for one painted blue-green as the chamber which held the lighter type fluid leaked--badly ! Ron Rich
As for the weight of the silicon fluid used--I never thought to check on this at the factory--and don't know.As for a process to re-fill the tone arms, I have attempted several ways. Best one I have found is to drill a small hole into the upper side of the round casting, use a needle injector to re-fill it close the hole with JB weld--and re-seal the edges with Red Glypt.  Ron Rich

Thanks for the detailed reply Ron.


My immediate concern is for an M100B. I'm just tired of pulling apart otherwise complete mechanisms just for a good tonearm. I've got a box of bad tonearms I've replaced; it might be time to rework some of them.

What type of oil/silicone can you recommend for refilling?

[Ron Rich]

Marty,
First--spin the tone arm, holding the pin-- a few times, often, the fluid has just all settled to the bottom, and spinning it will cause it to function again. I think I purchased the fluid from a company called "Turn Table Basics"--All of that info was on my old computer, which self-destructed a few months ago----seems there were three viscosities available--I used the center one--Ron Rich

[robnyc]

Quoting Ron: "Well, there is a basic dis-agreement here on this subject--one person believes that Seeburg engineers were incorrect to damp the tone arms".

I am probably that one person. Damping does nothing other than increase the effective vertical mass of an otherwise good-excellent arm. With damping in place you'll see slight stylus cantilever flexing (compression) even on seemingly flat records as they turn. The damping effectively makes the tracking force heavier or lighter as the it delays the arm's response to the warp.

When I asked Seeburg repair tech's here about this back in the 1980's I was told that it's purpose was to reduce skipping if the machine was jostled.

I've eliminated it on all Seeburgs I've used over the last 32 years. Through 2 million+ plays I've never had a damaged stylus or any other negative effect.

Rob NYC

[Ron Rich]

Hi Rob,
Yep--you are, "unique" ! lol Ron Rich

[Ron Rich]

Hi All,
I have a little time to "kill", so I'll write this now--
I waz tolt, by one of the mechanical engineers at the Seeburg factory that the wedge style needles were conceived in 1963/4. Seeburg/Pickering engineering worked together on this project. The new system was scheduled to go int production for the PFEA ("Electra-Fleetwood") models. They installed the first test unit into a LPC-1 cabinet. This was the first one with the light tone arm pressure. It was found that if placed on a floor that ""bounced", or in a location that had a very stiff floor, and a customer placed his hand on the phono cabinet top, the music would "warble".
This stopped the idea, that the new style cart (340 type), and (yellow/violet)needles were to be introduced that year. They spent another year, doing a re-design of the 160 selection, mechanism suspension system, to eliminate this problem. The new style cart/stylii were introduced the following year. During the SS-160 production, the sales of the yellow/violet stylii were increasing to proportions that made no sense. Both Seeburg and Pickering wanted to find out "why". Studies were done, needles were returned to Seeburg, then on back to Pickering. It was determined that the tips were being damaged somehow in the phono. The answer was determined to be that the damping fluid,was leaking out- was missing, and the needles were landing, at times, with such force, that if they happened to land inside, or very close to the lead-in grove, this would cause needle damage. We GAVE AWAY hundreds of pair of needles, and when available, gave away new, improved tone arms. Tone arms on the SS-160, and the very early production LS-1's, were red colored. Improved tone arms are painted a green/blue color-or, much later, totally un-painted. Note, this does NOT apply to the 100 select mechs that used either the green, or tan/brown needle as different style springs, and different tracking pressure, as well as mechanism placement within the cabinet precluded any problems showing up. Ron Rich

[robnyc]

Ron, a few points here:


1) Nearly every crap domestic (home) changer lands the stylus with more force than an undamped Seeburg arm. Both R-O and even Rowe AMI (1100-1200) actually bounce slightly.

2) As you know I've worked in recording and broadcast engineering. "Disk Jockeys" were notoriously rough on the Stanton 500/AL which is essentially the same cantilever as your Seeburg 340. Bent cantilevers from bashing and back cueing were common. Broken styli were almost non-existent. If you've ever worked in an old style radio or TV station where records were in tightly formatted use, you would see that the treatment that styli get was --far-- worse than anything in a Seeburg (and most other jukes as well).

3) I measured the actual transient variations of the tracking force in the seeburg arms using both earlier (mono) and later carts. With damping in place the tracking force varies approx +/- 2-2-1/2 gm. This doesn't matter much when tracking is 5-6 gm. However, when aiming for 2-3 gm that variation is very significant. On those more compliant cantilevers, you actually see it flex and compress.

Ron, I can't argue with what you were told, nor the fact that Seeburg continued to issue damped arms for decades after domestic turntable manufacturers banned them as problematic with the more compliant styli that came in the early 1960's. I can state that based on 32 years of operating dozens of Seeburgs in revenue service without damping I've yet to have a damaged styli.

Now, if only Seeburg had been as conscientious regarding fusing.......

Rob

[Ron Rich]

Rob
Yep--I agree on the fusing !!! --but all you need to do is find a SS-160, play a song and lean your hand against the top of the cabinet. If it still has an original, red colored tone, arm, it WILL "warbel"--if it has been replaced with one that has the improved damper, it will play just fine--I can instantly tell which arm is installed by doing that--I also have changed about "1000" (?), of those tone arms, under warranty-- Seeburg supplied a new tone arm for years, on an exchange basis-- I still recall the part number (253888) ! Ron Rich

[jukeboxmarty]

Thanks both of you, for the detailed input. I'm happy to get both sides of the issue.

I've noticed the varying tracking force of the damping especially with warped records and inferior needles.

Some of the (bad) batches of Pfanstiehl yellow needles were so finicky that warped records would cause the volume to fade in and out. I wound up returning those needles. Older style yellow needles seemed to handle the variations better.

Unfortunately, many the "new" stereo 'T' needles have the same issue. The acceptable window of tracking force is very narrow.

[Ron Rich]

Marty,
READ the above "sticky" about Seeburg needles--and "Wedge style needles" On the tracking force of both the Mono" and "T"type" stereo needles--I understand there have been recent improvements --I have yet to test either-