Let's mod a PL-41 !

[MrIgotNomoney]

Guys
I was thinking, for the PL-41, looking at photos of the Jelco SA-750D although it would be more work than just enlarging the mount hole and dropping in a Rega this arm looks more period correct. To me it would just look like it belonged on that table.
What do you guys think ??

 

[finnbow]

Guys
I was thinking, for the PL-41, looking at photos of the Jelco SA-750D although it would be more work than just enlarging the mount hole and dropping in a Rega this arm looks more period correct. To me it would just look like it belonged on that table.
What do you guys think ??

I'd probably opt for an older (and less expensive) Jelco arm, for both price and fit reasons. I think the mounting distance is 8-9 mm short of optimum for the existing hole. Even used, this arm commands about $500 on A'gon, I think. It is pretty though.

 

[MrIgotNomoney]

I'd probably opt for an older (and lexpensive) Jelco arm, for both price and fit reasons. I think the mounting distance is 8-9 mm short of optimum for the existing hole. Even used, this arm commands about $500 on A'gon, I think. It is pretty though.

Yep I agree 500 buck arm on a PL41 is a stretch, Jelco makes cheaper arms, but that thing sure is nice looking. Hey who knows a PL41 with a Jelco 750 might be a giant killer..
:thmbsp:
bob

 

[thedelihaus]

Typical Sumiko arm, MMT "S" shape, or FT-3/FT-4 straight, sells typically for $300-$400 depending on options and condition, and is a Jelco built arm.

Jelco sells the last of the NOS run via distributors for around $300, somewhat incomplete (missing din plug) as the jelco branded 370 series. I believe an exact size match to the Sumiko MMT/FT-3/4.

The supposed ideal mounting distance for an aftermarket arm is 222, with the mounting distance on the Sumiko as 221.7, a .3 mounting difference discrepancy.

Overall length is a supposed 237 length vs 239 for these arms- I assume with the mounting distance only .3 off, the effective length isn't as much an issue.

Base shaft is 19.05mm and base hole 20mm.

Other arms to consider are the Pioneer PA-1000 that sells for $450-$500, and the strictly low mass (but absolute favorite of mine) ADC LMF.

A fella out of Cypress, in Greece, has an LMF copy for $225. I say copy, as it is 90% the original ADC, but not quite 100%. The tracking weight method is much different, making me wonder if it really is an ADC or if someone bought the tooling and is counterfitting them???

 

[Isotonic]

Very interesting about the Jelco/Sumiko.

 

[MWalt]

I think you'll find the 237/222/15 geometry to be very common. Though measured to the best of my ability, I'm a little skeptical of my own measurements (i.e., 237/223/14) truly differing from this apparent standard. Pioneer's overhang is given as 9/16" in its user's manual, which translates to 14.3 mm. So, there may possibly be 0.7mm difference in overhang if a Rega is mounted in a 23 mm hole drilled concentrically with the Pioneer's 20mm mounting hole. OTOH, it may well be rounding error between English and metric measurements than can easily be made up for during cartridge alignment using an appropriate alignment protractor. From what I've read, the PL-41 is a Jelco arm and there are several Jelco arms of that era (and today) with the 237/15/22 geometry. I have a hard time believing Pioneer would spec out an arm with Jelco that differs by 0.7mm.

BTW, I've read somewhere recently on the interwebs that the height of a Rega tonearm from the plinth to the underside of the cartridge mounting location is 44 mm (on a stock Rega turntable). I measured my current setup (PL-41 with Denon DL-160 in an arm with VTA adjusted such that the arm is perfectly parallel with the record) and it measures 44 mm also. Imagine that!

Accordingly, it seems that the Rega may be very close to a drop-in, albeit with the need to have a machine shop enlarge the mounting hole by 3 mm.

PS - Positive report on thrust bearings to follow in my next post.:thmbsp:

Spoken like an engineer. Deli and I have discussed this very thing in relation to other arms that fall close to the specs you measured. It would be very difficult to get an exact measurement with the arm still in place, and we are only talking about a mm or so. I think you are right about 237/222/15 geometry.

This whole project is tough because a lot of you guys have mint or nearly mint PL-41's. I would be hard pressed to modify a deck like that. When I got mine I paid $75 for it. It had been oiled and a had a new belt. It was quiet and kept perfect speed. But the plinth had water damage and the metal base was chipped. So the plinth was reveneered in cherry and the metal base was powder coated in an aluminum color. The tonearm has been rewired in 33awg cardas and the plinth has been corked. Even the RCA's are upgraded. My PL-41 is already moddded and it is OK to cut it and put an aftermarket arm on it. For me it is not a matter of "if", it is "when" and "what".

 

[finnbow]

Another Thrust Bearing Update

I'm on the way to the post office to mail out the following today:

Naptown Rob - 3
Tromatic - 3
Mark Walters -1
midfiguy -1
pbinpb57 -2
bobschneider- 2
mfhale- 1
Westy56 -1
RickB -1
Bystander -1
Jimmy64 -1
Fisherdude – 2

Those that remain (with action to be taken in parentheses):

TJLitt - 1 (No payment yet)
Isotronic -2 (Clarification on number ordered pending. No payment yet)
MrIgotNomoney - 1 (Payment received, but without mailing address)

I installed mine yesterday and it works beautifully. I lubricated the spindle and bathed the thrust bearing in Pennzoil Platinum 5W-30 synthetic motor oil and it runs very smoothly and silently. I spun the platter by hand without the belt on the pulley and it continued to spin damn near forever - a good sign.

BTW, it raised the tonearm at least 0.10" thereby necessitating readjustment in VTA as the spindle had worn completely through the old bearing and the new bearing had increased the tonearm height accordingly. All is good.

 

[thedelihaus]

...I installed mine yesterday and it works beautifully. I lubricated the spindle and bathed the thrust bearing in Pennzoil Platinum 5W-30 synthetic motor oil and it runs very smoothly and silently. I spun the platter by hand without the belt on the pulley and it continued to spin damn near forever - a good sign.

BTW, it raised the tonearm at least 0.10" thereby necessitating readjustment in VTA as the spindle had worn completely through the old bearing and the new bearing had increased the tonearm height accordingly. All is good.

Very cool indeed.

A question- if one ran into height issues with an added tone arm, as in the arm not able to be low enough in he body to have proper VTA, could these Delrin units be stacked?

Or cut thicker?

Or, if someone added an arm board of 1/4" height and needed some more clearance, would this thrust plate cure the clearance issues?


If not, is there a way to raise the bearing housing/mounting?

 

[finnbow]

Very cool indeed.

A question- if one ran into height issues with an added tone arm, as in the arm not able to be low enough in he body to have proper VTA, could these Delrin units be stacked?

Or cut thicker?

Or, if someone added an arm board of 1/4" height and needed some more clearance, would this thrust plate cure the clearance issues?


If not, is there a way to raise the bearing housing/mounting?

Great minds think alike, Paul. I've been considering this very issue.

In response, I think you can do what you suggest, to a limited degree anyway. You could raise the spindle (by increasing bearing thickness/stacking) to just below the point where the retention clip on the bottom of the spindle rubs against the bottom of the sleeve bearing into which the splindle fits. I think this may give you up to 1/4" of play in the upwards direction.

I think one can get a sense of how much potential they have to raise the spindle (and accordingly the platter and tonearm) by tugging upward on the installed spindle (before placing the platter upon it). It will move upward until the retention clip contacts the bottom of the spindle's sleeve bearing. You can see the spindle's retention clip in photo I attached to yesterday's post.

If not, is there a way to raise the bearing housing/mounting?

I don't think that's really possible. The ~1/4" is essentially the limit in that if the platter were to go much higher, the belt would ride too low on the platter rim. I suppose one could go higher if they were to completely disassemble the bearing assembly, cut a given amount off of the top of the tube/sleeve and reinstall. One would also have to install the pulley/capstan higher on its shaft to accommodate appropriate positioning of the belt on the platter. I'm not sure I'd recommend this route, however - too much surgery.

 

[MrIgotNomoney]

Guys
I want to throw a tip out there.
The PL-41 bearing has a thin paper or fibre gasket that seals the bearing cap, Im assuming to keep the oil from leaking out. Everyone I have seen is destroyed as soon as the bearing cap is unscrewed.
What I did was to take a strip of teflon tape, the kind used in plumbing, lay out about a 6-7 inch piece flat and slice it longways down the middle.
Then wrap the threads of the bearing housing with the teflon tape, i made 2 complete wraps, do this before you oil the spindle and replace the cap.
To do all this I remove the bearing housing 3 screws, and lift out the bearing housing. When the housing is out I clean all the parts,wrap the bearing housing threads with the teflon tape. Then lube the spindle drop that back in. Then add a few drops of oil and replace the bearing cap. You will notice that the spindle will not settle down all the way because of the oil in the housing. What I did was to hold the bearing housing in my hand while pushing down on the spindle tip with my thumb.
Within a few minutes the air and a little oil bled out around the top area of the bearing housing around the spindle as it settled in.
No leakage what so ever from the screw on cap.

Also something to consider I also polished the spindle, using a drill press, very fine crocus cloth, I think 2000 grit then used metal polish till it reflected like a mirror. I also polished the thrust tip, I used a block of fairly soft wood, and liquid metal polish allowing the thrust tip to make an indentation in the block, a few drops of polish in the indentation and then letting the tip ride in the polish, I used very light pressure.
This polished the tip to perfection.
I used mobile 1 synthetic to lubricate my bearing.
bob

 

[Naptown Rob]

What do you guys think of the ADC LMF-2 as a tonearm candidate?

Measurements seem right.

Low mass (5.5g) carbon fiber arm. Too low? Am I limiting my cartridge choices too much?

 

[thedelihaus]

What do you guys think of the ADC LMF-2 as a tonearm candidate?

Measurements seem right.

Low mass (5.5g) carbon fiber arm. Too low? Am I limiting my cartridge choices too much?

I own one. It gets mention a few posts back.

The pair being sold out of Cypress is different than the original, and not sure if it's really an ADC or just parts that were made for ADC and are the surplus from the manufacturer, or if the manufacturer ran off more pieces later.

The most noticeable difference in in the different method of applying tracking force, and different tone arm weight- the original came with a handful of interchangeable weights, not just one.

The Cyprus seller mentions the weight variables in his specs, but this arm has one weight, which I think wascan earlier ADC arm's weight.

To setvthe record straight- his ad is incorrect saying the version he has for sale is the later model with anti-skating, as all LMF-2s had anti-skating.

So, originally thinking after-production knock-off, perhaps it's just new old stock and simplified construction, part LMF and part of the earlier, cheaper ADC offering, the ALT-1, combined. Read below about the ALT-1...

Original ADC LMF units sell for a starting price of $225-275 but are hard to come by. The LMF-1 is the fixed headshell version and even rarer. There's an earlier model, that I mentioned above, the ALT-1, but it is an average performer only, mediocre when compared to the LMF series, and got lukewarm press at the time.

It is a low mass arm and needs a cart of low weight to balance correctly- the rare ADC integrated headshell/cart combo is best, and it's not the more common integra version, so it is extremely rare and often suffers from suspension collapse it seems, do to age.

The arm should come with a series of different end weights that you change to match the cartridge weight.

The ortofon Super OM 20, 30 and 40 are a great alternative, and can be had for $179-$379 new old stock.

 

[MWalt]

OK Guys, looks like I will be the first victim in this experiment. I am getting a Sumiko Premier FT-3 tonearm for my PL-41. If I fail, I will sell it and get a Rega RB 700. I went this route because the arm is pretty well regarded and the price was right. Delihaus is rewiring it, and when I get it I am doing a direct install and will post the results.

 

[Naptown Rob]

I salute you Mr. Walters, but remember:

The early bird gets the worm,
But the second mouse gets the cheese...:scratch2:

 

[WmAx]

The Jelco SA250ST arm is a great arm for the price. I am not sure how hard it would be to mount the Jelco to that specific Pioneer, however. I, and I believe most others that have had the chance to use/inspect the Jelco, will probably recommend it over the Rega RB250 or RB300 arms.

Another way to get a good arm even cheaper is to have much patience an keep searching for tonearms on eBay until you come across a nice one for a low BUY IT NOW price. They do come up occasionally. A year or so ago I pointed a friend to a superb B.I.N. eBay deal on a used tonearm. He got it for about $110, and it's easily worth far more based on construction and performance. It was an arm from a top of the line Rotel from the 80's. It appears to be Jelco made to custom specifications for Rotel. It is roughly based on the SA250ST but a higher performance/build quality variant. It would easily cost(and be worth) $400-$600 if it was a current, new Jelco product, or it would cost twice that if it was another brand. Jelco offers greater value than most in terms of build quality/performance for the dollars spent. Remember that Jelco makes a lot of arms for famous brands which rebadge them.

-Chris

 

[thedelihaus]

While the Jelco 250 is a nice arm, the 750 is superior, and is reflected in the price- $300 vs. $500.

And the jelco 750 is basically the earlier Jelco 370, just slightly different sizing.

And the Jelco 370 is basically the Sumiko MMT.

And the Sumiko MMT, when using a straight tube and (i believe) the upgraded arm wire, is the Sumiko FT-3.

The Sumiko FT-4 adds even nicer wire and the aftermarket VTA on the fly base.

Now, keep in mind, all these include adjustable VTA, via hex head set screw.

The optional "on the fly" base uses a hex grub screw that features a ball bearing and spring, and allen screw shaft to adjust "on the fly".

HOWEVER- this base would require one to modify the PL-41 plinth- it's not a "drop-in" fit.

NOTE- I'm also a big fan of the Audioquest arms, the PT-6,7 and 8 especially, but the mounting shaft is wider than the Sumikos, and the arm length a tad shorter, so these ARE NOT a drop-in fit.


Remember- the Sumiko paperwork claims the arm base shaft is 19.05 mm, while the measurements of the Pioneer PL-41 hole is 20mm, according to fellow AKer's measurements. A good fit.



The Sumiko arms are very flexible- remember you can use fluid damping with them or run them without fluid damping- thus increasing available carts.

And although the 250/300 arm has more end-potential with mods, the mods run about $450, the arm $250-300, total cost is $700-$750 when you're finished.

These Jelco arms, I feel, are better in stock form, straight out of the box.

And they can typically be had for around $300 (and up) off Audiogon.


The mounting distance discrepancy, if we are going by Finnbow's measurements, is only a .3 mm difference.

 

[MWalt]

The Jelco SA250ST arm is a great arm for the price. I am not sure how hard it would be to mount the Jelco to that specific Pioneer, however. I, and I believe most others that have had the chance to use/inspect the Jelco, will probably recommend it over the Rega RB250 or RB300 arms.

Another way to get a good arm even cheaper is to have much patience an keep searching for tonearms on eBay until you come across a nice one for a low BUY IT NOW price. They do come up occasionally. A year or so ago I pointed a friend to a superb B.I.N. eBay deal on a used tonearm. He got it for about $110, and it's easily worth far more based on construction and performance. It was an arm from a top of the line Rotel from the 80's. It appears to be Jelco made to custom specifications for Rotel. It is roughly based on the SA250ST but a higher performance/build quality variant. It would easily cost(and be worth) $400-$600 if it was a current, new Jelco product, or it would cost twice that if it was another brand. Jelco offers greater value than most in terms of build quality/performance for the dollars spent. Remember that Jelco makes a lot of arms for famous brands which rebadge them.

-Chris

The Sumiko arm I chose was made by Jelco and is a much better arm than the SA250. Matter of fact it is a bit better than the Jelco750 as well.

 

[MWalt]

Looks like Deli beat me to it and explained things in his usual detailed manner.

 

[thedelihaus]

I salute you Mr. Walters, but remember:

The early bird gets the worm,
But the second mouse gets the cheese...:scratch2:

A possibility for a lower cost investment you should consider is the early, pre- 250 variants.

Jelco made arms for a bunch of manufacturers.

Now, problem is, these arms were of different lengths, and some used the 19.05 mm shaft, while others used the wider 23/25mm (approximate) shaft, like used on the Audioquest arms.

If you are able to get the seller to measure these to verify which the arm sports, then there's a few alternatives that fly under the radar.

Now, I cannot comment on how refined the wiring is, or what level the quality of the bearings are- remember, these were made to meet a price point- and this series doesn't allow provision for fluid damping.

But AR had one of their later arms built by Jelco, so look there.

Also, Systemdek offered an arm, built by Jelco.

And Mission too. Not the low mass finicky (but fantastic) early arms, but later, simpler arms.


These are all based loosely on what is now the 250 series.


And if you are keen, may be had for as low as $100, though typically $150-200.


The nicer Audioquest fluid damper arms and Sumiko arms, for reference, were offered by VPI and a few other high-end tables as a stock package deal.

 

[thedelihaus]

The Sumiko arm I chose was made by Jelco and is a much better arm than the SA250. Matter of fact it is a bit better than the Jelco750 as well.

You'll basically have a Jelco 750ST (straight) model, with what I consider the slightly different, and in my opinion, better geometry.

This, with improved Litz OFC wire or Cardas wire or OFC/silver wire (one of the three) with Cardas brand end clips.

It will also be a continuous, uninterrupted run of wire vs. the stock interrupted wire at 2 or 3 points.