Replacing a tonearm

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Wrayster
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Replacing a tonearm

Post by Wrayster » 17 Oct 2018 18:15

Hi all,

I have a Thorens TD-150 with a TP13 arm on it, (not the 13a version).

I have decide to change the tonearm, I'm getting a Rega R200 as I wanted something that at least looks like it's of a similar vintage and the reviews on here are very complementary.

Having searched the web I haven't yet found any advise on how to do this. Surely I'm looking in all the wrong places!

Can anyone advise on this or direct me to somewhere with more info? I'm guessing that there will be some generic guidelines of where the pivot of the tone arm should be installed in relation to the platter for example? And then there's VTA to consider.

Any Help gratefully received.

josephazannieri
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Re: Replacing a tonearm

Post by josephazannieri » 17 Oct 2018 19:36

Yo Wrayster:

The TD 150 with the TP13 arm should be the one with the square silver weights and no antiskate. It will also have a plastic armboard. The process will be similar to the process I went through when I replaced the TP 13A arm on my TD150 ABII with a Linn Basik LVX.

First thing is to remove the original arm and armboard and remove the cuing device. This will leave you with an empty space where the armboard used to be. Then you will need to make a new armboard out of some good hardwood. I used oak for mine. I have a set of measurements for the armboard which I will be glad to send you if you PM me with your Email address. VE will not take images from my computer.

Your Rega arm should have measurements with it, including the measurement between the turntable spindle and the arm pivot. My Linn had a template. First you need to mount the new armboard. I drilled holes in the board and held it to the metal frame with 1/2 inch #6 stainless steel flathead machine screws. Then I took a big carpenter's compass and swung an arc from the center of the turntable out the designated measurement. There is a little dimple in the center spindle of the TD 15o that makes this job really easy. Just put the compass pin in the dimple. Then I removed the armboard and put it in a drill press and carefully drilled the holes to the exact measurements given by arm maker. making sure that the new arm would lie parallel to the edge of the arm board. I needed 4 holes, one big one at center, and 3 little ones around the big one. Don't know what you will need for the Rega.

Once you have the holes drilled, you can mount the new arm to the board. You will have to be sure that the new arm lies parallel to the top of turntable of TD 150 with a record on it. You may have to raise the or lower the arm pivot to get the parallel alignment. You may find that new arm is heavier than the original TP 13. this will mean that you will have to tighten the springs to get turntable to ride level.

It will take some work, and you may have to put shims under the Rega arm if it rides too low.

And good luck from that wood-butchering old high rider,

Joe Z.

Wrayster
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Re: Replacing a tonearm

Post by Wrayster » 20 Oct 2018 13:32

Thanks again Joe. That’s very helpful. I’ve just received the new arm so hope to start work soon.

Bandit127
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Re: Replacing a tonearm

Post by Bandit127 » 20 Oct 2018 20:22

Jaoseph gives very good advice. I will repeat some of that in my observations.

I did this job on my mates TD125. I used a walnut board that turned out well and has been stable for the couple of years it has been used.

I was particularly careful to get the hole for the tonearm in the right place. I looked up the pivot to spindle spacing for the R200 in the database. I measured and checked 3 times before drilling. 1 mm or so error there is fine but 5 mm will probably give you alignment problems.

I don't know if the TP13 and R200 have the same spacing but if you don't know for sure, don't use the old armboard as a template for the tonearm hole.

I also replaced the rubber belt that drives the antiskate at the same time. That is a sod of a job because you have to disconnect the tonearm wires to remove the socket before you can get at the old (bits of) belt. You also need to take care that the magnets go back on the same alignment. There is a good thread with a how-to on here for that job if you need to do it and it was invaluable for me.

The R200 suits medium compliance cartridges. With (e.g.) a Shure M75ED2 loaded it sounds a bit too relaxed and soft. The Nagaoka MP110 suits it well. The M44 is also surprisingly good on that arm.

His deck certainly looks better with a good looking, curvy arm on it and he is still pleased with it.

Good luck with yours.
Last edited by Bandit127 on 20 Oct 2018 20:33, edited 1 time in total.

Bandit127
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Re: Replacing a tonearm

Post by Bandit127 » 20 Oct 2018 20:30

Some useful reading.
https://www.vinylengine.com/library/rega/r200.shtml

Hopefully you won't need this:
viewtopic.php?f=32&t=49784

Wrayster
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Re: Replacing a tonearm

Post by Wrayster » 21 Oct 2018 19:36

Hi Bandit

Thanks for your further advise. I’m going to order some cheap plywoood to practice making up a new armboard. The vertical pivot on the R200 seems to sit slightly higher (approx 4mm) than the TP13 so I was thinking of using a thinner armboard to compensate, do you think that’s necessary?

Also, I received the R200 and surprise surprise the anti-skate belt is shot so I’ll have to replace that (Seller has very kindly compensated me for that). I found a very helpful post on here describing how to do this. I’ve ordered a new belt but will have to make a spacer, any thoughts on the best way to do this?

The arm also requires a rewire so I’ll do that at the same time. I noticed the tonearm wires in the TP13 are screened. I’m planning on wiring the R200 in the same way the TP13 is, wires coming out of the bottom of the tonearm and soldered to terminals inside the turntable. This is party because I suspect the original RCA cables being quite heavy will limit the bounce on the sub chassis and partly because the R200 didn’t come with a socket in the bottom of it. The problem is I can’t find any screened tonearm cable. Do you think it will be ok rewiring it with a twisted pair of wires that aren’t screened?

nat
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Re: Replacing a tonearm

Post by nat » 21 Oct 2018 23:28

The armboard of the Thorens is fairly small, so warping probably isn't a significant issue, but you may find that plywood is actually perfectly satisfactory. I'd get void free plywood - Baltic is a common choice, though it has become expensive in the last few years. But a piece the size you need ought to be easily found in the scraps from any cabinet maker.

dysmike
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Re: Replacing a tonearm

Post by dysmike » 22 Oct 2018 01:38

nat wrote:
21 Oct 2018 23:28
The armboard of the Thorens is fairly small, so warping probably isn't a significant issue, but you may find that plywood is actually perfectly satisfactory. I'd get void free plywood - Baltic is a common choice, though it has become expensive in the last few years. But a piece the size you need ought to be easily found in the scraps from any cabinet maker.
Agreed, you won't need the whole 1.5x1.5m sheet of baltic birch, and the size you'd need would be easily considered scrap. Hasn't everything gotten more expensive in the last few years?

Bandit127
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Re: Replacing a tonearm

Post by Bandit127 » 22 Oct 2018 05:02

The tonearm body and arm tube form a perfectly good screen. No need for screened or twisted wire. In fact, no need for a rewire if all the wires currently work.

Two jobs worth doing for a service/upgrade are a 3 wire mains cable carrying the chassis earth and replacing the capacitors.

Wrayster
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Re: Replacing a tonearm

Post by Wrayster » 22 Oct 2018 21:36

Thanks all, I’ll look into the birch ply.

Bandit 127, caps have already been replaced in my 150 as I had a problem with the motor. I hoped it was the caps but no, it was the motor which I’ve now replaced. At some point I’d like to make a new plinth so will consider the 3 wire mains cable then I think.

Thanks again for the suggestions.

josephazannieri
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Re: Replacing a tonearm

Post by josephazannieri » 22 Oct 2018 22:05

Yo wrayster:

You can use plywood to play around with but you will find that you will be getting layers peeling off the plywood and also glue layers, even in good birch plywood. Remember, you will have to use a router or a dado cutter to cut about 1 mm into the edge of the new armboard because of the need to accommodate the thick edge of the sprung plate. From your description of Rega mount, you should be able to use big flat fender washers both under and over the new armboard to set the arm height so that you get arm level with your particular cartridge.

I suggest using a good grade of hardwood, such as oak, to make the final armboard. You can use a planer to cut the new armboard to the proper thickness. just follow the measurements that I gave you.

And good luck from the old router and planer,

Joe Z.

dysmike
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Re: Replacing a tonearm

Post by dysmike » 22 Oct 2018 22:22

I've really never had furniture grade ply (baltic birch or Appleply) peel. Now, I've seen 'birch plywood' at the home store do this. But never furniture grade (this is really void-less, stable, and made to veneer). In fact, by nature it is more stable than an identically dimensioned piece of solid wood.

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