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Thread: Fitting an RB250 on an SL-1200 MkII

  1. #1
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

    Default Fitting an RB250 on an SL-1200 MkII

    An SL-1200 MkII deck I did up and veneered for my other half a few years back needed some TLC.

    The original arm had been on several decks and the bearings were about done.
    I've never liked the Plastic yoke for mounting the bearings on the Technics arm, yes it is elctro plated plastic, I drilled one and got a surprise.
    I didn't want to spend mega bucks, so a used Rega was on the cards and I picked up a nice Moth badged RB250 on ePay for a good bit less than the price of a used Techie arm.

    Fitting the Rega arm is not straight forward, the Rega Platters sit high up, while the Technics sits low into the plinth. Consequently the Rega arm has to be mounted well down into the Technics mounting well, which causes problems of its own, but all these things can be resolved.

    I also wanted to use Baerwald alignment and had read the stories about cartridges barely fitting in the slots and exaggerated twisting of the cartridge being needed.
    After a bit of research it appeared this was due to the arm being mounted at the stock Rega Spindle to Pivot of 222mm. To achieve the Baerwald Null points, the effective length has to be increased, hence cartridges at the end of the slots.
    If the arm is mounted at 219.5mm the Baerwald Null points can be achieved at the stock Rega effective length of 237mm and twist is down to only 1.22 deg.
    With this in mind I set to on my project:





    I treated the deck to a new Lid, Platter matt, continuous Copper Litz rewire and an Ortofon 2M Blue.





    The Armboard is Ebony and was custom made by Steve at Magna Audio. Michell adjustable VTA and Technoweight were fitted.
    I modified the Rega arm lift to bring it up to a suitable position, the stock item is almost unusable when mounted in this location.





    This is what the cartridge looks like mounted for Baerwald at 219.5mm S to P. The 1.22 deg twist is barely noticeable and its well positioned in the slots.
    The full project and a Baerwald alignment protractor for Rega arms mounted at 219.5mm can be found on my website blog here:
    https://www.jkwynn.co.uk/Tech2_HTML/Tech2_Thumbs.html

    I hope she likes it
    Last edited by Qwin; 18-11-2020 at 09:03. Reason: Typo

  2. #2
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

    Default

    Just been listening to the deck.
    Wasn't expecting much as people have said Rega's sound dull on Techie decks.
    Well that's not what I'm finding.......
    The Techie/Rega/2M Blue work well together, Fresh, Crisp, Vibrant, Dynamic, with bags of detail.
    Bass on Level 42 - World Machine T1 is incredible.
    Its not an overly warm or a lush sound, but the 2M Blue has that reputation. It's going into a system that uses the warm sounding Arcam A85 Integrated with built in Phono stage, which I'm hoping will give an overall balanced presentation. That was the idea when picking the 2M Blue.
    Listening to America - first album, which is acoustic and I've a smile on my face, very pleased with the sound, plenty of richness and timber from the guitars.

    Maybe its the upgrades, the Ebony armboard in particular. I've not overtightened the arm into the armboard, I've heard it should only be hand tight using the Michell VTA adjusters big knurled fixing. Who knows!

    It's just getting better and better as things warm up.
    I have this till after lockdown and will be making the most of it.

    Edit: I have removed the Acrylic platter mat. It had detail and plenty of bass/punch, but I questioned how neutral and natural it sounded. Some strange placements in the soundstage, with certain items way to far back in the mix and others too prominent.
    I have lots of mats. After testing Rubber, Cork, Cork Rubber mix, Neoprene closed cell, Leather, Wool Felt, Acrylic Felt and combinations of each and various thicknesses. I have gone with a 2mm 100% wool felt against the platter with a 3mm 100% Acrylic felt on top of that. The Acrylic felt is denser and has a brighter crisper sound compared to Wool, this combination just does it for me on this deck. It gives the most natural tone across the full range of instruments and voices and everything seems placed correctly.
    I tried to optimise each as I auditioned, fine tuning VTA, anti skate and Phono settings, they made little difference to the overall flavour.
    This combo certainly doesn't work on my main deck, which has a 38mm thick Acrylic platter. What works works so I'm leaving it at that, time to move on to other projects.
    Last edited by Qwin; 19-11-2020 at 10:04. Reason: Mat changed

  3. #3
    Join Date: Jan 2013

    Location: Carlisle - UK

    Posts: 1,956
    I'm Ken.

    Default

    After doing more tweaking of settings, I began to realize that the anti skate on Rega arms is very sensitive, this is my first Rega so I'm not used to setting one up.
    Small movements of the anti skate button and eventually I dialled in the L/R balance and placement of instruments even further.
    I decided to give the acrylic platter another go and this time was able to fine tune the sound stage using the anti skate.
    Much better results, the level of detail and punch in the bass is better with the Acrylic than the Felt, now the sound placement is sorted, it is a much more enjoyable listening experience.
    I'll stick with the Acrylic now.

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